In glioma resection, accurate detection of tumor region is absolutely imperative because most of malignant glioma has a property of infiltration to normal brain tissues. At the same time, since there is a high relationship between tumor resection rate and patient prognosis, it is required to extirpate tumor as much as possible. We developed an intraoperative spectrum measurement system for 5-aminolaevulinic acid induced protoporphrin IX (PpIX) fluorescence, which includes a semiconductor LASER, a CCD spectrometer, a personal computer and a fluorescence measurement probe which weight is about 25g. In the probe, fluorescence and an excitation light path are completely coaxial using a dichroic mirror. We evaluated performances of the probe using agar gels that have similar optical properties to brain tissues. Results showed that the probe possesses sufficient ability to measure PpIX fluorescence with a spatial resolution of about 0.8mm around working-distance. 7 examinee measured error distance from working distance to evaluate positional stability with handheld. The result showed that there were fluctuations less than 5mm from appropriate probe location, such a little positional error doesn' t affect fluorescence measurement.
