Brain scintigrams in metastatic carcinoma

A review of clinical experience with two agents used in brain tumor imaging, 203Hg‐chlormerodrin and 99mTc‐pertechnetate, was made to determine true‐positive and false‐positive rates for the localization of metastatic brain tumors. We found no significant difference between the two agents in the true‐positive rate, 70% and 65%, respectively. False‐positive rate also revealed no significant differences, 12% and 5%, respectively. Experience with delayed scans using 99mTc‐pertechnetate suggests that true‐positive rates may be increased with a longer interval between injection and scan than was employed in most of these patients. Newer radiopharmaceuticals currently under investigation may also offer improved tumor detection.