1

Question 0

As an x ray beam passes through matter, the intensity ______ and the mean energy _______ by removal of low energy photons

Answer 0

decreases, increases

Question 1

Which of the following force carrier particles makes up the x ray beam?

Answer 1

photon

Question 2

Which of the following forms of electromagnetic radiation has greater energy than x rays?

Answer 2

Gamma

Question 3

What is the primary means of dental x ray attenuation?

Answer 3

Compton scattering (57%)

Question 4

The quantum theory of radiation has been successful at correlating experimental data on?

Answer 4

The production of x rays

Question 5

What happens when you increase kVP on a unit?

Answer 5

Increase mean energy and # of photons

Question 6

Within the X-ray tube the electrons stream from ____ to ____?

Answer 6

cathode (-) to anode (+)

Question 7

What is the primary source of radiation from the X-ray tube?

Answer 7

Bremsstrahlung

Question 8

What percentage of the kinetic energy of the electrons produced at the filament hitting the anode is converted into heat?

Answer 8

99%

Question 9

Deterministic effect says that?

Answer 9

• severity proportional to dose
• threshold
• tissue effects (ex. inutero)
• not really relevant in dental radiology

Question 10

Stochastic effect says that?

Answer 10

• risk proportional to dose
• no threshold
• cancer
• severity independent of dose

Question 11

Most of the radiation exposure in the world’s population from natural sources is caused by?

Answer 11

Radon

Question 12

Which tissue type has most radio sensitivity?

Answer 12

basal cells that are rapidly dividing in oral mucosa

Question 13

When patients have head/neck radiation they should avoid dental procedures for?

Answer 13

6 months

Question 14

Which of the following is true regarding radiation therapy to the jaws of children?

Answer 14

radiation therapy proceeding dental calcification can destroy the tooth bud (especially if undergoing chemo)

Question 15

Which organ has lowest susceptibility to radiation cancer?

Answer 15

Salivary glands

Question 16

Dental x ray beams are responsible for what percentage of the human made exposure to radiation?

Answer 16

less than 1%

Question 17

The lead foil ack used in film is positioned where?

Answer 17

behind the film and protective black paper so the photons are absorbed before proceeding further in the mouth

Question 18

The average dose for the individuals occupation exposed in the operation of dental x ray equipment is about what amount of allowable exposure?

Answer 18

1%

Question 19

Some states require x ray beam used in intraoral radiation to be collimated so the field of radiation to the patient’’s skin surface?

Answer 19

circular= 7cm or 2.75 in

Question 20

according to the linear non threshold hypothesis how much risk comes from radiation induced cancer from radiography?

Answer 20

possibility of some risk including carcinogenic and tissue damage when exposed to any amount of radiation

Question 21

When taking an x ray what principle obligates the dentist to do more good than harm?

Answer 21

justification (part of ALARA)

Question 22

In intraoral film speed, E and F speed film have some useful contrast image quality as D speed film?

Answer 22

same image quality just a lot faster so less radiation is given to the patient

Question 23

What size dental film is used for adult bit wings?

Answer 23

2

Question 24

When a dark room is used with a safe light how long before the safe light affects the quality of the image?

Answer 24

5 mins

Question 25

Changing which of the following variables will result in decreased film density?

Answer 25

increase the focal spot to the film distance