Chapter 10 Notes

Question 1

primary protective barriers are designed to

Answer 1

protect against direct exposure to primary x-ray beam

Question 2

secondary protective barriers are designed to

Answer 2

protect against exposure from scatter and leakage radiation

Question 3

current recommendation by the NCRP that equivalent dose limit for embryo-fetus not exceed

Answer 3

0.05 rem (0.5 mSv) in any month, once the pregnancy becomes known

Question 4

NCRP collects, analyzes, develops, and disseminates information on

Answer 4

radiation protection, radiation measurements, quantities, and units

Question 5

regulatory agencies

Answer 5

NRC and FDA

Question 6

stochastic effects

Answer 6

no threshold; random in nature; regardless of amount of dose, some will experience effect

Question 7

with stochastic effects, as dose increases

Answer 7

chance of occurrence increases

Question 8

deterministic effects

Answer 8

threshold; once threshold is surpassed, increase in dose will increase severity of response

Question 9

dose limits for general public

Answer 9

5 mSv (0.5 rem) for infrequent exposure; 1 mSv (0.1 rem) for continuous exposure

Question 10

cardinal rules of radiation protection

Answer 10

minimize time, maximize distance, and shielding

Question 11

what is your last line of defense

Answer 11

sheilding

Question 12

field size should never be larger than

Answer 12

IR

Question 13

collimation does what

Answer 13

reduces patient dose and improves image quality

Question 14

technique selection

Answer 14

high kVp/low mAs

Question 15

filtration removes what photons

Answer 15

low-energy

Question 16

most common filter material

Answer 16

aluminum

Question 17

2.5-mm aluminum equivalent (Al/eq) filtration required when operating at or above _____

Answer 17

70 kVp

Question 18

patient dose is still reduced with greater filtration by

Answer 18

reducing patient skin exposure when removing low-energy photons

Question 19

use _____ possible grid ratio to effectively remove scatter, without jeopardizing image quality

Answer 19

lowest

Question 20

gonadal shielding should be used any time gonads lie within _____ of primary beam

Answer 20

5 cm

Question 21

three types of gonadal shielding

Answer 21

flat contact, shaped contact, and shadow shields

Question 22

IR speed

Answer 22

fastest possible IR system will minimize patient dose

Question 23

patient exposure estimates

Answer 23

should be developed and available for routine procedures on average patients

Question 24

equipment should be surveyed annually by

Answer 24

radiologic medical physicist

Question 25

BEIR V report states that the fetus is particularly radiosensitive from _____ weeks gestation

Answer 25

8-15

Question 26

monthly equivalent dose limit for fetus

Answer 26

0.5 mSv (0.05 rem) per month once pregnancy is declared

Question 27

risk at _____ negligible compared to other risks

Answer 27

5 rad

Question 28

risk of malformation significant at

Answer 28

15 rad

Question 29

dose equivalent _____ to declared pregnant woman for entire pregnancy

Answer 29

5 mSv (0.5 rem)

Question 30

pregnancy declaration according to NRC must be

Answer 30

in writing, dated, include estimated date of conception

Question 31

assignment of pregnant workers to areas of lower exposure violates

Answer 31

application of ALARA for other workers