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The purpose of this report is to present the first documented application of GammaTile to an intra-cranial tumor of a patient with a symptomatic radiosensitive connective tissue disorder, a case where there were significant concerns with standard oncologic strategies. We hypothesized that GammaTile® (GT Medical Technologies, Tempe, Arizona, USA) would also be advantageous in the application of intra-cranial tumors in patients with conditions of increased radiosensitivity. We generated a standard external beam radiation therapy (EBRT) plan consisting of an overall 1.5 cm expansion to 59.4 Gy in 1.8 Gy fractions. Also, we developed a CyberKnife (Accuray, Sunnyvale, CA, USA) plan with a 5 mm expansion on the surgical cavity prescribed to 60 Gy in 30 fractions, to make an EBRT comparison using the same prescription volume as GammaTile. We report the first published application of GammaTile® brachytherapy to an intra-cranial malignancy in a patient with limited scleroderma. The dose delivered by GammaTile was compared to the dose that would be delivered with both typical volumes and small volumes of EBRT. The maximum dose delivered to the scar and scalp by GammaTile was reduced to half of that from other external beam techniques (~25 Gy vs. ~55 Gy). MRI imaging at 6 months and 12 months post-resection demonstrated no evidence of disease recurrence nor radiation necrosis. At the 12-month follow-up visit, the surgical scar was well-healed with no skin changes to the surrounding scalp. Dosimetrically and clinically, this report highlights the successful application of GammaTile to an intra-cranial tumor bed in a patient with scleroderma. [ABSTRACT FROM AUTHOR]

Background: Cone beam CT (CBCT) imaging has been integrated into the most recent version of the Leksell Gamma Knife for the primary purpose to facilitate fractionated therapy. Case description: This case study presents three patients where the CBCT system of the Gamma Knife Icon discovered potentially clinically significant frame shifts. In each case, patients were imaged with volumetric MR prior to stereotactic frame placement. Immediately following frame placement, diagnostic stereotactic CT imaging was acquired with a stereotactic indicator box attached to the frame. Following treatment planning and immediately before radiosurgery, a CBCT was acquired using the on-board imaging functionality of the Gamma Knife Icon, which provides a registration of the patient's anatomy to stereotactic space independent of that provided by the stereotactic frame/fiducials. Co-registration of the CT and CBCT provides an estimate of the difference between these two estimates of stereotactic coordinates. The vector magnitudes of the differences measured at the center of stereotactic space were 0.93mm, 2.64mm and 2.18 mm for Case 1, Case 2 and Case 3 respectively. Conclusions: Use of the CBCT functionality of the Gamma Knife Icon to verify the consistency of frame placement can prevent clinically significant targeting errors due to frame slippage or frame adapter mounting errors, and allows any required adjustments to be made without interrupting the overall treatment workflow. [ABSTRACT FROM AUTHOR]

Background: Cone beam CT (CBCT) imaging has been integrated into the most recent version of the Leksell Gamma Knife for the primary purpose to facilitate fractionated therapy. Case description: This case study presents three patients where the CBCT system of the Gamma Knife Icon discovered potentially clinically significant frame shifts. In each case, patients were imaged with volumetric MR prior to stereotactic frame placement. Immediately following frame placement, diagnostic stereotactic CT imaging was acquired with a stereotactic indicator box attached to the frame. Following treatment planning and immediately before radiosurgery, a CBCT was acquired using the on-board imaging functionality of the Gamma Knife Icon, which provides a registration of the patient's anatomy to stereotactic space independent of that provided by the stereotactic frame/fiducials. Co-registration of the CT and CBCT provides an estimate of the difference between these two estimates of stereotactic coordinates. The vector magnitudes of the differences measured at the center of stereotactic space were 0.93mm, 2.64mm and 2.18 mm for Case 1, Case 2 and Case 3 respectively. Conclusions: Use of the CBCT functionality of the Gamma Knife Icon to verify the consistency of frame placement can prevent clinically significant targeting errors due to frame slippage or frame adapter mounting errors, and allows any required adjustments to be made without interrupting the overall treatment workflow. [ABSTRACT FROM AUTHOR]

Background: Cone beam CT (CBCT) imaging has been integrated into the most recent version of the Leksell Gamma Knife for the primary purpose to facilitate fractionated therapy., Case Description: This case study presents three patients where the CBCT system of the Gamma Knife Icon discovered potentially clinically significant frame shifts. In each case, patients were imaged with volumetric MR prior to stereotactic frame placement. Immediately following frame placement, diagnostic stereotactic CT imaging was acquired with a stereotactic indicator box attached to the frame. Following treatment planning and immediately before radiosurgery, a CBCT was acquired using the on-board imaging functionality of the Gamma Knife Icon, which provides a registration of the patient's anatomy to stereotactic space independent of that provided by the stereotactic frame/fiducials. Co-registration of the CT and CBCT provides an estimate of the difference between these two estimates of stereotactic coordinates. The vector magnitudes of the differences measured at the center of stereotactic space were 0.93mm, 2.64mm and 2.18 mm for Case 1, Case 2 and Case 3 respectively., Conclusions: Use of the CBCT functionality of the Gamma Knife Icon to verify the consistency of frame placement can prevent clinically significant targeting errors due to frame slippage or frame adapter mounting errors, and allows any required adjustments to be made without interrupting the overall treatment workflow., Competing Interests: Authors’ disclosure of potential conflicts of interest Dr. Schlesinger reports grant from Elekta Instrument, AB, outside the submitted work. Dr. Trifiletti reports other support from Novocure, outside the submitted work. Drs. Dutta, Larner, Peach and Sheehan have nothing to disclose.