ARRT Prep

Radiation Physics and Radiobiology

If you are studying for the AART Radiography examination they have kindly provided you with the Content Specifications. In this section we have repeated the section on Radiation Physics and Radiobiology along with links to where to learn more about each section from us here at How Radiology Works. We will continue to build out our resources to support your preparation for other sections in the future.

PRINCIPLES OF RADIATION PHYSICS

X-Ray Production

a. source of free electrons (e.g., thermionic emission)

b. acceleration of electrons

c. focusing of electrons

d. deceleration of electrons

Target Interactions

a. bremsstrahlung

b. characteristic

X-Ray Beam

a. frequency and wavelength

b. beam characteristics

1. quality

2. quantity

3. primary versus remnant (exit)

c. inverse square law

d. fundamental properties (e.g., travel in straight lines, ionize matter)

Photon Interactions With Matter

a. Compton effect

b. photoelectric absorption

c. coherent (classical) scatter

d. attenuation by various tissues

1. thickness of body part

2. type of tissue (atomic number)

BIOLOGICAL ASPECTS OF RADIATION

SI units of measurement (NCRP #160)

a. absorbed dose (Gy)

b. equivalent dose (Sv)

c. exposure (C/kg)

d. effective dose (Sv)

e. air kerma (Gy)

Radiosensitivity

a. dose-response relationships

b. relative tissue radiosensitivities (e.g., LET, RBE)

c. cell survival and recovery (LD₅₀)

d. oxygen effect

Somatic Effects

a. short-term versus long-term effects

b. acute versus chronic effects

c. carcinogenesis

d. organ and tissue response (e.g., eye, thyroid, breast, bone marrow, skin, gonadal)

Acute Radiation Syndromes

a. hemopoietic

b. gastrointestinal (GI)

c. central nervous system (CNS)

Embryonic And Fetal Risks

Genetic Impact

a. genetically significant dose

b. goals of gonadal shielding