Fumitaka Matsuda1, Naokado Ikeda2, Yoshinaga Kajimoto1, Naosuke Nonoguchi1, Koji Takeuchi1, Masao Fukumura1, Shinji Kawabata1, Motomasa Furuse1, Tetsuo Sugano3, Taku Sato4, Kiyoshi Saito4, Toshihiko Kuroiwa1. 1. Department of Neurosurgery and Endovascular Neurosurgery, Osaka Medical College, 2-7 Daigaku-Machi, Takatsuki, Osaka 569-8686, Japan. 2. Department of Neurosurgery and Endovascular Neurosurgery, Osaka Medical College, 2-7 Daigaku-Machi, Takatsuki, Osaka 569-8686, Japan. Electronic address: neu098@osaka-med.ac.jp. 3. Mitsubishi Electric Engineering Co., Ltd., 1 Baba-Zusho, Nagaokakyo, Kyoto 617-8550, Japan. 4. Department of Neurosurgery, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima 960-1295, Japan.
Abstract
BACKGROUND: Fluorescence image guided surgery (FIGS) with 5-aminolevulinic acid for malignant gliomas improves surgical outcome. One of the problems during FIGS is photobleaching under surgical microscopic white light. A solid laser-based white light source for neurosurgery that we developed does not include light with a wavelength of around 405nm, which is strongly absorbed by protoporphyrin IX. In the present study, we examined the efficacy of this light source to prevent the photobleaching of protoporphyrin IX-induced fluorescence. METHODS: Filter papers transfused with protoporphyrin IX solution and a coronally sectioned F98 glioma rat model pretreated with 50mg/kg 5-aminolevulinic acid were continuously exposed to white light. One group was exposed to conventional xenon-based white light and another group was exposed to laser-based white light. Fluorescence at a wavelength of 635nm was measured with a radiospectrometer (in vitro study) and the relative fluorescence brightness was also measured in digital images (in vivo study) under excitation from violet blue light emitted from diodes every 5min. RESULTS AND CONCLUSION: Estimated time for 50% photobleaching was prolonged about two times in the laser-based white light exposure group compared with that in the xenon-based white light exposure group (9.1/18.7min). In the brain tumor rat model, it was also prolonged about 2.7 times (15.1/40.7min). A laser-based white light source may inhibit photobleaching during FIGS for malignant gliomas. This light source for neurosurgical microscopy has the potential to prolong the prognosis of malignant glioma patients.
BACKGROUND: Fluorescence image guided surgery (FIGS) with 5-aminolevulinic acid for malignant gliomas improves surgical outcome. One of the problems during FIGS is photobleaching under surgical microscopic white light. A solid laser-based white light source for neurosurgery that we developed does not include light with a wavelength of around 405nm, which is strongly absorbed by protoporphyrin IX. In the present study, we examined the efficacy of this light source to prevent the photobleaching of protoporphyrin IX-induced fluorescence. METHODS: Filter papers transfused with protoporphyrin IX solution and a coronally sectioned F98 gliomarat model pretreated with 50mg/kg 5-aminolevulinic acid were continuously exposed to white light. One group was exposed to conventional xenon-based white light and another group was exposed to laser-based white light. Fluorescence at a wavelength of 635nm was measured with a radiospectrometer (in vitro study) and the relative fluorescence brightness was also measured in digital images (in vivo study) under excitation from violet blue light emitted from diodes every 5min. RESULTS AND CONCLUSION: Estimated time for 50% photobleaching was prolonged about two times in the laser-based white light exposure group compared with that in the xenon-based white light exposure group (9.1/18.7min). In the brain tumorrat model, it was also prolonged about 2.7 times (15.1/40.7min). A laser-based white light source may inhibit photobleaching during FIGS for malignant gliomas. This light source for neurosurgical microscopy has the potential to prolong the prognosis of malignant gliomapatients.