CLINICAL-SIGNIFICANCE OF TL-201 AND GA-67 SCINTIGRAPHY IN PULMONARY TUBERCULOSIS

One hundred and thirty-nine patients with pulmonary tuberculosis were evaluated by means of gallium-67 and thallium-201 scintigraphy. The di sease was clinically active in 83 and inactive in 56. The uptake ratio between the lesion and the contralateral normal lung field was calcul ated. The ratio determined by Ga-67 scintigraphy was expressed as GR. and that determined by Tl-201 scintigraphy (early or delayedi as ER or DR, The Tl-201 retention index (RI) was calculated using the followin g equation: RI=DR-ER/ERx100. The sensitivity, specificity and accuracy of Tl-201 scintigraphy with respect to the activity of pulmonary tube rculosis were better than those of Ga-67 scintigraphy (the figures for Tl-201 scintigraphy were 88.0%, 82.1% and 85.6% respectively, and tho se for Ga-67 scintigraphy. 83.1%, 60.7% and 74.1%). We found a signifi cant correlation between GR and ER, but there was no significant corre lation between RI and ER, When the relationships between ER. C-reactiv e protein and 1-h erythrocyte sedimentation rate were examined among p atients with abnormal uptake, no significant relationships were noted, In the 27 patients who could be followed up, GR and ER decreased with duration of the therapy, indicating a decrease in disease ac tivity w hich was consistent with clinical findings. The RI was significantly h igher in the early stages of therapy than in the later stages (P<0.01) , suggesting a temporary delay in Tl-201 washout in the early stages, The washout seemed to be promoted by the effects of the therapy. Overa ll, it is concluded that Tl-201 scintigraphy is more useful and more s uitable than Ga-67 scintigraphy for the evaluation of disease activity and therapeutic effects in patients with pulmonary tuberculosis.