Labeling of diethylenetriamine-N,N,N0,N00,N00-
pentakis(methylenephosphonic) acid (DTPMP) with rhenium-
188 using stannous chloride as a reducing agent has
been investigated. Dependence of the yield of the 188Re–
DTPMP complex on the concentration of the reducing
agent, pH, reaction time, temperature, ascorbic acid and
amount of carrier added has been studied. Under optimum
conditions, the labeling yield of 188Re–DTPMP complex is
95% for the carrier-free 188Re but with the carrier-added
188Re the labeling yield is more than 97%. Furthermore, the
stability of the 188Re–DTPMP complex against pH change
and dilution with saline has been also studied. It is found
that the addition of carrier stabilizes the 188Re–DTPMP
complex against pH change and dilution.