New Update
Radiation in air is measured by - Answer- ✔✔Exposure or air kerma
Absorbed dose measures - Answer- ✔✔Tissue radiation
Equivalent dose measures - Answer- ✔✔Effects of radiation in tissue
ESE stands for - Answer- ✔✔Entrance skin exposure
ESE measures - Answer- ✔✔The intensity (quantity) of radiation in the air at the level of
the patient's skin
DAP stands for - Answer- ✔✔Dose Area Product
DAP measures - Answer- ✔✔The total amount of radiation delivered to the patient from
diagnostic imaging equipment
RADIATION IN AIR - Answer- ✔✔RADIATION IN AIR
Exposure = - Answer- ✔✔# of ionizations create in air by x-ray
Within the SI system, exposure in air is measured by - Answer- ✔✔Coulombs per
kilogram (C/kg)
Air Kerma measures - Answer- ✔✔Total energy of ionizations in air (intensity)
Air Kerma is quantified by - Answer- ✔✔Gray (Gy)
Air Kerma can be increased by - Answer- ✔✔Increasing kVp, mAs, decreasing distance
Air kerma can be decreased by - Answer- ✔✔Decreasing kVp, mAs, increasing
distance
The SI unit used to measure radiation exposure in air is:
A. Gray
B. Coulomb/kg
C. Sievert
D. Curie - Answer- ✔✔B. Coulomb/kg
,The Coulomb/kg is the SI unit used to measure the radiation in the air.
The SI unit for Air Kerma is:
A. Sievert
B. Gray
C. Coulomb/kg
D. Becquerel - Answer- ✔✔B. Gray
The unit of measurement for the Air Kerma is the Gray; however, because it is such a
large measurement, it is more common to see it expressed in milligray (mGy).
The radiation measurement coulomb/kilograms is used to describes:
A. Absorbed dose
B. Ionizations in air
C. Effective dose
D. Skin entrance dose - Answer- ✔✔B. Ionizations in air
Coulomb/kilogram is the SI measurement for ionizations (electric charge) in the air.
Which of the following statements are true regarding exposure and air kerma?
As mAs increases, exposure and Air Kerma increase
As kVp increases, exposure and Air Kerma decrease
As distance increases, exposure and Air Kerma decrease
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3 - Answer- ✔✔B. 1 and 3
Exposure and air kerma are both representations of the x-ray beam intensity. As mAs
increases so does exposure and air kerma. SID also affects exposure and air kerma
due to the effects of the inverse square law. When SID (distance) increases, the
exposure and air kerma decrease. When kVp is increased, both exposure and air kerma
increase (not decrease).
Ionization occurs when x-ray photons separate a(n) ___________ from an atom.
A. Proton
B. Electron
C. Neutron - Answer- ✔✔B. Electron
, Ionization happens with the gain or loss of an electron. In terms of diagnostic radiology,
ionization occurs when x-ray photons separate an electron from an atom and create two
charged particles (ions).
The acronym KERMA stand for:
A. Kilograms Energy Release Mass
B. Kilovoltage Energy Release Mass
C. Kinetic Electrons Released Momentum Activity
D. Kinetic Energy Released per unit Mass - Answer- ✔✔D. Kinetic Energy Released per
unit Mass
KERMA stands for Kinetic Energy Released per unit Mass.
Why is it important that medical physicists perform exposure tests annually on x-ray
equipment?
1 - Ensure that patients are not being over-exposed.
2 - Ensure that the x-ray machine is functioning properly.
3 - Ensure that the right amount of radiation is being produced for each exam.
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3 - Answer- ✔✔D. 1, 2, and 3
Medical physicists should perform exposure tests annually to ensure that patients are
not being over exposed, the machine is functioning properly, and the right amount of
radiation is being produced for each exam.
Exposure measures the number of ions created while air kerma measures the total
energy of the ions.
A. True
B. False - Answer- ✔✔A. True
Exposure measures the number of ions created, air KERMA measures the total energy
of ions in air. Both air kerma and exposure are used to measure the intensity of the x-
ray beam.
RADIATION IN TISSUE - Answer- ✔✔RADIATION IN TISSUE
The SI unit of measurement for absorbed dose - Answer- ✔✔Gray (Gy)
Radiation EFFECTS in tissue - Answer- ✔✔Equivalent dose (EqD), Effective dose (EfD)