Radiation Dose and safety Flashcards
(23 cards)
Which of the following refer to radiation exposure prior to and after the image acquisition?
A.Iterative reconstruction
B. ATCM
C.Overranging
D.Overbeaming
C. Overranging
this occurs when the radiation exposure begins prior to and after the image acquisition.
Compton scatter is what?
A.X-rays interaction with inner shell elections and being absorbed
B. An incdients x-ray interacting with inner shell electron
C. X-rays interaction with outer shell electrons and being absorbed
D. An incident x-ray interacting with an outer shell election
D. An incident x-ray interacting with an outer shell election
As the distance from the source to the iso-center of the gantry gets smaller, the patients radiation dose will
A. Decrease
B. Increase
C. stay the same
D.
B. Increase.
This is the same as bringing the SID on the x-ray tube closer to the patient, the dose will increase.
When calculating DLP (Dose length product), what relationship does scan length have with dose?
A.It does not play a role
B.It is disproportionate
C.It is proportional
C. Dose Length Product (DLP) is the total amount of exposure for an exam. This means the longer the scan, the more DLP there will be
Inherent filtration of the x-ray tube is typically:
A. 10 mm Al
B. 0.3mm AL
C. 3 mm AL
D. 7 mm AL
C. 3mm AL
Inherent filtration consists of 3mm aluminum equivalent.
The total amount of exposure with consideration of the can length is known as:
A. CTDI w
B. Effective dose
C. DLP
D. CTDI100
C. DLP
This is the total exposure for an exam that a patient recieves
Which of the following does NOT impact patient dose?
A. Decreasing mA
B. Increasking kV
C. Increasing SFOV
D. Increasing DFOV
D. Increasing DFOV
Display Field of View is frequently adjusted by the technologist based upon the anatomic area of interest for the exam. The DFOV is the portion of the acquired data that will be displayed on the matrix and does not impact dose.
DON’T GET CONFUSED WITH SFOV. SFOV is when you zoom in and focus on a smaller part of interest, like MAG on a C-arm.
Measurement of the ionization of the air is known as:
A. CTDI
B. Effective dose
C. Exposure
D. Absorbed dose
C. Exposure
Exposure is the measurement of the ionization of air.
Which of the following does not take into consideration the effects of spiral or helical scanning?
A. CTDI W
B. CTDI Vol
C. CTDI 100
D. CTDI
A. CTDI W
B. CTDI Vol
C. CTDI 100
D.CTDI
A. CTDIW weights the exposure and creates a more accurate dose approximation. However, this approximation does not account for the effects of spiral or helical scanning.
Of the following, which is most likely to cause an increase in the patient’s radiation dose?
A. Filtration
B. ATCM
C. Retrospective gating
D. Single phase imaging
C. Retrospective gating
ECG gating also allows for acquisitions to occur throughout the entire cardiac cycle. Images can be reconstructed once the acquisition has been completed to display only the desired phase of the cardiac cycle. This is known as retrospective gating, and increases the patient’s radiation dose.
Of the following which has a direct effect on patient dose?
A.Matrix
B.mAs
C. Window width
D. DFOV
B. mAs
Just the same as X-ray! for mA, more dose!
The area of the patient that is exposed to radiation is known as:
A. DLP
B. Dose profile
C. Effective dose
D. CTDI
B. Dose profile
The dose profile is the area of the patient that is being exposed to radiation.
All other factors remaining the same, which pitch would result in the least radiation dose to the patient?
A. 0.5
B. 0.8
C. 1.5
D. 1.0
C. 1.5
Pitch can be increased to extend the area of coverage and decrease scan time. A pitch of less than 1 means there is overlapping of slices, which results in higher patient dose. A pitch of greater than 1 means there is gaps between slices, which results in lower patient dose.
Failure to ensure the patient is iso-center in the gantry can result in which of the following?
A. Increased pt dose
B. inability to perform MPR
C. Increased scan time
D. It does not have an impact
A. Increased patient dose
The way in which the patient is centered within the gantry can have an impact on the overall radiation dose the patient will receive.
Which of the following will NOT reduce the occupational radiation exposure for a technologist?
A. Limiting the time you are in the room
B. Increasing the distance you are from the source
C. Utilizing appropriate lead shielding
D. Ensuring the pt is is iso-center in the gantry
D. Ensuring the pt is is iso-center in the gantry
TIME, DISTANCE, AND SHIELDING
This question is asking about your dose, not the pt
ECG gating reduces the patients radiation dose by:
A. Scanning throughout the entire cardiac cycle
B. Scanning during the only desired portion of the cardiac cycle
C. Increasing the pitch
D. Decreasing the Kv And mA needed
B. Scanning during the only desired portion of the cardiac cycle
ECG gating can be utilized to reduce a patient’s radiation dose. This method is most often utilized during CT Cardiac or CT Gated Thoracic Aorta exams. The use of ECG gating allows for acquisition to occur only during the desired phase of the cardiac cycle. This is known as prospective gating.
Which of the following considers the radiosensitivity of different tissues within a patient?
A. DLP
B. Exposure
C. Absorbed Dose
D. Effective Dose
D. Effective dose quantifies an equivalent whole-body radiation dose, from a partial body exposure. Effective dose considers the radiosensitivity of different tissues within the patient and each tissue is assigned a weighting factor. Effective dose is used to determine a weighted average of organ dose.
Which of the following is utilized in MDCT?
A. Fan beam
B. Array beam
C. Pencil beam
D. Cone beam
D. Cone beam
To calculate CTDI the acquisition must be:
A. Contigious
B. Overlapping
C. Axial
D. Contain gaps
A. Contiguous
X-rays interacting with inner shell electrons and being absorbed describes which of the following?
A. Photon flux
B. Compton scatter
C. Photoelectric effect
D. Attenuation
D. Photoelectric effect
Photoelectric effect consists of x-rays interacting with INNER shell electrons and being absorbed. Compton scatter is the OUTER SHELL elections
Which of the following is not required to be included in the structured dose report?
A. mA
B. DFOV
C. kV
D. Pitch
B. DFOV
The structured dose report will typically contain information used during the examination such as kV, mA, SFOV, pitch, detector collimation, and scan length. The DFOV is what you crop and display
Which of the following is NOT taken into consideration when optimizing the technical parameters for an exam?
A. Area of interest
B. Illness
C. Age
D. Weight
B. Illness
