Mosby's Safety Review Questions

Natural background radiation represents what percentage of humans' radiation exposure?

50%

the greatest source of natural background radiation exposure is

radon gas

cosmic radiation

is a part of natural background exposure

radon gas presents ...

a danger when undetected

xrays and gamma rays used in diagnostic imaging are

part of an artificial background radiation dose

A feature of fluoroscopic x-ray machines that automatically adjusts kVp and mA so as to maintain image brightness for necessary image quality is called:

automatic brightness control (ABC)

what term best describes the approximate skin dose where the xray beam is entering the patient?

air kerma

sievert is calculated by multiplying gray by

Wr (radiation weighting factor)

the total of air karma over the exposed area of the patient is called

dose area product (DAP)

which of the following is also known as coherent scattering

classical scatter

which of the following photon-tissue interactions do NOT occur in diagnostic radiography

pair production

which of the following is responsible for creating the conditions for contrast on the image

photoelectric interaction

which of the following produces scatter radiation that exits the patient and may fog the image

Compton interaction

which of the following produces scatter as a result of vibration of orbital electrons

coherent scatter

which of the following results in total absorption of an incident x-ray photon

photoelectric interaction

which of the following is the only photon-tissue interaction that does NOT result in ionization

coherent scatter

which of the following involves interactions between an incident photon and an atomic nucleus

pair production

which of the following photon-tissue interactions primarily involve k-shell electrons

photoelectric interaction

which of the following primarily involves loosely bound outer-shell electrons

Compton interaction

which of the following results in the production of a photoelectron that is ejected from the atom

photoelectric interaction

which of the following photon-tissue interactions necessitates the use of a gride

Compton interaction

which of the following interactions may result in occupational exposure for a radiographer

Compton interaction

what unit of measurement is bused for absorbed dose in tissue

GYt

what unit of measurement is used for effective dose limits

sievert

which of the following units would be used to describe the radiation present in a fluoroscopic room

Gy

the amount of energy deposited by radiation per unit length of tissue being traversed is

LET, which determines the use of a Wr when the equivalent dose is being calculated

what agency publishes radiation protection standards based on scientific research

national council on radiation protection and measurement (NCRP)

The agency that enforces radiation protection standards relating to radioactive material at the federal level is the:

Nuclear Regulatory Commission (NRC)

effective dose limit is defined as the 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

ALARA is an acronym for

As Low As Reasonably Achievable

What are graphs called that show the relationship between dose of radiation received and incidence of effects?

Dose-Response curves

which of the following is the basis for all radiation protection standards?

linear-nonthreshold effect

which of the following means there is no safe level of radiation and the response to the radiation is not directly proportional to the dose received?

nonlinear-nonthreshold effect

which of the following means there is no safe level of radiation and the response to the radiation is directly proportional to the dose received?

linbear-nonthreshold effect

which of the following means there is a safe level of radiation for certain effects and those effects are directly proportional to the dose received when the safe level is exceeded?

linear-threshold effect

which of the following means there is a safe level of radiation for certain effects and those effects are NOT directly proportional to the dose received when the safe level is exceeded

nonlinear-threshold effect

effects of radiation where the probability of occurrence, not severity of occurrence, is proportional to the dose are called

stochastic effects

effects of radiation that become more severe as dose increases are called

deterministic effects

according to the NCRP Report #116, what is the embryo or fetus equivalent dose limit per month

0.5 mSv

According to NCRP Report #116, the occupational cumulative effective dose limit = age in years X what dose

10 mSv

according to NCRP Report #116, the annual occupational effective dose limit is

50 mSv

according to NCRP Report #116, what is the annual effective dose limit for radiography students older than age 18

50 mSv

according to NCRP Report #116, what is the annual effective dose limit for the general public, assuming infrequent exposure

5 mSv

according to NCRP Report #116, what is the embryo or fetus equivalent dose limit for gestation

5 mSv

according to NCRP Report #116, what is the annual effective dose limit for the general public, assuming frequent exposure

1.0 mSv

according to the NCRP Report #116, what is the annual effective occupational dose limit for the lens of the eye

150 mSv

the Wr used in calculating equivalent dose takes into account which of the following

LET

LET and biological damage are ___________ proportional

directly

The ability of different types of radiation to produce the same biological response in an organism is called:

RBE

The phases of the cellular life cycle, in order, are:

Interphase (G1,S,G2), Prophase, Metaphase, Anaphase, Telophase

the process of cell division for germ cells is

meiosis

which of the following occurs when radiation transfers its energy to DNA

direct effect

which of the following states that each cell has a master molecule that directs all cellular activities and that, if inactivated, results in cellular death

target theory

which of the following describes the amount of radiation required to increase the number of mutations in a population by a factor of 2

doubling dose

what occurs when radiation transfers its energy to the cellular cytoplasm

indirect effect

which of the following induces radiolysis

indirect effect

what is the name for changes in genetic code passed on to the next generation

mutations

which of the following is responsible of producing free radicals

indirect effect

what occurs when the master molecule is struck by radiation

direct effect

which of the following poisons the cell with H2O2

indirect effect

most of the damage to a cell occurs as a result of

indirect effect

the law describing the most effective protection from ionizing radiation is the

inverse square law

the law that states that cells are most sensitive to radiation when they are nonspecialized and rapidly dividing is the

law of Bergonié and tribondeau

cells are more radiosensitive when

fully oxygenated

Blood count can be depressed with a whole-body dose of

0.25 Sv

the most radiosensitive cells in the body are the

lymphocytes

cells that are least sensitive to radiation exposure include

nerve and muscle cells

compared with ova in younger and older women, ova in women of reproductive age are

less radiosensitive

acute radiation syndrome (ARS) occurs

at doses beyond doses used during diagnostic radiography

somatic effects manifest in

the person who has been irradiated

which of the following is considered a late tissue effect

cataractogenesis

which of the following is used to limit the area of the patient being irradiated

collimator

which of the following is considered an early deterministic effect

erthymea

which of the following sets of exposure factors would result in the lowest dose to the patient?

low mAs, high kVp

which of the following is used as part of an effort to practice the ALARA concept

collimation

Cardinal rules of radiation protection

Time, distance, shielding

which of the following is used to survey an area for radiation detection and measurement

handheld ionization chamber

which of the following is accurate was low as 100 uGy

digital ionization dosimeter

which of the following provides for instant readout of an individual's exposure

digital ionization chamber

which of the following may be used to measure in-air exposures in a. fluoroscopic room

handheld ionization chamber

what protection device sounds an alarm to indicate the presence of radioactivity

geiger-mueller detector

which of the following is accurate as low as 50 uGy and must be sent via mail for readout

TLD

which of the following is a digital monitor that may be used to measure dose in an area

handheld ionization chamber

which of the following may be used for 3 months at a time

TLD

which of the following can be connected to a computer for dose readout

digital ionization chamber

which of the following is used to represent the mean marrow dose

MMD

which of the following represents the practice of keeping radiation dose low

ALARA

the timer used in fluoroscopy is used to alert the fluoroscopes after how many minutes of fluoroscopy scanning have elapsed

5

the most effective protection against radiation exposure

distance

If the dose of scatter radiation in fluoroscopy to the radiographer is 10 mGya, at a distance of 2 feet from the table, where should the radiographer stand to reduce the dose to 2.5 mGya?

4 feet from the table

lead aprons used in fluoroscopy must be at least

0.25 mm lead equivalent

which of the following is true concerning holding patients for radiographic exams

should be done only when absolutely necessary and then the holding should be done by a non-pregnant member of the patients family

the factors that must be considered in the design of structural shielding for a radiology room or department include

use, occupancy, workload

the lowest intensity of scatter radiation from the patient is located

at a 90-degree angle from the patient

minimal (M) readings on dosimeter reports mean

a dose below the sensitivity of the dosimeter has been received

A readout on the fluoroscopic monitor that indicates air kerma striking the surface of the patient is:

DAP meter

which of the following is the most sensitive personnel monitoring device

OSL dosimeter

Minimum source-to-skin distance for mobile radiography must be:

12 inches

positive beam limitation is also known as

automatic collimation

Added tube filtration should be adjusted by the radiographer:

never