An Evaluation of the Feasibility and Utility of Automated HyperArc Planning for Multiple Brain Metastases: A Comparative Dosimetric Analysiss
Abstract
Purpose: This study compared automated HyperArc (HA) planning with manually designed VMAT plans for treating patients with multiple brain metastases.
Materials and Methods: Ten patients with an average of 15 metastases (range: 10–23) were retrospectively analyzed. All underwent high-resolution CT imaging (1 mm slice thickness) registered to contrast-enhanced MRI. Targets were delineated by a radiation oncologist. For lesions ≥10 mm, the gross tumor volume (GTV) equaled the planning target volume (PTV); for smaller lesions, a 1 mm margin was added. VMAT plans used a single isocenter and non-coplanar arcs, while HA plans were generated with automated optimization. Prescribed doses ranged from 20 to 30 Gy, delivered over 3–5 fractions. Dosimetric parameters compared included conformity index (CI), gradient index (GI), homogeneity index (HI), healthy brain V10Gy and V12Gy, maximum and mean brainstem doses, and maximum doses to optic structures and lenses. Total monitor units (MU) were also assessed.
Results: Target coverage was similar between VMAT and HA, with no significant differences in CI (p = 0.721) or GI (p = 0.241). HA showed improved homogeneity and significantly reduced doses to healthy brain (lower V10Gy) and critical structures including brainstem (p = 0.009) and optic chiasm (p = 0.013). HA also required about 65% fewer MUs than VMAT (p = 0.007), indicating shorter treatment times.
Conclusion: HA planning provided superior sparing of healthy brain tissue and critical structures and improved treatment efficiency compared to VMAT. HA represents a promising automated approach for stereotactic radiosurgery in complex multi-target cases
Ethical Statement
This study was approved by internal ethics review board
Supporting Institution
This study was prepared without any external source of funding
References
- 1. Mehta MP, Tsao MN, Whelan TJ, et al. The American society for therapeutic radiology and oncology (ASTRO) evidence- based review of the role of radiosurgery for brain metastasis. Int J Radiat Oncol Biol Phys. 2005;63:37–46. doi: 10.1016/j.ijrobp.2005.05.023
- 2. Tsao M, Xu W, Sahgal A. A meta-analysis evaluating stereotactic radiosurgery, whole-brain radiotherapy, or both for patients presenting with a limited number of brain metastases. Cancer. 2012; 118:2486–93. doi: 10.1002/cncr.26515
- 3. Chang EL, Wefel JS, Hess KR, et al. Neurocognition in patients with brain metastases treated with radiosurgery or radiosurgery plus whole-brain irradiation: a randomised controlled trial. Lancet Oncol. 2009 ; 10:1037–44. doi: 10.1016/S1470-2045(09)70263-3
- 4. Serizawa T, Hirai T, Nagano O, et al. Gamma knife surgery for 1-10 brain metastases without prophylactic whole-brain radiation therapy: analysis of cases meeting the Japanese prospective multi-institute study (JLGK0901) inclusion criteria. J Neurooncol. 2010;98:163-7. doi: 10.1007/s11060-010-0169-x
- 5. Mohammadi AM, Recinos PF, Barnett GH, et al. Role of Gamma Knife surgery in patients with 5 or more brain metastases. J Neurosurg. 2012;117suppl:5-12. doi: 10.3171/2012.8.GKS12983
- 6. Clark GM, Popple RA, Prendergast BM, et al. Plan quality and treatment planning technique for single isocenter cranial radiosurgery with volumetric modulated arc therapy. PractRadiat Oncol. 2012;2:306–13. doi: 10.1016/j.prro.2011.12.003
- 7. Clark GM, Popple RA, Young PE, et al. Feasibility of single-isocenter volumetric modulated arc radiosurgery for treatment of multiple brain metastases. Int J Radiat Oncol Biol Phys. 2010;76:296–302. doi: 10.1016/j.ijrobp.2009.05.029
- 8. Ruggieri R, Naccarato S, Mazzola R, et al. Linac-based VMAT radiosurgery for multiple brain lesions: comparison between a conventional multi-isocenter approach and a new dedicated mono-isocenter technique. Radiat Oncol. 2018;13:38, doi: 10.1186/ s13014-018-0985-2
- 9. Ohira, S, Ueda, Y, Akino Y, et al. HA VMAT planning for single and multiple brain metastases stereotactic radiosurgery: a new treatment planning approach. Radiat Oncol. 2018;13: 13. doi. org/10.1186/s13014-017-0948-z
- 10. Ueda Y, Ohira S, Yamazaki H, et al. Dosimetric performance of two linear accelerator-based radiosurgery systems to treat single and multiplebrain metastases. Br J Radiol. 2019;92(1100):20190004. doi: 10.1259/bjr.20190004.
- 11. Becker, SJ, Lipson, EJ, Jozsef, G, et al. How many brain metastases can be treated with stereotactic radiosurgery before the radiation dose delivered to normal brain tissue rivals that associated with standard whole brain radiotherapy? J Appl Clin Med Phys. 2023; 24:e13856. doi.org/10.1002/acm2.13856
- 12. Paddick I and Lippitz B. A simple dose gradient measurement tool to complement the conformity index. J Neurosurg. 2006;105(Suppl):194–201. doi: 10.3171/sup.2006.105.7.194.
- 13. Popple RA, Brown MH, Thomas EM, et al. Transition From Manual to Automated Planning and Delivery of Volumetric Modulated Arc Therapy Stereotactic Radiosurgery: Clinical, Dosimetric, and Quality Assurance Results. PractRadiat Oncol. 2021;11(2):e163-e171. doi: 10.1016/j.prro.2020.10.013.
- 14. Minniti G, Clarke E, Lanzetta G, et al. Stereotactic radiosurgery for brain metastases: analysis of outcome and risk of brain radionecrosis. Radiat Oncol.2011;6(1):48. doi: 10.1186/1748-717X-6-48.
- 15. Korytko T, Radivoyevitch T, Colussi V, et al. 12 Gy gamma knife radiosurgical volume is a predictor for radiation necrosis in non-AVM intracranial tumors. Int J Radiat Oncol Biol Phys 2006;64:419–424. doi: 10.1016/j.ijrobp.2005.07.980.
- 16. Chen H, Li Z, Liao G, et al. HA performance in radiotherapy and its correlations with number and volume of multiple brain metastases, Radiation Medicine and Protection. 2024; 5(2):139–144. doi:10.1016/j.radmp.2024.05.004
- 17. Celen YY, Dinç Ö, Arslan ND, et al. HA Vmat and Vmat planning for stereotactic radiosurgery in multiple brain metastases, Journal of Radiation Research and Applied Sciences, 2023; 16(4): 100719. doi:10.1016/j.jrras.2023.100719
- 18. Ohira S, Sagawa T, Ueda Y, et al. Effect of collimator angle on HA stereotactic radiosurgery planning for single and multiple brain metastases. Med Dosim. 2020;45(1):85-91. doi: 10.1016/j. meddos.2019.07.004.
Details
| Primary Language | English |
|---|---|
| Subjects | Clinical Sciences (Other) |
| Journal Section | Research Articles |
| Authors | |
| Early Pub Date | September 23, 2025 |
| Publication Date | October 1, 2025 |
| Submission Date | May 1, 2025 |
| Acceptance Date | June 16, 2025 |
| Published in Issue | Year 2025 Volume: 16 Issue: 4 |
