INVIVO P-31 NMR-STUDY OF COMBINED HYPERTHERMIA AND PHOTODYNAMIC THERAPIES OF MAMMARY-CARCINOMA IN THE MOUSE

Although the sequence and time interval effects of combined photodynamic therapy (PDT) and hyperthermia tumor treatments have been studied using survival curves, tumor regrowth, and cloning assays, the metabolic response to combined treatment measured by nuclear magnetic resonance (NMR) spectroscopy has not yet been clarified. In this study, mammary carcinoma in the flank of C3H mice was subjected to PDT (12.5 mg/kg Photofrin II, 632 +/- 1 nm at 200 J/cm2) and water bath hyperthermia (43.5-degrees-C, 30 min) with no delay or 4 h delay between treatments. In vivo P-31-NMR spectroscopy was employed to measure energy metabolism and pH of the tumors before and serially after treatment for up to 1 week. The data revealed significant differences in the time course of hihg energy phosphate levels between treatment combinations, which may reflect the biological effectiveness of the combined treatments. Our observations indicate that P-31-NMR spectroscopy can be used to evaluate the metabolic response of tumors to treatment with combined PDT and hyperthermia.