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
查看答案
The difference in density in various regions of a radiograph is called
A. Collimation
B. Contrast
C. Filtration
Definition
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
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.
The following factors affect image sharpness except______.
A. geometric size of focal spot
B. movement unsharpness
C. projection distortion
D. elecronic nosie
微信支付 
支付宝支付