Question 1

The annual effective dose limit for a 24-year-old radiographer to ionizing radiation is ____ rem.

Accepted Answer

The annual effective dose limit for a radiographer (or any radiation worker) is 50 mSv (millisieverts) or 5 rem (roentgen equivalent man), which are equivalent values but expressed in different units.

Question 2

When no threshold dose for radiation exists, the effect is known as

Accepted Answer

Stochastic effects of radiation are those that occur randomly without a threshold dose, such as cancer and genetic mutations. Nonstochastic effects have a threshold dose and include tissue effects such as the deterministic (also called non-stochastic) effects of radiation like skin burns or cataracts. Therefore, when no threshold dose exists, the effect is stochastic.

Question 3

Deterministic effects of ionizing radiation include all of the following EXCEPT

Accepted Answer

Deterministic effects of ionizing radiation, such as sterility, cataracts, and skin erythema, have a threshold dose below which they do not occur. Cancer, however, is considered a stochastic effect, meaning it can occur without a threshold level of radiation and its probability increases with dose without a clear dose-response relationship at lower doses.

Question 4

If the distance between the individual and the source of radiation is doubled, the exposure to the individual will be reduced by a factor of

Accepted Answer

The exposure to radiation decreases with the square of the distance from the source, according to the inverse square law. Therefore, if the distance is doubled, the exposure is reduced by a factor of $2^2 = 4$.

Question 5

By design, primary barriers are able to intercept and absorb

Accepted Answer

Primary barriers are designed to intercept and absorb primary radiation, secondary radiation, and the useful beam, thus providing protection from all sources of radiation in a radiology room.

Question 6

Dose limits have been established for

Accepted Answer

Dose limits have been established for the whole body, certain tissues, and certain organs by various regulatory bodies such as the International Commission on Radiological Protection (ICRP). Therefore, all of the above choices are correct.

Question 7

Protective devices include all of the following EXCEPT

Accepted Answer

Compensating bolus material is not a protective device, but a material that is used to help ensure uniform radiation dose throughout the patient's body. Lead aprons, gloves, and glasses are all devices used to protect healthcare workers from radiation exposure.

Question 8

For fluoroscopic procedures with a kVp of 100 or more, the protective apron must possess a minimum of ____ lead equivalent.

Accepted Answer

For fluoroscopic procedures with a kVp of 100 or more, the protective apron must possess a minimum of 0.5 mm lead equivalent to ensure adequate protection against ionizing radiation.

Question 9

Which of the following technical factors are chosen to minimize patient dose?

Accepted Answer

High kVp/low mAs technique is the best choice to minimize patient dose as it reduces the amount of radiation absorbed by the patient while still maintaining good image quality. This is because higher kVp allows for better penetration of the radiation, requiring less radiation to reach the image receptor. Lower mAs ensures that exposure time is short and the total amount of radiation delivered to the patient is reduced.

Question 10

Secondary barriers are intended to intercept

Accepted Answer

Secondary barriers are designed to block both scatter radiation from the patient and leakage radiation from the x-ray tube. They are not designed to intercept the primary beam that exits the patient, as primary barriers are meant to do this. Therefore, the best choice is D (both a and b).

Question 11

Protective aprons and gloves are usually made of lead-impregnated vinyl within the range of ____ lead equivalency.

Accepted Answer

Protective aprons and gloves are typically made of lead-impregnated vinyl within the range of 0.25-1.0 mm lead equivalency. This thickness provides adequate protection against the radiation exposure that may occur during medical procedures. Option B (0.25-1.0 cm) and D (0.1-0.25 cm) are not accurate as they indicate a much thicker lead equivalency which is unnecessary and could make the protective gear too heavy and uncomfortable to wear. Option C (0.1-0.25 mm) is too thin and may not provide adequate protection for the user.

Question 12

Radiation exposure limits applicable to the protection of radiation workers are known as ____ limits.

Accepted Answer

Radiation exposure limits are expressed as dose limits, meaning the total amount of radiation a person may receive over a given period of time. These limits are set to ensure that radiation workers do not receive a dose that exceeds the level that could result in health effects such as radiation sickness or increased risk of cancer. Therefore, the correct choice is A) dose.

Question 13

To reduce an individual's exposure to ionizing radiation, all of the following would be acceptable EXCEPT

Accepted Answer

Wearing a radiation dosimeter at the collar would not reduce an individual's exposure to ionizing radiation. The purpose of a radiation dosimeter is to measure the amount of radiation an individual is exposed to, but it does not provide any physical protection from the radiation source. Therefore, this option would not be effective in reducing an individual's exposure. The other options (A, B, D) are all effective ways to reduce an individual's exposure to ionizing radiation.

Question 14

The cumulative effective dose limit for an occupational exposure to ionizing radiation is ____ mrem.

Accepted Answer

The answer of The cumulative effective dose limit for an...

Question 15

Proper x-ray beam collimation does all of the following EXCEPT

Accepted Answer

Proper x-ray beam collimation does reduce patient dose, improve radiographic image quality, and reduce scatter radiation. However, it does not eliminate the need for gonadal shielding because gonads are always located outside the primary beam and can still receive scattered radiation.

Question 16

The NCRP recommends a minimum total filtration of ____ for x-ray equipment operating above 70 kVp.

Accepted Answer

The NCRP (National Council on Radiation Protection and Measurements) recommends a minimum total filtration of 2.5 mm Al/Eq (Aluminum equivalent) for x-ray equipment operating above 70 kVp to ensure adequate protection by filtering out low-energy x-ray photons that contribute to dose without improving image quality.

Question 17

The annual effective dose limit for an individual in the general public for infrequent exposure to ionizing radiation is ____ rem.

Accepted Answer

The answer of The annual effective dose limit for an...

Question 18

Which one of the following agencies is a regulatory agency responsible for protecting both the public and occupationally exposed individuals from the effects of ionizing radiation?

Accepted Answer

The Nuclear Regulatory Commission (NRC) is a regulatory agency responsible for protecting both the public and occupationally exposed individuals from the effects of ionizing radiation. The National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP) are advisory bodies that provide guidance on radiation protection but do not have regulatory authority. The Internal Revenue Service (IRS) is a government agency responsible for tax collection and enforcement.

Question 19

For an individual to reduce exposure by a factor of 25, the distance between the individual and source of ionizing radiation should

Accepted Answer

The exposure to ionizing radiation decreases inversely proportional to the square of the distance from the source. So, if an individual wants to reduce their exposure by a factor of 25, the distance between the individual and the source of ionizing radiation should increase by √25 = 5 times. Therefore, option A) is the correct answer.

Question 20

What is the cumulative dose limit for a 36-year-old radiation worker?

Accepted Answer

The cumulative dose limit for a 36-year-old radiation worker is 360 mSv (millisieverts) according to the radiation protection regulations. This limit is set to minimize the risks of harmful effects from radiation exposure. It is a lifetime limit and includes both internal and external exposure. Option B is incorrect as it is too low, while options C and D are incorrect as they use different units of measurement (mrem instead of mSv).

Quiz 9: Radiation Protection Procedures for Patients and Personnel