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What is the optimal isodose line for stereotactic radiotherapy for single brain metastases using HyperArc?
- Source :
-
Journal of applied clinical medical physics [J Appl Clin Med Phys] 2024 Jun 11, pp. e14408. Date of Electronic Publication: 2024 Jun 11. - Publication Year :
- 2024
- Publisher :
- Ahead of Print
-
Abstract
- Purpose: The study aimed to investigate the optimal isodose line (IDL) in linear accelerator-based stereotactic radiotherapy for single brain metastasis, using HyperArc. We compared the dosimetric parameters for target and normal brain tissue among six plans with different IDLs.<br />Methods: This study included 30 patients with single brain metastasis. We retrospectively generated six plans for each tumor with different IDLs (80%, 70%, 60%, 50%, 40%, and 33%) using HyperArc. All treatment plans were normalized to the prescription dose of 35 Gy in five fractions which was covered by 95% of the planning target volume (PTV), defined by adding a 1.0 mm margin to the gross tumor volume (GTV). The dosimetric parameters were compared among the six plans.<br />Results: For GTV > 0.1 cm <superscript>3</superscript> , the ratio of brain-GTV volumes receiving 25 Gy to PTV (V <subscript>25Gy</subscript> /PTV) was significantly lower at IDL 40%-70% than at IDL 80% and 33% (p < 0.01, retrospectively). For GTV < 0.1 cm <superscript>3</superscript> , V <subscript>25Gy</subscript> /PTV decreased continuously as IDL decreased. The values of D <subscript>99%</subscript> and D <subscript>80%</subscript> for GTV increased with decreasing IDL. An IDL of 50% or less was required to achieve D <subscript>99%</subscript> of greater than 43 Gy and D <subscript>80%</subscript> of greater than 50 Gy. The mean values of D <subscript>99%</subscript> and D <subscript>80%</subscript> for IDL 50% were 44.3 and 51.9 Gy.<br />Conclusion: The optimal IDL is 40%-50% for GTV > 0.1 cm <superscript>3</superscript> . These lower IDLs could increase D <subscript>99%</subscript> and D <subscript>80%</subscript> of GTV while lowering V <subscript>25Gy</subscript> of normal brain tissue, which may help reduce the risk of radiation necrosis and improve local control.<br /> (© 2024 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)
Details
- Language :
- English
- ISSN :
- 1526-9914
- Database :
- MEDLINE
- Journal :
- Journal of applied clinical medical physics
- Publication Type :
- Academic Journal
- Accession number :
- 38863310
- Full Text :
- https://doi.org/10.1002/acm2.14408