Q: A radioactive source has an activity of $$2.0 \ \text{Ci}. $$What is its activity in becquerels (Bq)? $$ 1 \ \text{Ci} = 3.70 \times 10^{10} \ \text{disintegrations/s} $$

$$7.4 \times 10$$^{10}$$ \ \text{Bq}$$

Question 1

Which of the following best describes the difference between ionizing and non-ionizing radiation in terms of their effects on biological tissue?

Accepted Answer

Ionizing radiation can remove electrons from atoms and damage DNA, while non-ionizing radiation primarily causes thermal damage.

Question 2

A radioactive source has an activity of $$2.0 \ 	ext{Ci}. $$What is its activity in becquerels (Bq)? $$ 1 \ 	ext{Ci} = 3.70 	imes 10^{10} \ 	ext{disintegrations/s} $$

Accepted Answer

$$7.4 	imes 10$$^{10}$$ \ 	ext{Bq}$$

Question 3

Which SI unit is used to measure the absorbed dose of radiation?

Accepted Answer

Gray (Gy)

Question 4

A patient receives an absorbed dose of $$0.5 \ 	ext{Gy}$$ from fast neutrons (RBE $$\approx 10). $$What is the effective dose in sieverts (Sv)?

Accepted Answer

$$5 \ 	ext{Sv}$$

Question 5

Which of the following best describes the effective dose in radiation protection?

Accepted Answer

A weighted dose that accounts for both the type of radiation and the sensitivity of different organs

Question 6

Which of the following types of radiation typically has the highest Relative Biological Effectiveness (RBE)?

Accepted Answer

Alpha particles

Question 7

A worker receives an annual effective dose of $$4 \ 	ext{mSv}. Is $$this within the recommended occupational exposure limit according to NRC guidelines?

Accepted Answer

Yes, it is below the annual limit for workers.

Question 8

Which of the following procedures or exposures delivers an effective dose closest to the annual background radiation dose experienced by the average person?

Accepted Answer

Airline crew exposure flying New York to Tokyo route

Question 9

What does Relative Biological Effectiveness (RBE) quantify?

Accepted Answer

The biological damage caused by a type of radiation relative to a standard

Question 10

Which SI unit is used to measure radioactive decay (activity)?

Accepted Answer

Becquerel (Bq)

Question 11

A patient receives $$2 \ 	ext{Gy} of X-$$rays (RBE = 1) to the lungs. What is the effective dose in sieverts (Sv)?

Accepted Answer

$$2 \ 	ext{Sv}$$

Question 12

Which of the following is a primary reason for rotating the radiation source during cancer radiation therapy?

Accepted Answer

To minimize the dose to healthy tissue while maximizing the dose to the tumor

Question 13

Which imaging technique uses positron-emitting tracers and detects pairs of gamma rays produced by annihilation events?

Accepted Answer

PET

Question 14

What is the main difference between SPECT and PET scans?

Accepted Answer

PET uses positron-emitting tracers, SPECT uses gamma-emitting tracers

Question 15

In Nuclear Magnetic Resonance (NMR) spectroscopy, what causes a nucleus to absorb radiofrequency radiation?

Accepted Answer

Realignment of nuclear spins in an external magnetic field

Question 16

Which of the following correctly pairs a dosimetry quantity with its corresponding SI unit?

Accepted Answer

All of the above

Question 17

A patient is injected with a radioactive tracer for a PET scan. What is the primary physical process detected by the scanner?

Accepted Answer

Detection of gamma rays emitted in opposite directions following positron annihilation

Question 18

Which of the following is NOT a required condition for Acute Radiation Syndrome (ARS)?

Accepted Answer

The dose must be less than 0.1 Gy

Question 19

Which of the following best explains why aircrew are at increased risk for certain cancers?

Accepted Answer

They are exposed to higher levels of cosmic ionizing radiation at altitude.

Radiation Therapy and Medical Physics: Dosimetry, Biological Effects, and Imaging Techniques

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