ARRT Radiation Physics and Radiobiology 5

Question 1

Auger electrons are emitted following which process?

Accepted Answer

Electron capture or internal conversion

Answer

Auger electrons are emitted when an inner-shell vacancy (created by electron capture or internal conversion) is filled and the released energy ejects an outer-shell electron instead of producing a characteristic x-ray.

Question 2

Which statement correctly describes the four R's of radiobiology?

Accepted Answer

Repair, Redistribution, Repopulation, Reoxygenation

Answer

The four R's of radiobiology are Repair of sublethal damage, Redistribution of cells through the cell cycle, Repopulation of surviving cells, and Reoxygenation of hypoxic tumor cells.

Question 3

What is the primary purpose of added filtration in a diagnostic x-ray tube?

Accepted Answer

To remove low-energy photons that would only contribute dose without imaging benefit

Answer

Added filtration absorbs low-energy photons that would be absorbed by the patient without contributing to the image, thereby reducing patient dose while maintaining image quality.

Question 4

Radioactive equilibrium in which the daughter's activity equals the parent's activity is called:

Accepted Answer

Secular equilibrium

Answer

Secular equilibrium occurs when the parent's half-life is much longer than the daughter's, resulting in equal activities after many daughter half-lives have elapsed.

Question 5

The LD50/60 for humans exposed to whole-body radiation refers to:

Accepted Answer

The dose lethal to 50% of an exposed population within 60 days

Answer

LD50/60 is the whole-body radiation dose that is lethal to 50% of an exposed population within 60 days, typically estimated at 3–4 Gy for humans without medical support.

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT - American Registry of Radiologic Technologists Practice Test

ARRT Radiation Physics and Radiobiology 5