An estrogen derivative, β-estradiol or 1,3,5,(10)-estratriene-3,17β-diol) attached to diethylenetriamine pentaacetic acid
(DTPA) was synthesized in six experimental steps. At the end of these steps, a DTPA-attached estradiol derivative called deoxy-demethyl
homoestradiolyl-diethylenetriamine-pentaacetic acid (ESTDTPA) was obtained. The synthesized compounds were labeled with 99mTc. Thin layer radio chromatography (TLRC) was used to determine radiochemical yields and stabilities.Structural investigations
confirmed the structures. The labeling yield was satisfactory (about 95%), and 99mTc-ESTDPTA was stable in neutral medium at room temperature for 5 hours. Biodistribution studies were performed on normal
and DMBA-induced, tumor bearing female Albino Wistar rats. The activity per gram tissue was calculated, and time-activity
curves were plotted. ESTDTPA uptake by uterus reached a level of 20.73% dose/g, showing a maximum within 5 minutes after injection.
Ovary and breast showed similar biodistribution profiles. The kidneys, which are the primary organs of metabolism and excretion
of estrogen, showed a high 99mTc-ESTDTPA uptake. The imaging studies were performed on normal and tumor bearing female Albino Wistar rats using a Camstar
XR/T gamma-camera. Gamma-scintigraphy studies showed that tumors could be well visualized in a few minutes and clearly differentiated
from other organs, such as bladder and liver by 24 hours.