Radio-guided Brain Tumorectomy using a Gamma Detecting Probe and a Mobile Solid-state Gamma Camera Toyoyuki Kojima, M.D.,* Shin-ichiro Kumita, M.D.,† Fumio Yamaguchi, M.D., Ph.D.,* Sunao Mizumura, M.D.,† Takayuki Kitamura, M.D., Ph.D.,* Tatsuo Kumazaki, M.D., Ph.D.,† and Akira Teramoto, M.D., D.M.Sc.* *Departments of Neurosurgery and †Radiology, Nippon Medical School, Tokyo, Japan Kojima T, Kumita S, Yamaguchi F, Mizumura S, Kitamura T, Kumazaki T, Teramoto A. Radio-guided brain tumorectomy using a gamma detecting probe and a mobile solid-state gamma cam- era. Surg Neurol 2004;61:229 –38. BACKGROUND We herein report a technique to distinguish brain tumors from normal brain tissue during surgery using a gamma probe and a solid-state mobile gamma camera after 99m Tc-hexakis-2-methoxy-isobutyl-isonitrile ( 99m Tc-MIBI) is administered to patients immediately before operation. METHODS We examined 13 patients with brain tumors. Before the operation, 99m Tc-MIBI single photon emission computed tomography (SPECT) was performed to assess accumu- lation in the tumors. On the day of the operation, 99m Tc- MIBI was administered intravenously and craniotomy for tumor resection was performed. During the operation, the tumor was localized with a gamma probe and pre- removal scintigraphy images were taken with a mobile gamma camera. After tumor resection was completed, residual tumors were confirmed using it again. We com- pared accumulation found in the preoperative SPECT im- ages and intraoperative scintigraphy images, performed a histologic examination of adjacent tissues, and measured the dose the personnel was exposed to per operation. RESULTS In all patients, tumors were confirmed by a gamma probe and scintigraphy during the operation. Intraoperative ac- cumulation in tumors was significantly related to accu- mulation found in the preoperative 99m Tc-MIBI SPECT images. In 9 out of 13 patients, accumulation disappeared in the postremoval scintigraphy images, and no tumor tissue was found by histologic examination. Residual tu- mor tissue was found in 4 patients. Average exposure of the personnel per operation was 22.9  4.0 Sv. CONCLUSION Resection of brain tumors with a gamma probe and a mobile gamma camera was very useful since the area to be removed was easily identified and residual tumors could be detected. © 2004 Elsevier Inc. All rights reserved. KEY WORDS Brain neoplasms, technetium Tc 99m sestamibi, gamma cameras, scintillation counting, radionuclide imaging, sur- gery, computer-assisted. I n patients undergoing surgery to resect a brain tumor, it is very important for their postopera- tive management that one remove as much tumor tissue as possible without exacerbating neurologic symptoms in a microsurgery, if possible, so that tumor tissue will not be visualized in the postoper- ative images. However, removal of just the brain tumors by macroscopically distinguishing tumors from normal brain tissue during the operation is difficult. For intraoperative differentiation, tech- niques using fluorochrome [17] or intraoperative magnetic resonance imaging (MRI) [3,18] or com- puted tomography (CT) [4,8] scans to confirm the presence/absence of residual tumors have been re- ported. However, techniques using radioactivity uptake by tumor tissue to visualize brain tumors during surgery have not been reported. The myocardial perfusion imaging agent 99m Tc- hexakis-2-methoxy-isobutyl-isonitrile ( 99m Tc-MIBI) shows affinity for various tumors and has been used to visualize tumors [1,9,12,15]. We herein report a technique to distinguish brain tumors from normal brain tissue during surgery using a gamma probe and a semiconductor mobile gamma camera after 99m Tc-MIBI is administered to patients immediately before operation. Methods Before the study, we obtained the approval from the ethics committee of our hospital and informed Address reprint requests to: Toyoyuki Kojima, M.D., Home address 3-3-31 Minamiazabu, Minato-ku, Tokyo 106-0047 Japan. Received April 14, 2003; accepted July 23, 2003. © 2004 Elsevier Inc. All rights reserved. 0090-3019/04/$–see front matter 360 Park Avenue South, New York, NY 10010 –1710 doi:10.1016/j.surneu.2003.07.015