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.