image unsharpness

Question 1

name the 3 different types of un sharpness ?

Answer 1

1. Patient movement
2. Geometric unsharpness
3. Image distortion

Question 2

describe patient movement ?
why is it bad ?
what can be done to prevent this ?

Answer 2

literally the patient moving
* Blurs the image
* Give the patient clear instruction
* Ensure comfort
* Use immobilisation
* Sponge pads or sandbags

Question 3

are x-rays generated from a focal spot or point source

Answer 3

X-rays generated over an area (Focal spot)

Question 4

why is the sod and oid important

Answer 4

-The relationship between SOD and OID will affect the sharpness of the image

-Large SOD in relation to OID will reduce the penumbra

Question 5

how does the size of the focal spot affect image unsharpness

Answer 5

A fine focal spot gives a sharper image than a broad focal spot

Question 6

what is the negative of a fine focal spot?

Answer 6

Fine focal spot means the heat generated is in a smaller area and reduces the life of the tube