A KIT FOR THE INSTANT PREPARATION OF TC-99(M)-CITRATE FOR TUMOR AND INFLAMMATION SCINTIGRAPHY

A lyophilized kit has been developed to produce Tc-99(m)-citrate (99%) instantly when mixed with (TcO4-)-Tc-99-O-m. The ingredients of the k it, citrate and stannous chloride, are in a ratio of 100:1 (w/w) and a re bound to 700 MBq Tc-99(m), sufficient for use in a single patient. The shelf life of the kit when kept refrigerated is at least 3 months. The blood clearance and organ distribution of Tc-99(m)-citrate have b een studied in rabbits and mice respectively, showing its fast clearan ce (55% at 5 min) and low uptake by the reticuloendothelial system and other organs. The main route of clearance is via the kidneys. Scintig raphic studies in experimental mice have demonstrated high levels of a ccumulation of Tc-99(m)-citrate in turpentine-induced abscess (target- to-non-target ratio 4.2:1) and EAT implanted tumour in mice (T/NT 5:1) 1 h after its administration. In keeping with these animal studies, l ow uptake of Tc-99(m)-citrate by normal organs and fast blood clearanc e have been demonstrated in human patients with infection and tumour a s early as 5 min post-administration. This study documents a new kit d eveloped for the preparation of Tc-99(m)-citrate suitable for the scin tigraphic assessment of abscess, infection and tumour.