The authors have examined the
tumor affinity of various 99mTc-labelled
radiopharmaceuticals to Ehrlich's
tumor for the purpose of delineating positively human
malignant neoplasm. This paper includes
biologic distributions of 99mTc-Sn-diphosphonate (99mTc-EHDP), 99mTc-Sn-dimercaptosuccinic
acid (99mTc-DMSA) and 99mTc-Sn-diethyl
stilbestrol diphosphate (99mTc-DSDP, 99mTc-Honvan) as the second report on the
tumor affinity to the Ehrlich-bearing mice. (a)
Tumor concentration of 99mTc-EHDP was lowest and the positive delineation of implanted
tumor with 99mTc-EHDP was poorest in sequential images, though the active accumulation to some soft tissue maglinant
neoplasms, the
breast cancer and the
thyroid cancer, has been reported. (b)
Tumor concentration and
tumor to blood ratio of
99mTc-DMSA were not so high on the contrary of our expectation that 197Hg-DMSA may show the high
tumor concentration and the high
tumor to blood ratio like 197Hg
chlormerodrin as same renal scanning
radiopharmaceuticals. (c)
Tumor concentration of 99mTc-DSDP was highest.
Tumor to blood concentration ratio, however, was lower than that of the above mentioned
radiopharmaceuticals but
tumor to liver ratio and/or
tumor to lung ratio was over 1.0 at the earlier time.
Biologic distribution of 99mTc-DSDP was similar to that of 32P labeled DSDP and then it is presumed that 99mTc is labeled at
phosphate ester of DSDP which is dephospholytated immediately by phospholylase in vivo following the
intravenous injection. Therefore, it may be assumed that the accumulation mechanism of 99mTc-DSDP to Ehrlich's
tumor is related to the phospholylase activity in
neoplasms but is not known precisely.