special subjects
X Rays
Procedure for X Rays
For conventional x-ray imaging, a person is positioned so that the body part to be evaluated is between the x-ray source and a device that records the image. The examiner goes behind a screen that blocks x-rays and runs the x-ray machine for only a fraction of a second. The person must remain still when the x-ray is taken. Several x-rays may be taken to obtain images from different angles. An x-ray beam is aimed at the body part to be evaluated. Different tissues block different amounts of the x-rays, depending on the tissue’s density. The x-rays that pass through are recorded on a film or radiation detector plate, producing an image that shows the different levels of tissue density. The denser the tissue, the more x-rays it blocks and the whiter the image: Metal appears completely white (radiopaque). Bone appears almost white. Fat, muscle, and fluids appear as shades of gray. Air and gas appear black (radiolucent). 