COMPARISON OF TL-201 AND GA-67 SCINTIGRAPHY IN THE EVALUATION OF NON-HODGKINS-LYMPHOMA

Background: Gallium-67 (Ga-67) is widely used in the assessment of pat ients with lymphoma. Although highly sensitive in Hodgkin's disease an d high grade non-Hodgkin's lymphoma (NHL), its sensitivity is reported ro be reduced in lower grades of NHL. Several series have suggested t hat thallium-201 (Tl-201) may be more useful than Ga-67 in the evaluat ion of low and possibly intermediate grade NHL. Aim: To compare the se nsitivity and relative avidities (uptakes) of Tl-201 and Ga-67 in pati ents with NHL. Methods: A total of 36 pairs of studies were performed in 33 patients (14 male: 19 female; age range 16-84: years, mean 55 ye ars). All had whole body Ga-67 (400 MBq) and Tl-201 (100-200 MBq) stud ies (interval 0-three days) which were read by two experienced nuclear medicine physicians blinded to clinical history and results of other investigations. Results: Tl-201 had a higher sensitivity and avidity t han Ga-67 in patients with low grade NHL. In contrast, Ga-67 was sligh tly more sensitive and had a higher avidity in patients with both inte rmediate and high grade NHL. Conclusions: We conclude that Tl-201 is m ore sensitive and avid for low grade NHL than Ga-67 and that considera tion should be given to its use in this condition in conjunction with Ga-67 as it may provide complementary information. Routine use in inte rmediate grade NHL is less convincing as Ga-67 was superior in most ca ses, Ga-67 is more sensitive than Tl-201 in assessment of high grade N HL.