How to limit dose to patient and dental teams

Question 1

two aims of radiation protection

Answer 1

1. prevent deterministic certainty effects

2. limit the probability of stochastic effects to acceptable levels

Question 2

ICRP general principles of dose

Answer 2

1. must have net positive benefit
2. all exposure should be as low as possible
3. the equivalent dose should not exceed limits recommended by commission

Question 3

how to limit patient dose?

Answer 3

1.equipment - 70kv, adjustable kv ma and time, long fsd, rectangular collimation, tested
fast e/f speed film

2. clinical judgement -
3. radiographic techniques

Question 3

how to limit patient dose?

Answer 3

1.equipment - 70kv, adjustable kv ma and time, long fsd, rectangular collimation, tested
fast e/f speed film

2. clinical judgement -
3. radiographic techniques

Question 4

benefit of long fsd

Answer 4

distance between focal spot and end of spacer cone

beam is less divergent so area of irradiated is reduced

Question 5

benefit of 70kv

Answer 5

photons do not stop in the patient

Question 6

benefit of faster film

Answer 6

reduced exposure time
f speed is fastest
d speed not recommended anymore

Question 7

radiographic techniques that limit dose

Answer 7

use beam aiming devices

take min number of images

try to get right the first time

optimise digital images to max diagnostic yield

use appropriate lead aprons

Question 8

benefit of lead aprons?

Answer 8

no justification
actually unnecessary

thyroid protection more useful

Question 9

requirements for pregnant women

Answer 9

enquire if pregnant

only take absolutely necessary radiographs

Question 10

Golden rules

Answer 10

always stand at least 2m away or behind protective screen

never stand in line of beam

always stand outside controlled area

never hold film packet in patients mouth

must report over exposure

Question 11

clinical area limitation

Answer 11

thickness of surgery walls?

need for lead screens?