Diagnostic imaging: General principles of imaging

Question 1

What are the general principles of imaging and what are the different types of imaging available?

Answer 1

1.Image formation
A.X-rays are produced by an x-ray tube and are controlled by the milliampere(mA) and kilovoltage(kVp) settings
B.Differential absorption of the X-rays within the body allows for differences in opacities on the radiograph.
C.Multiple forms of imaging are available.
1.Conventional film-screen radiography
2.Digital radiography: Computed radiography(CR) and direct digital radiography(DDR).

Question 2

What needs to be checked before taking the radiograph?

Answer 2

Check for correct patient labelling, positioning, and inclusion of the entire area of interest

Question 3

How many images are usually recommended to be taken?

Answer 3

At least two(orthogonal, at right angles) or more images should be made to correlate a two-dimensional(2-D) radiograph with a three-dimension(3-D) patient.

Question 4

What are the five basic radiographic opacities and list them in order from least to most opaque.

Answer 4

From the least opaque to most opaque these include air, fat, water or soft tissue, bone and metal or contrast material.

Question 5

How are abnormalities described?

Answer 5

Abnormalities are described in terms of the following: size, number, opacity, contour or shape and location