1|Page
CT FINAL EXAM QUESTIONS AND
ANSWERS 100% PASS
CT technologists must understand both the ___________ & ___________ of examinations and take steps
to maximize the ________ & minimize the ____________. - ✔✔risks & benefits
positive, negative
What are the two components regarding radiation dose to the patient? - ✔✔1) appropriate patient
selection
2)minumizing the dose to the pt w/ out compromising the diagnostic image quality
CT scans provide one of the ____________ radiation doses in diagnostic radiology. *** (slide 3) -
✔✔higher
--large # w/ very thin slices
X-rays damage cells in _______ ways.....how? - ✔✔2; 1) Direct interaction between an x-ray photon and
DNA bonds with the nucleus of the cell within the patient. 2) X-ray photon indirectly produces ion pairs
in tissues as it passes through the body
X-rays damage cells in two ways: - ✔✔-Direct interaction with DNA bonds.
-Indirect effect caused by ionization of chemicals in the body.
Direct Interaction is also known as.... - ✔✔Target Theory
Gestating babies are ________ radiosensitive. - ✔✔most
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Radiation effects may be __________ but are more likely to be seen___________________ . - ✔✔-
immediate
-over a long period of time
What are the effects of x-ray radiation?(4) - ✔✔-cancer
-genetic effects of future generations
-Long term effects (10-20 yrs)
-effects of the embryo & fetus
--first trimester=maximum radiosensitivity
The unit of x-ray exposure in air - ✔✔Roentgen (R)
Units of absorbed dose - ✔✔radiation absorbed dose=rad
SI unit=Gray(Gy)
100 rad=1 Gy
1 rad= .01 Gy or 1 cGy
Convert the following:
50 rad =
200 Gy =
.1 rad = - ✔✔.5 Gy
20,000 rad
.001 Gy or 1mGy
Determine the total dose in Gy if an exam acquires
Emily Charlene © 2025, All Rights Reserved.
, 3|Page
300 slices producing 2 rads per slice. - ✔✔300 slices x 2 rad/slice = 600 rad x .01 = 6 Gy
Accounts for different types of ionizing radiation - ✔✔Quality factor (Q)
In CT, the quality factor is ? - ✔✔1
Attempts to account for the effects particular to the patient's tissue that has absorbed the radiation dose -
✔✔Effective dose
Effective dose attempts to quantify dose based upon the_________________ of certain tissues or organs. -
✔✔radiosensitivity
The uniformity of the dose __________ as the SFOV and patient thickness ___________. - ✔✔decreases
increase
organ doses are higher for children (or small adults) compared with (larger) adults - ✔✔........
Body scans are________uniform than head scans - ✔✔less
The central dose of a body scan is approximately one third - one half that of the peripheral dose - ✔✔.......
Z axis dose distribution profile describes variations that occur along the________________? - ✔✔length of
the patient
-Total dose is from the radiation to the selected slice and from scatter radiation, or "tails," from
neighboring slices
-In general, the tails will contribute approximately 25% to 40% to the total dose - ✔✔.......
Multiple scan average dose (MSAD) - ✔✔Dose calculated from multiple scans
Computed tomography dose index (CTDI) - ✔✔Reported to FDA
Slices must be contiguous
Emily Charlene © 2025, All Rights Reserved.
CT FINAL EXAM QUESTIONS AND
ANSWERS 100% PASS
CT technologists must understand both the ___________ & ___________ of examinations and take steps
to maximize the ________ & minimize the ____________. - ✔✔risks & benefits
positive, negative
What are the two components regarding radiation dose to the patient? - ✔✔1) appropriate patient
selection
2)minumizing the dose to the pt w/ out compromising the diagnostic image quality
CT scans provide one of the ____________ radiation doses in diagnostic radiology. *** (slide 3) -
✔✔higher
--large # w/ very thin slices
X-rays damage cells in _______ ways.....how? - ✔✔2; 1) Direct interaction between an x-ray photon and
DNA bonds with the nucleus of the cell within the patient. 2) X-ray photon indirectly produces ion pairs
in tissues as it passes through the body
X-rays damage cells in two ways: - ✔✔-Direct interaction with DNA bonds.
-Indirect effect caused by ionization of chemicals in the body.
Direct Interaction is also known as.... - ✔✔Target Theory
Gestating babies are ________ radiosensitive. - ✔✔most
Emily Charlene © 2025, All Rights Reserved.
,2|Page
Radiation effects may be __________ but are more likely to be seen___________________ . - ✔✔-
immediate
-over a long period of time
What are the effects of x-ray radiation?(4) - ✔✔-cancer
-genetic effects of future generations
-Long term effects (10-20 yrs)
-effects of the embryo & fetus
--first trimester=maximum radiosensitivity
The unit of x-ray exposure in air - ✔✔Roentgen (R)
Units of absorbed dose - ✔✔radiation absorbed dose=rad
SI unit=Gray(Gy)
100 rad=1 Gy
1 rad= .01 Gy or 1 cGy
Convert the following:
50 rad =
200 Gy =
.1 rad = - ✔✔.5 Gy
20,000 rad
.001 Gy or 1mGy
Determine the total dose in Gy if an exam acquires
Emily Charlene © 2025, All Rights Reserved.
, 3|Page
300 slices producing 2 rads per slice. - ✔✔300 slices x 2 rad/slice = 600 rad x .01 = 6 Gy
Accounts for different types of ionizing radiation - ✔✔Quality factor (Q)
In CT, the quality factor is ? - ✔✔1
Attempts to account for the effects particular to the patient's tissue that has absorbed the radiation dose -
✔✔Effective dose
Effective dose attempts to quantify dose based upon the_________________ of certain tissues or organs. -
✔✔radiosensitivity
The uniformity of the dose __________ as the SFOV and patient thickness ___________. - ✔✔decreases
increase
organ doses are higher for children (or small adults) compared with (larger) adults - ✔✔........
Body scans are________uniform than head scans - ✔✔less
The central dose of a body scan is approximately one third - one half that of the peripheral dose - ✔✔.......
Z axis dose distribution profile describes variations that occur along the________________? - ✔✔length of
the patient
-Total dose is from the radiation to the selected slice and from scatter radiation, or "tails," from
neighboring slices
-In general, the tails will contribute approximately 25% to 40% to the total dose - ✔✔.......
Multiple scan average dose (MSAD) - ✔✔Dose calculated from multiple scans
Computed tomography dose index (CTDI) - ✔✔Reported to FDA
Slices must be contiguous
Emily Charlene © 2025, All Rights Reserved.
