chapter 13 EXAM 6 FINAL

Question 1

for monitored xray personnel the risk may be compared with the occupational risk for persons employed in other industries considered reasonably safe. These jobs have a risk of fatal accidents generally estimated to be about

Answer 1

1x10^-4 per year

1 in 10,000 a year

Question 2

at a 90 degree angle to the primary xray beam at a distance of 1m the scattered xray intensity is generally about how much of the primary xray beam

Answer 2

about 1/1000 of the intensity of the primary xray beam

Question 3

what poses the greates occupational hazard in diagnostic radiology

Answer 3

scattered radiation

Question 4

what reduces the number of scattered radiation produced in a pt. and therefore reduces the radiographers dose

Answer 4

beam limitation devices

Question 5

for regular diagnostic xrays, your protective lead apron should be how much lead

Answer 5

0,25

Question 6

for fluoro your protective lead apron should be how much lead

Answer 6

0.5

Question 7

all aprons should be inspected for cracks or other defects every

Answer 7

year

Question 8

as the average energy of the beam increases, the percentage of radiation that is forward scattered does what and therefore…

Answer 8

increases

and therefore less side scattered radiation is available to strike imaging personnel

Question 9

use of high speed image receptors does what to the personnel exposure

Answer 9

decreases personnel exposure

Question 10

after the voluntary declaration of pregnancy, the RSO must

Answer 10

provide essential counseling

furnish an appropriate additional dosimeter

Question 11

in pregnant personnel, the monthly EqD to the embryo fetus must not exceed

Answer 11

0.5mSv

Question 12

in pregnant personnel, the EqD for the entier pregnancy must not exceed

Answer 12

5 mSv (0.5rem)

Question 13

attenuation by the maternal tissues ovelying the fetus reduces the dose to the fetus to aprox.

Answer 13

30 % of the abdominal dose

Question 14

t or f
when normal protective measures are taken it is nearly impossible for a radiographer to approach the fetal dose limit of 5mSv

Answer 14

true

Question 15

specially designed maternity protective aprons consist of what lead equivalent over the entire length and width

Answer 15

0.5 mm lead equivalent

Question 16

specially designed maternity protective aprons also have an extra what equivalent of lead protective panel that runs transversely across the width of the apron

Answer 16

1mm lead equivalent

Question 17

3 basic principles of radiation protection

Answer 17

time
distance
shielding

Question 18

the amt of radiation a worker receives is directly or indirectly proportional to the length of time the individual is in the path of ionizing radiation

Answer 18

directly proportional

Question 19

exposure =

Answer 19

exposure rate * expsoure time

Question 20

what is the most effective means of protection

Answer 20

distance

Question 21

inverse square law

Answer 21

expresses the relationship between distance and intensity

I1/I2=D2^2/D1^2

Question 22

the intensity of radiation is inversely or directly proportional to the square of the distance from the source

Answer 22

inversely

Question 23

if you double the distance, the dose reduces by

Answer 23

4

Question 24

if you triple the distance the dose reduces by

Answer 24

9

Question 25

2 types of protective shielding

Answer 25

1. structural protective barriers | 2. accessory protective devices

Question 26

structural protective barriers include

Answer 26

lead | concrete

Question 27

accessory protective devices include

Answer 27

aprons gloves thyroid shields protective glasses

Question 28

protective structural shielding includes

Answer 28

walls and doors in xray room to shield form personnel and general public

Question 29

whose responsibility is it for determining the exact protection requirements for a particular imaging facility

Answer 29

the medical physicist

Question 30

primary protective barrier

Answer 30

barrier designed to shield an area from primary radiation

Question 31

what is the purpose of a primary protective barrier

Answer 31

to prevent direct or unscattered radiation form reaching personnel or general public located on the other side of the barrier

Question 32

if the peak energy is 130 kVp the primary protective barrier in a typical installation consists of

Answer 32

1.6 mm lead

Question 33

when the xray tube is 1.5-2.1m from the wall in question, the primary protective barrier must extend upward

Answer 33

2.1m

Question 34

secondary protective barrier

Answer 34

barrier designed to shield an area from secondary radiation

Question 35

what is the purpose of a secondary protective barrier

Answer 35

to protect against leakage and scatter radiation

Question 36

a secondary barrier should overlap the primary protective barrier by aprox

Answer 36

1.27cm

Question 37

in a typical installation the secondary barrier consists of how much lead

Answer 37

0.8mm lead

Question 38

control booth barrier must extend how high upward and be permanently secured to the floor

Answer 38

extend 2.1m up from the floor

Question 39

the lead glass window consist of how much lead

Answer 39

1.5mm lead equivalent

Question 40

appropriate lead equivalent in the control booth ensures the radiographer will not exceed a max allowance of what per week

Answer 40

1mSv per week

Question 41

in a well designed facility exposure to personnel should not exceed what per week

Answer 41

0.02mSv per week

Question 42

modular xray barriers are available in what lead equivalent

Answer 42

0.3-2mm

Question 43

clear lead acrylic overhead protective barrier

Answer 43

used as overhead xray barriers to provide open view during special procedures and heart catheterizations

Question 44

when lead equivalent thickness increases...

Answer 44

attenuation increases when kVp stays the same

Question 45

a what mm lead apron would be appropriate for mamo

Answer 45

a 0.25mm lead apron

Question 46

the neck and thyroid shield should be a minimum of what lead equivalent

Answer 46

0.5mm lead

Question 47

in protective eyewear, the lenses contain a minimal lead equivalent of

Answer 47

0.35mm lead

Question 48

the methods and devices that reduce exposure to personnel during fluro are

Answer 48

``` adequate beam collimation adequate filtration gonadal shielding control of exposure factors use of high speed image receptors appropriate Source to skin distance ```

Question 49

the bucky slot shielding device must be at least what lead equivalent

Answer 49

0.25 lead eq

Question 50

without the bucky slot cover and the protective curtain in place the exposure rate for fluoroscopists would exceed what at a distance of what

Answer 50

1mGya/hr at a distance of 0.6m (2ft)

Question 51

where should the radiographer stand during mobile radiographic procedures

Answer 51

at a right angle to the xray beam

Question 52

in routine fluoro the max allowed entrance exposure rate dose to a pt. is

Answer 52

10 cGy/minute

Question 53

in HLC fluoro the max allowed entrance dexposure rate dose to a pt. can range upward to

Answer 53

20-40 cGy/minute

Question 54

NCRP currently recommends an annual EqD limit to the localized area of the skin and hands of

Answer 54

500 mSv

Question 55

most facilities room doors have attenuation for diagnostic energy xrays equivalent to that provided by

Answer 55

0.8mm of lead

Question 56

what are the 3 categories of radiation that can be generated in an xray room

Answer 56

primary radiation scatter radiation leakage radiation

Question 57

what part of the xray room requires the most protective shielding for safety purposes

Answer 57

the wall in the path of the direct radiation

Question 58

in a typical xray room the most important primary barrier is

Answer 58

behind the wall bucky unit

Question 59

if the xray tube housing is designed properly the leakage radiation will never exceed the regulatory limit of

Answer 59

1mGya/hr

Question 60

a busy general purposed xray room may have a workload of

Answer 60

500mA-min/week

Question 61

rooms in private offices may have workloads of less than

Answer 61

100mA-,in/week

Question 62

workload definition

Answer 62

product of the max mAs and the number of xray examinations performed each week

Question 63

use factor (U)

Answer 63

the percentage of time during which the xray beam is on and directed toward a primary protective barrier

Question 64

the use factor is also called

Answer 64

the beam factor

Question 65

occupancy factor (T)

Answer 65

a factor used to modify the shielding requirements for a particular barrier by taking into account the fraction of the work week during which the space beyond the barrier is occupied

Question 66

controlled area

Answer 66

a region adjacent to a wall of an xray room that is occupied by only occupationally exposed workers

Question 67

uncontrolled area

Answer 67

a region adjacent to a wall of an xray room such as a corridor or hall that is frequented by the general public

Question 68

for uncontrolled areas the weekly max permitted equivalent dose is equal to

Answer 68

20 microsieverts which is .02 mSv

Question 69

for controlled areas the weekly max permitted equivalent dose is equal to

Answer 69

1000 microsievert or 1 mSv