A Proposed Mechanism for^99mTc-Labeled Polyphosphate and Diphosphonate Uptake by Human Breast Tissue

Abstract

Local uptake of 99mTc-polyphosphate or 99mTc-diphosphonate by breast tissue was observed in 17 patients, occurring in normal breasts and also in benign and malignant breast lesions. Large concentrations of acid phosphatase were demonstrated histochemically in bone and in breast tissue of lactating rats and in human breast cancers. It is therefore proposed that focal uptake of polyphosphate and diphosphonate in bone and in soft tissues may be due to their binding to receptor sites on enzymes such as acid phosphatase.