HODGKIN-DISEASE - USE OF TL-201 TO MONITOR MEDIASTINAL INVOLVEMEMT AFTER TREATMENT

Purpose: To compare thallium-201 scintigraphy with gallium-67 scintigr aphy in the detection of residual or recurrent mediastinal Hodgkin dis ease after treatment. Materials and methods: The authors performed pla nar Ga-67 and Tl-201 scintigraphy in 39 patients aged 7-18 years (27 w ith mediastinal primary disease) after primary treatment. These scans and those in a control group of 14 patients with newly diagnosed known mediastinal Hodgkin disease were evaluated independently by two radio logists for abnormal mediastinal activity. Results were compared with chest computed tomographic (CT) findings and with the clinical criteri a of disease status. Interobserver agreement and consensus agreement o n gallium and thallium scan findings were evaluated with the kappa sta tistic, and the specificity of the two imaging methods was analyzed. R esults: All study patients were judged to be free of mediastinal disea se with CT and the clinical criteria. Interobserver agreement on findi ngs in the treated and control patients was stronger with gallium scin tigraphy (kappa +/- SD = 0.956 +/- 0.044) than with thallium scintigra phy (kappa = 01638 +/- 0.110). Specificity of ratings based on thalliu m (85% +/- 6) and gallium (90% +/- 5) scintigraphic findings of medias tinal disease did not differ significantly (P = .48). Specificity impr oved when the results of the two examinations were combined (97% +/- 2 ). Conclusion: Thallium scintigraphy can help to predict the absence o f mediastinal Hodgkin disease after treatment.