Radiolucent

Radiolucent: Permeable to one or another form of radiation such as X-irradiation (X-rays). Radiolucent objects do not block radiation but let it pass. The opposite of "radiolucent" is "radiopaque." Metal, for instance, is radiopaque. If a child swallows a metal paperclip, the paperclip may be visible on X-ray and appear as a white object (in the form of a paperclip) within the child's intestine. Plastic is usually radiolucent. If a child swallows a radiolucent plastic paperclip, that paperclip will not be visible on X-ray. Dyes that are radiopaque are used in radiology to make radiolucent structures radiopaque and so enhance the anatomic picture. An intravenous pyelogram (better known as an IVP) is an X-ray study of the kidneys that highlights the renal pelvis where the urine is collected and the ureters serve as conduits for the urine from the kidneys to the bladder.