Effects of Preloading of Stannous Compounds on the Distribution of ^99mTc-Pertechnetate^[*]

Summary

^99mTc-pertechnetate distribution studies were performed in rabbits and mice following pretreatment between 5—336 hours with various routinely used stannous complexes (HSA, MAA, GHT, DTPA, PYPs) containing different amounts of Sn⁺⁺ (0.17 —15.0 μ mg/kg). Beyond a concentration of 0.26 mg/kg of Sn⁺⁺ an alteration in ^99mTc-pertechnetate distribution was observed. The red blood cell was found to be the most prominent target. An in-vivo reduction of ^99mTc-pertechnetate apparently occurred by the presence of stannous ion within the red blood cell. Preloading time period between 5—24 hours did not alter the uptake of RBC/plasma ratio. Beyond that period it decreased slowly and still persisted up to 2 weeks following pretreatment. RBC/ plasma ratio of ^99mTcO₄ ^- increased with increased Sn⁺⁺ content of various commercially available pharmaceutical kits.

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