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Chun Po Yen, Jason Sheehan, Greg Patterson and Ladislau Steiner

involved the third ventricle. Two patients developed a new lesion in a location different from that of the previously treated lesion 2.5 and 4 years following GKS, and they underwent a second GKS. On MR images, all tumors were isointense to gray matter of the brain. The enhancement was variable including eight with mild to moderate enhancement and one without enhancement. The tumor volume at the time of GKS ranged from 1.4 to 19.8 cm 3 (mean 6 cm 3 ). Gamma Knife Surgery Technique The procedure has been detailed elsewhere. 31 Briefly, a stereotactic frame was

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Masao Tago, Atsuro Terahara, Masahiro Shin, Keisuke Maruyama, Hiroki Kurita, Keiichi Nakagawa and Kuni Ohtomo

–40)  median margin dose (range) 20 (18–20) Gamma knife surgery was performed using the Leksell gamma knife models (Elekta Instrument AB, Stockholm, Sweden). Treatment planning was performed using KULA or Leksell GammaPlan (Elekta Instruments AB) and stereotactic computerized tomography or MR images. The treatment protocol calls for the irradiation of the enhanced mass with a margin dose of 20 Gy. In cystic tumors only the mural nodule is targeted. In this series, all tumor margins were covered by the 50% isodose. Twenty-eight tumors received 20 Gy to the

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Gamma Knife surgery–induced meningioma

Report of two cases and review of the literature

Jason Sheehan, Chun PO Yen and Ladislau Steiner

– 713 , 2001 13 Karlsson B , Lindquist C , Steiner L : Prediction of obliteration after gamma knife surgery for cerebral arteriovenous malformations . Neurosurgery 40 : 425 – 431 , 1997 14 Kuratsu J , Takeshima H , Ushio Y : Trends in the incidence of primary intracranial tumors in Kumamoto, Japan . Int J Clin Oncol 6 : 183 – 191 , 2001 15 Liwnicz BH , Berger TS , Liwnicz RG , Aron BS : Radiation-associated gliomas: a report of four cases and analysis of postradiation tumors of the central nervous system . Neurosurgery

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Mooseong Kim, Sunghwa Paeng, Seyoung Pyo, Yeonggyun Jeong, Sunil Lee and Yongtae Jung

control, endocrinological improvement, and minimal complications. In invasive pituitary macroadenomas, complete resection is difficult without causing complications. Gamma Knife surgery for pituitary tumor achieves good treatment outcomes in terms of both tumor control and hormone control. Authors of several reports showed a tumor control rate between 64.7 and 94%, a hormone control rate between 81.8 and 100%, and a complication rate between 4.7 and 20%. Comparably, the fractionated radiotherapy group showed a tumor control rate between 76 and 97%, a hormone control

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Toru Serizawa, Masaaki Yamamoto, Osamu Nagano, Yoshinori Higuchi, Shinji Matsuda, Junichi Ono, Yasuo Iwadate and Naokatsu Saeki

major institutes according to the same local treatment strategies for metastases without prophylactic WBRT, as we previously reported. 4–8 This 2-institute study demonstrated no significant institutional differences in any of the treatment result items. Similarly, there were no major differences in patients. These results indicate that differences in dose planning for metastases do not affect either overall or neurological survival. Gamma Knife surgery alone for brain metastases, without prophylactic WBRT, is more widely applied in Japan than in the rest of the

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Roman Liscák, Vilibald Vladyka, Gabriela Simonová, Josef Vymazal and Josef Novotny Jr.

angiomas of the central nervous system in children. J Neurosurg 76: 38–46, 1992 37. Seo Y , Fukuoka S , Takanashi M , et al : Gamma knife surgery for angiographically occult vascular malformations. Stereotact Funct Neurosurg (suppl 1) 64 : 98 – 109 , 1995 Seo Y, Fukuoka S, Takanashi M, et al: Gamma knife surgery for angiographically occult vascular malformations. Stereotact Funct Neurosurg (suppl 1) 64: 98–109, 1995 38. Strugar J , Rothbart D , Harrington W , et al : Vascular

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Jason Sheehan, Chun Po Yen, Yasser Arkha, David Schlesinger and Ladislau Steiner

neurosurgeon is associated with a high risk of complications and tumor recurrence. Gamma Knife surgery affords a favorable risk-to-benefit profile for the treatment of small to moderately sized trigeminal schwannomas. Larger studies with open-ended follow up are needed to determine the optimal radiation dose as well as the long-term results and complication rates of GKS for trigeminal neuralgia. References 1 Akiyama T , Ikeda E , Kawase T , Yoshida K : Pseudocapsule formation after gamma knife radiosurgery for trigeminal neurinoma—case report . Neurol Med

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Cheng-Loong Liang, Kang Lu, Po-Chou Liliang and Han-Jung Chen

between March 2005 and August 2005. Gamma Knife Surgery Gamma Knife surgery was performed following the administration of a local anesthetic agent. After a Leksell model G stereotactic frame (Elekta AB) had been affixed to the head, each patient underwent stereotactic MR imaging to identify the tumor, optic nerve, and optic chiasm. Magnetic resonance imaging was performed in axial planes by using short repetition time sequences. Targeting was based on the axial images. The sequences were performed at 1-mm slice intervals. These imaging sequences provided graphic

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Dibyendu Kumar Ray, Chun Po Yen, Mary Lee Vance, Edward R. Laws, Beatriz Lopes and Jason P. Sheehan

. Follow-up to assess for clinical recurrence and delayed hypopituitarism must be performed. At our center, delayed hypopituitarism after radiosurgery has been observed in ~ 20–30% of patients with pituitary adenoma; hypopituitarism typically occurs within the first 5 years following radiosurgery. 14 Conclusions Gamma Knife surgery may be a viable treatment option for patients with lymphocytic hypophysitis in whom surgical or medical management has failed. Experience with a larger number of such patients will provide more information on this method of treatment

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Shoji Yomo, Yasser Arkha, Anne Donnet and Jean Régis

morbidity or death after microsurgical procedures is uncommon but never negligible, even in modern surgical practice. 8 , 25 , 38 Gamma Knife surgery has become established as a minimally invasive treatment for TN over the last 2 decades. 11 , 15 , 23 , 24 , 31 , 37 It would appear reasonable to apply this less invasive solution to GPN, the pathophysiology of which appears to be similar to that of TN. We have found only 1 other case in the literature of GPN treated using GKS, 34 and therefore the role of GKS in the treatment of refractory GPN remains unclear. Case