99mrpc

This method is based on the accessibility of the pores in the stationary phase for 99mrpc-iabeled molecules of different molecular sizes. The sample is eluted from a vertical column packed with porous beads of the gel by gravity or low pressure. Smaller Tc species penetrate the pores and are retained on the column, while larger molecules are excluded and are therefore rapidly eluted from the column. This separation technique has particular application for macromolecules, proteins (serum albumin, immunoglobulins [e.g., monoclonal antibodies and their fragments]), but has also been used for separation of small-molecular-weight Tc-diphosphonate complexes. 

The kit contains the lyophilized, sterile ingredients in a multidose vial. Labeling with 99mrpc-pertechnetate is carried out under aseptic conditions by adding a suitable volume of sterile Tc eluate, up to 3.7 GBq (100 mCi) to the reaction vial. The reaction is allowed to proceed at room temperature for 20 min. Tc-tin colloid is a sterile, pyrogen-free, opalescent solution suitable for intravenous injection. The pH is 4.0-6.0 on pH paper. 

Kits containing tin-pyrophosphate as a sterile, nonpyrogenic formulation are either reconstituted with sterile saline or with sterile sodium Tc-pertechnetate solution. 99mrpc-pYp jjas been used for imaging myocardial infarction the cold kits serve as stannous agent for in vivo labeling of RBC. No bacteriostatic preservative is present in kits. 

A special formulation of medronate (Amerscan Stannous Agent) is used for in vivo loading of red blood cells with stannous ion, preparatory to labeling with sodium 99mrpc-pertechnetate. 

Pentavalent Tc(V)-DMSA differs structurally and has been evaluated for imaging medullary carcinoma of the thyroid (Ohta et al. 1984 Ramamoorthy et al. 1987). The sensitivity of lesion detection is 95% no false positive uptake of Tc(V)-DMSA was seen in nine patients with a histologic diagnosis of medullary carcinoma. Accumulation of Tc(V)-DMSA was seen in both bone and soft tissue metastases. In comparison, 99mrpc-MDP detected all known metastases in bone, but none in soft tissue (Clarke et al. 1988). 

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