Rad 260: Safety Flashcards
Mosby's Review book
Exit radiation (image-producing radiation) are
X-rays that emerge from the patient and strike the image receptor; composed of primary and scattered photons
Attenuation is
The absorption and scatter (loss of intensity) of the x-ray beam as it passes through the patient
Most common photon–tissue interactions in diagnostic radiography are______ and______ interactions.
Photoelectric and Compton
Cardinal Principles of Radiation Protection
Time, distance, and shielding
Fluoroscopy timer that sounds alarm after_______ of beam-on time.
5 minutes (300 seconds)
Amount of filtration that reduces the intensity of the x-ray beam to half of its original value—measured at least annually by a qualified radiation physicist.
Half-value layer
Main parts of the cell are the
Cell membrane, cytoplasm, and nucleus
Early tissue reactions (deterministic) include:
1.Erythema
2.Epilation
3.Decreased blood count
4.Acute radiation syndrome
Late tissue reactions (deterministic) include:
1.Cataractogenesis: Causes cataracts to form
2.Thyroid: cancer or cessation of function
3.Effect on fertility
Stochastic effects (probabilistic) include:
1.Carcinogenesis: radiation-induced malignancy
2.Nonmalignant radiodermatitis
3.Embryologic effects: Most sensitive during the first trimester of gestation
4.Genetic mutations
a.Indicates that no level of radiation can be considered completely safe
b.A response occurs at every dose
c.The degree of response to exposure is directly proportional to the amount of radiation received
Linear-nonthreshold relationship
Linear-threshold relationship
a.Indicates that at lower doses of radiation exposure (to the left of the line intersecting the x-axis), no response is expected
b.When the threshold dose is exceeded, the response is directly proportional to the dose received
Absorption of x-ray photons in the atoms of the body
Photoelectric effect
a.Indicates that at lower doses of radiation exposure (to the left of the curve intersecting the x-axis), no response is expected
b.When the threshold dose is exceeded, the response is not directly proportional to the dose received and is increasingly effective per unit dose
Nonlinear-threshold relationship
Nonlinear-nonthreshold relationship
a.Indicates that no level of radiation can be considered completely safe
b.A response occurs at every dose
c.The degree of the response is not directly proportional to the dose received
d.The effect is large even with a small increase in dose
Photon-tissue interaction that produces radiation that may expose others in the room during fluoroscopy
Compton
The unit of radiation absorbed in air is
Graya
The unit of radioactivity is the
Becquerel
Unit of effective dose and equivalent dose
Sievert
X-rays that emerge from the patient and strike the image receptor
Exit radiation
Primary radiation
Radiation exiting the x-ray tube
Ionizing radiation
Radiation that possesses the ability to remove electrons from atoms by a process called ionization
Unit of equivalent dose is calculated as:
Sv = Gy × WR
Unit of effective dose is calculated as:
Sv = Gy × WR × WT
Meiosis
Describes the process of division of germ cells
Erroneous information passed to subsequent generations via cell division
Mutation
A ______ is placed in the x-ray beam to remove long-wavelength (low-energy) x-rays.
Filter
Cosmic radiation:
Is a part of natural background exposure
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 (ABC)
The total of air kerma over the exposed area of the patient is called:
Dose area product
What agency publishes radiation protection standards based on scientific research?
National Council on Radiation Protection and Measurements (NCRP)
The agency that enforces radiation protection standards relating to radioactive material at the federal level is the:
Nuclear Regulatory Commission (NRC)
______occurs when radiation transfers its energy to DNA.
Direct effect
_______states that each cell has a master molecule that directs all cellular activities and that, if inactivated, results in cellular death.
Target theory
_______ is the amount of radiation required to increase the number of mutations in a population by a factor of 2.
Doubling dose
Most of the damage to a cell occurs as a result of:
Indirect effect
