Definition

Adjective: * Not transparent to X-rays or other forms of radiation: A substance or object described as radio-opaque does not allow X-rays or similar radiation to pass through it. This property causes it to appear as a distinct, light or white area on a radiographic image (like an X-ray film), in contrast to radio-lucent structures which allow radiation to pass through and appear dark.

Usage and Examples

• Adjective:
  • The surgeon used radio-opaque markers to track the position of the surgical instruments during the procedure.
  • A radio-opaque dye is often injected into the bloodstream to make blood vessels visible on an angiogram.
  • Metal objects like coins or jewelry are highly radio-opaque and show up clearly on airport security scans.

Advanced Usage

• Medical Imaging: The term is primarily used in clinical and diagnostic contexts. It describes agents (like contrast media containing iodine or barium) or natural structures (like bones or metal) that absorb radiation, creating contrast on an image to outline organs, vessels, or foreign objects.
• Comparative Use: It is often used in contrast to its opposite, radiolucent.
  • Bone is radio-opaque, while lung tissue is relatively radiolucent.

Variants and Related Words

• Radiopaque (adj): An alternative, equally correct spelling without the hyphen. (e.g., ).
• Radiopacity (n): The noun form describing the quality or degree of being radio-opaque. (e.g., ).
• Opaque (adj): In general use, means not transparent to light. "Radio-opaque" is a specific technical extension of this meaning to electromagnetic radiation.

Synonyms

• Radiodense (adj): A near-synonym frequently used in medical imaging, emphasizing that the material has high density to radiation.

Antonyms

• Radiolucent (adj): Transparent to X-rays or other forms of radiation; allowing them to pass through.

Adjective

1. not transparent to X-rays or other forms of radiation
   • barium sulfate is radiopaque