Photodetection with 5-aminolevulinic acid-induced protoporphyrin IX in therat abdominal cavity: Drug-dose-dependent fluorescence kinetics

In 75% of cases, ovarian carcinoma has already metastasized in the abdomina l cavity at the time of diagnosis. For determination of the necessity for a supplementary therapy, in addition to surgical resection, it is important to localize and stage microscopical intraperitoneal metastases of the tumor , Intraperitoneal photodetection of tumor metastases is based on preferenti al tumor distribution of a fluorescent tumor marker. The time-dependent dif ferences in drug concentration between tumor and normal (T/N) tissues can b e used to visualize small tumors. We performed fluorescence measurements on abdominal organs and tumor in the peritoneal cavity of rats. 5-Aminolevuli nic acid (ALA)-induced protoporphyrin IX (PpIX) was used as the fluorescent marker, Three different drug doses (100, 25 and 5 mg/kg) were used and PpI X fluorescence profiles were followed up to 24 h after intravenous administ ration. Maximum T/N ratios were found 2-3 h after administration of ALA wit h all drug doses. A significant T/N tissue contrast was obtained for all ab dominal organs tested after administration of 5 mg/kg.