Safety - Radiation physics and radiobiology Flashcards
What is the primary result of electrons decelerating in the anode during x-ray production
Emission of light
Production of scatter
Emission of gamma rays
Production of heat
Production of heat
The primary result of electrons decelerating in the anode is the production of heat.
Approximately 99% of the kinetic energy of the electrons is converted into heat, with
only a small fraction contributing to x-ray production. The emission of light, gamma
rays, and the production of scatter are not direct results of this process in the context
of x-ray production
What is the radiation weighting factor for x-ray radiation
1
5
10
20
1
The radiation weighting factor for x-ray radiation is 1. This means that x-rays are far
less damaging than alpha radiation, which has a weighting factor of 20
Which factor is most critical in determining the biological impact of radiation on tissues
The type of tissue irradiated
The age of the patient
The dose rate of the radiation
The patient’s medical history
The dose rate of the radiation
The dose rate of the radiation is most critical in determining the biological impact on
tissues. A higher dose rate means a greater amount of radiation is delivered over a shorter period, leading to more significant biological damage. The type of tissue
irradiated, the age of the patient, and the patient’s medical history also play roles, but
the dose rate is a primary determinant of the severity of radiation effects
What unit of measurement can be used to describe the biological risk of exposure to radiation?
Becquerel
Coulomb/kilogram
Gray
Sievert
Sievert
The unit of measurement that can be used to describe the biological risk of exposure
is the sievert. The becquerel is used to measure radioactivity. The coulomb/kilogram
is used to define the number of ionizations in air. The gray is used to measure
absorbed dose
Which of the following is the correct formula for calculating the equivalent dose EqD
Absorbed dose (D) / Radiation weighting factor (WR)
Absorbed dose (D) / Tissue weighting factor (WT)
Absorbed dose (D) x Radiation weighting factor (WR)
Absorbed dose (D) x Tissue weighting factor (WT)
Absorbed dose (D) x Radiation weighting factor (WR)
Equivalent dose EqD is calculated as Absorbed dose D x Radiation weighting
factor WR. Equivalent dose takes into account the fact that different radiation types
cause different amounts of biologic damage in the body. Tissue weighting factors are
based on the sensitivity of specific tissue types and is used to calculate effective
dose, not equivalent dose
Which of the following variables is described as the force with which electrons travel through a
circuit?
Amperage
Gravity
Resistance
Voltage
Voltage
Voltage is described as the force with which electrons travel through a circuit. It can
also be termed potential difference and an electromotive force. Amperage is the
measurement of the rate at which electrons flow. Gravity is a force which tries to pull
two objects toward each other. Resistance is the property of an element in a circuit
that resists or impedes the flow of electricity.
Because of the binding energy of a K-shell tungsten atom, the minimum electron energy necessary to create a characteristic photon is:
65 keV
70 keV
75 keV
80 keV
70 keV
Because of the binding energy of a K-shell tungsten atom, which is 69.5 keV, the
minimum electron energy necessary to create a characteristic photon is 70 keV.
Therefore, electrons with less than 70 keV would lack the energy to remove the K
shell electron.
Which dose measurement is used to compare the stochastic risk of non-uniform exposure to
radiation?
Effective dose
Equivalent dose
Radiation weighting factor
Tissue weighting factor
Effective dose
The effective dose is used to compare the stochastic risk of non-uniform exposure to
radiation. Body tissues react differently to radiation and cancer induction occurs at a
different rate of dose in different tissues. Hence, the effective dose is the risk of
developing fatal cancer in the tissue in question
