Detection of metastases in the skeleton with radioactive colloidal gold.

Abstract

Radioactive colloidal gold (198Au) is rapidly removed from the blood, following intravenous injection, by the reticuloendothelial system. Most of the injected colloid is taken up by the liver, but a small part (about one tenth) is taken up by the bone marrow. This permits the obtaining of a scintigram of areas rich in isotope such as bone marrow; in those where the metastatic foci are present, a lacular picture is seen in a very early phase, before the tumour proliferation has caused alterations of the bone structure. The tracer's intense fixation in the liver does not permit the obtaining of clear images from the central part of the body and the authors have therefore concentrated on the pelvis, an area rich in bone marrow and where metastatic invasion is frequent. In patients without bone marrow invasion the uptake of 198Au is rather uniform, the different portions of the pelvis appearing clearly drawn, with the exception of the central areas of the iliac bones, which appear as clear areas. In metastases, medullary invasion, shown by the gammagraphy, is always wider than on X-ray films. The metastatic images are usually multiple and have an evident infiltrating character.