In vivo 19F MR Studies of Fluorine Labeled Photosensitizers in a Murine Tumor Model

The main focus of this report is the MR spectroscopy of the changes in the concentration of fluorine labeled photosensitizer that occur following the IP administration. This process is studied by 19F in vivo MR methodology in a murine tumor model. The animal model used in these studies was mice bearing radiation induced fibrosarcoma (RIF) tumor on the foot dorsum. The mice were injected with a solution of ∼ 100 micro-moles of the fluorinated photosensitizer and the 19F MR examination of the photosensitizer in the tumor or the muscle was performed. The pharmacokinetic (PK) profile for each labeled compound was generated using the 19F MR data at various time points post photosensitizer administration. The pharmacokinetic parameters were analyzed and the relationship of these results to photodynamic therapy is discussed. 19F MR methods clearly demonstrate utility in measuring the pharmacokinetic profiles and provide a new approach in the evaluation of appropriate photosensitizers for use in preclinical mammalian systems.