超星 - 专业英语自测

单选题

X-ray production occurs at the _____.

A. Cathode
B. anode
C. Filament
D. stator

单选题

When the anode angle is less than 45 degrees, _____.

A. the actual focal spot is smaller than the effective focal spot
B. the effective focal spot is smaller than the actual focal spot
C. the actual focal spot is equal to the effective focal spotthe angle has no effect on focal spot

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单选题

The disadvantage of a small target angle is _____.

A. greater field coverage
B. more uniform radiographic density
C. increased heat distribution & capacity
D. greater anode heel effect

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单选题

According to the Line-Focus Principle, the following factors are able to alter the size of focal spot EXCEPT______.

A. size of filament
B. anode angle
C. SID
D. electron beam size

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单选题

The difference in density in various regions of a radiograph is called

A. Collimation
B. Contrast
C. Filtration
Definition

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单选题

Geometric unsharpness can be improved by keeping the film as close as possible to the anatomy to be examed during an exposure.

A. True
B. False

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单选题

In order to take advantage of the "heel effect", which positioning approach is more proper?

A. The anode side of the tube should be positioned towards the thick part of the patient.
B. The anode side of the tube should be positioned towards the dense part of the patient.
C. Place the part to be studied under the cathode side.
D. Anode side of the tube should be positioned closest to the chest wall of the patient when doing mammography examination.

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单选题

The following factors affect image sharpness except______.

A. geometric size of focal spot
B. movement unsharpness
C. projection distortion
D. elecronic nosie

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单选题

The X-ray intensity is lower on the anode side of the tube due to______.

A. line focus principle
B. heel effect
C. filament temperature
D. anode inclination

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单选题

The geometric sharpness of an image is affected by____.

A. focal spot. A large focal spot is easy to obtain good radiographic definition
B. source object distance (SOD). A large SOD is easy to blur image.
C. object film distance (OFD). A large OFD is easy to make image blur.
D. none of the above.

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