Rad 260: Safety

Question 1

What are dose-response curves?

Answer 1

Graphs that illustrate the relationship between radiation dose and the response of the organism to exposure; may be linear or nonlinear, threshold or nonthreshold.

Question 2

What are early somatic effects of radiation?

Answer 2

Hematopoietic syndrome; gastrointestinal (GI) syndrome; central nervous system syndrome.

Question 3

What are genetic effects?

Answer 3

Effects of radiation on the genetic code of a cell; affects the next generation.

Question 4

What are late somatic effects of radiation?

Answer 4

Carcinogenesis; cataractogenesis; embryologic effects; thyroid dysfunction; life span shortening.

Question 5

What are somatic effects?

Answer 5

Effects of radiation on the body being irradiated.

Question 6

What are stochastic effects?

Answer 6

Randomly occurring effects of radiation; the probability of such effects is proportional to the dose (increased dose equals increased probability, not severity, of effects).

Question 7

What are the cardinal principles of radiation protection?

Answer 7

Distance, time, shielding.

Question 8

What are tissue reactions?

Answer 8

Effects of radiation that become more severe at high levels of radiation exposure and do not occur below a certain threshold dose.

Question 9

What does ALARA stand for?

Answer 9

As low as reasonably achievable; concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at minimal levels.

Question 10

What does NCRP Report #102 recommend?

Answer 10

Makes recommendations on equipment design and protection regarding lead shielding and fluoroscopic and mobile exposure rates.

Question 11

What does NCRP Report #116 define?

Answer 11

Defines annual exposure limits; makes recommendations pertaining to risk–benefit analysis of radiation exposure; states that somatic and genetic effects should be kept to a minimum when radiation is used for diagnostic imaging.

Question 12

What does the NRC do?

Answer 12

Enforces radiation protection standards at the federal level related to the use of radioactive material.

Question 13

What is a Becquerel?

Answer 13

Unit of activity.

Question 14

What is a direct effect?

Answer 14

Effect that occurs when radiation directly strikes DNA in the cellular nucleus.

Question 15

What is a Gray?

Answer 15

Unit of absorbed dose, measured in joules per kilogram (J/kg); 1 Gy = 1 J/kg.

Question 16

What is a heterogeneous beam?

Answer 16

X-ray beam that contains photons of many different energies.

Question 17

What is a mutation?

Answer 17

Erroneous information passed to subsequent generations via cell division.

Question 18

What is a Sievert?

Answer 18

Unit of effective dose and equivalent dose.

Question 19

What is air kerma?

Answer 19

Unit of exposure.

Question 20

What is an indirect effect?

Answer 20

Effect that occurs when radiation strikes the water molecules in the cytoplasm of the cell.

Question 21

What is artificially produced radiation?

Answer 21

Also called man-made radiation (e.g., medical x-rays).

Question 22

What is attenuation?

Answer 22

Absorption and scatter (loss of intensity) of the x-ray beam as it passes through the patient.

Question 23

What is equivalent dose?

Answer 23

Equal to the effective dose multiplied by the radiation weighting factor.

Question 24

What is exit radiation?

Answer 24

X-rays that emerge from the patient and strike the image receptor.

Also known as remnant radiation or image-producing radiation.

Question 25

What is Graya?

Answer 25

Unit of radiation absorbed in air.

Question 26

What is Grayt?

Answer 26

Unit of radiation absorbed in tissue.

Question 27

What is ionizing radiation?

Answer 27

Radiation that possesses the ability to remove electrons from atoms by a process called ionization.

Question 28

What is linear energy transfer (LET)?

Answer 28

Amount of energy deposited by radiation per unit length of tissue.

Question 29

What is natural background radiation?

Answer 29

Radiation contained in the unpolluted environment.

Question 30

What is primary radiation?

Answer 30

Radiation exiting the x-ray tube.

Question 31

What is radiolysis of water?

Answer 31

Effect that occurs as radiation energy is deposited in the water of the cell; the result of radiolysis is an ion pair in the cell: a positively charged water molecule (HOH+) and a free electron.

Question 32

What is the best protection against radiation exposure?

Answer 32

Distance.

Question 33

What is the Compton effect?

Answer 33

Scatter of x-ray photons from the atoms of the body.

Question 34

What is the cumulative effective dose?

Answer 34

Lifetime occupational exposure must not exceed the radiographer’s age multiplied by 10 mSv.

Question 35

What is the effective dose limit?

Answer 35

Upper boundary dose that can be absorbed, either in a single exposure or annually, with a negligible risk of somatic or genetic damage to the individual; effective dose implies whole-body radiation exposure.

Question 36

What is the ICRP?

Answer 36

Organization that publishes international radiation protection guidelines.

Question 37

What is the Law of Bergonié and Tribondeau?

Answer 37

Cells are most sensitive to radiation when they are immature, undifferentiated, and rapidly dividing.

Question 38

What is the NAS/NRC-BEIR?

Answer 38

Organization that studies biological effects of ionizing radiation and publishes resulting data.

Question 39

What is the NCRP?

Answer 39

Organization that publishes radiation protection guidelines for the United States.

Question 40

What is the photoelectric effect?

Answer 40

Absorption of x-ray photons in the atoms of the body.