module 1

Question 1

Which scanner allows for continuous rotation of the x-ray tube while the patient moves simultaneously through the gantry aperture?

Answer 1

spiral/helical scanner

Question 2

The range of CT numbers in an image is called the:

Answer 2

window width (WW)

Question 3

T/F: CT is better at recording very small differences in tissue contrast compared to conventional tomography.

Answer 3

true

Question 4

All the following apply to computed tomography (CT) except:
a. a computer is used to reconstruct cross-sectional images of the patient.
b. X-ray film is used as the detector.
c. special detectors are used to detect X-rays that have passed through the patient at multiple angles.
d. mathematical methods are used to reconstruct images.

Answer 4

X-ray film is used as the detector (CT uses specialized electronic detectors to collect data)

Question 5

A high-kilovolt (kV) technique is necessary in CT imaging for all the following reasons except:
a. to reduce the contrast of bone relative to soft tissues.
b. to reduce the dependence of attenuation coefficients on photon energy.
c. to increase the probability of beam hardening.
d. to produce a high-radiation flux at the detector.

Answer 5

to increase the probability of beam hardening.

Question 6

The gantry houses:

x-ray tube
collimators
slip rings
all of the above

Answer 6

all of the above

Question 7

______ refers to the way the x-ray beam is emitted from the tube housing, passes through the patient, and is acquired by the CT detectors.

Answer 7

beam geometry

Question 8

To date, there have been ____ major generations of CT equipment.

Answer 8

7

Question 9

Using _______, the data acquired during a single scan can also be processed differently to display primarily soft tissue or bony anatomy.

Answer 9

computer algorithms

Question 10

CT tube voltages typically range from:

Answer 10

80-140 kV