A tomographic imaging direction, backwards relative to a short axis of the human body from the back to the front.

Prepcat (brand name Lafayette) is a barium sulfate suspension for computed tomography examinations of the gastrointestinal (GI) tract. The dosage and application depend on the specific procedure.
UPPER G.I. OPACIFICATION: The patient should drink 300 mL of ready-to-use Prepcat approximately 2 hours before the CT scan and an additional 300 mL approximately 15 minutes prior to examination.
If rapid upper gastrointestinal tract transit is desired, administer the product chilled.
TOTAL BOWEL OPACIFICATION: The patient should drink 300 mL the night preceding the examination, 300 mL two hours prior to the examination and 300 mL approximately 15 minutes prior to examination.

The primary radiation is the useful beam emitted from the x-ray source.

A printer can be used to capture a hard copy of the image from the display.

Two quantities (x, y) are called proportional if they vary in such a way that one of the quantities is a constant multiple of the other, or equivalently if they have a constant ratio (k = y/x). This constant ratio (k) is called the proportionality constant or constant of proportionality of the proportionality relation.