Relation of Radiation Dose with Cranial Nerve Preservation and Tumor Control in Acoustic Neuroma Treated with Gamma Knife SurgeryKeywords: vestibular schwannoma, outcome, gamma knife, radiosurgery, hearing preservationInteractive ManuscriptAsk Questions of this Manuscript: What is the background behind your study?The utility of L-methyl-11Cmethionine (11C-Met) PET for diagnosing various malignant brain tumors has been demonstrated. What is the purpose of your study?Based on our experiences with malignant brain tumor patients treated undergoing gamma knife radiosurgery (GKRS), we describe how this imaging technique can be applied to dose planning. Describe your patient group.This question was not answered by the author Describe what you did.The authors present 142 GKRS procedures for malignant brain tumors (malignant glioma; 56, metastatic brain tumor; 77, others; 5), using MR and 11C-Met PET images for dose planning, all conducted between July, 2005 and August, 2011. Before May, 2009 (89 procedures), 11C-Met PET images were fused with stereotactic post-contrast MR images using a personal computer; the application software used for fusing the two images was Dr. View (Asahi Kasei Information Systems, Co., Ltd., Tokyo). The fusion images were transferred into the Leksell GammaPlan System. After June, 2009, when Gamma Plan ver 8.0 became available, the coregistration function of 11C-Met PET images to stereotactic post-contrast MR images was used in 53 procedures. Describe your main findings.The earlier fusion technique required meticulous manipulations which could only be performed by highly experienced physicians or technicians. Also, it was time-consuming. However, a threshold level of 11C-Met uptake could be numerically determined the using standardized uptake value (SUV) with this technique. On the other hand, while the coregistration technique is very easy and quick, and does not require experienced personnel, a threshold level of 11C-Met uptake cannot be numerically determined using SUV. Describe the main limitation of this study.This question was not answered by the author Describe your main conclusion.Further advancements in the Gamma Plan System are expected to allow a threshold level of 11C-Met uptake to be numerically determined based on SUV. Describe the importance of your findings and how they can be used by others.Advanced image fusion techniques will be important for radiosurgical planning. The utility of L-methyl-11Cmethionine (11C-Met) PET for diagnosing various malignant brain tumors has been demonstrated. Based on our experiences with malignant brain tumor patients treated undergoing gamma knife radiosurgery (GKRS), we describe how this imaging technique can be applied to dose planning. The authors present 142 GKRS procedures for malignant brain tumors (malignant glioma; 56, metastatic brain tumor; 77, others; 5), using MR and 11C-Met PET images for dose planning, all conducted between July, 2005 and August, 2011. Before May, 2009 (89 procedures), 11C-Met PET images were fused with stereotactic post-contrast MR images using a personal computer; the application software used for fusing the two images was Dr. View (Asahi Kasei Information Systems, Co., Ltd., Tokyo). The fusion images were transferred into the Leksell GammaPlan System. After June, 2009, when Gamma Plan ver 8.0 became available, the coregistration function of 11C-Met PET images to stereotactic post-contrast MR images was used in 53 procedures. The earlier fusion technique required meticulous manipulations which could only be performed by highly experienced physicians or technicians. Also, it was time-consuming. However, a threshold level of 11C-Met uptake could be numerically determined the using standardized uptake value (SUV) with this technique. On the other hand, while the coregistration technique is very easy and quick, and does not require experienced personnel, a threshold level of 11C-Met uptake cannot be numerically determined using SUV.
Further advancements in the Gamma Plan System are expected to allow a threshold level of 11C-Met uptake to be numerically determined based on SUV. Advanced image fusion techniques will be important for radiosurgical planning. Project Roles:
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