Lecture 14

Question 1

What is the effect of increasing object film distance on magnification?

Answer 1

Increase object film distance results in increased magnification

Question 2

What is the effect of increasing the object film distance on the blurriness of the image ?

Answer 2

As the object film distance increases the magnification will become greater and this effectively makes the image blurrier

Question 3

Will single or double emulsion film have better detail?

Answer 3

Single emulsion film has better detail

Question 4

How can distortion be avoided in radiology?

Answer 4

To avoid distortion bone needs to be parallel with the film

Question 5

Why is the positioning of central rays important?

Answer 5

The central ray needs to be directed through a radio-lucent gap otherwise there will be an artifactual narrowing of the gap space

Question 6

Why is it important to have at least 2 views?

Answer 6

Depth perception is very important, hence we always require at the very least 2 views.

Question 7

What is summation?

Answer 7

Opacities are added together. Film density = sum of all superimposed structures are added at that point.

Question 8

What is this an example of?

Answer 8

Summation

Question 9

What is border effacement?

Answer 9

Where physical structures of same oppacity are in physical contact resulting in a loss of margins.

Question 10

What is the mach effect?

Answer 10

This is when two structures are super-imposed and create an imaginary line at the division line between the two structures. These are often mistaken for fractures.