Rad Safety (Boards)

natural background radiation representes what percentage of humans’ annual radiation exposure

50%

the greatest source of natural background radiation exposure is

radon gas

is a part of natural background exposure

cosmic radiation

presents a danger when undetected

radon gas

x-rays and gamma rays used in diagnostic imaging are

part of an artifical background radiation dose

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

automatic brightness control

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

air kerma

sievert is calculated by multiplting gray by

WR

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

dose area product

what type of photon-interaction is also known as coherent scattering

classical scatter

what photon-tissue interactions so not occur in diagnostic radiography

pair production

what is responsible for creating the conditions for contrast on the image

photoelectric interactions

what produces scatter as a result of vibration of orbital electrons

compton interaction

what produces scatter as a result of vibration of orbital electrons

coherent scatter

what results in total absorption of an incidient x-ray photon

photoelectric interactions

what is the only photon-tissue interaction that does not result in ionization

coherent scatter

what involves interactions between an incident photon and an atomic nucleus

pair production

what photon-tissue interaction primarily involves K-shell electrons

photoelectric interactions

what primarily involves loosely bound outer-shell electrons

compton interaction

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

photoelectric interaction

what photon-tissue interactions necessitates the use of a grid

compton interactions

what interactions may result in occupational exposure for a radiographer

compton interactions

what unit of measurement is used for effective dose limits

Gy (t)

what unit of measurement is used for effective dose limits

sievert

what unit would be used to describe the radiation present in the fluoroscopic room

Gy (a)

the amount of energy deposited by radiation per unit length of tissue being transversed 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 measuremtn (NCRP)

the agency that enforces radiation protection standards relating to radioactive materuial at the federal level is the

nuclear regulatory council (NRC)

effective dose limit is defined as the upper boundary dose that

can be absorbed, either in a signle exposure or annually, with a neglible risk of somatic or genetic damage to the individual

ALARA stands for

as low as reasonable achievable

what are graphs called that show the relationship between dose of radiation recieved and incidence of effects

dose-response curve

what is the basis for all radiation protection standards

linear-nonthreshold effect

what 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

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

linear-nonthreshold effect

what means there is a safe level of radiation for certain effects and those effects are directly proportional to the dose recieved when the safe level is exceeded

linear-nonthreshold effect

what means there is a safe level of radiation for certain effects and those effects are not directly proprtional to the dose recieved when the safe level is exceeded

non-linear 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 m ore severe as dose increases are called

deterministic effects

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

0.5 mSvaccording to NCRP report #116,

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

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 NCRP report #116, what is the annual effective occupational dose for the lens of the eye

150 mSv

the W® used in calculating equivalent dose takes into account what

LET

LET and biological damage are

directly proportional

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

RBE

the phases of the life cycle in order are

interphase (G1,S,G2), prophase, metaphase, anaphase and telophase

the process of cell division for germ cells is called

meiosis

what occurs when radiation transfer its energy to DNA

direct effect

what states that each cell has a master molecule that directs all cellular activities and that, if inactivated, results in cellular death

target theory

what 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

what induces radiolysis

indirect effect

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

mutations

what is responsible for producing free radicals

indirect effects

what occurs when the master molecule is struck by radiation

direct effect

what poisons that cells with H2O2

indirect effect

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

indirect effect

the law that describes the most effect 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 bergonie and tribondeau

cells are more radisensitive 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

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 occurs

at doses beyond boses used during diagnostic radiography

somatic effects manifest in

the personal who has been irradiated

which is considered a late tissue effect

cataractogenesis

what is used to limit the area of the patient being irradiated

collimator

what is considered an early deterministic effect

erythema

what is a set of exposures factors would results in the lowest dose to the patient

low mAs, high kVp

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

collimation

the cardinal rules of radiation protection are

time, distance and shielding

what is used to survey an area for radiation detection and measurement

handheld ionization chamber

what is accurate as low as 100 μGy

digital ionization chamber

what provides for instant readout of an individual exposure

digital ionization dosimeter

what may be used to measure in-air exposures in a fluorscopic room

handheld ionization chamber

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

geiger-mueller detector

what is accurate as low as 50 μGy and must be sent via mail for the readout

TLD

what is a digital monitor that may be used to measure dose in an area

handheld ionization device

what may be be used for 3 months at a time

TLD

what can be connected to a computer for dose readout

digital ionization detector

what is used to represent the mean marrow dose

MMD

what represents the practice of keeping radiation dose low

ALARA

the timer used in fluorscopy

is used to alert the fluorscopist after 5 minutes of fluoro scanning have elapsed

the most effective protection against radiation exposure for the radiographer is

distance

is the dose of scatter radiation in fluoroscopy to the radiographer is 10 mGy at a distance of 2 feet from the table, where should the radiographer stand to reduce the dose t0 2.5 mGy

4 feet from the table

lead aprons used in fluorscopy must be at least

0.25 mm lead equivalent

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

use, occupancy, workload

the lowest intensity of scatter radiation from the patient is located

at a 90-degree angle from the patient

minimal readings of dosimeter reports mean

a dose below the sensitivity of the dosimeter has been recieved

a readout on the fluoro monitor that indicates air kerma striking the surface of the patient is

DAP meter

what 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

what is the term used to describe the human sequence of events followinh gih-level radiation exposur and leading to death in a short time

acute radiation syndrome