Fluoro & Rad Protection

Review QuestionsFor WEB RT 255 wk 7/8

1

IMAGE INTENSIFIER

• __________ – Input Phosphor• _______________ – Output phosphor• ELECTRON FOCUSING LENS• + CURRENT ATTRACTS e TO ANODE• _________ KVP POTIENTIAL ACROSS TUBE

2

MEASURED IN ???? IP VS OP

IMAGE INTENSIFIER

• FUNCTION:• CHANGE XRAY PHOTONS TO • __________ PHOTONS (INPUT PHOSPHOR)• TO __________(PHOTOCATHODE)

3

Defines?

• The ratio of the number of light photons striking the output screen to the ratio of the number of x-ray photons striking the input screen is called _____________

4

MAG MODE VS PT DOSE

• MAG USED TO ENLARGE SMALL STRUCTURE OR TO PENETRATE THROUGH LARGER PARTS

• FORMULA:????

• PATIENT DOSE IS INCREASED IN THE MAG MODE –

• DEPENDANT ON SIZE OF INPUT PHOSPHOR

5

MAG MODE VS PT DOSE

• MAG USED TO ENLARGE SMALL STRUCTURE OR TO PENETRATE THROUGH LARGER PARTS

• PATIENT DOSE IS INCREASED IN THE MAG MODE –

• DEPENDANT ON SIZE OF INPUT PHOSPHOR

• FORMULA:????

6

TV Monitor

• Name of Pattern of electon beam?• # of lines for Conventional vs Digital monitors• Horizontal Resolution?• Vertical Resolution?

7

KELL FACTOR

VERTICAL RESOLUTIONABILITY TO RESOLVE OBJECTS SPACED APART IN A VERTICAL DIRECTION

MORE DOTS(GLOBULES) = MORE SCAN LINES = MORE/BETTER RESOLUTION

• RATIO OF VERTICAL RESOLUITON• # OF SCAN LINES

• KELL FACTOR FOR 525 LINE SYSTEM• IS ____________________

8

VIDEO/CAMERA TUBE

PLUMICON, VIDICON, ORTHOCON, CCD’s • Function?• CONNECTED BY

• MOST COMMOM• BETTER RESOLUTION & Lower pt dose?• – VERY $$$$• Type used in Digital Units?

9

Image Quality

• Terms that are necessary to know:–Vignetting is–Pincushion effect–Quantum mottle is– The _____of the II will always have the best

resolution.– Lag is

10

Image Quality• Terms that are necessary to know:– Vignetting is the loss of brightness at the periphery of the

II due to the concave surface– Pincushion effect is the drop off at the edges of the II due

to the curved surface– Quantum mottle is the grainy appearance on the image

due to statistical fluctuations – The center of the II will always have the best resolution.– Lag is the blurry image from moving the II too fast

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Image Quality - Define

• Contrast is controlled by?• Resolution• Size Distortion is affected by• Quantum mottle – What is it and what causes it?

12

Regulations about the operation

• Fluoroscopic tubes operate at currents that range from

• With ___________the most common• AEC rate controls: equipment built after 1974

with AEC shall not expose in excess of __R/min;

• equipment after 1974 without AEC shall not expose in excess of ____ R/min

13

Other regulations

• Must have a ____________ switch• Must have __________ exposure timer• Must have an ______to prevent exposure without II

in place• Tube potential must be tested ________• Brightness/contrast must be tested _______• Beam alignment and resolution must be tested

_____• Leakage cannot exceed __________

14

SSD – TUBE TO SKIN DISTANCE

• FIXED UNITS• ____PREFERRED• _____MINIMUM

MOBILE UNITS ( C-ARMS)_____ MINIMUM

15

more regulations

• Must have a device to prevent operation at a SOD of less than ___________

• A bucky slot cover must be provided• Aprons must be at least _______Pb equivalent• ________Al equivalent filtration is required• Must provide at least _____ and preferably ______

between source and table top

16

Fluoroscopy exposure rate

• For radiation protection purposes the fluroscopic table top exposure rate must not exceed __________/min.

• The table top intensity should not exceed ____ R/min for each mA of current at____ kVp

17

measurement

1 Rem = .01 Sievert1 REM = _____mSv

1 Rem = _____mRem?

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measurement

100 R = 1 C/kg1Rad = 1/100 Gray1 Rem = .01 Sievert

(Rad + QF = REM)1 REM = 10 mSv

1 Rem = 1000mRem

19

PUBLIC EXPOSURE ?

• ______ OF OCCUPATIONAL • NON MEDICAL EXPOSURE• _____ RAD OR _____MRAD• UNDER AGE 18 AND STUDENT• .1 rem 1 mSv

• Pg 98 RTA BOOK

20

• INTERGRAL DOSE –

• 100 ERGS OF TISSUE = 1 RAD EXPOSURE• OR ___ RAD =___ERGS

21

PATIENT PROTECTION

• NAME 4 WAYS TO LIMIT DOSE TO THE PATIENT DURING FLUORO EXAM

22

According to your California syllabus, list more 6 things that will reduce patient

exposure:

23

GONAD SHIELDING

• MUST BE . ______ OF LEAD• MUST BE USED WHEN GONADS WILL LIE

WITHING _____ OF THE COLLIMATED AREA (RHB)

• KUB. Lumbar Spine Pelvis • male vs female shielding

24

Gonad shielding & dose

• ♀ receive _____ more dose than

• ♂ for pelvic x-rays

• 1 mm lead will reduce exposure

(primary) by about ______♀

• by about ________♂

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Degree of scatter??26

Degree of scatter??

• 135 under 45 over

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KEEP I.I. CLOSE TO PATIENT

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Over vs under the table fluoro tubes

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Framing and patient dosesyll = Pg 31 which is BEST

• The use of the available film area to control the image as seen from the output phosphor.– Underframing– _______ is best, (58 % lost film surface) – Overframing,(part of image is lost) – Total overframing

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EXPOSURE RATES FLUORO

• IF MACHINE OUTPUT IS 2 R/MA/MIN = WHAT IS PT DOSE AT 1.5 MA FOR 5 MIN STUDY?

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EXPOSURE RATES FOR FLUORO

• CURRENT STANDARD • _______ R/MIN (INTENSIFIED UNITS)• HLC: BOOST MODE _______ R/MIN

32

RADIATION PROTECTIONThe Patient is the largest scattering

object

• Lower at a _____ DEGREE ANGLE from the patient + PRIMARY BEAM

AT 1 METER DISTANCE -• _______ OF INTENSITY

PRIMARY XRAY or 0.1%

33

The law requires that total filtration during fluoroscopy should be

__________________

34

Between spot film cassettes and photospot films,

the_____will increase patient dose. However, between the two the

______will produce better image quality.

35

The x-ray tube current automatically increases to ________level of mA

when a spot film is taken.

36

List one RECORDING method that HAS LOWER

PATIENT DOSE: ______________________

37

When recording dynamic images using cine, the higher the frames per second,

the ___________ the patient dose

38

PERSONNEL PROTECTION

• STANDING BEHIND A PROTECTIVE PRIMARY (-of ____ pb) BARRIER:

• PRIMARY RADIATION EXPOSURE _____REDUCED

• PORTABLE BARRIER = _____REDUCTION

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PERSONNEL PROTECTION

• PROTECTIVE APRONS – • 0.25 PB = ____ ↓ TO SCATTER• 0.5 PB = _____ ↓ TO SCATTER• THYROID SHEILDS (____________ mm pb)• GLOVES (____________ mm pb)

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PERSONNEL PROTECTIONMONITORING

• FILM BADGE• TLD• POSL

• POCKET DOSIMETER

• RING BADGE

• Which is most sensitive to radiation?

• Which one has a permanent record?

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PERSONNEL PROTECTIONMONITORING

• DOSE LIMITS• WHOLE BODY __________• EYES _________________• EXTREMITIES (BELOW ELBOW/KNEES)

42

Who should wear 2 badges

name 2

43

Who wears a ring dosimeter?

44

TLDSensitive to ___mrem?

45

Report available at least _________Preserved for a minimum of _____years

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RHB NOTIFICATION (

• IMMEDIATE – REPORT WITHIN• _________________________• TOTAL DOSE OF 25 rems• Eye dose – 75 rem• Extremity – 250 RADS

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RHB NOTIFICATION (EXP IN 24 HOURS)

• OVEREXPOSURE –• Report within ________________

• TOTAL DOSE OF 5 rems• Eye dose – 15 rem• Extremity - 50 REMS

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LICENSE RENEWAL

• WITHIN ________OF EXPRIATION• NOTIFICATION OF CHANGE OF ADDRESS

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• HIGH RADIAITON AREA –• ___________mRem ( 0.1 rem / (1 msV)– @ 30 cm from the source of radiation

•

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• RADIATION AREA –• RHB: • __________ ( 0.005 rem / (.05 msV)– @ 30 cm from the source of radiation

• PUBLIC _______ per week* (STAT)

51

A “controlled area” is defined as one1. that is occupied by people trained in

radiologic safety2. that is occupied by people who wear

radiation monitors3. whose occupancy factor is 14. ALL OF THE ABOVE

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CARDINAL RULES

• ______________________• _______________________• ____________________

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HVL TVL

• The amount of material required to reduce the energy of the beam by……..

• HVL _______________________

• TVL _____________________

• Examples 100 – 50 - 25 – 12.5 – 6.25 - 3.12• ?How many to reduce to 1/2 ? 1/10th ?

54

an occupationally exposed individual, federal law limits annual occupational

whole body radiation dose to

____________ rem

__________mSv

55

For female workers of child bearing age who are or may be pregnant, this occupational

dose limit is reduced (with respect to the fetus) to:

Preferably distributed evenly over the entire gestation period

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Pregnancy & Embryo

Mother – occupational worker (5 rem)• Baby – (______ mRem)• __________ rem/ year

__________rem/month

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• The NCRP states that: the risk (to the embryo/fetus) is considered to be negligible at 5 rads or less when compared to the other risks of pregnancy • and the risk of malformation is

significantly increased above control levels only at doses above ___________rads

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• is significantly increased above control levels only at doses above 15

rads

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• Name of 1?• 2?• 3?

• ? is the type of biological dose response effect that is considered in for radiation safety purposes

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DOSE

• CINE - ____mR per frame (30 OR 60f/sec)______ mr per “look”

• WHAT WOULD BE THE PATIENT’S DOSE FOR A 2 MIN PROCEDURE

• AT 30 F/SEC?

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• If at ½ foot from the radiation source the intensity of exposure is 240 mR per hour and you remain at this location for 10 minutes, you then moved 2 feet away from the radiation source and remained there for 20 minutes? What is your total exposure?

62

– If at one foot from the radiation source the intensity of exposure is 240

• milliroentgens (mR) per hour and you remain at this location for 10 minutes

• you will receive and exposure of 40 milliroentgens (mR). What source and remained there for 20 minutes?

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The greatest contribution of unnecessary radiation exposure to the patient comes

from the x-ray operator’s failure to

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The greatest contribution of unnecessary radiation exposure to the patient comes

from the x-ray operator’s failure to – collimate the x-ray beam to the area of clinical

interest only– use proper gonadal shielding– use past screens and films– use proper exposure (technical factors

65

All of the following must be posted in areas where x-ray production machines are utilized except:

• each x-ray supervisor and operator permit• each certified radiologic technologist certificate and

technologist fluoroscopy permit• Radiologic Health Department Form RH-2364,

“Notice to Employee”• each physician’s license for the healing arts

66

– During a 2 minute (fluoroscopy exposure time) routine upper GI series examination; a typical x-ray exposure to the patient is:

– How do you calculate with only this information?

67

• When the target to panel (tube to patient) distance is increased from 12 to 18 inches the ESE to patient is approximately:

• a. Increased by 45 % • c. Decreased by 100 %• b. Increased by 25 % • d. Decreased by 45%

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• At 1 foot from a source the output intensity is 300 mR/hr and you were there for 20 minutes.

• What is the intensity total if you moved 2 feet away and remained for an additional 40 minutes?

69

You are fluoroscoping a patient using 80 kilivolt peak (kvp) technique. At this

• Kilovolt peak (kvp) the intensity of the x-ray beam at table top should not exceed how many roentgens per minute for each milliampere (ma) of current?

• 0.2 roentgens per minute• 1.0 roentgens per minute• 2.2 roentgens per minute• 5.0 roentgens per minute

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• The NCRP states that: the risk (to the embryo/fetus) is considered to be negligible at 5 rads or less when compared to the other risks of pregnancy ,

• and the risk of malformation is significantly increased above control levels only at doses above how many rads:

• a. 7 b.10 c.15 d. 25

71

• A “high radiation” area is any area , accessible to individuals, in which there exists radiation at such levels that an individual could receive in any one hour a dose to the whole body in excess of how many millirems ?

• a.5 b. 10 c. 50 d. 100

72

• Which of the following technical factors will create the highest skin entrance dose to the patient?

• A. 80 kvp 300 ma .5s no filter • B. 80 kvp 300ma 1/10s no filter• C. 80 kvp 1000ma 1/20s 2.5mm al eq. filter • D. 80 kvp 800ma 1/60 sec .05mm al eq filter

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• The exposure rate to a tech at 4 feet from the source is 240 m R/hr. What distance would be necessary to reduced the rate below 60 mR/hr?

• A. 1 foot • B. 6 feet • C. 2 feet • D. 9 feet

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• If 85 kvp, 400ma 0.12s = 150mR - what is the mr/mas?

• A. 0.32 • B. 3.1 • C. 33.1 • D. 17.6

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• Each time an x-ray beam scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity?

• A. 1/10 • B. 1/100 • C. 1/500 • D. 1/1000

76

The California Radiation ControlRegulations define dose to mean radiation absorbed per unit mass. Whole-Body dose means exposure to which of the following:

• I Major portions of the whole body • II Head and trunk• III Gonads• IV Lens of the eye • V Active blood-forming organs • VI Whole body excluding extremitiesa. I only b. I, III, IV & VI only c. I & IV only d. all of the above

77

• Which of the following gives the least patient exposure?

• a. mirror optical system• b. vidicon TV camera • c plumicon TV camera• d. image orthicon

78

• Which of the following gives the best resolution?

• a. mirror optical system• b. vidicon TV camera • c plumicon TV camera• d. image orthicon

79

• During a CINE exam in which 35 mm film and a frame rate of 30 frames per second are utilized, what is the approximate skin exposure in roentgens/minutes?

• a. 1 (given 2mr/frame)• b. 2 – 5 • c. 5 – 10 • d. over 10

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• It may be advisable to wear a second personal monitoring device if a worker is:

• 1. performing routine radiological procedures

• 2. pregnant• 3. a student• 4. performing special procedure • examinations

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