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Showing 3 results for Whole Brain Radiotherapy
Dr. G. Yavas, C. Yavas, O.v. Gul, H. Acar, O. Ata,
Volume 12, Issue 4 (10-2014)
Abstract
Background: Palliative whole brain radiotherapy (WBRT) has been the standard treatment for brain metastases. Ionizing radiation is known to be one of the most potent cataractogenic agents. We aimed to evaluate two different radiotherapy techniques with respect to the doses received by the organs at risk (OAR) in patients with brain metastasis who undergone WBRT. Materials and Methods: Ten consecutive patients with brain metastasis were included. For each patient, two different treatment plans were created for whole brain. Helmet-field (HF) (anterior border was 2 cm posterior to lens, inferior border was the bottom of C2 vertebra) and classical technique with collimation (CT) (anterior border was defined as skin fall off, inferior border was the bottom of cranial base) were generated for all patients. Two techniques were compared with respect to the doses received by the OAR including bilateral lenses, optic nerves and eye-balls, the dose homogeneity index (DHI), and the monitor unit counts (MU) required for the treatment. Student-t test was used for statistical analysis. Results: There was no difference between two techniques in terms of both DHI (p: 0.182) and MU counts (p: 0.167). The maximum and mean doses received by the right lens, left lens and right eye-ball were significantly reduced with CT (p values for maximum doses 0.007, 0.012 and 0.010 for median doses 0.027, 0.046 and 0.002 respectively). Conclusion: CT was found to be more advantageous, with respect to the lens doses in addition the dose received by the right eye-ball during WBRT.
Ph.d., R. Vysakh, R. Ganapathi Raman, S.o. Muhammed, N. Puzhakkkal,
Volume 21, Issue 1 (1-2023)
Abstract
Background: Treatment planning for Hippocampal avoidance whole-brain radiotherapy (ha-WBRT) is demanding and time-consuming due to the position of the Hippocampus and low dose tolerances. This study evaluates the feasibility of fixed field volumetric modulated arc therapy (fVMAT) for ha-WBRT using the Elekta Agility™ collimator system and Monaco treatment planning system. Materials and Methods: Fifteen patients treated for WBRT were subjected to fVMAT and conventional VMAT (cVMAT) planning with similar optimisation criteria. Jaws were restricted above and below the Hippocampus for the fVMAT plans with isocenter positioned at the brain's center, dividing the brain target into two. In contrast, Jaws were not restricted for cVMAT plans. Plans were compared in terms of dose constraints, dose conformity, and dose homogeneity. Plan complexity was compared in terms of modulation degree (MD), and delivery efficiency was checked by performing patient-specific quality assurance. Results: Both plans met the RTOG-0933 dose requirements. The fVMAT plans showed statistically significant improved target coverage (D98%, V30Gy), target homogeneity, and conformity. There was no statistically significant change in hippocampus doses between the two plans. The fVMAT plans showed lesser plan complexity with average MD of 3.34±0.5 compared to cVMAT plans (average MD of 4.21±0.4, p=0.00011). The increased plan complexity was reflected in the delivery efficiency as cVMAT showed higher average gamma failure for patient3.84%(p=0.0004) and a target volume 7.13% (p=0.0359) structures. Conclusions: According to the obtained results, the Elekta Agility™ collimator system and Monaco treatment planning system can generate better ha-WBRT plans using the fVMAT technique.
S. Muthu, G. Mudhana,
Volume 23, Issue 2 (5-2025)
Abstract
Background: This study assessed the efficacy of HyperArc planning for whole-brain radiation therapy (WBRT) with hippocampal sparing, comparing it to conventional coplanar volumetric modulated arc therapy (VMAT) techniques using high-definition multileaf-collimators (HDMLC) and millennium MLC (MMLC). Materials and Methods: In this retrospective study, 25 patients with brain metastases received hippocampus-sparing WBRT by RTOG-0933 trial guidelines. Three treatment plans (HyperArc, VMAT-HDMLC, VMAT-MMLC) were created using Eclipse v16.1 Treatment Planning System (TPS), with a prescribed dose of 30Gy in 10 fractions. The Dosimetric parameters assessed included D98%, D2%, HI, Dmax for PTVeval, and Dmax, Dmean, and D100% for hippocampus and other critical structures. Additionally, Monitor Units (MUs) and delivery checks using portal dosimetry were considered. Results: All plans met RTOG-0933 criteria for PTV and OARs. HyperArc matched VMAT-HDMLC in D98% (28.41 Gy vs. 28.38 Gy), outperforming VMAT-MMLC (28.04 Gy). HyperArc surpassed both VMAT techniques in D2% (32.83 Gy vs. 33.24 Gy vs. 34.06 Gy), HI (0.14 vs. 0.15 vs. 0.18), and Dmax (34.84 Gy vs. 35.5 Gy vs. 36.36 Gy). In hippocampus sparing, HyperArc achieved lower Dmax (12.99 Gy vs. 13.73 Gy vs. 14.76 Gy), Dmean (9.58 Gy vs. 10.23 Gy vs. 10.64 Gy), and D100% (8.25 Gy vs. 8.70 Gy vs. 8.85 Gy) values. Further, the HyperArc method provided better organ-at-risk sparing and higher gamma results. Conclusion: All three methods met RTOG-0933 dosimetric goals, with HyperArc outperforming VMAT. Optimized VMAT collimator angles at 0° and 90° improved organ-at-risk doses, exceeding conventional planning in PTV coverage and hippocampal sparing.
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