Absorption and preferential vagina-to-uterus distribution after vaginal administration of Tc-99m-pertechnetate in postmenopausal women

Objective: To investigate in vivo and in humans the mechanisms and kinetics of vagina-to-uterus distribution. Design: Controlled clinical study. Setting: Volunteers in an academic research environment. Patient(s): Six postmenopausal women undergoing transabdominal hysterectomy were selected. Intervention(s): Women received 0.2 mL of Tc-99m-pertechnetate vaginally. I n three patients the cervical canal was previously sealed by means of surgi cal glue. Six postmenopausal women who had received Tc-99m-pertechnetate in travenously for a thyroid scintigraphy were considered as a control. Main Outcome Measure(s): Radioactivity was assessed every 30 minutes for 6 hours in the pelvis and in body regions where Tc-99m-pertechnetate normally accumulates (thyroid, salivary glands, and stomach). Result(s): Uterine activity appeared after 60 minutes and peaked between 12 0 to 210 minutes. These same times were observed in the patients who had a sealed cervix. Thyroid uptake appeared after 180 minutes and peaked between 210 and 330 minutes. Uterine uptake did not occur in any of the intravenou s patients; their thyroid uptake was rapid, appearing after 30 minutes. Conclusion(s): Preferential vagina-to-uterus distribution, at least in post menopausal women, is not simply due an intracanalicular passage but is medi ated by absorption of substances and probably by a countercurrent transfer mechanism. (Fertil Steril (R) 2001;76:1108-12. (C) 2001 by American Society for Reproductive Medicine.).