Glossary Definitions

Question 1

What are the units for absorbed dose?

Answer 1

rad (stands for radiation absorbed dose)

Gray (Gy) *SI unit

Question 2

What is the process by which an x-ray beam of radiation is reduced in intensity by absorption or scattering when passing through material?

Answer 2

attenuation

Question 3

What does the Law of Bergonie and Tribondeau say?

Answer 3

the more undifferentiated the cell line, the greater the radiosensitivity

Question 4

What is the cathode?

Answer 4

electrode in the x-ray tube from which electrons are emitted; it is a negative electrode

Question 5

What is the anode?

Answer 5

also referred to as the target, toward which electrons are accelerated from the cathode ; anode is a positive electrode

Question 6

Which direction do electrons flow?

Answer 6

from cathode to anode

Question 7

What is the compton effect?

Answer 7

(aka scattering) interaction btwn an incoming x-ray photon and an outer shell electron of an atom of the irrradiated object in which the photon surrrenders a portion of its kinetic energy to dislodge the electron from its orbit

Question 8

Which process accounts for most of the scattered radiation produced during xray?

Answer 8

compton effect

Question 9

what is the instrument used to measure film density (which is the degree of blackening of film) by measuring the ratio of light intensity on the film to the light intensity transmitted by the film?

Answer 9

densitometer

Question 10

what is a geiger-mueller (GM) counter?

Answer 10

highly sensitive, gas-filled radiation detection device

Question 11

What is the deterministic effect?

Answer 11

non-stochastic effect

*the severity determines the outcome

Question 12

What is the process most responsible for the dose of radiation the patient receives during a radiographic procedure?

Answer 12

photoelectric absorption

Question 13

what is photoelectric absorption?

Answer 13

interaction between an xray photo and an orbital electron in which the photon surrernders all of its kinetic energy to teh electron and ceases to exist

Question 14

what is the device that automatically terminates an exposure when the required film density has been achieved?

Answer 14

phototimer

Question 15

what is the primary protective barrier?

Answer 15

barrier sufficient to attenuate the useful beam

Question 16

when is quantum mottle most visible?

Answer 16

in a high-resolution, high-contrast image

Question 17

what is quantum mottle?

Answer 17

statistical fluctuations in the radiographic image which result in a grainy appearance

Question 18

What is the instrument used to expose film to precisely controlled steps of increasing light intensity?

Answer 18

sensitometer

Question 19

What is the device made up of different density filters shaped in a step-like form where each step orr filter differs in density by the square root of 2 called?

Answer 19

step wedge (penetrometer)

Question 20

How do you convert Sv and rems?

Answer 20

1 Sv= 100 rems