Chapter 5: Radiation Protection

Question 1

What is the first step in limiting the amount of x-radiation received by a dental patient?

Answer 1

Proper prescribing, or ordering of dental images

Question 2

What does x-radiation cause

Answer 2

biologic changes in living cells and can adversely effect all living tissues

Question 3

situations in which radiographs may be indicated

Answer 3

previous periodontal or endodontic treatment
history of pain and trauma
history of family dental anomalies

evidence of periodontal disease

Question 4

What appropriate thigs should the dental xray tubehead have

Answer 4

aluminum filter
lead collimator
PID

Question 5

What are the two types of filtration ?

Answer 5

1. Inherent filtration

2. added filtration

Question 6

what is inherent filtration?

Answer 6

when primary beam passes through glass window of xray tube insulating oil and tubehead seal

Question 7

What is added filtration ?

Answer 7

placement of aluminum disks in path of xray beam between collimator and tubehead seal

Question 8

what is the purpose of an aluminum disk ?

Answer 8

filters out longer wavelengths with low energy which is harmful is not useful in diagnostic imaging

Question 9

What is total filtration?

Answer 9

Inherent + added filtration

Question 10

xray machines operating below 70 kV require a minum total of ____ mm aluminum filtration

Answer 10

1

Question 11

what is collimation

Answer 11

restricts size and shape of xray beam to reduce patient exposure

Question 12

what is a collimator

Answer 12

Lead plate with hole in the middle that fits over the opening of the machine housing

Question 13

what shapes do the collimator have

Answer 13

rectangle and circular

Question 14

which collimator is better? rectangle or circular’?

Answer 14

rectangle bcause it restricts 60% less

Question 15

federal regulations require than xray beams are not to be more than ____ mm

Answer 15

2.75

Question 16

what is the purpose of the Position Indicating Device (PID)

Answer 16

directs xray beam

Question 17

what are the two shapes of a PID

Answer 17

rectangular(16in) round (8 in)

Question 18

which PID shape produces less divergence of the xray beam ?

Answer 18

rectangular

Question 19

purpose of the thyroid collar

Answer 19

flexible lead shield that protects thyroid gland

reccomended for intra oral

Question 20

Purpose of lead apron

Answer 20

flexible shield placed on chest and lap of patients to protect reproductive organs and blood forming tissues.

Question 21

Most effective film in reducing patients exposure to x-radiation

Answer 21

f speed film

Question 22

What do beam alignment devices do ?

Answer 22

helps stabilize the receptor in the mouth and reduces chances of movement.

recommended for periapical and bitewings

Question 23

what is the optimal kV and mA setting to limit patient exposure

Answer 23

60-80 kV and and mA setting of 6-8 mA

at the shortest time possible.

Question 24

How must the dental radiographer avoid the primary beam ?

Answer 24

by positioning himself perpendicular to the primary beam or 90-135 degree angle to beam

Question 25

what must the dental radiographer never do

Answer 25

hold the receptor in place for the patient

hold or stabilize the xray tubehead.

Question 26

what is leakage radiation

Answer 26

any xray leakage except for the primary beam that is emitted from the dental tubehead.

Question 27

what is Maximum Permissable Dose (MPD)

Answer 27

a maximum dose equivalent that a body is permitted to receive within a specific period.

Question 28

MPD of those who work with radiation

Answer 28

50 mSv / year

Question 29

MPD of those who work in radiation and are pregnant

Answer 29

0.5 mSv during months of pregnancy

Question 30

MPD of the general public

Answer 30

1 msV/ year