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Jason Sheehan

Gamma Knife has its own fair share of superlatives. It is frequently considered the most accurate and precise intracranial radiosurgical platform. The device has been used to treat more than 1 million patients worldwide and, thus, is the most frequently used dedicated device for intracranial stereotactic radiosurgery. Elekta, the device’s manufacturer, recently noted the 50th anniversary of the first patient to be treated with the Leksell Gamma Knife in a clinical setting, with the patient undergoing radiosurgery for a pituitary adenoma at Sophiahemmet Hospital in

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Editorial

Radiation oncology partnership and its impact on neurosurgery

Jason Sheehan

plan, and pushing the treatment initiation button on a radiosurgical device. Also, our radiosurgical education should comprised more than a 2-day course sponsored by a device manufacturer. Radiosurgery appears deceptively simple to some, and yet the unintended consequences of poor technique, inappropriate patient selection, and misadministration can prove more disastrous than the slipping of a scalpel or microsurgical instrument. As the field of SRS is advanced, we have much to share and much to learn from our radiation oncology and other surgical colleagues

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Editorial

Radiosurgery

Jason Sheehan

proposal that volume-staged radiosurgery followed by embolization may lead to improved obliteration rates. The only major concept that has not been well defined in this series of articles is the complementary role of embolization and radiosurgery in patients with AVMs. Embolization materials and catheter delivery devices have evolved substantially over the past few years. The decision to combine embolization with radiosurgery, the objectives of the embolization procedure, the timing of the respective procedures, and the type of embolization materials used in AVM patients

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David Schlesinger, Zhiyuan Xu, Frances Taylor, Chun-Po Yen and Jason Sheehan

a vacuum-assisted dental fixation device mounted on a carbon-fiber frame to obtain noninvasive immobilization. A vac-lock–type vacuum cushion is placed posterior to the patient's head to help determine a comfortable, reproducible position. A vacuum pump, known as the “patient control unit” or PCU, serves to create suction between the patient's dental impression and the patient's palate. The vacuum level is monitored by the system to alert the operator if the suction level decreases by a threshold amount, which acts as a surrogate for patient motion. The vacuum

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Jason Sheehan and David Schlesinger

disease. 3 However, even more noteworthy, 13.1% of patients in the current study had radiosurgery as their sole treatment. There was no survival difference noted between those in whom GKS was used as a primary treatment versus a salvage treatment. Prior WBRT did not portend improved survival. It is widely known that the current Gamma Knife and other modern radiosurgical devices can be used to efficiently and safely treat patients with more than 10 brain metastases in a single session. 1 , 11 In 2002, Yamamoto and colleagues 12 reported on a series of 80 patients

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David J. Salvetti, Tara G. Nagaraja, Ian T. McNeill, Zhiyuan Xu and Jason Sheehan

salvage therapy. The practicality of treating patients with 5 or more lesions has also been greatly enhanced by the current Gamma Knife Perfexion system along with other radiosurgical devices that have increased efficiency for treating multiple lesions in a single session. Given that most patients treated with radiosurgery will succumb to systemic disease prior to intracranial dysfunction, the goal in treating intracranial metastases should be to prevent symptom progression and maintain functional status. This is accomplished through adequate tumor control. The

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Yu-Hua Huang, Tao-Chen Lee, Tsung-Han Lee, Chen-Chieh Liao, Jason Sheehan and Aij-Lie Kwan

and subsequently developed delayed brain swelling was also included in the category of secondary decompressive craniectomy. When brain swelling was limited to 1 cerebral hemisphere, unilateral hemicraniectomy was performed. For bilateral hemispheres or frontal swelling, bilateral hemicraniectomy or bifrontal craniectomy was chosen, respectively. The dura mater was opened, and the opening was extended to the bone margins. The brain surface was covered loosely by the remaining dura or an artificial dural substitute without a closure. An intracranial pressure device

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Hung-Chuan Pan, Ming-Hsi Sun, Jason Sheehan, Meei-Ling Sheu, Clayton Chi-Chang Chen, Hsu-Tung Lee, Wen-Ta Chiu and Dar-Yu Yang

ophthalmic 15 15  inferior ophthalmic 1 1  IPS 1 8  sphenopalatine 1 2  vein of Galen 0 1  cortical 1 4 Treatment Modality and Radiosurgical Dose Planning From September 2000 to September 2003, XKnife radiosurgery was the instrument we used for treatment (Clinical 21 EX, Varian Medical System), and for every patient we performed quality accuracy assurance each time. 6 From October 2003 to August 2008, the Gamma Knife model C (Elekta Instruments AB) was the radiosurgical device used to treat patients. The beam accuracy

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Sheng-Tzung Tsai, Hsin-Chi Tsai, Chung-Chih Kuo, Hsiang-Yi Hung, Chien-Hui Lee and Shin-Yuan Chen

median 24-month follow-up. We are conducting an ongoing study of deep brain stimulation (DBS) for OCD in Asia, which makes us interested in Dr. Sheehan's report. As he mentioned, growing evidence shows that GKS could provide OCD patients unwilling to undergo DBS or radiofrequency ablation with a safer approach and reasonable improvement. 3 Although the precise correlation between radiosurgical technique and patient outcome will be confirmed in future larger trials, a placebo effect cannot be eliminated in such a non-blinded treatment and device study. In 2009, the

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Stephen Monteith, Jason Sheehan, Ricky Medel, Max Wintermark, Matthew Eames, John Snell, Neal F. Kassell and W. Jeff Elias

ultrasound energy to be electrically steered in such a way that the defocusing effect of the human calvaria is obviated. In one such device, 1024 individual ultrasound elements are arranged in a hemispheric orientation to allow ultrasound energy to be focused on a central point in the brain (ExAblate Neuro, InSightec; Fig. 1 ). Hynynen et al. 19 , 20 demonstrated the feasibility of treating intracranial lesions with animal models prior to the development and use of such systems in humans. McDannold et al. 34 then went on to successfully treat 3 patients with