We compared treatment plan quality based on target coverage and normal brain tissue sparing for two intracranial stereotactic radiosurgery systems: TrueBeam STx using VMAT and Gamma Knife (GK). Ten patients with 24 tumors (seven with 1-2 and three with 4-6 ranging from 0.1 to 20.2 cc), previously treated with GK Model 4C (prescription doses ranging from 14-23 Gy), were re-planned for VMAT using Eclipse treatment planning system. Various photon beam energies and MLC leaf widths with and without jaw tracking were studied to achieve optimal plans. Plan qualities were assessed by target coverages using Paddick Conformity Index (PCI), normal-brain-tissue integral dose (Gy-cc) and sparing. In all cases critical structure dose criteria were met. The average PCI was 0.76±0.21 for VMAT and 0.46±0.20 for GK plans (p≤0.001), respectively. On average 81% reduction of 12 Gy normal-brain-tissue volumes was achieved by VMAT. The average integral dose ratio of GK to VMAT plans was 1.50±0.61 (p=0.006). VMAT was capable of producing higher quality treatment plans in terms of target coverage and normal brain tissue sparing than GK while using optimal beam geometries and optimization techniques.
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Neurosurgery
January 2025
Department of Biomedical Sciences, Humanitas University, Milan, Italy.
Background And Objectives: Understanding and managing seizure activity is crucial in neuro-oncology, especially for highly epileptogenic lesions like isocitrate dehydrogenase (IDH)-mutant gliomas. Advanced MRI techniques such as diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) have been used to describe microstructural changes associated with epilepsy. However, their role in tumor-related epilepsy (TRE) remains unclear.
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January 2025
Radiation Safety and Quality Assurance division, National Cancer Center Hospital East, Chiba, 277-8577, Japan.
The impact of three-dimensional (3D) dose delivery accuracy of C-arm linacs on the planning target volume (PTV) margin was evaluated for non-coplanar intracranial stereotactic radiosurgery (SRS). A multi-institutional 3D starshot test using beams from seven directions was conducted at 22 clinics using Varian and Elekta linacs with X-ray CT-based polymer gel dosimeters. Variability in dose delivery accuracy was observed, with the distance between the imaging isocenter and each beam exceeding 1 mm at one institution for Varian and nine institutions for Elekta.
View Article and Find Full Text PDFPhys Med Biol
January 2025
Radiotherapy and Radiosurgery department, Iatropolis Clinic, 54 Ethnikis Antistaseos ave., Athens, Attica, 15231, GREECE.
Using the concept of biologically effective dose (BED), the effect of sublethal DNA damage repair (SLR) on the bio-efficacy of prolonged radiotherapy treatments can be quantified (BED). Such treatments, lasting more than 20 min, are typically encountered in stereotactic radiosurgery (SRS) applications using the CyberKnife (CK) and Gamma knife systems. Evaluating the plan data from 45 Vestibular Schwannoma (VS) cases treated with single fraction CK-SRS, this work demonstrates a statistically significant correlation between the marginal BEDSLR delivered to the target (m-BEDSLR) and the ratio of the mean collimator size weighted by the fraction of total beams delivered with each collimator ((_w^m)Cs), to the tumor volume (Tv).
View Article and Find Full Text PDFMed Dosim
January 2025
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Most of conventional 2-dimensional (2D) methods verify dose of multiple targets separately one-by-one for Single-isocenter Multiple-target (SIMT) brain plans, which are inefficient and sub-optimal. This study presented a practical method to verify the dose of 2 targets simultaneously for improved efficiency and accuracy. Fifteen Stereotactic Radiation Therapy (SRT) and sixteen Stereotactic Radiosurgery (SRS) plans were used for this study.
View Article and Find Full Text PDFActa Neurochir (Wien)
January 2025
Department of Neurosurgery and Neurooncology, Medical University of Lodz, Barlicki University Hospital, Lodz, Poland.
Background: The internal venous system of the brain is a crucial anatomical landmark during accesses to the third ventricle through the foramen of Monro. Many classifications based on radiological assessment of the system have been developed, but they tend to be descriptive and do not highlight favorable anatomical variants. The aim of our study was to create a system based on morphometric measurements to facilitate preoperative decision-making regarding access to third ventricle tumors.
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