Patient-Image Optimization and Radiographic Factors

Vocabulary flashcards covering patient factors, body habitus, tissue composition, pathology effects, image quality, and distortion in radiography.

Sthenic

A body habitus category described as strong and active.

Hyposthenic

A body habitus category described as thin but healthy appearing, generally requiring less technique.

Hypersthenic

A body habitus category described as big in frame and usually overweight.

Asthenic

A body habitus category described as small, frail, emaciated, and often elderly.

Calipers

An instrument with two bent or curved legs used for measuring the thickness of a solid anatomical part.

General Rule for Thickness

For every $4\,cm$ of additional body part thickness, x-ray beam attenuation is doubled and penetration to the image receptor is cut in half.

Radiolucent

Describing tissues or structures that attenuate few x-rays and appear black on a radiograph, such as lungs.

Radiopaque

Describing tissues or structures that absorb x-rays and appear white on a radiograph, such as the heart, liver, and spine.

Photoelectric Interactions

Absorption interactions that produce the white (radiopaque) or lighter areas in a radiographic image.

Compton Scatter

Radiation interaction that lays down a blanket of fog at the image receptor, causing poor contrast resolution.

Destructive Pathology

Pathology that decreases tissue thickness, mass density, or average atomic number, resulting in increased radiolucency.

Constructive Pathology

Additive pathology that causes tissue to become more radiopaque.

Spatial Resolution

The ability of an imaging system to resolve and render a small high-contrast object on the image, serving as the best measure of sharpness of image detail.

Contrast Resolution

The ability to distinguish between and image similar tissues, serving as the best measure of visibility of image detail.

Distortion

The misrepresentation of object size and shape on the radiographic image.

Elongation

Shape distortion where the anatomic part of interest appears bigger than normal, resulting from poor alignment of the image receptor or the x-ray tube.

Foreshortening

Shape distortion where the anatomic part of interest appears smaller than normal.

Artifacts

Unintended optical density on a radiograph or another film-type image receptor, categorized as IR, software, or object artifacts.