Tc-Rhenium Sulfide Nanocolloid

Chemical name Rhenium sulfide nanocolloid Tin(ll)-sulfide nanocolloid Tc-(Re)-sulfide nanocolloid 99mTc-(Sn)-sulfide nanocolloid Listed trade names NanoCis (TCK-17) (A-l-B) CIS Bio Lymphoscint (Solco) GE Healthcare 

Kit components A Rhenium sulfide 0.48 mg Ascorbic acid 7.0 mg Gelatin 9.6 mg Water for injection 1.0 ml Hydrochloric acid (cone.) 37.4 pi Kit components B Sodium pyrophosphate-10H2O 3.0 mg Stannous chloride-2 H2O 0.5 mg 

The NanoCis kit (TCK-17) consists of two vials, A and B. Vial A contains a sterile, pyrogen-free solution of ingredients. Vial B contains lyophilized sodium pyrophosphate and stannous chloride. Two milliliters of sterile water for injection are added to vial B to dissolve its content. Half a milliliter of solution B is transferred to vial A, and mixed well. Then, 1-2 ml of Tc eluate is added under aseptic conditions (not less than 370 MBq [10 mCi] to assure a specific activity of 100 MBq/ml/0.15 mg). The reaction vial is placed into a boiling water bath for 15-30 min. After cooling, the labeled colloid is ready for use. 99mTc-(Re)-sulfide nanocolloid is a sterile, pyrogen-free, brown solution, suitable for subcutaneous (interstitial) injection. The pH is between 4.0 and 7.0 on pH paper. 

Factors causing low colloid formation (low specific activity) are primarily related to pH, incorrect order of mixing, low heating temperature, heating a large volume, inadequate boiling time, or a defect of kit formulation. Tc eluate used for colloid preparation should be obtained from a generator by daily elution in order to minimize Tc carrier preferably, a small volume is added in order to reduce the concentration of ion (Ponto et al. 1987). 

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