radiogold colloid

[rādē-ō-gōld′]
n.
  1. A colloidal dispersion of a radioactive isotope of gold that emits a negative beta particle and a gamma ray for each atom of gold present, used for irradiating closed serous cavities and for liver scans.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.