Safety - book

What is defined as radiation that possesses the ability to remove electrons from atoms by a process called ionization

ionizing radiation

___ effects are effects of radiation on the body being irradiated

Somatic

___ effects are effects of radiation on the genetic code of a cell that affects the next generation

Genetic

This is known as the radiation contained in the unpolluted environment

natural background radiation

____ ____ radiation is also called man-made radiation

artificially produced

Radiation exiting the x-ray tube is known as ___ radiation

primary

exit radiation can also be called ___ or ____

remnant or image-producing

X-rays that emerge from the patient and strike the image receptor are known as ___ radiation

exit (remnant or image-producing)

Define attenuation

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

An x-ray beam that contains photons of many different energies is known as a ____ beam

heterogeneous

____ effect is the absorption of x-ray photons in the atoms of the body

photoelectric

____ is the scatter of x-ray photons from the atoms of the body

compton

What is known as the unit of exposure

Air kerma

What is gray measured in?

joules per kilogram (1 Gy = 1J/kg)

What is known as the unit of absorbed dose?

Gray

Grayₐ is a unit of radiation absorbed in the ___

air

Grayₜ is a unit of radiation absorbed in ___

tissue

Effective dose and equivalent dose use the same unit, what is the unit they are measured in?

Sievert

___ is the unit of activity

Becquerel

What is the name of the organization that studies biological effects of ionizing radiation and publishes resulting data

NAS/NRC-BEIR

What does NAS/NRC-BEIR stand for?

National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation

What is the name of the organization that publishes international radiation protection guidelines?

ICRP

What does ICRP stand for?

International Commission on Radiologic Protection

What is the name of the organization that publishes radiation protection guidelines for the United States?

NCRP

What does NCRP stand for?

National Council on Radiation Protection and Measurements

What is the name of the organization that enforces radiation protection standards at the federal level related to use of radioactive material?

NRC

What does NRC stand for?

Nuclear Regulatory Commission

NCRP Report #___ makes recommendations on equipment design and protection regarding and shielding and fluoroscopic and mobile exposure rates

102

NCRP Report #___ 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

116

This is known 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; effective dose implies whole-body radiation exposure

effective dose limit

This is known as the lifetime occupational exposure that must not exceed the radiographers age multiplies by 10 mSv

cumulative effective dose

____ dose is equal to the effective dose multiplied by the radiation weighting factor

equivalent

___ is the concept of radiologic practice that encourages radiation used to adopt measures that keep the dose to the patient and themselves at minimal levels

ALARA

What does ALARA stand for?

As low as reasonably achievable

______ curves are graphs that illustrate the relationship between radiation dose and the response of the organism to exposure

dose-response curve

What type of effect from radiation is probablistic?

stochastic

___ effects are randomly occurring effects of radiation; the probability of such effects is proportional to the dose

stochastic

Tissue reactions are also referred to as ___

deterministic

These are known as effects of radiation that become more severe at high levels of radiation exposure and do not occur below a certain dose

tissue reactions (deterministic)

What does LET stand for?

Linear Energy Transfer

What is defined as the amount of energy deposited by radiation per unit length of tissue?

LET

What is defined as the ability to produce biological damage and varies with LET

RBE

What does RBE stand for?

Relative Biological Effectiveness

___ effect occurs when radiation directly strikes DNA in the cellular nucleus

Direct

___ effect occurs when radiation strikes the water molecules in the cytoplasm of the cell

Indirect

____ of water occurs as radiation energy is deposited in the water of the cell; results in a positively charged water molecule and a free electron

radiolysis

What is defined as erroneous information passed to subsequent generations via cell division

mutations

What does the Law of Bergonie and Tribondeau state?

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

HE syndrome, GI syndrome, and CVS syndrome are all types of early or late somatic effects?

early somatic effects

Carcinogenesis, Cataracts, Embryologic effects, thyroid dysfunction, and lifespan shortening are all types of early or late somatic effects?

late somatic effects

What are the cardinal principles of radiation protection?

time, distance, and shielding

What is the best protection against radiation exposure?

distance

An OSL badge, TLD, and digital ionization dosimeter are all ___ ___ ___

personnel monitoring devices

What does OSL stand for?

optically stimulated luminescence

What does TLD stand for?

thermoluminescent dosimeter

_____ is the average dose of radiation to the bone marrow

mean marrow dose

What are the 3 things that KERMA stands for?

Kinetic Energy Released in MAter

Kinetic Energy Released in MAterial

Kinetic Energy Released per unit MAss

What are all the units of radiation meaurement?

• exposure

• absorbed dose

• effective dose

• equivalent dose

• effective dose

• radioactivity

Air kerma is measured in what unit?

Gray (Gy)

1 Gy = __ J/kg

1

Coulombs/kilogram is sometimes used to measure ____

exposure

____ dose is the amount of energy absorbed per unit mass of tissue

Absorbed

What is the unit of absorbed dose?

Gray (Gy)

What does the radiation weighting factor take into account?

the type of radiation being used

T/F: Radiation weighting factor considers LET

True

The product of absorbed dose time the radiation weighting factor is ____

equivalent dose (measured in Sv)

T/F: high LET causes more biological damage

True

T/F: alpha particles and neutrons have low-LET

False, they have high LET

X-rays and gamma rays have low or high LET?

low LET

Which causes less biological damage, low or high LET?

low

Gy x Wᵣ = ___

Sv

What is the Wᵣ of x-rays and gamma rays?

1 Gy

Gy x Wᵣ x Wₜ = ___

Sv

____ dose estimates the risk present when various tissues are irradiated

effective

Wₜ considers the relative ____ of the irradiated organ or body part

radiosensitivity

____ dose is the product of absorbed dose times the radiation weighting factor times the tissue weighting factor

effective

This is the unit used to measure the quantity of radioactive material (the number of atoms deaying per second)

Radioactivity

What is the unit used to represent radioactivity?

Becquerel (Bq)

Where is the unit of radioactivity primarily used?

nuclear medicine

Who is primarily responsible for protecting the patient from unnecessary exposure?

Radiographer (limit repeat exposures and use small amounts of radiation)

Who has shared responsibility for radiation safety of the patient

radiologist and physician (best accomplished through consultations and should not order unecessary exams)

T/F: Safe use of radiation in diagnostic imaging to determine the extent of disease or injury should outweigh the risk involved from the exposure

True

T/F: X-ray exposure involves a transfer of energy through photon-tissue interactions

True

Ionization can result in all of the following except:

• unstable atoms

• free electrons

• increased cellular motion

• production of low energy x-rays

• formation of new molecules harmful to the cell

• abnormal function or loss of function

increased cellular motion

What is the difference between somatic and genetic damage?

Somatic is damage to the exposed individual

Genetic damage to the genetic code of germ cells contained in DNA that can be passed to the next generation

What is the greatest source of natural background exposure to humans?

radon

T/F: medical imaging is an example of human-produced radiation

True

Which imaging modality accounts for the largest increase in total dose and medical dose to the population?

CT

T/F: total radiation dose to the U.S. population has doubled since the 1980’s

True

The total annual background radiation dose is ___ mSv

6.25

T/F: terrestrial, internal, and cosmic radiation are all forms of natural basckground radiation

True

Natural background radiation contributes to ___ mSv annually

3.0

CT accounts for what percent of total radiation exposure?

24%

Medical background radiation contributes ___ mSv

3.2

What are the 2 most common tissue interactions in radiology?

photoelectric and compton

Compton interaction can also be called ___ or ___

compton scattering or modified scattering

When a photoelectric interaction occurs, what shell does it interact with in the cell?

K-shell

What are the 4 types of tissue reactions that can occur as a result of a photon interaction?

1. photoelectric

2. compton

3. coherent

4. pair production

T/F: photodisintegration occurs in diagnostic imaging

False

Which tissue interaction occurs within an outer-shell?

compton