Ga-67 scintigraphy for the evaluation of recurrences and residual masses in patients with lymphoma

Ga-67 scintigraphy has proven to be of value in the evaluation of patients with lymphoma, especially in their management after treatment. In this study, computed tomography (CT) and Ga-67 scans were compared in 53 patients with lymphoma who had previously been treated. Twenty-eight were patients in continuous clinical remission in whom recurrence was suspected. The remaining 25 patients were studied between 1 and 3 months post-treatment to assess a residual mass. The sensitivity for the detection of lymphoma recurrence was 88% for Ga-67, with two false-negative results, and 59% for CT, with seven false-negative results. In the diagnosis of recurrence, the specificity of Ga-67 was 100% and that of CT 72%, with three false-positive results. Therapeutic response was assessed in 25 patients and the ability to predict response to treatment resulted in a specificity of 86% for Ga-67 and 81% for CT. Treatment failed in four patients, as detected by Ga-67 scan, whereas CT did not detect any of these. In the remaining 21 patients who showed good response to treatment, there were three false-positive results for Ga-67 and four for CT. Ga-67 scintigraphy can detect relapse more accurately and much earlier than CT, as well as diagnose complete remission after treatment. Therefore, Ga-67 scintigraphy should be used routinely in monitoring response to treatment in lymphoma.