Quality of the radiographic image • Contrast • Image geometry • Characteristics of the x-ray beam • Image sharpness and resolution

Perception of the radiographic image • Partial images-we all

see

the same partial images but we don’t necessarily

perceive

the same object • Contrast • Context

Effect of partial image

The effect of contrast

The effect of context

Image geometry • Positioning of the film, object and x-ray beam • Focal spot size and principle of line focus • Focal spot-object distance (FSOD), object to film-distance (OFD)

Ideal image geometry requirements

Focal spot size, heat distribution and image sharpness • Focal spot 1mm • Heat needs to be distributed over as large as possible area • Principle of line focus

Focal spot-to film distance(FSFD)

FSFD • Increasing the distance between the focal spot and the object results in an image with increased sharpness and less magnification of the object

Object-to film- distance (OFD)

• Decreasing the distance between the object and the film increases the sharpness and result in less magnification of the object

Image shape distortion

Cont’d

Bisecting angle technique shape distortion

Cont’d