Final lecture questions

Question 1

Which of the following is/are considered low-LET radiation(s)? X-rays 2. Alpha particles 3. Gamma rays

Answer 1

1 & 3 - xrays and gamma rays

Question 2

Which of the following curves illustrates the radiation sensitivity of a particular type of cell?
cell specialization curve
cell extrapolation curve
dose-response curve
cell survival curve

Answer 2

cell survival curve

Question 3

Which of the following groups of cells is least radiosensitive?
adult nerve cells
nerve cells in an embryo-fetus
lymphocytes
immature spermatogonia

Answer 3

adult nerve cells

Question 4

When LET increases, the chance of producing a significant biologic response in the radiosensitive DNA macromolecule____

Answer 4

grows

Question 5

If a person receives radiation exposure sufficient to cause the gastrointestinal syndrome, fatality occurs primarily because of

Answer 5

catastrophic damage to the epithelial cells that line the gastrointestinal tract, resulting in the death of the exposed person within 3 to 5 days from a combination of infection, fluid loss, and elect

Question 6

The term LD 50/30 signifies the whole-body dose of radiation that can be lethal to

Answer 6

50% of the exposed population in 30 days

Question 7

Atrophy refers to

Answer 7

shrinkage of organs and tissues after a high radiation dose is received

Question 8

Which of the following are classified as early tissue reactions of ionizing radiation

Answer 8

Nausea, epilation, and intestinal disorders

Question 9

Radiation-induced cataracts in humans follow a ____ dose-response relationship

Answer 9

threshold, nonlinear

Question 10

What of the following late effects caused by exposure to ionizing radiation is considered to be most important?
cataract formation
embryologic or birth defets
cancer
none; all are considered to be of equal importance

Answer 10

cancer

Question 11

in general, laboratory experiments with mice prove that cataracts may be induced with doses of ionizing radiation as low as

Answer 11

0.1 Gyt

Question 12

Existing data on radiation-induced genetic effects in humans

Answer 12

are both contradictory and inconclusive

Question 13

Which of the following terms involves a random effect of ionizing radiation?
early tissue reactions
change in white blood cell count
reddening of the skin
stochastic event

Answer 13

stochastic event

Question 14

Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 46 years old

Answer 14

460 mSv (ch. 10 table)

Question 15

The effective dose (EfD) limiting system supersedes

Answer 15

the maximum permissible dose (MPD) system

Question 16

The ALARA concept adopts an extremely conservative model with respect to the relationship between

Answer 16

ionizing radiation and potential risk

Question 17

Which of the following is not an x-ray beam limitation device?

Answer 17

filter

Question 18

the protective tube housing services as a shield against ______ entering the x-ray tube, thereby preventing electric shock while also facilitating cooling of the x-ray tube

Answer 18

the high voltage

Question 19

If the luminance of the collimator light source is adequate, the localizing light beam will satisfactorily outline the margins of the radiographic beam on the area of clinical interest on

Answer 19

all patients

Question 20

When using digital fluoroscopy systems, making use of the last image hold feature can

Answer 20

be an effective dose reduction technique

Question 21

Which of the following x-ray procedures increases the radiographer’s risk of exposure to ionizing radiation compared to radiography?

1. Mobile C-arm fluoroscopy
2. interventional procedures that use high level control fluoro
3. mobile rad

Answer 21

1, 2, & 3

Question 22

Whenever scattered radiation decreases, the radiographer’s exposure

Answer 22

decreases

Question 23

which of the following adjustments in technical exposure factors decreases the production of scattered radiation during routine radiographic procedures?

Answer 23

increases kVp and decreases mAs in compensation

Question 24

A protective curtain, or sliding panel, with a minimum of 0.25-mm lead equivalent, should normally be positioned between the fluoroscopist and the patient to intercept which of the following types of radiation?

Answer 24

scattered radiation above the tabletop