RAD260 Safety

Question 1

Heterogeneous Beam

Answer 1

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

Question 2

NCRP Report #102

Answer 2

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

Question 3

NCRP Report #116

Answer 3

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 4

Relative biological effectiveness (RBE)

Answer 4

ability to produce biological damage; varies with the LET.

Question 5

Linear energy transfer (LET)

Answer 5

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

Question 6

Air kerma

Answer 6

unit of exposure.

Question 7

National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation (NAS/NRC-BEIR)

Answer 7

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

Question 8

International Commission on Radiologic Protection (ICRP)

Answer 8

organization that publishes international radiation protection guidelines.

Question 9

National Council on Radiation Protection and Measurements (NCRP)

Answer 9

organization that publishes radiation protection guidelines for the United States.

Question 10

Effective dose limit

Answer 10

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 11

Dose-response curves

Answer 11

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 12

Stochastic (probabilistic) effects

Answer 12

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 13

Law of Bergonié and Tribondeau

Answer 13

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

Question 14

Early somatic effects of radiation

Answer 14

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

Question 15

Late somatic effects of radiation

Answer 15

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

Question 16

Compton interaction

Answer 16

Incoming x-ray photon strikes a loosely bound, outer-shell electron.

Question 17

Coherent scatter

Answer 17

Produced by low-energy x-ray photons.

Question 18

Photon–Tissue Interactions

Answer 18

Attenuation describes changes in the intensity of the x-ray beam as it traverses the patient.

Question 19

Embryo-fetus

Answer 19

total equivalent dose for gestation is 5 mSv.

Question 20

Centrosomes

Answer 20

Participate in cell division.

Question 21

Ribosomes

Answer 21

Synthesize protein.

Question 22

Lysosomes

Answer 22

Contain enzymes for intracellular digestive processes.

Question 23

Mitochondria

Answer 23

Produce energy.

Question 24

Golgi apparatus

Answer 24

Combines proteins with carbohydrates.

Question 25

Endoplasmic reticulum

Answer 25

Acts as a transportation system to move food and molecules within the cell.

Question 26

Nucleus

Answer 26

Contains deoxyribonucleic acid (DNA—the master molecule) and the nucleolus (with ribonucleic acid [RNA]).

Question 27

Prophase

Answer 27

nucleus enlarges.

Question 28

Metaphase

Answer 28

nucleus elongates.

Question 29

Anaphase

Answer 29

two complete sets of chromosomes.

Question 30

Telophase

Answer 30

separates the two sets of genetic material; division complete; 46 chromosomes in each new somatic cell.

Question 31

Direct Effect

Answer 31

Occurs when radiation transfers its energy directly to the DNA (the master molecule) or RNA.

Question 32

Hematopoietic syndrome

Answer 32

Decrease in total number of all blood cells.

Question 33

Doubling dose

Answer 33

Amount of radiation that causes the number of mutations in a population to double (is approximately 1.56 Sv for humans).

Question 34

Beam limitation

Answer 34

protects the patient by limiting the area of the body and the volume of tissue being irradiated.

Question 35

Collimator

Answer 35

Variable aperture device.

Question 36

Cylinder cones

Answer 36

Metal cylinders that attach to the bottom of the collimator.

Question 37

Aperture diaphragm

Answer 37

Flat piece of lead with a circle or square opening in the middle.

Question 38

Filtration

Answer 38

is placed in the x-ray beam to remove long-wavelength (low-energy) x-rays.

Question 39

Inherent filtration

Answer 39

Glass envelope of the x-ray tube.

Question 40

Added filtration

Answer 40

Aluminum sheets placed in the path of the beam near the x-ray tube window.