[Muscular fixation of thallium-201 in lower limb arteriopathies before and after injection of Royat thermal gas].

Thirty patients with peripheral vascular disease (grade II) were studied by way of thallium-201 (Tl-201) muscular scan in order to assess a possible muscular effect of the Royat spa natural gas. Immediately after a 1.1 MBq/kg Tl-201 IV injection, a dynamic scintigraphic study was performed during 15 minutes in order to obtain a time-activity curve (characterized by Tmax) over the thighs, at rest. Then static anterior and posterior views were performed over thighs and calves during 4 minutes each. Perfusion ratios were calculated as thigh/knee and calf/ankle. The GE maxi 400 T gamma-camera was connected to an Informatek treatment system, zones of interest being chosen to obtain anterior and posterior thigh/knee, leg/ankle uptake ratios. Two studies were realized: the first one in basal conditions, the second one 7 days later, immediately after a s/c injection of natural gas. The later study was preceded by a static counting to subtract the residual muscular activity. After gas injection, one observed that Tmax was shorter, on the average, and that the difference between time-activity curves observed during the first study disappeared for patients with unilateral disease. A significant Tl-201 uptake increase was observed for the anterior image of the calf, while no difference was noted on posterior images, natural gas being injected on the front face of legs. This was particularly clear for patients with unilateral disease and receiving only unilateral gas injection.