manaaki tangata taiao hoki protecting people and their environment through science specialist...
Post on 27-Dec-2015
214 Views
Preview:
TRANSCRIPT
Manaaki Tangata Taiao Hokiprotecting people and their environment through science
Specialist Science Solutions
HEAPHY 1 & 2
PLENARY
Tony COTTERILL
Fri 30th Aug 2013
Session 3 / Talk 4
14:30 – 14:50
ABSTRACT
This presentation will be in two parts:
Under the Radiation Protection Act 1965 practitioners require a license to use irradiating apparatus and/or radioactive materials for medical imaging. Through a license condition licensees are required to report to the regulatory authority specified radiation incidents involving the exposure of patients.
In diagnostic radiology notified radiation incidents are generally of low dose and consequently minimal risk. However, a significant proportion of notified incidents involve computerized tomography scans where patient doses are more significant. Also, on rare occasions incidents have included procedures involving the injection of patients with contrast media or radiopharmaceuticals. Causes of incidents include clerical errors, failure of staff to follow the so-called three-point check (e.g. name, date of birth and address), and referral errors such as the mislabeling of a request form.
This presentation will give a summary of reported incidents in diagnostic radiology between July 2009 and the end of November 2011.
The National Radiation Laboratory (NRL) has surveyed the use of conventional plain radiography in New Zealand since 1983. Since NRL's last supplemental survey in 1992 there have been improvements in technology, particularly with the widespread transition from film to digital imaging indicating the need for a new survey. The most recent survey was carried out by NRL in 2010 and involved collecting data nationally. This presentation reports the findings for this latest survey and presents national diagnostic reference levels
Manaaki Tangata Taiao Hokiprotecting people and their environment through science
Specialist Science Solutions
Diagnostic Radiology: 1/ A Summary Of Reported Radiation Incidents2/ The Results of a National Survey Of Patient Doses In Conventional Plain Film Radiography
Tony Cotterill, Glenn StirlingNational Centre for Radiation Science
(formally the National Radiation Laboratory)
© ESR 2012
ESR - a Crown Research Institute
• Established July 1992
• Government owned
• One of eight CRIs
• Covered by CRI Act (1992)
© ESR 2012
NCRS (formally NRL) provision of services• National training centre
- RPS course
- RPO course (non-medical)
- Regulatory Core of Knowledge
- Bespoke training courses
• Radiation Protection Advisor (RPA)
- corporate RPA
- senior medical/health physicist as the portfolio manager
- simplicity of a single contract for the provision of all required radiation protection advice and services
- comprehensive and flexible and cost effective
© ESR 2012
Incident reporting• To Ministry of Health’s ORS
• A radiation incident involving the exposure of a patient to a radiation dose much greater than intended
- ‘much greater than intended’ guideline multiplying factors - high dose eg, CT 2- medium dose eg, AP abdomen 10- low dose eg, chest 20
• A radiation exposure of a patient where none was intended, as in the case of mistaken identity
• A radiation exposure of the embryo/foetus where the exposure had not been included in the justification process
• An unexpected skin injury to a patient resulting from a prolonged radiation exposure in an interventional procedure
Tony Cotteril 5
© ESR 2012
Reported main cause of incidents:July 2009 to December 2011
Tony Cotteril 6
Equipment failure Inadequate procedures Human error Clerial error Referrer error Other0
10
20
30
40
50
60
70
No.
of I
ncid
ents
171 reported~ 6 per month63 major centres
© ESR 2012
Analysis of causes (1)Cause Additional details provided on causes Corrective and preventive
actions taken by radiology departments
Equipment failure.
These include: Patients administered radiopharmaceuticals just
prior to imaging equipment failure. Servicing error on fluoroscopy unit. CR cassette failure. Image storage computer failure. Image processor failure.
Limited possible actions as faults were unpredictable.
Inadequate procedures.
Hand-over issues when main ordering system that had been down was restored.
Hand-over issues between ED and Radiology. Incorrect patient identification. Accidental CR cassette erasure. Inadequate training of staff on x-ray equipment.
Process review and staff training.
Human error. Most involved misidentification of the patient.
Process review and staff training. More consistent application of the
three-point check.
Tony Cotteril 7
© ESR 2012
Analysis of causes (2)Clerical error. Referral incorrectly entered on to RIS.
CT images accidentally deleted. NM images accidentally corrupted while
attempting amendment. Incorrectly booked for an x-ray when only a US
had been requested. Misinterpreted ambiguous exam coding. Patient previously administered with
radiopharmaceutical, mistakenly turned away when returned for scan.
Process review and staff training. Computerised referral systems. Computerised post-processing of
images.
Referrer error. Most involved referral forms with inaccurately completed clinical details (eg, forms where the incorrect pre-printed patient’s details label had been inadvertently attached), or duplicate requests.
Checking of clinical details with patients when presenting.
Computerised referral systems.
Other. Mostly due to patients not knowing that they were pregnant.
Staff training. Consideration of the use of
pregnancy tests for the high dose abdominal CT procedures.
Tony Cotteril 8
© ESR 2012
Incidents involving: July 2009 to December 2011
Tony Cotteril 9
Pregnant patient Skin injury Wrong Patient Other0
20
40
60
80
100
120
No.
of I
ncid
ents
© ESR 2012
Modalities of incidents; July 2009 to December 2011
Tony Cotteril 10
Nuclear Medicine CT Fluoroscopy Plain Radiography0
20
40
60
80
100
120
No.
of I
ncid
ents
© ESR 2012
Patient dose of incidents; July 2009 to December 2011
Tony Cotteril 11
<1 1 to 10 >100
10
20
30
40
50
60
70
80
90
Effective dose (mSv)
No.
of I
ncid
ents
© ESR 2012
2/ Results of a National Survey Of Patient Doses In Conventional Plain Film Radiography
Tony Cotteril 12
© ESR 2012
Number of conventional radiographyprocedures (excluding theatre mobiles)
• ~ 13% increase per capita• an average a person will be x-rayed once every
two years• Approximately 90% digital
Tony Cotteril 13
Year
1983-84 2010
Population (millions) 3.22 4.23
Number of x-rays per year 1.5 million 2.2 million
Number of x-rays per 1000 of population
470 530
© ESR 2012
Numbers of conventional radiographyprocedures for different age groups
• Marked increase in the number x-rays of older adults with less paediatric x-rays
• Demographics (eg, ageing population) alone doesnot account for this shift.
Tony Cotteril 14
0
50
100
150
200
250
300
350
400
450
0-<1 1-4 5-9 10-14 15-19 20-24 25-29 30-39 40-49 50-59 >-59
Age group (years)
Pat
ien
ts p
er 1
000
x-ra
ys
1983-84 survey
2010 survey
© ESR 2012
Relative frequency of the main types ofconventional radiography procedures
• The contribution of conventional plain radiography procedures to the diagnostic radiology population dose per capita has dropped (243 to 99 µSv per capita per annum)
This is probably because of a shift of higher dose procedures to other modalities such as CT
Tony Cotteril 15
TypeYear
1983-84 (%) 2010 (%)Limbs & extremities 31 33Pelvic region, lumbo-sacral spine 12 25
Chest, heart, lungs 35 22Ribs & sternum, thoracic spine, shoulder girdle
5 10
Head, neck 10 7Abdominal soft tissue 7 3
© ESR 2012
U.S. population exposure 2006
National Council on Radiation Protection and Measurement. Report No. 160.
62 million CT examinations
~ 6 mSv per person
Tony Cotteril 16
© ESR 2012
Diagnostic Reference Levels (DRL) in termsof ESD (mGy) compared with other studies
• Little change in DRL
Tony Cotteril 17
Projection(70 kg patient)
British Institute of Radiology (UK) (1986)
(Current values in
CSP5)
HPA (UK) (2005)
AAPM (USA) (2005)
This survey (NZ)
(2010)
Chest PA 0.3 0.2 0.3 0.3Chest LAT 1.5 0.6 - 1.1
Lumbar spine AP 10 5 7 7
Lumbar spine LAT 30 11 - 27
Pelvis AP 10 4 - 5Abdomen AP 10 4 6 7
© ESR 2012
Conclusions
• There has been a small increase in the number of conventional plain radiography procedures being performed compared to 1983/84
• The age distribution of patients undergoing conventional plain radiography procedures, since NRL’s survey in 1983-84, shows a marked increase in the x-raying of older adults withless paediatric x-rays. Demographics alone do not account for this shift
• The contribution of conventional plain radiography procedures to the diagnostic radiology population dose per capita has dropped. This is because of a shift of procedures to modalities such as CT.
• Little change in the DRL
Tony Cotteril 18
© ESR 2012
top related