PURPOSE: To evaluate the geometric positioning and immobilization performance of a vacuum bite-block repositioning head frame (RHF) system for Perfexion (PFX-SRT) and linac-based intracranial image-guided stereotactic radiotherapy (SRT). METHODS AND MATERIALS: Patients with intracranial tumors received linac-based image-guided SRT using the RHF for setup and immobilization. Three hundred thirty-three fractions of radiation were delivered in 12 patients. The accuracy of the RHF was estimated for linac-based SRT with online cone-beam CT (CBCT) and for PFX-SRT with a repositioning check tool (RCT) and offline CBCT. The RCT's ability to act as a surrogate for anatomic position was estimated through comparison to CBCT image matching. Immobilization performance was evaluated daily with pre- and postdose delivery CBCT scans and RCT measurements. RESULTS: The correlation coefficient between RCT- and CBCT-reported displacements was 0.59, 0.75, 0.79 (Right, Superior, and Anterior, respectively). For image-guided linac-based SRT, the mean three-dimensional (3D) setup error was 0.8 mm with interpatient (Sigma) and interfraction (sigma) variations of 0.1 and 0.4 mm, respectively. For PFX-SRT, the initial, uncorrected mean 3D positioning displacement in stereotactic coordinates was 2.0 mm, with Sigma = 1.1 mm and sigma = 0.8 mm. Considering only RCT setups <1mm (PFX action level) the mean 3D positioning displacement reduced to 1.3 mm, with Sigma = 0.9 mm and sigma = 0.4 mm. The largest contributing systematic uncertainty was in the superior-inferior direction (mean displacement = -0.5 mm; Sigma = 0.9 mm). The largest mean rotation was 0.6 degrees in pitch. The mean 3D intrafraction motion was 0.4 +/- 0.3 mm. CONCLUSION: The RHF provides excellent immobilization for intracranial SRT and PFX-SRT. Some small systematic uncertainties in stereotactic positioning exist and must be considered when generating PFX-SRT treatment plans. The RCT provides reasonable surrogacy for internal anatomic displacement. Copyright (c) 2010 Elsevier Inc. All rights reserved.
PURPOSE: To evaluate the geometric positioning and immobilization performance of a vacuum bite-block repositioning head frame (RHF) system for Perfexion (PFX-SRT) and linac-based intracranial image-guided stereotactic radiotherapy (SRT). METHODS AND MATERIALS: Patients with intracranial tumors received linac-based image-guided SRT using the RHF for setup and immobilization. Three hundred thirty-three fractions of radiation were delivered in 12 patients. The accuracy of the RHF was estimated for linac-based SRT with online cone-beam CT (CBCT) and for PFX-SRT with a repositioning check tool (RCT) and offline CBCT. The RCT's ability to act as a surrogate for anatomic position was estimated through comparison to CBCT image matching. Immobilization performance was evaluated daily with pre- and postdose delivery CBCT scans and RCT measurements. RESULTS: The correlation coefficient between RCT- and CBCT-reported displacements was 0.59, 0.75, 0.79 (Right, Superior, and Anterior, respectively). For image-guided linac-based SRT, the mean three-dimensional (3D) setup error was 0.8 mm with interpatient (Sigma) and interfraction (sigma) variations of 0.1 and 0.4 mm, respectively. For PFX-SRT, the initial, uncorrected mean 3D positioning displacement in stereotactic coordinates was 2.0 mm, with Sigma = 1.1 mm and sigma = 0.8 mm. Considering only RCT setups <1mm (PFX action level) the mean 3D positioning displacement reduced to 1.3 mm, with Sigma = 0.9 mm and sigma = 0.4 mm. The largest contributing systematic uncertainty was in the superior-inferior direction (mean displacement = -0.5 mm; Sigma = 0.9 mm). The largest mean rotation was 0.6 degrees in pitch. The mean 3D intrafraction motion was 0.4 +/- 0.3 mm. CONCLUSION: The RHF provides excellent immobilization for intracranial SRT and PFX-SRT. Some small systematic uncertainties in stereotactic positioning exist and must be considered when generating PFX-SRT treatment plans. The RCT provides reasonable surrogacy for internal anatomic displacement. Copyright (c) 2010 Elsevier Inc. All rights reserved.
Authors: Ning Wen; Joshua Kim; Anthony Doemer; Carri Glide-Hurst; Indrin J Chetty; Chang Liu; Eric Laugeman; Ilma Xhaferllari; Akila Kumarasiri; James Victoria; Maria Bellon; Steve Kalkanis; M Salim Siddiqui; Benjamin Movsas Journal: Radiother Oncol Date: 2018-05-25 Impact factor: 6.280
Authors: Gopinath Mamballikalam; S Senthilkumar; C O Clinto; P M Ahamed Basith; R C Jaon Bos; Tems Thomas Journal: Rep Pract Oncol Radiother Date: 2021-02-25
Authors: Danushka S Seneviratne; Laura A Vallow; Austin Hadley; Timothy D Malouff; William C Stross; Steven Herchko; Deanna H Pafundi; Daniel M Trifiletti; Jennifer L Peterson Journal: J Radiosurg SBRT Date: 2020