Effect of cerenkov radiation-induced photodynamic therapy with¹⁸f-fdg in an intraperitoneal xenograft mouse model of ovarian cancer

Ovarian cancer (OC) metastases frequently occur through peritoneal dissemination, and they contribute to difficulties in treatment. While photodynamic therapy (PDT) has the potential to treat OC, its use is often limited by tissue penetration depth and tumor selectivity. Herein, we com-bined Cerenkov radiation (CR) emitted by¹⁸F-FDG accumulated in tumors as an internal light source and several photosensitizer (PS) candidates with matched absorption bands, including Ver-teporfin (VP), Chlorin e6 (Ce6) and 5′-Aminolevulinic acid (5′-ALA), to evaluate the anti-tumor ef-ficacy. The in vitro effect of CR-induced PDT (CR-PDT) was evaluated using a cell viability assay, and the efficiency of PS was assessed by measuring the singlet oxygen production. An intraperito-neal ES2 OC mouse model was used for in vivo evaluation of CR-PDT. Positron emission tomogra-phy (PET) imaging and bioluminescence-based imaging were performed to monitor the biologic uptake of¹⁸F-FDG and the therapeutic effect. The in vitro studies demonstrated Ce6 and VP to be more effective PSs for CR-PDT. Moreover, VP was more efficient in the generation of singlet oxygen and continued for a long time when exposed to fluoro-18 (¹⁸F). Combining CR emitted by¹⁸F-FDG and VP treatment not only significantly suppressed tumor growth, but also prolonged median survival times compared to either monotherapy.