Q: A medical X-ray typically exposes a patient to about 20 mrem. How many sieverts ($$Sv) is $$this?

$$20 \text{ mrem} \times \frac{1 \text{ Sv}}{100,000 \text{ mrem}} = 2 \times 10$$^{-4}$$ \text{ Sv}$$

Q: If a tissue absorbs 2 rad of alpha particle radiation, what is the dose in rem for most tissues?

$$2 \text{ rad} \times 10 = 20 \text{ rem}$$

Q: A person absorbs 1 rad of radiation. If their body mass is 70,000 g, how much energy (in joules) is absorbed?

$$1 \text{ rad} \times 70,000 \text{ g} \times 0.01 \text{ J/g} = 700 \text{ J}$$

Q: A patient receives 0.2 Gy of radiation from a gamma ray source. What is the equivalent dose in rem?

$$0.2 \text{ Gy} \times 100 \text{ rad/Gy} \times 1 \text{ (factor for gamma rays)} = 20 \text{ rem}$$

Q: Which radioactive isotope is used in PET scans and what is its decay process?

$$^{18}\text{F}$$; positron emission

Question 1

Which of the following statements correctly describes the difference between the curie (Ci) and the becquerel (Bq) as units of radioactivity?

Accepted Answer

The curie (Ci) is based on the number of disintegrations per second in 1 gram of radium, while the becquerel (Bq) is the SI unit defined as 1 disintegration per second.

Question 2

A patient receives a dose of 0.5 Gy of radiation. How many rad is this equivalent to?

Accepted Answer

$$0.5 	imes 100 = 50$$ rad

Question 3

Which of the following best explains why irradiation of food does NOT make the food itself radioactive?

Accepted Answer

The radiation only kills microorganisms and does not transfer radioactive atoms to the food.

Question 4

A medical X-ray typically exposes a patient to about 20 mrem. How many sieverts ($$Sv) is $$this?

Accepted Answer

$$20 	ext{ mrem} 	imes \frac{1 	ext{ Sv}}{100,000 	ext{ mrem}} = 2 	imes 10$$^{-4}$$ 	ext{ Sv}$$

Question 5

If a tissue absorbs 2 rad of alpha particle radiation, what is the dose in rem for most tissues?

Accepted Answer

$$2 	ext{ rad} 	imes 10 = 20 	ext{ rem}$$

Question 6

Which radioactive isotope is commonly used for imaging the thyroid gland and for treating thyroid tumors?

Accepted Answer

$$^{131}	ext{I}$$

Question 7

During a PET scan, which process produces the gamma rays detected by the scanner?

Accepted Answer

Gamma rays are produced when positrons annihilate with electrons in the body.

Question 8

A person absorbs 1 rad of radiation. If their body mass is 70,000 g, how much energy (in joules) is absorbed?

Accepted Answer

$$1 	ext{ rad} 	imes 70,000 	ext{ g} 	imes 0.01 	ext{ J/g} = 700 	ext{ J}$$

Question 9

Which factor is used to convert rad to rem for beta particle exposure?

Accepted Answer

1

Question 10

Which of the following is TRUE regarding the average annual exposure to radiation for a typical person?

Accepted Answer

Over 80% of exposure is from natural sources such as radon gas and cosmic rays.

Question 11

A patient receives 0.2 Gy of radiation from a gamma ray source. What is the equivalent dose in rem?

Accepted Answer

$$0.2 	ext{ Gy} 	imes 100 	ext{ rad/Gy} 	imes 1 	ext{ (factor for gamma rays)} = 20 	ext{ rem}$$

Question 12

Which of the following effects is most likely to occur after short-term exposure to 300 mrem of radiation?

Accepted Answer

Visible 'burns' in skin, nausea, vomiting, fatigue

Question 13

Which radioactive isotope is used in PET scans and what is its decay process?

Accepted Answer

$$^{18}	ext{F}$$; positron emission

Question 14

If a tissue absorbs 1 rad of alpha radiation to the eye, what is the dose in rem?

Accepted Answer

$$1 	ext{ rad} 	imes 30 = 30 	ext{ rem}$$

Question 15

Which of the following isotopes is used for gamma ray irradiation of tumors?

Accepted Answer

$$^{60}	ext{Co}$$

Question 16

A person is exposed to 500 mrem of radiation. According to the effects table, what is the most likely health outcome?

Accepted Answer

Loss of white blood cells; hair loss

Question 17

Which of the following best describes the process of positron emission from $$^{18}	ext{F} in $$PET scans?

Accepted Answer

$$^{18}_9	ext{F} \$$rightarrow ^{18}$$_8	ext{O} $$+ ^{0}$$_{+1}\beta$$

Question 18

Which of the following is a correct conversion between rem and sievert ($$Sv$$)?

Accepted Answer

$$1 	ext{ Sv} = 100 	ext{ rem}$$

Question 19

Which isotope is used for anemia diagnosis in medical applications?

Accepted Answer

$$^{59}	ext{Fe}$$

Radiation Units, Health, and Applications of Radioactivity

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