EVALUATION OF TC-99M-ERYTHROMYCIN AND TC-99M-STREPTOMYCIN SULFATE FOR THE VISUALIZATION OF INFLAMMATORY LESIONS

Tc-99m-erythromycin (E) and Tc-99m-streptomycin sulphate (SS) were prepared with > 98% labelling efficiency. The labels were stable up to 24 h of testing, using ITLC-SG strips and acetone and saline as solvents. The biodistributions of both radiopharmaceuticals versus Ga-67-citrate were studied in mice with turpentine-induced abscesses at 6 days post-induction. The mice were sacrificed at 1, 3 and 6 h post-injection of 15 MBq of Tc-99m-E or Tc-99m-SS. Mice injected with Ga-67-citrate were sacrificed at 4 and 24 h. The maximum abscess-to-muscle ratios obtained by biodistribution studies were 2.36 +/- 1.04 (6 h), 2.38 +/- 0.38 (6 h) and 4.76 +/- 2.04 (4 h) with Tc-99m-E, Tc-99m-SS and Ga-67-citrate, respectively. The maximum abscess-to-contralateral tissue ratios by ROIs over respective areas on scintigrams were 2.38 +/- 0.16 (6 h), 3.21 +/- 0.14 (3 h) and 3.24 +/- 0.92 (24 h) for Tc-99m-E, Tc-99m-SS and Ga-67-citrate, respectively. The uptake mechanism might be infiltration into interstitial space due to increased capillary permeability.