Radiography: Radiation Physics and Radiobiology

Question 1

Which of the following produces the most dangerous form of scatter radiation: the Compton effect, Grenz rays, coherent scattering, or the photoelectric effect?

Answer 1

The Compton effect

Question 2

According to what principle can RTs reduce their radiation dose by one-fourth when they double their distance from the radiation source?

Answer 2

**The inverse square law **

Question 3

What is the main reason an X-ray beam signal loses strength as it travels away from the X-ray tube?

Answer 3

**Divergence of the X-ray beam **

Question 4

The wavelength of an X-ray photon is measured as the distance between _________________ .

Answer 4

crests

Question 5

An extension of what equation describes the relationship between photon energy and photon wavelength as being inversely proportional?

Answer 5

Planck’s constant/equation

Question 6

What is the most common interaction that occurs between X-rays and contrast media that’s used for certain radiographic procedures?

Answer 6

The photoelectric effect

Question 7

Which of the following cells in the body are NOT considered to be highly radiosensitive: basal cells, erythroblasts, lymphocytes, or nerve cells?

Answer 7

Nerve cells

Question 8

The reddening of skin due to irradiation is known as ____________________ .

Answer 8

erythema

Question 9

X-rays and gamma rays are often also called ______________.

Answer 9

**photons **

Question 10

Structures that absorb X-rays and appear bright or white on radiographs are classified as being _______________.

Answer 10

**radiopaque **

Question 11

Generally speaking, the probability of Compton scattering occurring _______________ as X-ray energy _________________ .

Answer 11

decreases; increases

Question 12

Genetic cell damage, malignant disease, and cell death are the main effects of _____________ .

Answer 12

**cell irradiation **

Question 13

The measurement of biological damage to living tissue as a result of radiation exposure is called the ________________ .

Answer 13

dose equivalent

Question 14

Radiation dose levels as low as ______________ have caused observable effects.

Answer 14

**0.10 Gys **

Question 15

The ____________________ of radiation occurs when DNA is damaged.

Answer 15

direct effect

Question 16

What X-ray photon-to-tissue interaction primarily involves K-shell electrons?

Answer 16

**Photoelectric absorption/effect **

Question 17

What is also known as classical or Thompson scattering?

Answer 17

Coherent scattering

Question 18

What results when the effects of radiation become more severe as radiation dose increases?

Answer 18

Deterministic effects

Question 19

The effects of radiation where the long-term probability of occurrence, not the severity of occurrence, are proportional to the radiation dose are known as ________________ .

Answer 19

stochastic effects

Question 20

The majority of a projectile electron’s kinetic energy is converted into ______________ .

Answer 20

heat

Question 21

___________________ are the result of projectile electrons that are slowed down by positively charged nuclei and change direction.

Answer 21

Bremsstrahlung X-rays

Question 22

________________ is kinetic energy that’s released in a unit mass of air (also considered radiation exposure).

Answer 22

Air kerma

Question 23

The _________________ is the amount of energy per unit mass absorbed by an object that has been irradiated.

Answer 23

absorbed dose

Question 24

The total reduction in the number of X-rays remaining in an X-ray beam after it penetrates tissue is called _____________________________ .

Answer 24

attenuation

Question 25

The difference between the ways and amounts that parts of the body interact with and absorb radiation is called ____________________ .

Answer 25

differential absorption

Question 26

Cancer and genetic defects are examples of what type of effects?

Answer 26

Stochastic effects

Question 27

The initiation of cancer growth or development is called _________________ .

Answer 27

carcinogenesis

Question 28

What percentage of the total energy applied to an X-ray tube target is converted into X-rays?

Answer 28

About 1%

Question 29

__________________________ is the emission of electrons after being stimulated by heat, commonly by the X-ray tube filament.

Answer 29

Thermionic emission

Question 30

The X-ray beam is most intense at which part of the X-ray tube?

Answer 30

**The cathode end **

Question 31

What is the measurement of the average annual gonadal radiation dose of individuals who are of childbearing age?

Answer 31

**The genetically significant dose **

Question 32

What is the formula for calculating the cumulative effective dose?

Answer 32

Multiplying the person’s age by 10 mSv

Question 33

_____________________is the amount of energy deposited by radiation per unit length of tissue.

Answer 33

**Linear energy transfer **

Question 34

What does the following equation calculate?
Radiation weighting factor (WR) × Tissue weighting factor (WT) × Absorbed dose (D)

Answer 34

The effective dose

Question 35

Radiation that’s emitted from the X-ray tube and directed towards the patient for imaging purposes is called __________________ .

Answer 35

the primary beam

Question 36

Radiation that spreads in many directions after interacting with a substance or tissue is called ____________________

Answer 36

scatter radiation

Question 37

A graphical depiction of the relationship between the radiation received and a patient’s response to it is called _________________.

Answer 37

a dose-response curve

Question 38

_________________ is the measurement of the damage done by a given type of radiation per unit of energy deposited in biological tissues.

Answer 38

Relative biological effectiveness (RBE)