Chapter 14 Notes

Question 1

the maximum dose received by the patient is where

Answer 1

at the skin entrance to the body

Question 2

formula for entrance skin exposure

Answer 2

mR/mAs

Question 3

formula for fluoroscopy entrance skin exposure

Answer 3

R/min

Question 4

exposure is

Answer 4

radiation intensity in air

Question 5

exposure is measured in

Answer 5

roentgens (R)

Question 6

dose is

Answer 6

the amount of radiation absorbed

Question 7

dose is measured in

Answer 7

rad

Question 8

entrance skin exposure is calculated at

Answer 8

minimum SOD

Question 9

it is better to _____ exposure, rather than _____ exposure

Answer 9

overestimate; underestimate

Question 10

mR/mAs charts are typically calculated at what distance

Answer 10

40 inches SID (100 cm)

Question 11

higher kVp’s produce _____ mR/mAs

Answer 11

higher

Question 12

FDA limit for standard fluoroscopy exposure rates

Answer 12

11.5 R/min (10 cGy/min)

Question 13

FDA limit for high-level control fluoroscopy exposure rates

Answer 13

23 R/min (20 cGy/min)

Question 14

what is the interrelationship of prime factors

Answer 14

(mAs)x(kVp squared)/(distance squared)

Question 15

increasing kVp without compensation in mAs will

Answer 15

increase patient dose

Question 16

increasing kVp with a compensation in mAs will

Answer 16

decrease patient dose

Question 17

increasing mAs without compensation from other technical factors will

Answer 17

increase patient dose

Question 18

mAs at the lowest level possible will

Answer 18

reduce patient dose

Question 19

an increase in SID or SOD results in

Answer 19

decrease in entrance skin exposure (ESE)

Question 20

a decrease in OID will

Answer 20

increase SOD and decrease ESE

Question 21

increased filtration will decrease ESE with

Answer 21

modification in kVp

Question 22

increased filtration will increase ESE with

Answer 22

modification in mAs to maintain image quality

Question 23

a decrease in primary beam size will

Answer 23

decrease patient dose

Question 24

a significant decrease in field size will often require

Answer 24

an increase in mAs

Question 25

three major types of gonad shielding

Answer 25

flat contact, shadow, and shaped contact

Question 26

a higher ratio grid will

Answer 26

require increase in mAs and increases patient dose

Question 27

use lowest ratio grid necessary to

Answer 27

minimize patient dose

Question 28

use of an intensifying screen will

Answer 28

reduce dose (faster screen speed)

Question 29

use of film will

Answer 29

decrease dose (increases film speed)

Question 30

use of film processing will

Answer 30

have no effect on dose when properly maintianed

Question 31

digital image receptor systems respond to

Answer 31

0.01 mR to 100 mR

Question 32

what percent of radiation exposure received by the general public is a result of diagnostic radiographic examinations

Answer 32

15%

Question 33

which radiographic exams result in the highest ESEs

Answer 33

L-spine, pelvis, and hip

Question 34

when area of interest is as close to IR as possible

Answer 34

increased recorded detail, decreased distortion, and places area as far from entrance exposure as possible

Question 35

immobilization will

Answer 35

eliminate motion, decrease tissue density through compression, and reduces dose

Question 36

what percent of repeats are the result of improper technical factors

Answer 36

>50%

Question 37

increasing the number of pulses from the generator will

Answer 37

cause substantial decrease in patient ESE

Question 38

k-edge is created by

Answer 38

characteristic photons

Question 39

characteristic photons interact with matter through

Answer 39

photoelectric interactions

Question 40

mAs has a _____ relationship with exposure

Answer 40

direct

Question 41

increasing filtration will

Answer 41

reduce ESE, even when kVp is compensated

Question 42

increased field size will

Answer 42

increase total dose, even when mAs or kVp are adjusted

Question 43

flat contact shield

Answer 43

positioned over gonads at skin surface

Question 44

shadow shield

Answer 44

positioned in primary beam below collimator

Question 45

shaped contact

Answer 45

worn by patient to surround gonads

Question 46

what region does not permit the use of shields

Answer 46

pelvic region

Question 47

decreasing subject part density

Answer 47

decreases scatter production and reduces patient dose

Question 48

using a higher speed film will

Answer 48

decrease dose

Question 49

most acceptable images produced use about _____ exposure to receptor

Answer 49

1 mR

Question 50

asymptomatic patients should only be examined when

Answer 50

is significant cause; after considering incidence and severity of condition; detection reliability of exam; usefulness of exam in treatment

Question 51

symptomatic patients should fit what two criteria for x-ray exams

Answer 51

exam is capable of providing desired information; the information, if negative, is expected to contribute to the management of the patient

Question 52

establish credibility with patient by

Answer 52

answering questions; taking medical history; manipulate x-ray equipment; and exhibiting a professional demeanor

Question 53

Proceeding with an exam after a patient refuses puts the radiographer at risk of malpractice action. This is usually as

Answer 53

assault and battery