Gallium 67 scintigraphy is useful clinically for assessment of tumor viability after treatment of Hodgkin's and nonHodgkin's lymphoma. Because more than 50% of the patients with complete response have a residual mass after treatment, computed tomography is not a good test to determine if a patient has reached a complete response. 67Ga scintigraphy, on the other hand, has a sensitivity of 76% to 100% and specificity of 75% to 96% to determine if a residual mass is a residual cancer or made up only of fibrosis and necrosis. Early diagnosis of recurrence is important in order to start therapy when the tumor can, potentially, still be controlled. The sensitivity of 67Ga for diagnosis of recurrence is 95% and the specificity 89%. Scintigraphy has been shown to diagnose recurrence sometimes months before other tests. 67Ga scintigraphy also has the potential to separate rapid from slow responders during therapy. Even when it has been known for many years, 67Ga has proved recently to be a useful test in assessing lymphoma patients after treatment.