57p. · 2014-05-19 · title training in diagnostic ultrasound: essentials, principles, and...
TRANSCRIPT
DOCUMENT RESUME
ED 423 735 HE 031 471
TITLE Training in Diagnostic Ultrasound: Essentials, Principles,and Standards. Report of a WHO Study Group. Technical ReportSeries 875.
INSTITUTION World Health Organization, Geneva (Switzerland).REPORT NO WHO-TRS-875ISBN ISBN-92-4-120875-9ISSN ISSN-0512-3054PUB DATE 1998-00-00NOTE 57p.
AVAILABLE FROM WHO Publications Center USA, 49 Sheridan Avenue, Albany, NY12210; Tel: 1-518-436-9686; Fax: 1-518-436-7433; e-mail:Qcorpgicompuserve.com ($12.60).
PUB TYPE Guides - Classroom Teacher (052)EDRS PRICE MF01/PC03 Plus Postage.DESCRIPTORS Allied Health Personnel; Developing Nations; *Diagnostic
Tests; Foreign Countries; Higher Education; *MedicalEducation; Medical Students; Nurses; Physicians;*Professional Training; *Standards
IDENTIFIERS *Ultrasonics; World Health Organization
ABSTRACTThis report defines the essential training and skills
necessary for the effective employment of diagnostic ultrasound in differenthealth care settings. It reviews the present situation in ultrasonography andthe trends in the utilization of diagnostic ultrasound in clinical pract*ce.The report also examines worldwide practice with respect to ultrasonographytrainjng for physicians, sonographers, and other categories of medicalprofessionals, such as midwives, nurses, and assistant physicians. Itpresents outlines of recommended training curricula for physicians ingeneral, advanced, and specialized ultrasonography and discusses variousother factors that must be taken into account in organizing the trainingprocess. The report describes the recommended training for allied healthprofessionals specializing in ultrasonography and presents the basic scienceand instrumentation aspects of the curricula. It then discusses the level ofcompetence that should be reached by those trained in the use of diagnosticultrasound, as well as the recommended standards for training programs,including the requirements for instructors and training centers.Recommendations for the implementation of training programs are included. Anappendix outlines the applications of diagnostic ultrasound. (Contains 36references.) (MDM)
********************************************************************************
Reproductions supplied by EDRS are the best that can be madefrom the original document.
********************************************************************************
,,4, TRAINING IN DIAGNOSTIC,2 ' ULTRASOUND: ESSENTIALS,
PRINCIPLES AND STANDARDS
Ar) Vechnical Re ort &to875
1
I I
PERMISSION TO REPRODUCE ANDDISSEMINATE THIS MATERIAL HAS
BEEN GRANTED BY
WHO
TO THE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)
U.S. DEPARTMENT OF EDUCATIONOffice of Educational Research and Improvement
EDUCATIONAL RESOURCES INFORMATIONCENTER (ERIC)
EliThis document has been reproduced asreceived from the person or organizationoriginating it.
0 Minor changes have been made toimprove reproduction quality.
Points of view or opinions stated in thisdocument do not necessarily representofficial OERI position or policy.
Report of a
WHO Study Group
World Health OrganizationGeneva
t
The World Health Organization was established in 1948 as a specialized agencyof the United Nations serving as the directing and coordinating authority forinternational health matters and public health. One of WHO's constitutional func-tions is to provide objective and reliable information and advice in the field ofhuman health, a responsibility that it fulfils in part through its extensive programmeof publications.
The Organization seeks through its publications to support national health strate-gies and address the most pressing public health concerns of populations aroundthe world. To respond to the needs of Member States at all levels of development,WHO publishes practical manuals, handbooks and training material for specificcategories of health workers; internationally applicable guidelines and standards;reviews and analyses of health policies, programmes and research; and state-of-the-art consensus reports that offer technical advice and recommendations fordecision-makers. These books are closely tied to the Organization's priority activi-ties, encompassing disease prevention and control, the development of equitablehealth systems based on primary health care, and health promotion for individualsand communities. Progress towards better health for all also demands the globaldissemination and exchange of information that draws on the knowledge andexperience of all WHO's Member countries and the collaboration of world leadersin public health and the biomedical sciences.
To ensure the widest possible availability of authoritative information and guidanceon health matters, WHO secures the broad international distribution of its publica-tions and encourages their translation and adaptation. By helping to promote andprotect health and prevent and control disease throughout the world, WHO's bookscontribute to achieving the Organization's principal objective the attainment byall people of the highest possible level of health.
The WHO Technical Report Series makes available the findings of various interna-tional groups of experts that provide WHO with the latest scientific and technicaladvice on a broad range of medical and public health subjects. Members of suchexpert groups serve without remuneration in their personal capacities rather thanas representatives of governments or other bodies; their views do not necessarilyreflect the decisions or the stated policy of WHO. An annual subscription to thisseries, comprising about 10 such reports, costs Sw.fr. 132.- (Sw.fr. 92.40 indeveloping countries).
3
This report contains the collective views of an international group of experts and
does not necessarily represent the decisions or the stated policy of the World Health Organization
875
TRAINING IN DIAGNOSTICULTRASOUND: ESSENTIALS, PRINCIPLES
AND STANDARDS
Report of a
WHO Study Group
World Health Organization
Geneva 1998
4
WHO Library Cataloguing in Publication Data
Training in diagnostic ultrasound essentials, principles and standards report of aWHO study group
(WHO technical report series ; 875)
1.Ultrasonography 2.Diagnostic imaging standards 3.Guidelines 4.Health per-sonnel education I.Title II.Series
ISBN 92 4 120875 9 (NLM ClaSsification: WN 200)ISSN 0512-3054
The World Health Organization welcomes requests for permission to reproduce or translateits publications, in part or in full. Applications and enquiries should be addressed to theOffice of Publications, World Health Organization, Geneva, Switzerland, which will be glad-to provide the latest information on any changes made to the text, plans for new editions,and reprints and translations already available.
@ World Health Organization 1998Publications of the World Health Organization enjoy copyright protection in accordance withthe provisions of Protocol 2 of the Universal Copyright Convention. All rights reserved.
The designations employed and the presentation of the material in this publication do notimply the expression of any opinion whatsoever on the part of the Secretariat of the WorldHealth Organization concerning the legal status of any country, territory, city or area or of itsauthorities, or concerning the delimitation of its frontiers or boundaries.
The mention of specific companies or of certain manufacturers' products does not implythat they are endorsed or recommended by the World Health Organization in preference toothers of a similar nature that are not mentioned. Errors and omissions excepted, the namesof proprietary products are distinguished by initial capital letters.
Typeset in Hong KongPrinted n Spain
97/11650 Best-set/Fotojae 7500
5
Contents
1. Introduction1.1 Background to the Study Group's report1 2 Structure of the report
2. The world situation with respect to ultrasonography
1
25
5
2.1 Assessment of current practice 5
2.1.1 Performance and interpretation 5
2.1.2 Delivery of services 6
2.1.3 Equipment and techniques 7
2.1.4 Recognized indications for ultrasonography 7
2.2 Trends in ultrasonography 8
2.3 Current ultrasonography training 8
2.4 Variations in training and practice 8
2.5 Sonographers 10
2.6 Trends in ultrasonography training 11
3. Ultrasonography curricula for medical students and physicians 1 1
3.1 Curriculum for medical students 11
3.2 Curriculum for general (level I) ultrasonography forphysicians 12
3.2.1 General features of the curriculum 12
3.2.2 Specific content 13
3.2.3 Duration of training and required number of studies 16
3.2.4 Evaluation 16
3.2.5 Continuing medical education 17
3.3 Curriculum for advanced (level II and III) ultrasonography for physi-cians 17
3.3.1 Purpose 17
3.3.2 Prerequisites 17
3.3.3 Areas covered 17
3.3.4 Content and duration 17
3.3.5 Practical training 18
3.3.6 Evaluation 18
3.3.7 Continuing medical education 18
3.3.8 Ultrasound in various specialties 19
4. Ultrasonography training for sonographers and other allied healthprofessionals 21
4.1 Introduction 21
4.2 A definition of a sonographer 21
4.3 Limitation of practice 21
4.4 Curriculum for general (level I) ultrasonography forsonographers and other allied health professionals 22
4.4.1 Purpose 22
4.4.2 Prerequisites 22
4.4.3 General and specialized training 22
4.4.4 Curriculum 22
4.4.5 Duration of training and required number of studies 23
4.4.6 Clinical and ancillary information 23
III
iv
4.4.7 Principles of scanning 244.4.8 Requirements for teachers of sonographers 244.4.9 Evaluation 254.4.10 Continuing medical education 254.4.11 Specialized training 25
5. Basic sciences and instrumentation curricula 265.1 Introduction 265.2 Prerequisites 27
5.2.1 Mathematics 275.2.2 Physics 275.2.3 Biology 27
5.3 Basic sciences and instrumentation curriculum for generalultrasonography 285.3.1 Basic sciences 285.3.2 Equipment 295.3.3 Quality assurance 305.3.4 Equipment management 305.3.5 Artefacts 30
5.4 Basic sciences and instrumentation curriculum for advancedultrasonog raphy 315.4,1 Basic sciences 315.4.2 Equipment 335.4.3 Quality assurance 345.4.4 Artefacts 34
5.5 Course duration 355.6 Evaluation 35
6. Training centres and resources 356.1 Needs and priorities 356.2 Teacher training 366.3 Materials and techniques 376.4 Evaluation 376.5 Teacher-training programmes 376.6 Licensing and accreditation 386.7 Continuing education 386.8 Training centres 38
6.8.1 Regional (international) centres 386.8.2 National centres 39
6.9 Equipment 396.9.1 Ultrasound equipment 396.9.2 Training equipment 40
6.10 Access to patients 406.11 Space and equipment requirements 40
7. Conclusions and recommendations 40
Acknowledgements 41
References 41
Selected further reading 43
AnnexApplications of diagnostic ultrasound 45
7
WHO Study Group on Training in Diagnostic Ultrasound:Essentials, Principles and Standards
Philadelphia, USA, 22-26 March 1996
Members
Professor S. Bhargava, All India Institute of Medical Sciences, New Delhi, India
Professor C. Bruguera, Diagnostic Imaging Teaching Institute, Buenos Aires,Argentina
Dr G.G. Cerri, University of sac) Paulo, São Paulo, Brazil
Professor S.H. Eik-Nes, National Centre for Fetal Medicine, Trondheim UniversityHospital, Trondheim, Norway
Professor M.R. El-Meligy, Faculty of Medicine, Cairo University, Cairo, Egypt
Professor H.A. Gharbi, Department of Radiology, Children's Hospital, Tunis,Tunisia
Professor B.B. Goldberg, The Jefferson Ultrasound Research and Education Insti-tute, Thomas Jefferson University Medical College and Hospital, Philadelphia,PA, USA (Chairman)
Professor H.T. Lutz, Department of Medicine, No.1 Medical Clinic, Bayreuth, Ger-many
Professor C.R.B. Merritt, Department of Radiology, Ochsner Clinic, New Orleans,LA, USA (Rapporteur)
Dr D.E. Robinson, Ultrasonic Laboratory, Division of Radiophysics, CommonwealthScientific and Industrial Research Organisation, Chatswood, New South Wales,Australia
Mrs D. Szabunio, Ultrasound Department, Women's College Hospital, Toronto,Ontario, Canada
Dr M.W. Wachira, Department of Diagnostic Radiology, University of Nairobi,Nairobi, Kenya (Vice-Chairman)
Professor H. Watanabe, Kyoto Prefectural University of Medicine, Kyoto, Japan
Professor P.N.T. Wells, Department of Medical Physics and Bioengineering andUniversity Department of Hospital Medicine, Bristol General Hospital, Bristol,England
Dr Xu Zhi-Zhang, Zhong Shan Hospital, Shanghai Medical University, Shanghai,China
Representatives of other organizations
International Federation for Medical and Biological Engineering
Dr P.A. Lewin, Department of Electrical and Computer Engineering and BiomedicalEngineering and Science Institute, Drexel University, Philadelphia, PA, USA
International Society and Federation of Cardiology
Professor A.E. Belinsky, Buenos Aires, Argentina
International Society of Radiographers and Radiological Technologists
Ms C. Babiak, Michener Institute for Applied Health Sciences, Toronto, Ontario,Canada
International Society of Radiology
Dr P. Arger, Radiology Department, University Hospital of Pennsylvania, Philadel-phia, PA, USA
Society of Diagnostic Medical Sonographers (USA)
Dr M. Berman, Roslyn Heights, NY, USA
World Federation of Sonographers
Dr R. Curry, Program Director, 1997 World Federation of Sonographers Meeting,Sickerville, NJ, USA
Ms K. Griffiths, President, World Federation of Sonographers, Dundas, Australia
World Federation for Ultrasound in Medicine and BiologyProfessor A.E. Belinsky Buenos Aires, Argentina
Secretariat
Dr S. Hancke, Head, Ultrasonic Laboratory, Gentofte Hospital, University ofCopenhagen, Copenhagen, Denmark (Temporary Adviser)
Professor Emeritus P.E.S. Palmer, University of California, Davis, California, CA,USA ( Temporary Adviser)
Dr V. Volodin, Medical Officer, Radiation Medicine, WHO, Geneva, Switzerland(Secretary)
Dr A. Wasunna, Director, Programme on Health Technology, WHO, Geneva,Switzerland
Professor M.C. Ziskin, Center for Biomedical Physics, Temple University School ofMedicine, Philadelphia, PA, USA (Temporary Adviser)
9
vi
1. IntroductionA WHO Study Group on Training in Diagnostic Ultrasound: Essen-tials, Principles and Standards met in Philadelphia, PA, USA, from 22to 26 March 1996 to consider methods of improving the training andclinical performance of physicians and allied health professionals'who use ultrasound for diagnostic applications. The meeting wasopened by Dr A. Wasunna, Director, Programme on Health Technol-ogy, WHO, Geneva, on behalf of the Director-General.
Diagnostic ultrasound is a rapidly developing imaging technologywhich is widely used in both industrialized and developing countries.Since its introduction in the 1960s, ultrasound has found widespreadapplication in anatomical imaging, blood-flow measurement, andevaluation of physiology in almost all aspects of medicine (/). Asultrasound instruments have become smaller, less expensive, andeasier to use, diagnostic ultrasound has become increasingly popularamong a wide variety of physicians. Ultrasound imaging techniquehas replaced or complemented a large number of radiographic andnuclear medicine procedures and has opened new areas of diagnosticinvestigation (see Annex). For example, in many cardiovascular dis-eases diagnostic ultrasound has replaced invasive methods as theprimary means of evaluation. In obstetrics, where radiography is nolonger generally used, diagnostic ultrasound has provided an impor-tant means of assessing fetal viability and age, evaluating fetal devel-opment, and diagnosing fetal, uterine, and placental abnormalities. Insome countries (e.g. Austria, Germany, Iceland and Norway), routineultrasound examinations are offered through government pro-grammes to all pregnant women during the second trimester. Ultra-sound is considered as the primary imaging modality for the detectionof most gynaecological, hepatic, biliary, pancreatic, splenic, and renaldiseases and for examination of the scrotal contents, bladder, andprostate. In many developing countries, diagnostic ultrasound mayfind an important application as an epidemiological screening anddiagnostic procedure for a number of parasitic diseases, such as am-oebiasis, schistosomiasis, and echinococcosis.
Good medical practice requires ultrasonography practitioners to con-sider the risks and benefits of diagnostic examinations, and to take allproper measures to ensure maximum patient benefit with minimumrisk. The use of diagnostic ultrasound should be encouraged wherethere is a likelihood of clinical benefit and discouraged in cases for
Allied health professionals are recognized health professionals (e.g. sonographers,midwives, nurses) who are not physicians.
1 01
which no such benefit is expected (2). Ultrasonography has estab-lished an enviable safety record. There has not yet been any publishedreport of harmful biological effects due to diagnostic ultrasound, oneither patients or operators (3-6). As a result, there tends to be littleregulation of diagnostic ultrasound equipment, which facilitates itsacquisition. In fact, few countries currently regulate the use of diag-nostic ultrasound. Moreover, diagnostic ultrasound equipment is lessexpensive than most other imaging equipment. The low cost and lackof regulation mean that diagnostic ultrasound equipment is oftenused by personnel without adequate training.With the introduction of endovaginal, endorectal, transoesophageal,echocardiographic, intraoperative, pulsed and colour Doppler ultra-sound and other specialized techniques, the difficulties of performingexaminations and interpreting their results have significantly in-creased. The use of diagnostic ultrasound by individuals withoutproper training and experience adds to the likelihood of unnecessaryexaminations and misdiagnosis. The need for adequate education andtraining in ultrasonography exists in both industrialized and develop-ing countries. Moreover, the challenge of providing adequate trainingin ultrasonography is made more difficult by the diversity of its utili-zation, since no single medical specialty has a monopoly on its use.Diagnostic ultrasound is recognized as a safe, effective, and highlyflexible imaging modality capable of providing clinically relevant in-formation about most parts of the body in a rapid and cost-effectivefashion. Obtaining maximum clinical benefit from diagnostic ultra-sound, as well as ensuring the optimal utilization of health care re-sources, requires a combination of appropriate instrumentation andskills in both the performance and interpretation of examinations.The proper, safe, and effective use of diagnostic ultrasound is there-fore highly dependent on the user, who has a major impact on theexamination's overall benefit. In fact, the skill and training of the userare often more important than the equipment used. For this reason,standards for ultrasonography training are a prerequisite for the pro-vision of diagnostic ultrasound services of high quality.In view of ultrasonography's growth and the acquisition of equipmentby those with minimal training, some patients may be harmed bymisdiagnosis resulting from improper indications for use, poor exami-nation technique, and errors in interpretation (7, 8).
1.1 Background to the Study Group's reportThe purpose of this report is to define the essential training and skillsnere.cqary fnr thp. Affertive. Rmpinyme.nt nf dingnnctir ultracnunri indifferent health care settings. Preparation of the report has been
2 .1 1
guided by several WHO publications, including Future use of newimaging technologies in developing countries: report of a WHO Scien-tific Group (9), Effective choices for diagnostic imaging in clinicalpractice: report of a WHO Scientific Group (10) and Manual of diag-nostic ultrasound (11), published in collaboration with the WorldFederation for Ultrasound in Medicine and Biology.The WHO Scientific Group on Clinical Diagnostic Imaging com-mented on the wide variety of imaging techniques and the limitedavailability of some of these methods in certain parts of the world(10). Three levels of imaging equipment were described. Level Iincludes standard radiography equipment, as for the WHO BasicRadiological System (now called the World Health Imaging Systemfor Radiography (WHIS-RAD))1, general purpose diagnostic ultra-sound equipment, and equipment for conventional linear tomographyand for fluoroscopy with image intensification. Level II includeslevel I equipment and techniques plus sophisticated radiography,sophisticated ultrasonography (including Doppler), mammography,angiography, digital subtraction angiography (DSA), macro-radiography, computerized tomography (CT), radionuclide scintigra-phy (including single-photon emission computerized tomography(SPECT)), and thermography. Level III includes all level I and IIequipment and techniques, as well as magnetic resonance imaging(MRI), positron emission tomography (PET), and advanced radionu-clide scanning with labelling by means of monoclonal antibodies(immunoscintigraphy). Level I resources are typical of many parts ofthe world; level II and III resources are usually found only in affluentregions. Ultrasonography is recognized as important for good patientcare at each of these levels, whether it be general ultrasonography atlevel I centres or advanced ultrasonography, including Doppler tech-niques, at level II and III centres.As stated by the WHO Scientific Group on Clinical Diagnostic Imag-ing, "more important than the equipment is the availability of skills.An error in diagnosis because of inadequate education and experi-ence is as dangerous as being without the equipment, and the successof any interventional procedure (e.g. angiography) is very dependenton the skill and experience of the responsible physician." The Scien-tific Group further noted that "in particular, the effective use of anultrasound scanner, although less expensive than other imagingequipment, is very dependent on the physician" (10).
Details for WHIS-RAD can be found in Technical specifications for the World HealthImaging System for Radiography the WHIS-RAD. Geneva, World Health Organization,1995 (unpublished document WHO/RAD/TS/95.1; available on request from Programmeon Health Technology, World Health Organization, 1211 Geneva 27, Switzerland).
3
4
According to the WHO Scientific Group on the Future Use of NewImaging Technologies in Developing Countries, a general physicianshould perform a minimum of 200 obstetric and abdominal examina-tions with a general purpose ultrasound scanner before he or she canbe considered able to interpret scans with any reliability. However,for a physician to become a competent sonologist,' the Group recom-mended at least 6 months' full-time training in a recognized centre,with additional experience being advisable (9). The present StudyGroup has reviewed these and other recommendations in the light ofrecent progress in ultrasonography.
The Scientific Group on the Future Use of New Imaging Technol-ogies in Developing Countries also noted that "the difficulties inmaking an accurate diagnosis from ultrasound images are such thatthe purchase of ultrasound equipment without making provision forthe training of an operator is contrary to good health care practiceand is unlikely to be cost-effective". This same Scientific Group rec-ommended that "wherever possible, ultrasound examinations shouldbe carried out by trained physicians", and went on to add that, if non-physicians are to perform examinations, they need to have at least ayear's full-time training and should always work under the supervi-sion of an experienced sonologist. These recommendations were en-dorsed by the authors of the Manual of diagnostic ultrasound andreflect the opinion of this Study Group as well.
The need for training in the use of diagnostic ultrasound for commu-nity-based surveys to evaluate morbidity due to schistosomiasis wasstressed in the recommendations of a WHO Expert Committee'sreport The control of schistosomiasis (12). The importance of ultra-sound in the surveillance and management of problems related toechinococcosis has also been noted (13).
Properly developed programmes for training physicians and alliedhealth professionals in ultrasonography exist in only a few industrial-ized countries (14). There are no detailed international recommenda-tions or guidance for training those who are using or wish to use thisimaging technique. It was partly for these reasons that WHO pre-pared the Manual of diagnostic ultrasound, which provides guidanceon the ultrasound diagnosis of a wide variety of common conditions atthe primary and first-referral levels of health care. It is intended foruse by physicians, sonographers,2 nurses, and midwives with basictraining in ultrasonography, working with a general purpose ultra-
' A sonologist is a physician qualified to perform and interpret ultrasound examinations.2 A sonographer is a technician quaiified to perform assigned ultrasound examinations
and procedures (see p. 21).
13
sound scanner, but without ready access to expert advice. However,the manual is not intended to be a textbook on diagnostic ultrasoundand should not be considered to replace the need for proper training.
1-:2 Structure of the report-Section 2 of this report reviews the present situation in ultrasonogra-phy and trends in the utilization of diagnostic ultrasound in clinicalpractice. It also examines worldwide practice with respect to ultra-sonography training for physicians, sonographers and other catego-ries of medical professionals (e.g. midwives, nurses, assistantphysicians). Section 3 presents outlines of recommended training cur-ricula for physicians in general, advanced, and specialized ultrasonog-raphy and discusses various other factors that must be taken intoaccount in organizing the training process. Section 4 describes therecommended training for allied health professionals specializing inultrasonography. Section 5 presents the basic science and instrumen-tation aspects of the curricula described in sections 3 and 4. Thevarious sections of the report, and in particular section 6, discuss thelevel of competence that should be reached by those trained in the useof diagnostic ultrasound, as well as the recommended standards fortraining programmes and the training process, including the recom-mended requirements for instructors and training centres. Section 7summarizes the recommendations of the Study Group.
It is recognized that some of the principles and approaches used intraining in the use of diagnostic ultrasound still require further clari-fication, and that in some countries it may be difficult to apply certainrecommendations in full. The Study Group regards the curricula pre-sented here as the minimum that should be required everywhere;however, even partial implementation of the recommendations madehere would represent progress in training and improved clinical utili-zation of this useful technology.
2. The world situation with respect toultrasonography
2.1 Assessment of current practice
2.1.1 Performance and interpretation
The earliest clinical uses of diagnostic ultrasound were for evalu-ation of the uterus during pregnancy, and of the breast, abdomen,heart, and pelvic organs, and were pioneered by physicians andresearchers from a number of specialties (/). The introduction of
14 5
Doppler ultrasound for the evaluation of blood flow in the 1970smade possible additional clinical applications. With the develop-ment of specialized instruments for endovaginal, endorectal, endo-oesophageal, and intravascular (endoluminal) scanning, ultrasoundhas been adopted by a broad range of medical specialties and isnow an essential method of diagnosis and guidance for interventionor therapy in many fields. The Annex summarizes by specialty thecommon applications of diagnostic ultrasound.
The versatility of ultrasonography in aiding the diagnosis of a broadrange of diseases, coupled with the widespread availability of rela-tively low-cost general purpose scanners with good performance, hasencouraged the use of diagnostic ultrasound throughout generalmedicine and paediatric practice and other specialties. The level ofknowledge and training on the part of practitioners is accordinglyhighly diverse (14-19).
Although ultrasound examinations are generally performed and in-terpreted by physicians, in some parts of the world allied health'professionals, including sonographers and midwives, are responsiblefor the performance of ultrasound imaging. However, the interpreta-tion of abnormal ultrasound images and diagnostic decision-makingare the responsibility of physicians in all countries.
2.1.2 Delivery of services
Previous WHO publications have included basic ultrasonographywith diagnostic radiography as essential elements of basic diagnosticimaging services. The relatively compact size of general purpose ul-trasound units, their uncomplicated power requirements, and theirportability permit the delivery of diagnostic ultrasound services in avariety of settings where other imaging modalities cannot be em-ployed. Training requirements for practitioners of ultrasonographymust therefore provide not only for specialized users in well equippedmedical centres, but also for practitioners in remote environments.
In level I settings, ultrasound services are likely to be provided in aclinic or hospital by a general physician or in some cases by a midwife.
In level II and III settings, ultrasonography is likely to be practised ina radiology department or by a clinical ultrasound specialist, oftenusing equipment with special features such as Doppler and colourDoppler, or endoluminal transducers. In some countries sono-graphers are responsible for the performance of such examinations.
Worldwide, there is great variation in both the sophistication of ultra-sound equipment and the qualifications of those providing diagnostic
ultrasound services. In addition to its use in general medicine, ultra-sonography is practised by a variety of specialists, including radiolo-gists and sonologists, and is consequently used for a wide range ofexaminations. An indication of training needs according to the avail-ability of diagnostic imaging equipment is given in Table 1.
2.1.3 Equipment and techniques
WHO has published specifications for a general purpose ultrasoundscanner (9, 11). This is a general purpose imaging unit without Dop-pler or flow-imaging capability, and is recommended as suitable for amedical centre with standard X-ray equipment, such as the WHOBasic Radiological System (now called the World Health ImagingSystem for Radiography; see footnote, p. 3). Such a combination istypical of most parts of the world. More sophisticated diagnosticultrasound, including pulsed spectral Doppler and colour Dopplerand specialized probes for endovaginal, endorectal, endo-oesopha-geal, intraoperative, laparascopic, and endoluminal applications, isavailable in more affluent areas of the world, usually in the hands ofspecialists.
2.1.4 Recognized indications for ultrasonography
Clinical conditions for which diagnostic ultrasound is generally recog-nized as the imaging procedure of choice have been described else-where (10). In addition, diagnostic ultrasound is recognized as aprimary or secondary imaging procedure in a broad range of clinicalsituations.
Table 1Ultrasound training needs according to equipment availability
Professional categoryLevel of Level ofequipment training required General Specialized
Sufficient to per- Family physician,form common ex- trauma physician,aminations safely sonographerand accurately
Midwife, paediatrician
II Sufficient to accept Radiologist, Obstetrician/gynaecologist,and manage referrals sonologist cardiologist, other
specialists (see Annex)
III Advanced, for teaching Radiologist Advanced specialistsand research (organ-oriented (perinatologists and
sub-specialties), sub-specialized internistssonologist and surgeons) '
1 6 7
2.2 Trends in ultrasonographyImportant trends in the use of diagnostic ultrasound include a grow-ing recognition of its cost-effectiveness and importance in clinicalproblem-solving. This has resulted in its increased use for both diag-nostic and interventional procedures. At the same time, the perfor-mance, reliability, and flexibility of ultrasound scanners haveincreased, resulting in lower costs per unit of performance. Thus, boththe complexity of ultrasound equipment and the variety of its uses areincreasing throughout the world.
However, because of the variability in training, the quality of diagno-sis is improving in some areas but declining in others. An importantfactor is that the rate of change in technology and the pattern ofutilization is not being met by the increased production of a sufficientnumber of trained users in many parts of the world. The lack ofuniform and generally accepted standards for training compounds theproblem.
2.3 Current ultrasonography trainingWorldwide, it is likely that much of the ultrasonography currentlyperformed is carried out by individuals with in fact little or no formaltraining. Further, the need for basic training is greater in developingthan in developed countries. Wherever users have little or no formaltraining in ultrasound principles, clinical examination techniques, ordiagnosis, training should be a priority, as a significant benefit inhealth care will result from improved skills in the performance andinterpretation of ultrasound examinations.
In some developed countries, ultrasonography is included as a part offormal training in several medical specialties, including radiology,cardiology, obstetrics, and surgery (20, 21). However, uniform stan-dards for training physicians do not generally exist (22). Many ultra-sonography practitioners do not have adequate experience, and aneven greater number would benefit from additional training. How-ever, educational opportunities are often limited, and a standard cur-riculum to ensure the mastery of minimum essential skills has notbeen defined. In developed countries the greatest need is for trainingto maintain and increase levels of competence, whereas in developingcountries both entry-level training and continuing education are pri-mary needs (15, 16, 18, 19, 23).
2.4 Variations in training and practiceIn most countries, trainees in diagnostic imaging (i.e. radiology) arerequired to learn and understand the use of diagnostic ultrasound in
1 r
all clinical situations. In most radiology training programmes in theUnited States, at least 3 months but usually more are devoted entirelyto ultrasonography. After completion of specialized training, manyradiologists in the United States continue for an additional year ofadvanced ultrasonography training. In other countries, ultrasonog-raphy training requirements may be more (e.g. Israel), or lessdemanding (e.g. Turkey). In non-imaging specialties, trainingrequirements also vary. Scandinavian countries require courses of 30hours of ultrasonography training for obstetrics, 20 hours for cardiol-ogy, and 24 hours for gastroenterology.
There is similar variation among those who practise ultrasonography.For instance, in Germany, ultrasound scanning is performed exclu-sively by physicians; at present, no allied health professionals may usediagnostic ultrasound either alone or under supervision. Many ultra-sound examinations in Germany are carried out in private (non-hospital) practice (more than 18 million in 1994). Ultrasonographytraining for German physicians forms part of their internship, andconsists of theory and practice components, often directed towardsthe specialty they will practise. Post-training evaluation is rare, butthe organization of training programmes is well established. Thetraining guidelines and quality control measures aimed to ensurethe skills of those practising ultrasonography have been created bythe German health insurance system, not by a medical or academicbody (24).
In Japan, the Japanese Society of Ultrasound Medicine has formed agroup of teacher/physicians responsible for the training of doctorsand other health professionals applying for accreditation in ultra-sonography. This accreditation has not yet been accorded an officialstatus.
In Australia and New Zealand, the Australasian Society for Ultra-sound in Medicine (ASUM) in 1970 formally recognized the need forcomprehensive education to ensure high quality practice in ultra-sonography (19). Diplomas were established for sonologists (1976)and sonographers (1979); these diplomas have effectively becomeprerequisites for those providing training in ultrasonography. Never-theless, as in Japan, there is still no legal accreditation requirementfor those practising ultrasonography. A system of self-regulation op-erates within medical colleges (associations), whose members consti-tute the majority of ultrasonography practitioners. Non-members arenot, however, subject to the same requirements.
In the United Kingdom, ultrasonography is a component of trainingin radiology, which is restricted to those having at least 2 years of
9
training in general medicine. In addition, radiologists are trained onlyat centres accredited by the Royal College of Radiologists, which isalso responsible for continuing medical education in the field. Jointprogrammes with other Royal Colleges, such as the Royal College ofObstetricians and Gynaecologists, are also being organized to provideadvanced training in ultrasonography. Participants in these trainingprogrammes must attend 100 ultrasound sessions comprising a totalof 300 hours of instruction. Training in cardiac ultrasonography isprovided by the British Society of Echocardiography, affiliated to theBritish Cardiac Society, which has established levels of required train-ing and education. The requirements include attendance at not lessthan 100 examinations per year after completion of training.
In Latin America, several different approaches to training exist. Insome countries, ultrasonography is taught during specialized medicaltraining, and consequently reaches only newly qualified physicians.Such training includes a required course in theory and 1000 practicalexaminations under supervision. For advanced specialization in ultra-sound, short (1-3 months) and long (6-12 months) courses exist, aswell as 1-week refresher courses.
In China, training schemes for both general and advanced ultrasonog-raphy exist, and can be attended at various stages of the medicalcareer (e.g. post-graduate, fellowship). Continuing education pro-grammes are currently being established. Similar training patternsexist in only a few other developing countries (e.g. India).
In the rest of the developing world, however, the situation is quitedifferent. Diagnostic ultrasound services are often not available at all,or only at an inadequate level. They may be general ultrasonographyservices, for specific applications (e.g. obstetrics), or oriented towardsproblems such as hepatic parasites, urinary disease, or gastrointestinalinfections and infestations. The equipment is often old or inadequate,because of a lack of funds. Consequently, it can be technically out ofdate, or suffer from poor maintenance and unavailability of spareparts. There are very few formal training programmes in ultrasonog-raphy, with the exception of some centres where radiologists aretrained at university hospitals. Radiological societies may organizeshort refresher courses, but in much of the developing world adequateultrasonography training or services are lacking. The accreditation ofusers and the control of quality are also rare.
2.5 SonographersRela tively few countries (e.g. Australia. Canada, Japan, NewZealand, the United Kingdom, and the United States) have well
10 19
recognized and established guidelines and requirements for trainingsonographers (25-28). In most other countries, ultrasonography isperformed exclusively by physicians, with the occasional exception ofmidwives (e.g. in Scandinavian countries). Where established trainingprogrammes for sonographers and midwives exist, they are compre-hensive and require very high standards of knowledge and practice(see for example 18, 19, 25-27).
2.6 Trends in ultrasonography trainingAwareness of the need for ultrasonography training is increasing, andthere are growing opportunities for the formal training and accredita-tion of both physicians and allied health professionals, particularly indeveloped countries.
New technologies such as electronic media, global telecommunica-tions, and the Internet make possible novel approaches to training. Indeveloped countries, requirements for continuing medical educationto maintain and increase levels of competence, particularly in special-ized areas, are increasing. In some countries, changes in health carepractices and medical regulations are stimulating the institution offormal accreditation programmes for physicians and allied healthprofessionals, as well as the accreditation of diagnostic services, in-cluding diagnostic ultrasound services.
3. Ultrasonography curricula for medical studentsand physicians
3.1 Curriculum for medical students
In view of the importance of ultrasonography as a primary diagnosticimaging method, all medical students should receive an introductionto its principles and uses, as well as to the relevant anatomy. Althoughthis training need not be extensive, it should include at least:
the basic principles of ultrasound imaging and its differences fromradiographic and other methods, including the use of mechanical(acoustic) energy rather than ionizing electromagnetic energy;the anatomy of the axial, longitudinal, and coronal planes examinedin ultrasound scanning, with special emphasis on the sectional anato-my of the abdomen and pelvis;a review of the major clinical indications and applications of ultra-sound in diagnosis and intervention and the relationship ofultrasound to other imaging modalities, including cyst/solid differ-entiation and real-time features.
g 11
Evaluation of knowledge of ultrasonography, both theoretical andpractical, should be included in the evaluation of medical students.
3.2 Curriculum for general (level I) ultrasonography for physiciansIn level I settings, diagnostic ultrasound examinations are likely to beperformed by a general physician using a general purpose ultrasoundscanner. These physicians will .be expected to perform safely andaccurately a variety of examinations of all parts of the body. Thecurriculum for training physicians must therefore include instructionin the performance and interpretation of diagnostic ultrasound ex-aminations, and related areas of physics and instrumentation.
3.2.1 General features of the curriculum
12
Basic physical principlesThe physical principles relating to ultrasound and its interaction withtissues that should be covered in the general curriculum are outlinedin section 5.3. These include basic terminology, the physics of wavesand their interaction with different tissues of the body, includingamplitude, intensity, attenuation, perpendicular and oblique inci-dence, and scattering, the range equation, transducer constructionand its effect on ultrasound waves, methods of focusing and resolu-tion, useful frequency ranges, artefacts, biological effects, and safety.
Principles of scanningThe trainee should become familiar with:
orientation of the image for standard display formats (head/foot andright/left orientation) and image annotation;image background (light echoes on a dark background versus darkechoes on a light background);scanning planes (sagittal, parasagittal, axial, coronal, and oblique)and image annotation for the scanning planes;proper adjustment of equipment controls (system gain, time gaincompensation (TGC), depth of field of view, and focal zoneplacement);protocols for routine examinations, including standard transducers,the area to be imaged, and any required measurements anddocumentation;frequency, resolution, and their relationship;the recognition and identification of common artefacts and strategiesto reduce or eliminate them, as well as recognition of artefacts thatcan enhance diagnostic accuracy;permanent image documentation.
21
AnatomyThe trainee should master:
basic anatomy as visualized with ultrasound, with an emphasis on theanatomy of abdominal, pelvic, and fetal structures, soft tissue anato-my, and major vascular structures;sectional anatomy, including the relationships of major structures inthe sagittal, axial, and coronal planes;normal anatomical size and position;common anatomical variations;normal fetal anatomy.
PathologyThe training should cover congenital, inflammatory, degenerative,metabolic, and neoplastic pathology and pathophysiology and com-mon traumatic conditions affecting the major organs, soft tissues, andvascular structures.
The general indications for and limitations of ultrasonography shouldbe taught.
The basic diagnostic criteria for the interpretation of scans should becovered, including tissue characteristics, normal and abnormal organtissue patterns, and the differentiation of cystic and solid masses.
Standard methods for the reporting and documentation of resultsshould be covered.
3.2.2 Specific content
The following presents the specific content that should be covered inthe general ultrasonography curriculum, according to principal ana-tomical region (abdomen, chest, etc.). Physicians successfully com-pleting the course should be able safely, accurately, andconsistently to recognize the ultrasonographic appearance of thenamed structures or features, diagnose the conditions specified below,and perform the evaluations and measurements referred to. Varia-tions in ultrasonographic appearance related to age and sex should beincluded in the course content as appropriate.
Abdomen
Liver:size and shape;parenchyma;intrahepatic vessels;
13
14
focal lesions, including cysts, abscesses, tumours, trauma, andparasites;perihepatic fluid collections;normal and abnormal echogenicity (including both focal anddiffuse disease).
Gallbladder and biliary tract:gallbladder size, wall, and contents, including calculi andAscaris;biliary tract dilatation and evaluation of the jaundicedpatient;normal bile duct measurements and physiological variations.
Pancreas:normal and abnormal echogenicity;diffuse pancreatic disease;focal lesions, including cysts, abscesses, tumours, and cal-cifications.
Spleen:size and shape;focal lesions;trauma.
Kidneys and adrenals:size, shape, and location;diffuse parenchymal disease;focal lesions, including cysts, tumours, and calculi;obstructive uropathy and perirenal fluid collections.
Ureters and bladder:obstruction;parasites;tumours;infections;diverticula;calculi.
Peritoneal cavity and gastrointestinal tract:intraperitoneal fluid collections;bowel masses;obstruction;intussusception;pyloric stenosis.
Retroperitoneal space:masses;adenopathy;fluid collections.
Major abdominal vessels:normal measurements;
23
aortic aneurysm;inferior vena cava thrombus.
Chest
Diaphragm.Subdiaphragmatic and supradiaphragmatic fluid collections.Pleural effusions, masses, and thickening.Peripheral lung masses.Gross mediastinal adenopathy.Thymus.
Female pelvis
Normal physiological changes in the uterus and ovaries.Diseases of the urinary bladder, uterus, ovaries, fallopian tubes, andrelated blood vessels, muscles, and ligaments.Cystic, solid, and complex masses as well as inflammatory condi-tions, haematocolpos, endometriosis, and related gynaecologi-cal complications.
Note: Endovaginal techniques should not be included in this course.
Obstetrics
Normal first trimester:embryonic and early fetal anatomy;yolk sac;amniotic and chorionic cavities;biometry including crownrump length, amniotic sac diameter,and yolk sac size;multiple pregnancy;cardiac activity and confirmation of viability.
Abnormal first trimester:ectopic pregnancy;complete and incomplete abortion;vaginal bleeding;fetal death;hydatidiform mole;major recognizable fetal malformations and developmentalabnormalities (e.g. anencephaly);pelvic mass.
Second and third trimester:development of fetal anatomy;placenta (location and size) and umbilical cord (including two-vessel cord and location of cord insertion);biometry of the cranium, abdomen, and femur;
47. 24 15
assessment of fetal age;amniotic fluid volume (normal volume and causes and criteriafor diagnosis of oligohydramnios and polyhydramnios);intrauterine growth retardation;gross fetal abnormalities, including anencephaly, hydro-cephalus, neural tube defects, abdominal wall defects, renalanomalies, and limb shortening.
Other applications
Thyroid gland.Scrotal contents.Breast (both the muscles and the subcutaneous tissues for masses,abscesses, and abnormal fluid collections).Osteomyelitis, fractures, and callus.
Neonatal scanning
Hydrocephalus.Pyloric stenosis.Abdominal masses.Hydronephrosis.Bladder abnormalities.Adrenal masses.Haemorrhage.Congenital hip dislocation.
3.2.3 Duration of training and required number of studies
The training programme should include lectures and practical dem-onstrations running over a period of 3-6 months, and the traineeshould participate in 300-500 ultrasound examinations during thisperiod. The practical demonstrations should include examinationsappropriate for the disease profile of the country or region where thetraining is conducted. In most countries, an appropriate distributionof examinations would be:
abdominal examinations (50%);obstetric examinations (20%);gynaecological examinations (20%);examinations of other parts (10%).
3.2.4 Evaluation
At the end of the course the trainee should be assessed by a recog-ni7ed competent authority (see section 6) in both theoretical andpractical aspects of ultrasonography and, if successful, accredited.
16 25
3.2.5 Continuing medical education
Continuing medical education that keeps the practitioner abreast ofadvances in technology and clinical practice is highly recommended.
3.3 Curriculum for advanced (level ll and Ill) ultrasonography forphysicians
3.3.1 Purpose
The purpose of the advanced ultrasonography curriculum for physi-cians is to ensure a level of training sufficient to perform high qualityultrasound examinations, using, when necessary, the more sophisti-cated ultrasound equipment available at levels II and III (which maycorrespond to the secondary and tertiary levels of health care in somecountries). The physician successfully completing the curriculumshould be able to perform all routine ultrasound examinations andalso receive referred patients.
3.3.2 Prerequisites
The trainee should be a physician engaged in clinical practice as ageneralist or specialist.
3.3.3 Areas covered
The curriculum should develop the necessary skills in physics, ab-dominal imaging, obstetrics, gynaecological examinations, and thescanning of other parts. Doppler, endovaginal, endorectal, andinterventional procedures should be included.
3.3.4 Content and duration
The following material should be mastered:
advanced-level physics of ultrasound imaging: terminology, arte-facts, the biological effects of ultrasound (safety), and advanced-level Doppler theory (see section 5.4);instrumentation and equipment operation, set-up, and quality assur-ance (including issues related to endoluminal scanning);advanced ultrasound examination techniques and procedures, in-cluding control of infection;detailed cross-sectional anatomy;indications for and limitations of ultrasonography;criteria for diagnostic interpretation (including difficult and compli-cated cases);ultrasonically guided aspiration and biopsy;methods of reporting and documentation.
2 6 17
The curriculum should include both theoretical and practical aspectsof advanced-level ultrasonography. The period of training should beat least 3 years (full time), if the trainee has not completed priorpostgraduate medical training (specialization). If the trainee has al-ready successfully completed a training programme in radiology, 3-9months of additional training in ultrasonography are recommended.If the trainee has successfully completed postgraduate medical train-ing in a field other than radiology, 1-2 years of additional training areadvised.
For trainees who have not already qualified as radiologists, the theo-retical component of the programme should include advanced-levelphysics and instrumentation. The statistics, computer science, pathol-ogy, pathophysiology, paediatrics, cross-sectional anatomy, surgery,and internal medicine that would normally be covered in a radiologytraining programme should also be included.
3.3.5 Practical training
During practical training, the trainee should perform a broad range ofexaminations under the supervision of experienced sonologists. Theseexaminations should include those appropriate for the disease profileof the country or region in which the training is conducted. In mostcountries, an appropriate distribution would be:
abdominal examinations (30%);obstetric examinations (20%);gynaecological examinations (10%);paediatric examinations (10%);examinations of peripheral vascular structures (15 %);echocardiographic examinations (5%);examinations of other parts (10%).
Doppler, endovaginal, endorectal, and endo-oesophageal examina-tions and interventional ultrasound procedures should be included asappropriate.
3.3.6 Evaluation
At the end of the course, the trainee should be required to passwritten, oral, and practical examinations, covering both theoreticaland practical aspects. Upon successful completion of the examina-tions, the trainee should be granted the appropriate accreditation.
3.3.7 Continuing medical educationContinuing medical education that keeps the practitioner abreast ofthe latest advances in technology is highly recommended.
18 2 7
3.3.8 Ultrasound in various specialtiesDiagnostic ultrasound is used in many medical specialties, and specifictraining is recommended for clinical-imaging specialists in certainareas. In many cases, these specialists will have access to equipmentwith more capability than the general purpose ultrasound scanner,with features such as pulsed and colour Doppler and transducers withinterventional capability. For the use of diagnostic ultrasound in oneof the fields named below, training should include:
the basic sciences and instrumentation curriculum for advancedultraSonography (see section 5.4);detailed knowledge of the anatomy, pathology, and physiology re-lated to the specialty;instruction in the ultrasound techniques and equipment relevant tothe specialty.
In addition, training should:
ensure participation in a sufficient number of specialized ultrasoundexaminations to attain and maintain proficiency;emphasize the need for continuing medical education;encourage formal documentation of competence in performance andinterpretation of examinations;be carried out at an authorized centre for an adequate period of time(to be defined according to the requirements of various specialties).
The following sections present the additional material that is requiredfor the use of diagnostic ultrasound in the named specialties.
Obstetrics and gynaecology
Detailed embryonic and fetal anatomy.Diagnosis and management of fetal, uterine, and placentalanomalies.Where appropriate, instruction in fetal blood sampling, fetal bloodtransfusion, chorionic villus sampling, and other invasive proceduresperformed under ultrasonic guidance.Detailed examination of the organs of the female pelvis,including theuterus, ovaries, and pelvic vessels; endovaginal examinations andinterventional procedures.Detailed breast examinations, including ultrasonically guided biopsy.
Cardiology
Detailed normal and abnormal cardiac anatomy.Detailed cardiac physiology, pathophysiology, and pathology.
2819
20
Evaluation of cardiac chamber size and dynamics, diagnosis of valvu-lar and pericardial disease, measurement of blood pressure gradients,determination of blood flow volumes, detection and assessment ofvalvular regurgitation, demonstration and quantification of intracar-diac shunts, and detection of intracavitary masses.Detailed instruction in M-mode, two-dimensional, and Doppler im-aging techniques.Where appropriate, the techniques and interpretation of stressechocardiography, transoesophageal scanning, and the use ofcontrast media.
Note: Ultrasonography training for paediatric echocardiographyshould cover the same material.
Urology
Detailed instruction in the anatomy, physiology, and pathology ofthe adrenals, kidneys, urinary bladder, prostate and seminal vesi-cles, urethra, penis, and scrotal contents.Instruction in techniques of intracavitary scanning of the bladder,transrectal scanning and interventional procedures using ultrasonicguidance; endovaginal scanning.Where appropriate, colour Doppler imaging and the use of contrastagents should be covered.
Gastroenterology
Endoscopic ultrasound of the mediastinal gastrointestinal tract,liver, biliary tree, and pancreas.Endoscopic examination of the bile and pancreatic ducts.Where appropriate, interventional ultrasound techniques andDoppler imaging with contrast agents.
Internal medicine
The use of Doppler ultrasound and appropriate interventional pro-cedures.Echocardiography and training in the diagnosis of diseases ofthe visceral and peripheral arteries and veins may be included asappropriate.
Surgery
Interventional, laparoscopic, and intrannerative ultrasound:Musculoskeletal examinations, as appropriate.
-29
4. Ultrasonography training for sonographers andother allied health professionals
4.1 IntroductionThe practice of ultrasonography varies throughout the world. In somecountries, scanning can be carried out by trained allied health profes-sionals under the supervision of physicians, but in others only physi-cians perform examinations. Allied health professionals includenurses and nurse/midwives, radiographers, nuclear medicine tech-nologists, assistant physicians, and cardiac and vascular technologists(15, 16, 28). Where ultrasound is used extensively, as in obstetrics,allied health professionals have proved to be very effective in deliver-ing diagnostic ultrasound services (29, 30). In specialized clinical areassuch as echocardiography and vascular or ophthalmic ultrasound,such personnel can be extremely helpful for both patient and doctor.However, since the effectiveness of ultrasonography is highly depen-dent on the skill of the operator, this assistance requires extensivetraining.
4.2 A definition of a sonographerIn some countries the profession of "sonographer" has been recog-nized (26, 27, 31). The definition in one such country is as follows:
Sonographers are highly skilled professionals qualified by technologicaleducation to provide patient services using diagnostic ultrasound under thesupervision of a doctor of medicine. Sonographers or allied healthpersonnel provide this service in a variety of medical settings, where thephysician is responsible for the use and interpretation of ultrasoundprocedures. Sonographers and other allied health personnel assistphysicians in gathering sonographic data necessary to reach diagnosticdecisions (25).
The same definition also states that "the profession of diagnosticmedical sonography includes general sonography, cardiac sonog-raphy, and various subspecialties. The profession requires judgmentand the ability to provide appropriate health care services". Thisdefinition is given as an example; other countries may wish to estab-lish their own definition of and criteria for professional sonographers.
4.3 Limitation of practiceAlthough sonographers are well trained and highly skilled, responsi-bility for the interpretation and reporting of the results of ultra-sound examinations (apart from confirmation of normality), aswell as the legal responsibility for all aspects of patient care, necessar-ily rests with the supervising physician. In most countries, endo-luminal and endocavitary ultrasound examinations are performed by
0 21
physicians only, but in some countries these studies can be carried outby sonographers. In all countries, however, interventional ultrasound,including biopsy, drainage, therapy, and amniocentesis, is performedexclusively by physicians.
4.4 Curriculum for general (level I) ultrasonography forsonographers and other allied health professionals
4.4.1 Purpose
The purpose of the general ultrasonography curriculum forsonographers and other allied health professionals is to ensure thatusers of diagnostic ultrasound have sufficient training to provide highquality health care. Training in the curriculum should result in anappropriate level of technical and clinical knowledge.
4.4.2 Prerequisites
Candidates for training should have completed 2-3 years of healthcare training, including courses in anatomy, physiology, and patho-logy.
If the candidate enters training directly from the secondary schoollevel, it will then be necessary to provide supplementary educationprior to ultrasonography training. The supplementary educationshould include sufficient instruction in anatomy, physiology, pathol-ogy, medical ethics, and physics for the practice of ultrasonography.
4.4.3 General and specialized training
Training may, as appropriate, be either general or specialized. Insome clinical areas, specialized training may have to follow generaltraining, but in others specialized training may be initiated directly.The training programme should consequently be structured appro-priately.
The ultrasonography curriculum should provide for adequate time forthe acquisition of clinical skills, and should require a specified numberand range of ultrasound examinations. Protocols for the performanceof ultrasound examinations are an important means of maintainingquality; because disease patterns vary, diagnostic medical depart-ments or preferably national governments should establish examina-tion protocols that sonographers and other allied health personnelshould follow.
4.4.4 Curriculum
The curriculum for training sonographers and nther allied healthprofessionals is the same as the general curriculum for physicians,
22
31
with the exceptions that the diagnostic conclusions and the reportingand documentation of the results of examinations arc the responsibil-ity of physicians.
4.4.5 Duration of training and required number of studies
The number of examinations necessary to ensure competence canvary for different applications of diagnostic ultrasound. Various phy-sicians' and allied health professionals' organizations have estab-lished minimum numbers of ultrasound examinations in a number ofspecific areas. There is, however, no generally accepted number ofexaminations required to achieve proficiency. The following mayserve as a guide:
abdominal examinations (250);examinations of the neck (25);examinations of scrotal contents (25);pelvic examinations (50);first trimester pregnancy examinations (50);second and third trimester examinations (200);neonatal examinations (50).
The actual number required in a given curriculum may depend on thegeographical area, the educational setting, and the disease profile ofthe population.
If endovaginal examinations are performed, the use of aseptic tech-nique is very important, and additional training for this type of proce-dure should be offered.
4.4.6 Clinical and ancillary information
In addition to the topics of the general ultrasonography curriculum,the following should be covered:
Medical history. How to obtain and describe a medical history,including laboratory or other test values related to the examination.Patient preparation and care. Patients should be informed about howto prepare for an examination by ultrasound. Printed instructionsand explanations of any special preparation are desirable.Ethics. Operators should respect the privacy of patients and ensurethe aVailability of adequate changing rooms, gowns, etc. Results ofexaminations should be released only as directed by the supervisingphysician. The use of ultrasound should be limited to recognizeddiagnostic and therapeutic purposes (determination of fetal sex,except as reoi .-ed for sex-linked disease screening, is not a medi-cally valid reason for ultrasound examination).
32 23
Confidentiality.The confidentiality of medical information (e.g. medi-cal history and the results of sonographic examinations) should berespected.Infection control. Transducer cleaning and disinfection as necessaryare essential for the control of infection. Established practice in-cludes thorough cleaning with soap and water using a cleaning brushand immersion in cleaning solutions (e.g. chlorine, antiseptic). Otherpossible precautions should comply with established practice in thecountry.Patient's rights. The rights of the patient should always be respected,including the right to refuse to be examined; the patient's cultural andreligious beliefs should be accorded consideration.The patient shouldbe informed of any risks before examination, should be allowed tohave a relative present if he or she wishes, and should be keptadequately informed during the course of the examination.Medical equipment. Sonographers and other allied health profession-als who use diagnostic ultrasound should have an appropriate knowl-edge of medical equipment, including the operation of intravenousunits, cardiac monitors, oxygen and suction equipment, catheters,chest and drainage pumps, and other equipment.Patient's condition. Sonographers should be able to assess the patientwith respect to his or her level of consciousness and anxiety on thebasis of respiration, colour, etc.Medical terminology. Sonographers should be familiar with the ap-propriate use of medical terminology.
4.4.7 Principles of scanning
Sonographers should be familiar with:
generally accepted standards of image orientation;examination protocols;scanning planes;proper adjustment of equipment;the relation between frequency and resolution;scanning artefacts;permanent documentation of images.
4.4.8 Requirements for teachers of sonographers
Teachers should have successfully completed a course of at least thesame level as that they teach. It is further suggested that teachers beaccredited in their area of instruction. Appropriate accreditationcould be 2ranted bv the national health authority, an academic insti-tution, the national diagnostic ultrasound society, or another similar
24 33
body. The Study Group recommends that teachers have at least a yearof clinical experience in ultrasonography.
Teachers should regularly attend ultrasonography meetings and con-ferences to ensure that their knowledge of this rapidly developingfield remains up to date. They should maintain an active and continu-ing involvement in clinical ultrasonography.
Section 6 further discusses the recommended requirements for teach-ers of ultrasonography.
4.4.9 Evaluation
Sonographers and other allied health professionals who use diagnos-tic ultrasound should, wherever possible, obtain recognition of theircompetence through established organizations granting recognizedcredentials. Countries without such an organization are encouragedto establish mechanisms to assess competence in ultrasonography.Examinations should assess knowledge of the material describedabove. It is further recommended that credentials be reassessed atregular intervals. Criteria based on competence in ultrasonographycan be employed; whatever the criteria, the evaluation should beobjective.
4.4.10 Continuing medical education
Continuing medical education is important for the maintenance ofcompetence in ultrasonography. The Study Gr Oup recommends thatsonographers and other allied health professionals using diagnosticultrasound provide evidence of continuing medical education. Hospi-tals, medical schools, and government sponsored programmes shouldprovide opportunities for such medical education.
4.4.11 Specialized training
Sonographers and other allied health professionals will need addi-tional training to be able to use diagnostic ultrasound in specializedclinical areas requiring real-time, Doppler, duplex, and colour Dop-pler techniques. Such applications include cardiac, ophthalmic, andvascular ultrasonography.
Ultrasonography of the vascular systemVascular technologists or allied health professionals performingultrasound examinations of the vascular system should have anunderstanding of the anatomical structures, physiology, and haemo-dynamics of the vascular system. They should be able to recognize,identify, and appropriately document the sonographic appearance of
3 4 25
vascular disease. Other non-invasive techniques in addition to diag-nostic ultrasound may be a required component of accreditation forthe vascular use of diagnostic ultrasound.
Ultrasonography of the eyeAn ophthalmic sonographer or allied health professional performingultrasound examinations of the eye should be competent in the useand interpretation of real-time ultrasound. The use and interpretationof A-mode Doppler or colour Doppler ultrasound may also be re-quired. The ophthalmic sonographer should be able to recognize anddocument the sonographic appearance of normal and abnormal in-traocular and retrobulbar structures, as well as recognize, identify,and document ocular disease, foreign bodies, and trauma.
Ultrasonography of the heartA cardiac sonographer or allied health professional performing ultra-sound examinations of the heart should be able to recognize andidentify the sonographic appearance of the anatomic structures of theheart and large vessels and to assess their physiology andhaemodynamics by means of ultrasound. He or she should be able torecognize, identify, and appropriately document the sonographic ap-pearance of acquired cardiac disease and congenital anomalies.
5. Basic sciences and instrumentation curricula
5.1 IntroductionAn understanding of the basic physical and scientific principles under-lying ultrasonography and its instrumentation is essential to achievethe maximum diagnostic benefit from this technology. A good foun-dation in basic principles will aid the user in obtaining diagnosticinformation with the ultrasound scanner while avoiding common pit-falls that impair diagnosis.
The curriculum in basic sciences and instrumentation has two mainobjectives:
to provide the ultrasonography practitioner with sufficientknowledge to operate the ultrasound scanner effectively and obtainthe necessary data, with due regard for data quality and patientsafety;to provide an understanding of the nature of the artefacts that may bepresent in ultrasonographic data, so that they can be recognized anderrors in interpretation can be avoided.
26 35
The curriculum has two parts. The first is intended for those who willpractise general ultrasonography (physicians and non-physicians,mainly with a general purpose ultrasound scanner) and should betaught to all those following one of the level I ultrasonography cur-ricula. The second part contains additional information required forthose following an advanced or specialized curriculum using moresophisticated equipment (32). Completion of the first part is a pre-requisite for undertaking the second part. The two, however, canbe combined into a single course covering all material.
5.2 PrerequisitesThe curriculum assumes knowledge of mathematics and physics suffi-cient to understand the material presented.
5.2.1 Mathematics
A basic knowledge of mathematics is required to understand theconcepts of ultrasound. The following list of topics is representative:
graphs (concepts necessary for understanding ultrasound displays);algebra ( i.e. manipulation of a simple equation);trigonometry (for understanding the Doppler equation);logarithms (for decibel (dB) notation).
Note: The latter two topics are necessary only for the advanced cur-riculum.
5.2.2 Physics
Knowledge of the following physical quantities and principles is nec-essary for adequate comprehension of the basics of ultrasonography:
frequency;force and pressure;density;speed and velocity;simple wave motion;basic electricity.
5.2.3 Biology
Some knowledge of biology is necessary to understand the tissuereflection and scattering of ultrasound waves, and for an appreciationof the possible biological effects and safe use of ultrasound:
blood and blood flow (tissue perfusion and cooling);cells and organs (the cell cycle and cellular susceptibility to damage);
t'; 3 627
tissue types (according to ultrasound transmission and reflectionproperties like average wave speed, attenuation, and echogenicity):
soft (i.e. average speed and attenuation);hard (e.g. bone);cystic (e.g. polycystic kidney);solid (e.g. muscle, liver);calcified (e.g. certain diseased cardiac valves, atheromatousplaques);complex (e.g. malignant tumour, placenta);gas containing (e.g. lung, alimentary tract).
5.3 Basic sciences and instrumentation curriculum for generalultrasonography
5.3.1 Basic sciences
28
PhysicsThe concepts necessary for understanding the properties of ultra-sound as used for clinical examination include:
the definition of ultrasound;frequency, sound speed, and wavelength;reflection (at perpendicular and oblique incidence) and scattering;wave attenuation;
9 dB notation;useful frequency ranges;generation and detection of ultrasound waves;pulseecho principle and the range equation;the Doppler phenomenon (basics only).
Biological effects and safetyThe operator will need to be familiar with the circumstances in whichcaution in instrument settings should be exercised so that the recom-mended maximum exposure limits are not approached:
9 the safety record of clinical use (see p. 2);the safety guidelines that should be observed:
mechanical and thermal safety indices (it is important to coverthe phenomenon of cavitation);maximum energy output (varies according to machine);
non-ultrasonic safety aspects:contamination;electric shock;thermal injury (from excessive probe temperature);mechanical injury (e.g. from improper use of endoprobes).
3 7
Imaging methodsTo understand the scanning protocols used for particular examina-tions and the artefacts that can be produced, the operator will requireknowledge of the following elements of image formation:
the pulseecho principles of image generation (range equation);the principles of ultrasound beam formation and focusing (bothspatial and temporal resolution);the ultrasound display modes commonly used:
two-dimensional mode;M-mode (fundamentals only);
ultrasound beam steering and corresponding scan formats (rectilin-ear, sector, parallelogram);the relation of frame rate and real-time scanning;the principles of grey-scale imaging:
dynamic range (in dB) and possibilities for image post-processing;tissue echogenicity (i.e. "texture" as represented in grey-scale);artefacts that can enhance diagnostic accuracy (e.g. shadows).
5.3.2 Equipment
The operator should be familiar with the following aspects of ultra-sound equipment:
operating frequency (choice varies depending on average wavepenetration, attenuation, scattering, etc.);scan format and probe type (choice depends on the size of thescanned anatomical plane and the possibility of access via acoustic"windows");scanner controls:
ultrasound power output;overall receiver gain, swept gain (e.g. time gain compensation);focal length;
display controls:brightness;contrast;image selection and storage (freeze-frame);
image-record features:patient identification;indication of distance scale (use of calipers);calculations of gestational age from biparietal diameter, cross-sectional areas, etc.;
image-recording capabilities (e.g. self-processing or not, single ormultiformat):
38 29
film;video printer;video cassette recorder.
5.3.3 Quality assurance
Although ultrasound scanners of the recent generation are muchmore stable than older ones, it is important to implement aprogramme of quality assurance to ensure that a deterioration inequipment performance does not affect the quality of diagnosis (33).The specific features of the quality-assurance programme should bedetermined with regard to local circumstances. As a minimum, scansof a standard object obtained with standard machine settings shouldbe recorded and retained on file. A standard object can be either afixed element of the operator's anatomy, when appropriate, such asthe mesenteric artery, or a "phantom". Phantoms simulate humantissue and blood flow properties and can be scanned for quality-assurance purposes. Past scans should be reviewed after each regularquality-assurance check, in order to detect any deterioration in imagequality.
The following aspects of image quality should be checked routinely:
spatial resolution (i.e. the ability to separate closely spaced reflectors);contrast resolution (i.e. the ability to distinguish between smalldifferences in echogenicity).
5.3.4 Equipment management
The ultrasound operator should be able to make appropriate deci-sions about the following aspects of equipment management:
the specifications to request when purchasing (e.g. appropriatenessfor intended use, compatibility with local power supply, etc.);acceptance testing (does the machine match the initial specifica-tions?);machine maintenance and repair (the operator will need to take intoaccount the availability of spare parts and the possibility of arrangingfor support by service technicians);equipment life-cycle (including plans for machine replacement andlong-term cost estimates).
5.3.5 A rte f a c ts
The ability to recognize the wide variety of artefacts that occur inultrasonic images is vital for correct diagnostic interpretation. Thisrecognition requires a good knowledge of the topics already men-tioned, as well as of the following specific subjects.
30
The operator should thoroughly understand the basic assumptions ofgood image formation:
propagation of straight, narrow ultrasound beams for geometricalaccuracy;avoidance of multiple pulse reflection;use of a constant sound-speed for accurate image registration anddistance measurement.
The operator should also be familiar with the following commonartefacts:
beam-width artefacts, affected by:beam width;beam sidelobes;beam (slice) thickness;
multiple reflection artefacts:mirror reflection;reverberation;
acoustic shadowing, enhancement, and attenuation;refraction artefacts:
geometrical distortion or duplication;changes in image intensity.
5.4 Basic sciences and instrumentation curriculum for advancedultrasonographyThe following curriculum is designed for more advanced applicationsof ultrasound and should be taught together with the clinical curricu-lum described in section 3.3. The actual topics covered should beappropriate to the techniques used in the particular ultrasound prac-tice. It is assumed that all the material in the basic sciences andinstrumentation curriculum for general ultrasound has been masteredbefore the following material is presented.
5.4.1 Basic sciences
It is expected that at the successful completion of this curriculum thegraduate will have an understanding that is both broader and deeperthan that of a graduate of a general (level I) ultrasonography course,normally oriented towards use of a general purpose ultrasoundscanner.
PhysicsUltrasonography practice with the sophisticated equipment availableat levels II and III requires an understanding of the following:
units of intensity used for acoustic output specification;
4 0k .4.4,
31
advanced-level theory of the Doppler effect;the use of contrast agents (e.g. encapsulated gas microbubbles).
Biological effects and safetyThis section should provide an understanding of the phenomena in-volved in potential effects of ultrasound on biological tissue, ratherthan a simple description of required safety limits.
Biological tissues can be affected by:
thermal mechanisms (can cause, for example, the coagulation ofproteins);non-thermal mechanisms (e.g. destruction of cell membranes due tostreaming);the use of Doppler techniques (sometimes involving higher poweroutput than non-Doppler ultrasound);the use of contrast agents (may enhance cavitation);the use of endoprobes (risk of physical injury);interventional techniques (risk of infection).
Imaging methodsThe advanced course should include a more detailed study of equip-ment capabilities and the factors affecting equipment performance.The following topics should be covered:
beam focal zones during the pulse (transmit) and echo (receive)phase;frame rate according to pulse rate and image complexity;making measurements from M-mode recording;dynamic range;factors affecting needle visualization, particularly the tip, duringultrasonically guided puncture.
Doppler methodsAs only basic Doppler theory is covered in the general ultrasoundcurriculum, the presentation for the advanced course should start atan elementary level, including:
continuous wave and pulsed mode Doppler ultrasound;operating frequency (determined by the wave-scattering propertiesof, for example, blood, and the wave attenuation of overlying tissue);frequency spectral display (visualization of the energy and timedistribution of Doppler frequencies);control of aliasing (occurs when the pulse repetition frequency is lessthan twice the highest Doppler shift frequency);
32
Doppler analysis:determination of true velocity from the Doppler frequency andthe angle between the scanning beam and the measuredvelocity;determination of the frequency spectrum (for derivation of theDoppler shift frequency and for indication of flow disturbance).
Combined methodsBoth duplex scanning (two-dimensional real-time imaging containinga single line of Doppler information) and colour Doppler scanninguse a combination of Doppler and non-Doppler techniques. The fol-lowing elements should be covered:
velocity determination and frequency spectral display (duplexscanning);frequency, power, velocity, and selection of colour scale (colourDoppler).
5.4.2 Equipment
Real-time scannerThe following features are present in sophisticated machines but notin a general purpose ultrasound scanner:
focal-zone selection;frame-rate selection;intracavitary probes.
Continuous-wave DopplerThe continuous-wave Doppler technique is used mainly in ultrasoundstudies of the vascular system and in fetal heart monitoring. It typi-cally offers:
audio output of the Doppler shift frequency;display of heart rate as measured by Doppler ultrasound;frequency spectral display;Doppler filters for elimination of irrelevant signals;paper chart recording.
Pulsed-wave DopplerPulsed-wave Doppler is used when discrimination in distance to thetarget or region giving rise to Doppler signals is required. It involves:
selection of sample window (depth and length);selection of pulse repetition frequency.
4 2 33
Colour flow imagingCertain features are specific to colour flow imaging:
colour scale selection (colour is used to represent flow velocity andflow direction; usually red indicates flow towards the probe, and blue,flow away from the probe);the write-priority setting (can suppress the display of colour when theechogenicity exceeds a chosen threshold, which helps to distinguishsolid tissue);size selection of colour display region (usually kept as small aspossible to allow higher frame rate);beam steering (particularly with linear array scanners);spectral variance display (indicating flow disturbance and usuallydisplayed in green).
Power imagingPower imaging displays the amount of blood flow (as measured byDoppler power) within a grey-scale image of surrounding tissue. Theoperator should be familiar with the proper adjustment of:
colour gain (determines the minimum quantity of flow necessary toproduce a colour display);frequency threshold (sets the minimum flow velocity necessary forcolour display);intensity threshold (suppresses echoes from solid tissue).
5.4.3 Quality assurance
Quality assurance for advanced operators should cover:
a review of material related to quality assurance from the generalultrasound curriculum;the use of Doppler phantoms (containing moving targets or a liquidsimulating blood flow);correct use and disinfection of endoprobes.
5.4.4 Artefacts
Doppler techniques are associated with a number of specific artefacts.The advanced ultrasound operator will need to be able to recognizethese as well as acquire a deeper understanding of, and better abilityto recognize, the artefacts discussed in the general ultrasound course.The trainee should become familiar with:
multiple reflection artefacts with Doppler ultrasound:mirror reflection;reverberation;
34
two kinds of Doppler aliasing:frequency spectral aliasing (occurs when the Doppler shiftfrequency exceeds half the pulse repetition frequency);range ambiguity (occurs when pulse repetition frequencyexceeds the reciprocal of echo time);
artefacts due to colour frame rate that can occur when the frame rateis so slow that changes occur in flow conditions during frame acqui-sition.
5.5 Course durationEach basic science and instrumentation course (general and ad-vanced) should require 20 hours of instruction time.
5.6 EvaluationA practical evaluation of the trainee's ability to operate the scannerand correctly interpret scans is the most important measure ofachievement with respect to the curriculum. A written examination isalso important.
6. Training centres and resourcesHigh-quality, cost-effective training for physicians and allied healthprofessionals performing diagnostic ultrasound procedures is neededworldwide. The rapid dissemination of ultrasound equipment of alllevels of sophistication, with very often no local restrictions on pur-chase or utilization, exacerbates the need for such education.
6.1 Needs and prioritiesTraining needs in developed and developing countries are different.While both need adequately trained personnel, the ability to providethem varies significantly (see section 1.1). In many developed coun-tries, national diagnostic ultrasound societies and governmentalorganizations have together developed standards or recommenda-tions for training and, in some countries, accreditation. In thesecountries, awareness of the need for high standards of practice inultrasonography has in some cases led to the official recognition oftraining institutions as well as accreditation of individual practitio-ners. However, even in developed countries, there is concern aboutthe improper or inappropriate use of diagnostic ultrasound and aboutthe acquisition and use of ultrasonography equipment by those whoare not properly trained to use it. In developing countries, the scarcityof appropriately educated physicians has led to a much greater
LLIA 35
potential for users of diagnostic ultrasound to have insufficient train-ing, increasing the possibilities of inappropriate diagnoses and in-complete or incorrect treatment. Moreover, governmental controlsand organizational guidelines are more often lacking in developingcountries.
This report has established some principles for adequate training indiagnostic ultrasound at both basic and advanced levels. In addition,the need for the proper organization of training programmes and ofsupport for teachers and infrastructure, including educational centresand teaching materials, has been indicated.
6.2 Teacher trainingThe training of ultrasonography teachers is a fundamental element ofany strategy to implement this report's recommendations. Effectiveteaching requires not only a thorough knowledge of the subject mat-ter, but also a high level of interest in teaching and the willingness todevote time and effort to achieve excellence. To be an effective ultra-sonography teacher, an individual must have a thorough understand-ing of all aspects of the use of diagnostic ultrasound and must haveattained professional competence at a level no less than that requiredof his or her students. Ideally, the teacher's knowledge should begreater than that required of his or her students. An example of theideal teacher in ultrasonography is an experienced sonologist orsonographer actively performing clinical ultrasound examinations inthe specialty areas in which he or she is teaching. However, coursesin basic science and instrumentation may be provided by a scientistor engineer with the appropriate background in ultrasonography.Experience in all aspects of general ultrasonography for teaching atthe basic level is required; more advanced training needs teacherswith either higher levels of competence in general ultrasonographyor expertise in particular areas of specialization. In addition to athorough knowledge of ultrasonography and clinical expertise,teachers should also have a good understandingS of techniques andmethodologies of pedagogy. Although this can be obtained fromspecialized teacher-training programmes, it is also recognized thatsuch expertise can be obtained from years of experience in teachingultrasonography. Thus, a specialized certificate in teaching, althoughnot a necessity, has been recognized as helpful in some countries.
Recommendations of state, regional, or national organizations shouldbe taken into account by ultrasonography instructors in formulatingtheir course plans and in their actual teaching. This report provides anoutline of the information that chouki he covered in trainingprogrammes at various levels; however, modifications should be made
36 4 5
according to regional variations in the prevalence of disease, or otherfactors (34).
6.3 Material and techniquesUltrasonography teachers should endeavour to make use of all avail-able training materials and technologies. Wherever possible, conven-tional didactic lectures should be supplemented by directed reading intextbooks, published procedure protocols, and journal articles. Inaddition, videotape, CD-ROM, and interactive media are valuablemeans of extending the coverage of material taught. Interactive diag-nostic ultrasound simulators will probably become available in thefuture and should prove useful for increasing skills (35, 36). Instruc-tion in scanning techniques and extensive hands-on experience undersupervision is also an important aspect of training. Obtaining suffi-cient hands-On experience with patients may require the student toundergo a training period away from the primary didactic learningsite, as the availability of specific types of clinical experience may varyfrom site to site. Outside expertise should also be used wheneverpossible: in ideal circumstances, training would be provided not onlyby individuals permanently associated with the training centre butalso by invited lecturers who can provide a different perspective.However, cost plays an important role, and a reasonable substitutewould be the use of videotapes and CD-ROMs from a variety ofsources. In the future, satellite and other communication links mayopen new possibilities for distance learning. Electronic teaching aidsare becoming increasingly available worldwide and can provide avaluable supplement to a training programme provided they are usedwith the guidance of an on-site teacher.
6.4 Evaluation
Where appropriate, the use of both pre-training and post-trainingexaminations is recommended (i.e. written and practical examina-tions). Whenever possible, examinations should be developed by ex-perts other than the teaching staff so that the performance of bothteachers and students can be impartially evaluated. Such examina-tions should not preclude or substitute for those prepared by theteacher to provide regular feedback concerning the effectiveness ofteaching and students' capabilities for assimilating and utilizingknowledge provided in the training programme.
6.5 Teacher-training programmesThe development and implementation of intensive training pro-grammes specifically for ultrasonography instructors is desirable and
4 6 37
has been established practice for many years in some countries (e.g.Germany). Models of such programmes have been developed atthe Jefferson Ultrasound Research and Education Institute in theUnited States, at present the only recognized WHO CollaboratingCentre for Continuing and General Education in Diagnostic Ultra-sound. In the Jefferson Institute programmes, participants receive notonly the latest information about clinical and technical knowledge inthe field in which they are going to teach, but also instruction in themethods and techniques of teaching. Programmes such as theseshould be developed at other major training centres throughout theworld.
6.6 Licensing and accreditationLicensing and accreditation of ultrasound practitioners and teachersare the responsibility of local, national, or regional governmentalauthorities, professional societies, or other recognized organizations.Licensing and accreditation programmes vary widely from country tocountry (see section 2). In general, a formal system of accreditationhelps raise the standard of ultrasonography practice.
6.7 Continuing educationRegardless of the level of expertise acquired, all instructors and prac-titioners of ultrasonography should pursue continuing educationthrough "refresher" courses and conferences, as well as those offeringupdates on new technology and practice. The latter are particularlyimportant if the individual wishes to expand his or her expertise intonew areas. Periodic reaccreditation is also highly desirable.
6.8 Training centres
Particularly in countries where there is the greatest need for qualifiedpractitioners and instructors, it is advisable that regional and nationaltraining centres be established, either independently or associatedwith an established educational institution, (e.g. a university or uni-versity hospital).
6.8.1 Regional (international) centres
Regional centres should be established with the collaboration of allcountries in a region, and preferably with the assistance of interna-tional professional organizations.
38
The principal responsibilities of a regional centre should include:
4 7
the collection and dissemination of information on all aspects ofultrasonography, including new, techniques and developments inequipment;the development of training programmes for those who will usediagnostic ultrasound in patient care;the training of instructors of ultrasonography;the maintenance of the quality of teaching in national training centreswithin the region;the establishment and maintenance of standards for qualifying ex-aminations (in some regions, examinations may be the responsibilityof the regional centre and should in such cases be recognized andaccepted in each country in the region).
6.8.2 National centres
National centres should be recognized by relevant national authori-ties and professional organizations and should have the right to holdexaminations and issue diplomas or certificates after satisfactorycompletion of a recognized course of study. It is highly desirable thatwell qualified experts from other institutions and professional societ-ies be involved in the assessment process.National centres should maintain practice equipment and a library ofprint and audiovisual material.National centres should ensure that locally important diseases receiveproper attention.Both regional and national centres can be important for improvingthe standard of ultrasonography. Both should be involved in andpromote research on local health problems and provide informationto other countries.
6.9 EquipmentTraining centres should have adequate equipment and should beresponsible for the implementation of educational programmes.
6.9.1 Ultrasound equipment
For level I training, a general purpose ultrasound scanner is required.
For more advanced training, the equipment and transducers appro-priate to the subjects taught are required. This equipment should beof the current generation and should have been distributed within theregion within the last 3-5 years.Equipment for image recording should be available and used rou-tinely during training. Such equipment should include videotape-recording, a hard-copy device, and image storage facilities.
4 8 39
Equipment for training should be well maintained and subject toregular quality assurance checks. As far as possible, training equip-ment should be of the same type that will be used after qualification.
6.9.2 Training equipment
The use of tissue-simulating phantoms is desirable for testing spatialand contrast resolutions. Phantoms or dummies for practising scan-ning and ultrasonically guided puncture (where appropriate) are alsodesirable.
Videotape and 35-mm slide-viewing facilities should be provided.
6.1 0 Access to patientsTraining centres should have access to patients presenting a range ofconditions appropriate for the areas taught.
6.1 1 Space and equipment requirements
The space available for scanning and instruction should be consistentwith the number of trainees to be accommodated. One scanner foreach five trainees is desirable, but no more than ten trainees should beassigned to a single scanner. Appropriate classroom and study spaceshould be available for all students.
7. Conclusions and recommendations
40
1. The appropriate training of the users of diagnostic ultrasound isthe most important requisite for the improvement and rationalapplication of ultrasonography in medical practice.The use of diag-nostic ultrasound by individuals with inadequate knowledge andskills increases the likelihood of unnecessary patient examinationsand misdiagnosis and imposes additional costs on the health caresystem.
2. The purchase and use of diagnostic ultrasound equipment should berestricted to those who have successfully completed an adequatetraining programme or have achieved a proven level of competencein ultrasonography.The Study Group endorses the conclusion of theWHO Scientific Group on the Future Use of New Imaging Techno-logies in Developing Countries that the "purchase of ultrasoundequipment without making provision for the training of an operatoris contrary to good health care practice and is unlikely to be cost-effective" (9).
3. The Study Groinn strongly recommends that appropriate eurrirnlashould be adopted for the general, advanced, and specialized train-
4 9
ing of medical doctors and allied health professionals who usediagnostic ultrasound. Examples of such curricula have been pro-vided (see sections 375).
4. WHO, international governmental and nongovernmental organiza-tions, and professional associations should be actively involved inthe development of training programmes for the use of diagnosticultrasound. Such involvement should include setting training stan-dards and organizing and carrying out training courses (with accredi-tation of trainees) together with continuing education programmes.
5. Since diagnostic ultrasound technology is developing rapidly, regu-lar equipment upgrading is essential, particularly in institutionswhere training is provided.
6. The equipment, training, and practice of ultrasonography should beoriented towards local health care problems, and should have apositive effect on the quality of health care in the country concerned.
AcknowledgementsThe Study Group wishes to thank the World Federation for Ultrasound in Medicineand Biology for its financial support and active participation in the preparation ofthe meeting. The Study Group would also like to thank the WHO CollaboratingCentre for Continuing and General Education in Diagnostic Ultrasound (JeffersonUltrasound Research and Education Institute) as well as the Thomas JeffersonUniversity, in particular its President P.C. Brucker and Vice-President J.J.Saukkonen, for making available secretarial and other administrative support andfor graciously hosting the meeting. The helpful assistance of Dr C. Borras, RegionalAdviser, WHO Regional Office for the Americas, was also appreciated.
References1. Goldberg BB, Kimmelman BA. Medical diagnostic ultrasound: a retrospective on
its 40th anniversary. Rochester, NY, Eastman Kodak, 1988:1-49.
2. Wells PNJ. The prudent use of diagnostic ultrasound. Ultrasound in medicineand biology, 1987,13:391-400.
3. Bioeffects considerations for the safety of diagnostic ultrasound. AmericanInstitute of Ultrasound in Medicine. Bioeffects Committee. Journal of ultrasoundin medicine, 1988,7(Suppl. 9).
4. WFUMB Symposium on Safety and Standardisation in Medical Ultrasound.Issues and recommendations regarding thermal mechanisms for biologicaleffects of ultrasound. Hornbaek, Denmark, 30 August-1 September 1991.Ultrasound in medicine and biology, 1992,18:731-810.
5. Bioeffects and safety of diagnostic ultrasound. Laurel, MD, American Institute ofUltrasound in Medicine, 1993.
6. Medical ultrasound safety. Part I: Bioeffects and biophysics. Part II: Prudent use.Part III: Implementing ALARA. Laurel, MD, American Institute of Ultrasound inMedicine, 1994.
5 0 41
42
7. Larsen JF, Larsen T. Unskilled ultrasound scanning in gynecology and obstet-rics can lead to serious risks [in Danish]. Ugeskrift for Lw.ger, 1991,153:2187-2188.
8. Bundy AL. Legal concerns in diagnostic ultrasound: an overview. In: FleischerAC et al, eds. Sonography in obstetrics and gynecology: principles and practice.5th ed. Stamford, CT, Appleton & Lange, 1996:1027-1031.
9. Future use of new imaging technologies in developing countries. Report of aWHO Scientific Group. Geneva, World Health Organization, 1985 (WHO Tech-nical Report Series, No. 723).
10. Effective choices for diagnostic imaging in clinical practice. Report of a WHOScientific Group. Geneva, World Health Organization, 1990 (WHO TechnicalReport Series, No. 795).
11. Palmer PES, ed. Manual of diagnostic ultrasound. Geneva, World HealthOrganization, 1995.
12. The control of schistosomiasis. Second.report of the WHO Expert Committee.Geneva, World Health Organization, 1993 (WHO Technical Report Series, No.830).
13. Kurjak A, Breyer B. The use of ultrasound in developing countries. Ultrasound inmedicine and biology, 1986,12:611-621.
14. Rational use of diagnostic imaging in paediatrics. Report of a WHO Study Group.Geneva, World Health Organization, 1987 (WHO Technical Report Series, No.757).
15. Syllabus and regulations for the certificate examination in medical ultrasoundand the award of the diploma in medical ultrasound. London, College ofRadiographers, 1988.
16. Sj6berg N-0, Mar§al K. Postgraduate education in ultrasound diagnosis inobstetrics and gynaecology in Sweden. Early human development, 1992,29:117-120.
17. Basic ultrasound training for general practitioners. Report of a Joint WorkingParty. London, Royal College of General Practitioners & Royal College ofRadiologists, 1993.
18. Educational guidelines for diagnostic sonography. Rockville, MD, AmericanInstitute of Ultrasound in Medicine, 1993.
19. Diploma of medical ultrasonography: handbook. Willoughby, New South Wales,Australasian Society for Ultrasound in Medicine, 1995.
20. Filly RA. Radiology residency training in diagnostic sonography: recommenda-tions of the Society of Radiologists in Ultrasound. Radiology, 1989,172:577.
21. Smith CB et al. Quantification of training in obstetrical ultrasound: a study offamily practice residents. Journal of clinical ultrasound, 1991,19:479-483.
22. Ahram J, Feinstein SJ, De Phps H. Survey of ultrasound training in obstetricsand gynecology residency training program is in tf-ie United States. Obstetricsand gynecology, 1987,70:405-407.
51
23. Moreau JF, Bessis R, Le Guern H. L'ultrasonographie médicale en France:propositions pour le futur. [Medical ultrasonography in France: proposals for thefuture.] Journal d'echographie et de médecine ultrasonore, 1991,12:258-263.
24. Sonderdruck aus Vertragen der kassenarztlichen Bundesvereinigung.Ultraschallvereinbarung vom 10 Februar 1993. [Reprint of the contracts of theFederal Health Insurance Association. Ultrasound agreement of 10 February1993.] Germany, Federal Health Insurance Association, 1993.
25. Essentials and guidelines of an accredited educational program for the diagnos-tic medical sonographer. USA, Joint Review Committee on Education in Diag-nostic Medical Sonography, 1987.
26. The scope of practice for the diagnostic sonographer. Dallas, TX, Society ofDiagnostic Medical Sonographers, 1993.
27. Examination information & application. Cincinnati, OH, American Registry ofDiagnostic Medical Sonographers, 1995 (unpublished document available onrequest from American Registry of Diagnostic Medical Sonographers, 2368Victory Parkway, Suite 510, Cincinnati, OH, 45206).
28. International survey on radiation medicine technology. Tokyo, Japanese Asso-ciation of Radiological Technologists, 1995.
29. Guidelines for obstetrics and gynecology review. Dallas, TX, Society of Diagnos-tic Medical Sonographers, 1992.
30. Guidelines for abdomen review. Dallas, TX, Society of Diagnostic MedicalSonographers, 1994.
31. The role of the sonographer (February 1996). Australasian Society for Ultra-sound in Medicine newsletter, April 1996:13-14.
32. Standard for real-time display of thermal and mechanical acoustic outputindices on diagnostic ultrasound equipment. Rockville, MD and Washington,DC, American Institute of Ultrasound in Medicine and National Electrical Manu-facturers Association, 1992.
33. AIUM quality assurance manual for gray-scale ultrasound scanners. Stage 2.Laurel, MD, American Institute of Ultrasound in Medicine, 1995.
34. Increasing the relevance of education for health professionals. Report of a WHOStudy Group on Problem-Solving Education for the Health Professions. Geneva,World Health Organization, 1993 (WHO Technical Report Series, No. 838).
35. Ville Y et al. Development of training model for ultrasound-guided invasiveprocedures in fetal medicine. Ultrasound in obstetrics and gynecology, 1995,5:180-183.
36. Lee W et al. Interactive multimedia for prenatal ultrasound training. Obstetricsand gynaecology, 1995, 85:135-140.
Selected further readingThe Study Group noted that a number of documents related to themaintenance of high standards of practice in ultrasonography arealready being distributed by various organizations.
C.- 52 43
American Institute of Ultrasound in Medicine1. Ultrasound practice accreditation: standards and guidelines for the
accreditation of ultrasound practices. 1996.2. Guidelines for performance of the abdominal and retroperitoneal
ultrasound examination. 1994.3. Guidelines for performance of the ultrasound examination of the
female pelvis. 1995.4. Guidelines for performance of the ultrasound examination of the
prostate and surrounding structures. 1991.
(Available on request from American Institute of Ultrasound inMedicine, 14750 Sweitzer Lane, Suite 100, Laurel, MD 20707-5906,USA.)
Australasian Society for Ultrasound in Medicine5. Guidelines for the 18-20 week obstetrical scan. 1991.6. Guidelines for the performance of third trimester ultrasound. 1995.7 . Policy on ultrasonographer training. 1988.
(Available on request from Australasian Society for Ultrasound inMedicine, 2/181 High Street, Willoughby, New South Wales, 2065,Australia.)
World Health Organization8. Meeting on ultrasonography in schistosomiasis. Proposal for a prac-
tical guide to the standardized use of ultrasound in the assessment ofpathological changes , 1-4 October 1990, Cairo , Egypt. Geneva,WorldHealth Organization, 1991, Annex A (unpublished document TDR/SCH/ULTRASON/91.3, available on request from SpecialProgramme for Research and Training in Tropical Diseases, WorldHealth Organization, 1211 Geneva 27, Switzerland).
53
44
AnnexApplications of diagnostic ultrasound
Diagnostic ultrasound is used in nearly all fields of medicine and is theprimary imaging modality in a large number of clinical situations. It isalso widely employed as a secondary imaging modality for a broadrange of conditions. Diagnostic ultrasound is an integral part of thepractice of radiology, cardiology, internal medicine, surgery, and ob-stetrics. Its high clinical usefulness coupled with the relatively low-cost equipment and lack of ionizing radiation are resulting in itsincorporation into a growing number of clinical specialties for bothgeneral and specialized applications. Examples of the common uses ofdiagnostic ultrasound grouped by specialty are shown in the followingtable. Some variation in applications occurs from country to country.
Specialty Applications
Radiology All paediatric examinationsNeck, thyroid, and parathyroidChest and mediastinumHeartBreastAbdominal organs, peritoneum, and retroperitoneumFemale pelvisScrotal contentsObstetric examinationsSoft tissues, bone, muscles, tendons, and jointsVisceral arteries and veinsPeripheral arteries and veinsIntraoperative applicationsInterventional procedures (biopsy, aspiration, etc.)
Cardiology HeartLarge vessels
Obstetrics FetusUterusPlacenta
Gynaecology UterusOvariesAdnexa
Neurology and neurosurgery Extracranial arteriesIntracranial arteriesBrain
Paediatrics BrainHipsAbdomen:
5 445
PelvisHeartSoft tissuesScrotal contents
Gastroenterology Gastrointestinal tractLiverBiliary systemPancreaSpleen
Urology AdrenalsKidneysUretersUrinary bladderProstateSeminal vesiclesScrotal contents
Surgery (including general, Abdomen (fontrauma)orthopaedic, vascular, and Intraoperative examinations (brain, spine, colon, andgastroenterological surgery) rectum)
PelvisInterventional procedures (biopsy, aspiration, etc.)BreastSoft tissuesJoints and bonesExtracranial arteries and veinsLarge vessels
Angiology Peripheral arteries and veinsExtracranial arteries
Internal medicine Abdominal organsRetroperitoneal organsChest and mediastinumOther parts (excluding breast, scrotum)Visceral and peripheral arteries and veinsHeart (as a subspecialty)Infectious diseases (e.g. schistosomiasis and
echinococcosis)
5546
SELECTED WHO PUBLICATIONS OF RELATED INTEREST
Price (Sw.fr.)*Effective choices for diagnostic imaging in clinical practice.Report of a WHO Scientific Group.WHO Technical Report Series, No. 795, 1990 (131 pages)
Rational use of diagnostic imaging in paediatrics.Report of a WHO Study Group.WHO Technical Report Series, No. 757, 1987 (102 pages)
Future use of new imaging technologies in developing countries.Report of a WHO Scientific Group.WHO Technical Report Series, No. 723, 1985 (67 pages)
The control of schistosomiasis.Second report of the WHO Expert Committee.WHO Technical Report Series, No. 830, 1993 (93 pages)
Manual of diagnostic ultrasound.PES Palmer, ed.1995 (350 pages)
Manual of radiographic technique.T Holm et al.1986 (256 pages)
Manual of radiographic interpretation for general practitioners.PES Palmer et al.1985 (216 pages)
Manual of darkroom technique.PES Palmer1985 (25 pages)
16.
14.
7.
12.
65.
30.
23.
8.
Further information on these and other WHO publications can be obtained from
Distribution and Sales, World Health Organization, 1211 Geneva 27, Switzerland
* Prices in developing countries are 70% of those listed here.
Diagnostic ultrasound is a rapidly developing imaging technologywidely used in both industrialized and developing countries. Forcertain diagnostic applications, ultrasound has replaced commonlyused radiographic imaging techniques as the method of choice,and it has also made possible new areas of diagnostic investiga-tion. Moreover, equipment for ultrasound imaging tends to becheaper and more widely available than imaging equipmentrequiring the use of ionizing radiation. This combination of factorshas resulted in the proliferation of diagnostic ultrasound units, andin some cases their use by individuals without proper training, orunder conditions of inadequate control.
This report, the outcome of a recent WHO Study Group, is con-cerned with the essentials, principles, and standards of training forthis important technology. The Study Group ha analysed prob-lems in the effective use of diagnostic ultrasound and reviewedcurrent training practice worldwide. For the first time, outlines ofrecommended training curricula for the general, advanced, andspecialized use of diagnostic ultrasound are presented. Recom-mended standards for training programmes, training centres, andthe training process are also discussed. The report highlights therole played by professional societies, but also calls attention to theneed for appropriate legislation and regulation.
The Study Group's recommendations are relevant to all thoseinvolved in the use of diagnostic ultrasound technology, even incountries where existing standards of practice are high. In additionto ultrasound specialists, the report should be of particular interestto those responsible for medical education or for formulatingpolicies regarding the use of health technology.
Price: Sw. fr. 14.Price in developing countries: Sw. fr. 9.80 ISBN 92 4 120875 9
U.S. Department of EducationOffice of Educational Research and Improvement (OERI)
National Library of Education (NLE)Educational Resources Information Center (ERIC)
REPRODUCTION RELEASE(Specific Document)
I. DOCUMENT IDENTIFICATION:
Title: Training in Diagnostic Ultrasound: Essentials, Principles and Standards.WHO Technical Renort Series 875.
Author(s):
Corporate Source:World Health Organization
Publication Date:1998
II. REPRODUCTION RELEASE:
In order to disseminate as widely as possible timely and significant materials of interest to the educational community, documents announced in themonthly abstract journal of the ERIC system, Resources in Education (RIE), are usually made available to users in microfiche, reproduced paper copy,and electronic media, and sold through the ERIC Document Reproduction Service (EDRS). Credit is given to the source of each document, and, ifreproduction release is granted, one of the following notices is affixed to the document.
If permission is granted to reproduce and disseminate the identified document, please CHECK ONE of the following three options and sign at the bottomof the page.
The sample sticker shown below will beaffixed to all Level 1 documents
PERMISSION TO REPRODUCE ANDDISSEMINATE THIS MATERIAL HAS
BEEN GRANTED BY
TO THE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)
Level 1
12rCheck here for Level 1 release, permitting reproductionand dissemination in microfiche or other ERIC archival
media (e.g., electronic) and paper copy.
Signhere,--)please
The sample sticker shown below will beaffixed to all Level 2A documents
PERMISSION TO REPRODUCE ANDDISSEMINATE THIS MATERIAL IN
MICROFICHE, AND IN ELECTRONIC MEDIAFOR ERIC COLLECTION SUBSCRIBERS ONLY,
HAS BEEN GRANTED BY
2A
TO THE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)
Level 2A
Check here for Level 2A release, permitting reproductionand dissemination in microfiche and in electronic media
for ERIC archival collection subscribers only
The sample sticker shown below will beaffixed to all Level 28 documents
PERMISSION TO REPRODUCE ANDDISSEMINATE THIS MATERIAL IN
MICROFICHE ONLY HAS BEEN GRANTED BY
2B
TO THE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)
Level 2B
Check here for Level 2B release, permittingreproduction and dissemination in microfiche only
Documents will be processed as indicated provided reproduction quality permits.If permission to reproduce is granted, but no box is checked, documents will be processed at Level 1.
I hereby grant to the Educational Resources Information Center (ERIC) nonexclusive permission to reproduce and disseminate this documentas indicated above. Reproductigh from the ERIC microfiche or electronic media by persons other than ERIC employees and its systemcontractors requires permission from the copyright holder. Exception is made for non-profit reproduction by libraries and other service agenciesto satisfy information needs of educators in response to discrete inquiries.
Signature:
Organization/Address:
Printed Name/Position/Title:
Dr P.A. ButlerChief Officc of PuhlicationoTtennee791
24 06 022 791 48 94E-Mail Address:but lerp whô . ch
Date:28.8.98
(over)
III. DOCUMENT AVAILABILITY INFORMATION (FROM NON-ERIC SOURCE):
If permission to reproduce is not granted to ERIC, or, if you wish ERIC to cite the availability of the document from another source, pleaseprovide the following information regarding the availability of the document. (ERIC will not announce a document unless it is publicly ,
available, and a dependable source can be specified. Contributors should also be aware that ERIC selection criteria are significantly morestringent for documents that cannot be made available through EDRS.)
Publisher/Distributor:
Address:
Price:
IV. REFERRAL OF ERIC TO COPYRIGHT/REPRODUCTION RIGHTS HOLDER:
If the right to grant this reproduction release is held by someone other than the addressee, please provide the appropriate name andaddress:
Name:
Address:
V. WHERE TO SEND THIS FORM:
Send this form to the following ERIC Clearinghouse:
ERIC CLEARINGHOUSE ON HIGHER EDUCATION
THE GEORGE WASHINGTON UNIVERSITYONE DUPONT CIRCLE, SUITE 830WASH INGTON, D.C. 20038-1183
However, if solicited by the ERIC Facility, or if making an unsolicited contribution to ERIC, return this form (and the document beingcontributed) to:
ERIC Processing and Reference Facility1100 West Street, 2nd Floor
Laurel, Maryland 20707-3598
Telephone: 301-497-4080Toll Free: 800-799-3742
FAX: 301-953-0263e-mail: [email protected]
WWW: http://ericfac.piccard.csc.com
EFF-083 (Rev. 9/97)PREVIOUS VERSIONS OF THIS FORM ARE OBSOLETE.