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Edvardsson A, Gorgisyan J, Andersson KM, Vallhagen Dahlgren C, Dasu A, Gram D, Björk-Eriksson T, Munck af Rosenschöld P. Robustness and dosimetric verification of hippocampal-sparing craniospinal pencil beam scanning proton plans for pediatric medulloblastoma. Phys Imaging Radiat Oncol 2024; 29:100555. [PMID: 38405431 PMCID: PMC10891325 DOI: 10.1016/j.phro.2024.100555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Background and Purpose Hippocampal-sparing (HS) is a method that can potentially reduce late cognitive complications for pediatric medulloblastoma (MB) patients treated with craniospinal proton therapy (PT). The aim of this study was to investigate robustness and dosimetric plan verification of pencil beam scanning HS PT. Materials and Methods HS and non-HS PT plans for the whole brain part of craniospinal treatment were created for 15 pediatric MB patients. A robust evaluation of the plans was performed. Plans were recalculated in a water phantom and measured field-by-field using an ion chamber detector at depths corresponding to the central part of hippocampi. All HS and non-HS fields were measured with the standard resolution of the detector and in addition 16 HS fields were measured with high resolution. Measured and planned dose distributions were compared using gamma evaluation. Results The median mean hippocampus dose was reduced from 22.9 Gy (RBE) to 8.9 Gy (RBE), while keeping CTV V95% above 95 % for all nominal HS plans. HS plans were relatively robust regarding hippocampus mean dose, however, less robust regarding target coverage and maximum dose compared to non-HS plans. For standard resolution measurements, median pass rates were 99.7 % for HS and 99.5 % for non-HS plans (p < 0.001). For high-resolution measurements, median pass rates were 100 % in the hippocampus region and 98.2 % in the surrounding region. Conclusions A substantial reduction of dose in the hippocampus region appeared feasible. Dosimetric accuracy of HS plans was comparable to non-HS plans and agreed well with planned dose distribution in the hippocampus region.
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Affiliation(s)
- Anneli Edvardsson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
- Medical Radiation Physics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Jenny Gorgisyan
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
- Medical Radiation Physics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | | | | | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Daniel Gram
- Department of Clinical Oncology and Palliative Care, Radiotherapy, Zealand University Hospital, Næstved, Denmark
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Oncology – Section of Radiotherapy, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Björk-Eriksson
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Regional Cancer Centre West, Western Sweden Healthcare Region, Gothenburg, Sweden
| | - Per Munck af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
- Medical Radiation Physics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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Veselsky T, Syruckova T, Kindlova A, Osmancikova P. Pituitary adenoma treatment plan quality comparison between linear accelerator volumetric modulated arc therapy and Leksell Gamma Knife® radiosurgery. Med Dosim 2021; 46:440-448. [PMID: 34312022 DOI: 10.1016/j.meddos.2021.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/16/2021] [Accepted: 06/14/2021] [Indexed: 11/26/2022]
Abstract
The aim of this study was to compare radiosurgical treatment plan quality of a linear accelerator with Leksell Gamma Knife (LGK) for pituitary adenoma irradiation. Thirty pituitary adenoma patients were evaluated in this study. Treatment plans were prepared on LGK and stereotactic linear accelerator Varian TrueBeam STx. Volumetric Modulated Arc Therapy (VMAT) plans (21 plans with 2 coplanar arcs and 9 plans with 4 non-coplanar arcs) were calculated for linear accelerator. All the plans were evaluated in terms of conformity, selectivity, gradient index and organ at risk (OAR) sparing. VMAT produced dosimetrically comparable treatment plans to LGK regarding conformity and selectivity (New Conformity Index (NCI): 1.76 ± 0.65 for 4 arc VMAT, 2.33 ± 1,16 for 2 arc VMAT and 1.96 ± 0.71 for LGK; Selectivity Index (SI): 0.63 ± 0.16 for 4 arc VMAT, 0.51 ± 0.16 for 2 arc VMAT and 0.58 ± 0.17 for LGK). Gradient index (GI) was superior for LGK plans (GI: 2.74 ± 0.20 for LGK and 5.28 ± 2.29 for 4 arc VMAT). OAR sparing for optics, brainstem, and hypophysis was similar for both modalities while target volume coverage was maintained the same. Finally, treatment time resulted in favor of VMAT plans (in this study VMAT plans were almost 5 times faster than LGK treatment regarding beam on time). According to the results of this study stereotactic linear accelerator with VMAT treatment could be used as a reasonable alternative to LGK for pituitary adenoma radiosurgery but only if the same head fixation method accuracy and target volume delineation are maintained for both modalities.
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Affiliation(s)
- T Veselsky
- Motol University Hospital, Oncology Clinic, Prague 5, Czech Republic; Military University Hospital, Department of Radiation Therapy, Prague 6, Czech Republic; Na Homolce Hospital, Medical Physics Department, Prague 5, Czech Republic.
| | - T Syruckova
- Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno, Czech Republic
| | - A Kindlova
- Motol University Hospital, Oncology Clinic, Prague 5, Czech Republic
| | - P Osmancikova
- Motol University Hospital, Oncology Clinic, Prague 5, Czech Republic; Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Prague 110 00, Czech Republic
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