ASRT 10 (STUDY!) Flashcards
The amount of the x-ray beam that will be scattered or absorbed from a monoenergetic beam per unit of material thickness is called the:
Linear attenuation coefficient.
The obstruction of the bowels caused by failure of peristalsis is called:
A. Ileus.
B. Intussusception.
C. Volvulus.
D. Crohn’s disease.
A. Ileus.
The number of views obtained by the CT system during data acquisition is the:
Sampling frequency.
For an oblique-axial MPR of the shoulder, the scan plane should be perpendicular to the:
Glenoid fossa.
The ability of the CT system to detect small differences between linear attenuation coefficients is called its:
Contrast resolution.
When there is no overlap between slices, the _________ equals the CTDI.
MSAD.
The evaluation of the _________ involves the positioning of several ROI measurements at different locations along the center & periphery of an image to determine if there are any significant value differences.
Spatial uniformity.
Planes that are oriented at right angles to each other are called:
Orthogonal.
What is the best window level & width to visualize the gray and white matter of the brain?
WL 35; WW 100.
The typical scan delay for a CT scan of the soft tissue neck is:
25 seconds following the 2nd injection of a split bolus.
How much contrast is typically used for a CT brain perfusion/
50 mL.
The typical scan range for a CTA of the chest to rule out a pulmonary embolism is from:
just below the lowest hemidiaphragm to the lung apices.
The approximate HU of blood is:
20.
A __________ detector array uses detectors of various sizes, with the thinnest in the center & wider detectors toward the edges.
Adaptive.
Tactile communication cues involves the use of ________ to impart meaning.
Touch.
All of the following are clinical indications for CTA of the CoW and carotids, EXCEPT:
A. acute stroke.
B. dural sinus thrombosis.
C. carotid atherostenosis.
D. carotid injury.
B. dural sinus thrombosis.
Dose measurements are calculated & reported by a physicist for each CT scanner, using the:
CTDI measurement.
A 16-slice MDCT system has access to ________ data channels.
16.
- In this case, the slice number equals data channels!
Automatic tube current modulation automatically adjusts the _________ based on the estimated attenuation of the pt at a specific location.
mA.
For cardiac calcium scoring, the scan field should be set:
from 1 cm below the carina to just below the heart apex.
True/False: MPRs can be 2D or 3D.
False - they can only be 2D images!
Normal range for BUN level is:
7-25 mg/dL.
The __________ is used to determine the radiation dose for a specific CT exam.
DLP.
Which of the following factors controls the temporal resolution of a CT system?
A. gantry rotation time.
B. ECG wave form synchronization.
C. kVp.
D. mA.
A. Gantry rotation time.