Rad Protection Prescription

Question 1

greatest source of background radiation?

Answer 1

radon alpha particles in the lung

Question 2

trend in medical radiation since 80s

Answer 2

has gone up, mostly CT scan and nuclear medicine

Question 3

Non-occupational dose limits for stochastic, deterministic, fetus?

Answer 3

Stochastic: 5mSv
Deterministic: 50mSv for lens, skin, extremities
Fetus: 0.5mSv per month

Question 4

Effective dose of rectangular collimation bitewings
FMX
Pano

Answer 4

bitewings: 5 uSv
FMX: 35 uSv
Pano: 9-26 uSv

Question 5

Principle of justification

Answer 5

benefit of exposure exceeds low risk of harm

Question 6

Principle of optimization

Answer 6

dentists should use means to reduce unnecessary exposure to patients and themselves

Question 7

dose limitation for diagnostic xray exposure?

Answer 7

no legal limits

Question 8

Patient selection criteria means

Answer 8

ID patients who would benefit from radiographs

prescribe radiographs only after

Question 9

Guidelines for recall
new patient

recall at risk

recall not at risk

Answer 9

new: posterior bitewings + pano/periapical selections

recall at risk: 6-12 (18 for partially edentulous)

recall not at risk: 12-24 for children, 18-36 for adults, 24-36 for partially edentulous

Question 10

Any film slower than ____ should not be used

Answer 10

E-speed

Question 11

Digital sensors vs F speed? (exposure)

Answer 11

equal or greater dose savings

Question 12

intensifying screens good for?

Answer 12

dose reductin

Question 13

Decreasing distance from xray tube to skin vs. exposure, image quality?

Answer 13

exposed tissue volume reduced by 10-25%

image quality more sharpness, less fog

Question 14

Rectangular collimation dose compared with circular? area?

Answer 14

60-70% area reduction

45-95% dose reduction

Question 15

Rectangular collimation vs image quality?

Answer 15

reduces scatter (fog)

Question 16

3mm Al = what % reduction in exposure?

Answer 16

80%

Question 17

How much aluminum needed for 50-70kVp

70+kVP?

Answer 17

1.5, 2.5mm

Question 18

Aprons are not neccessary wen?

Answer 18

All NCRP recs are met

Question 19

Collars needed when? When not needed?

Answer 19

needed for children/pregnant. Not for pano

Question 20

Film and sensor holders for:
posterior PA:
anterior PA:
Bitewing:

Answer 20

posterior PA: yellow tab, yellow ring, bent rod
anterior PA: white tab, blue ring, bent rod
Bitewing: blue tab, red ring, straight rod

Question 21

Kilovoltage operating potential? Should? MUST?

Answer 21

MUST be between 50 and 100 kVp

SHOULD be between 60 and 80 kVp

Question 22

High kVp benefits? Low?

Answer 22

High - reduces pt dose

Low - improves contrast

Question 23

anterior and posterior PA Tube current, kVp, exposure time?

Answer 23

6 mA, 70 kVp, 0.1 seconds

Question 24

bitewing current, kVp, exposure time?

Answer 24

6 mA, 70 kVp, 0.125 seconds

Question 25

No barrier guidelines for personnel?

Answer 25

Distance: 6 feet from source
Position: 90-135 degrees from xray beam