The optimization of fluorescence imaging of brain tumor tissue differentiated from brain edema-In vivo kinetic study of 5-aminolevulinic acid and talaporfin sodium

Objective: We aimed to clarify the optimal timing for the fluorescence imaging of brain tumor tissue differentiated from brain edema after the administration of photosensitizers. Methods: We have performed an in vivo study of the kinetics of 5-aminolevulinic acid (5-ALA) in comparison with talaporfin sodium using the rat brain tumor model and rat vasogenic edema model produced by cold injury. The in vivo kinetics of 5-ALA and talaporfin sodium in brain tumor model and the vasogenic edema model was determined by a fluorescence macroscope and a microplate reader. Results: The in vivo kinetic study of 5-ALA showed mild fluorescence intensity of protoporphyrin IX (PpIX) in brain tumor differentiated from vasogenic edema. The mean lesion-to-normal-brain ratio (L/N ratio) in the group of brain tumor model 2 h after the administration of 5-ALA was 7.78 +/- 4.61, which was significantly higher (P < 0.01) than that of the vasogenic edema 2 h after the administration of 5-ALA (2.75 +/- 1.12). In vivo kinetic study of talaporfin sodium showed high fluorescence intensity and retention in brain tumor differentiated from vasogenic edema. The mean L/N ratio of the fluorescence intensity in the group of brain tumor model 12 h after the administration of talaporfin sodium was 23.1 +/- 11.9, which was significantly higher (P < 0.01) than that of the vasogenic edema 12 h after the administration (8.93 +/- 8.03). Conclusions: The optimization of fluorescence imaging of brain tumors differentiated from brain edema is possible in the case of 5-ALA within 6 h, and also possible in the case of talaporfin sodium beyond 12 h. (c) 2009 Elsevier B.V. All rights reserved.