Chapter 6 second half

Question 1

How tall must primary protective barriers be?

Answer 1

at least 7 ft tall

Question 2

Leakage radiation from the x-ray tube housing shall not exceed ____ mR/hr at a distance of 1 meter from the tube

Answer 2

100

Question 3

Lead aprons worn during a mobile exam must have a lead equivalency of at least _____ mm.

Answer 3

0.5

Question 4

The cardinal rules of radiation protection include

Answer 4

• time
• distance
• shielding

Question 5

When wearing a lead apron, a pregnant radiographer is required to wear their fetal dosimeter

Answer 5

at the waist level, inside the lead apron

Question 6

Factors which determine protective barrier thickness include:

Answer 6

• time occupancy
• workload
• use

Question 7

Applying the inverse square law, if we double our distance from the source, the intensity at our new distance is _____ as much as the original intensity

Answer 7

1/4

Question 8

define primary protective barriers

Answer 8

• located perpendicular to the line of travel of the primary x-ray beam
• up to 140 kVp
• should consist of 1/16 in lead (Pb) or equivalent

Question 9

define secondary protective barriers

Answer 9

• parallel to the line of travel of the x-ray tube
• cover areas exposed to scatter or leakage radiation
• require 1/32 inch lead (Pb) or equivalent

Question 10

what are some examples of secondary protective barriers?

Answer 10

• plaster
• concrete

Question 11

what is the average glass shielding?

Answer 11

• 1.5 mm Pb equivalent

Question 12

define time of occupancy

Answer 12

• denotes the amount of time a hospital is occupied by people
• consists of controlled and uncontrolled

Question 13

define controlled area (T)

Answer 13

• an area occupied by radiation personnel
• given a factor of 1
• a radiation worker is always present

Question 14

define uncontrolled area (T)

Answer 14

• occupied by the general public (non-radiation personnel)
• designated as full, partial or orccasional
• hallway factor if 1/4
• stairways and elevators a factor of 1/16

Question 15

what are some examples of uncontrolled areas?

Answer 15

• stairways
• unattended elevators
• outside areas

Question 16

Uncontrolled area design limits require barriers to reduce the exposure rate to less than ____ mrem/week.

Answer 16

10

Question 17

controlled area design limits require barriers to reduce the expo- sure rate to less than ____ mrem/week

Answer 17

100

Question 18

define workload (W)

Answer 18

• which takes into account weekly average tube current and tube operating time,
• measured in milliampere-minutes/week (mA-min/wk)

Question 19

define use factor (U)

Answer 19

• the percentage of time that the X-ray beam is energized and directed toward a particular wall.

Question 20

define HVL

Answer 20

• half value layer
• lead thickness that will reduce the intensity of radiation by 50%

Question 21

what causes a lead apron to be heavy?

Answer 21

• the lead equivalency of the apron

Question 22

where should the personnel monitor be worn?

Answer 22

• at the collar level, outside of the lead apron

Question 23

what type of aprons do pregnant women wear?

Answer 23

• long aprons that run from the xiphoid process (bottom portion of the sternum) to the pubic symphysis

Question 24

how many personnel monitors do pregnant women wear? where are they placed?

Answer 24

• 2
• 1 is at the collar level, outside of the apron
• 1 is at the waist level, INSIDE the apron

Question 25

how far is it recommended for the radiographer to stand away from the x-ray tube?

Answer 25

6 ft

Question 26

what's the formula for inverse square law?

Answer 26

I1/!2 = D2^2/D1^2

Question 27

what are some examples of immobilizations?

Answer 27

- tape - angle sponges - sandbags - foam pads