Part 6: Protection

Question 1

ALARA principle assumes what?

Answer 1

That there is no threshold of radiation dose necessary to achieve a biological effect

Question 2

Stochastic effects means the ___ of an effect occurring rather than the ___.

Answer 2

probability

severity

Question 3

Stochastic effects are regarded as a function of ____.

Answer 3

radiation dose without a threshold

Question 4

Nonstochastic effects mean those effects for which the ____ varies with ___.

Answer 4

severity

radiation dose

Question 5

Stochastic or nonstochastic?

carcinogenesis

Answer 5

stochastic

Question 6

Stochastic or nonstochastic?

cataracts

Answer 6

Nonstochastic

Question 7

Stochastic or nonstochastic?

bone marrow depletion

Answer 7

Nonstochastic

Question 8

Stochastic or nonstochastic?

non-malignant skin damage

Answer 8

Nonstochastic

Question 9

Stochastic or nonstochastic?

Somatic effects

Answer 9

Stochastic

Question 10

Any occupationally exposed individual should not receive a dose more than ___ rem in one calendar year.

Answer 10

5 rems

Question 11

What is the source of the chief radiation exposure to the operator?

Answer 11

Scatter radiation from the pt

Question 12

X-ray tube current and ABC should be monitored how often?

Answer 12

once per week

Question 13

What % reduction in scatter radiation exposure does the 0.5mm lead equivalent apron achieve?

Answer 13

99.9%

Question 14

Protective gloves of ___ and ___mm lead equivalent are available and must be worn whenever the hand is directly under the x-ray beam.

Answer 14

0.25mm

0.5mm

Question 15

Protective curtain (overlapping protective drapes) of at least ___mm lead equivalent should be positioned between the ___ and the ___.

Answer 15

0.25mm

patient

fluoroscopist

Question 16

Mobile screen desks usually come in what increments of mm lead equivalent?

Answer 16

1.0mm and 2.0mm

Question 17

What are the 2 types of acceptable personnel radiation monitoring devices?

Answer 17

Film badge
Thermoluminescent dosimeter (TLD)

Question 18

In addition to the film badge or TLD, what other monitoring devices can be worn?

Answer 18

pocket chamber or dosimeter

audible warning device

Question 19

What is the primary purpose of the filter in the film badge?

Answer 19

to permit dose measurements over a wide range of energies

Question 20

FIlms used for film badge dosimeter are sensitive to exposure equivalent to doses as low as ___ and as high as ___.

Answer 20

10 milirad

700 rads

Question 21

1 rem of x-rays is approximately equivalent to ___ rad.

Answer 21

1

Question 22

What is the most common material used in the TLDs?

Answer 22

lithium fluoride

in solid chip form

Question 23

What are TLDs sensitive to?

Answer 23

light

(have to be stored sealed)

Question 24

How do TLDs work?

Answer 24

1. ionizing radiation interacts with lithium fluoride crystals
2. crystals raised to higher energy states of excitation, become trapped
3. crystals heated in measuring device and light is emitted proportional to radiation absorbed and measured

Question 25

Which are more accurate: TLDs or film badges?

Answer 25

TLDs

Question 26

Main disadvantages to TLDs

Answer 26

Can only read exposure once, thus not a permanent record they’re $$$

Question 27

What is a small pencil sized instrument that discharges a capacitor by ionization of air within the chamber when in the presence of ionizing radiation?

Answer 27

Pocket ionization chamber

Question 28

What are the two types of pocket ionization chambers used for personnel monitoring?

Answer 28

self-reading special-device-reading

Question 29

Some disadvantages to pocket ionization chamber monitoring?

Answer 29

no permanent record calibrate periodically sensitive to mechanical shock subjective reading limited dose range possible loss of info if exposed over its maximum

Question 30

Should a pocket ionization chamber be used alone?

Answer 30

NO only with film badge or TLD

Question 31

Benefit of wearing an audible warning device in addition to a TLD or film badge

Answer 31

you can have immediate dose feedback (others take a couple weeks to read and get results back)

Question 32

Where can you wear an audible warning dose-rate meter?

Answer 32

clipped to garment or belt placed in a pocket

Question 33

When wearing a lead apron, where should the monitoring device be placed?

Answer 33

one the collar on the outside of the protective apron

Question 34

Annual dose limits for: whole body skin and extremities lens of eye

Answer 34

5 rem or 0.05 Sv 50 rem or 0.5 Sv 15 rem or 0.15 Sv

Question 35

Convert 50 rem to Sv

Answer 35

0.5 Sv

Question 36

TLDs and film badges are usually changed how often?

Answer 36

monthly