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Flattening filter free Stereotactic radiosurgery for brain metastases using dynamic conformal arcs: 6 MV or 10 MV?

Published online by Cambridge University Press:  18 January 2021

Glenn Whitten
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
Ursula Daly
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
Candice D. McCallum
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
Jackie Harney
Affiliation:
Clinical Oncology, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, UK
David Conkey
Affiliation:
Clinical Oncology, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, UK
Tom Flannery
Affiliation:
Department of Neurosurgery, Royal Victoria Hospital, Belfast Health & Social Care Trust, Belfast, UK
Denise M. Irvine
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
Christina Skourou
Affiliation:
St. Luke’s Radiation Oncology Centre Beaumont Hospital, Beaumont, Dublin 9, Ireland
Alan R. Hounsell
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK The Patrick G Johnston Centre for Cancer Research, Queen’s University of Belfast, Belfast, UK
Conor K. McGarry*
Affiliation:
Radiotherapy Physics, Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK The Patrick G Johnston Centre for Cancer Research, Queen’s University of Belfast, Belfast, UK
*
Author for correspondence: Conor K. McGarry, Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, UK, BT9 7AB. E-mail: conor.mcgarry@belfasttrust.hscni.net

Abstract

Introduction:

Stereotactic radiosurgery (SRS) has proven itself as an effective tool in the treatment of intracranial lesions. Image-guided high dose single fraction treatments have the potential to deliver ablative doses to tumours; however, treatment times can be long. Flattening filter free (FFF) beams are available on most modern linacs and offer a higher dose rate compared to conventional flattened beams which should reduce treatment times. This study aimed to compare 6 MV FFF and 10 MV FFF to a 6 MV flattened beam for single fraction dynamic conformal arc SRS for a Varian Truebeam linac.

Materials and methods:

In total, 21 individual clinical treatment plans for 21 brain metastases treated with 6 MV were retrospectively replanned using both 6 MV FFF and 10 MV FFF. Plan quality and efficiency metrics were evaluated by analysing dose coverage, dose conformity, dose gradients, dose to normal brain, beam-on-time (BOT), treatment time and monitor units.

Results:

FFF resulted in a significant reduction in median BOT for both 6 MV FFF (57·9%; p < 0·001) and 10 MV FFF (76·3%; p < 0·001) which led to reductions in treatment times of 16·8 and 21·5% respectively. However, 6 MV FFF showed superior normal brain dose sparing (p < 0·001) and dose gradient (p < 0·001) compared to 10 MV FFF. No differences were observed for conformity.

Conclusion:

6 MV FFF offers a significant reduction in average treatment time compared to 6 MV (3·7 minutes; p = 0·002) while maintaining plan quality.

Type
Original Article
Copyright
© The Author(s), 2021. Published by Cambridge University Press

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References

Sheehan, J P, Yen, C, Lee, C, Loeffler, J S. Cranial Stereotactic Radiosurgery: Current Status of the Initial Paradigm Shifter. J Clin Oncol 2014; 32 (26): 28362846.CrossRefGoogle ScholarPubMed
Lippitz, B, Lindquist, C, Paddick, I, Peterson, D, O’Neill, K, Beaney, R. Stereotactic radiosurgery in the treatment of brain metastases: the current evidence. Cancer Treatment Rev 2013; 40 (1): 4859.CrossRefGoogle ScholarPubMed
De Salles, A A, Gorgulho, A A, Pereira, J L, McLaughlin, N. Intracranial stereotactic radiosurgery: concepts and techniques. Neurosurg Clin N Am 2013; 24 (4): 491498.CrossRefGoogle ScholarPubMed
Hoogeman, M S, Nuyttens, J J, Levendag, P C, Heijmen, B J N. Time Dependence of Intrafraction Patient Motion Assessed by Repeat Stereoscopic Imaging. Int Radiat Oncol 2008; 70 (2): 609618.CrossRefGoogle ScholarPubMed
Cashmore, J. The characterization of unflattened photon beams from a 6 MV linear accelerator. Phys Med Biol 2009; 53 (7): 19331946.CrossRefGoogle Scholar
Kragl, G, Baier, F, Lutz, S et al. Flattening filter free beams in SBRT and IMRT: dosimetric assessment of peripheral doses. Med Phys 2011; 21: (2): 91101.Google ScholarPubMed
Georg, D, Knöös, T, McClean, B. Current status and future perspective of flattening filter free photon beams. Med Phys 2011; 38 (3): 12801293.CrossRefGoogle ScholarPubMed
Fogliata, A, Fleckenstein, J, Schneider, F et al. Flattening filter free beams from TrueBeam and Versa HD units: evaluation of the parameters for quality assurance. Med Phys 2016; 43 (1): 205.CrossRefGoogle ScholarPubMed
Dimitriadis, A, Kirkby, K J, Nisbet, A, Clark, C H. Current status of cranial stereotactic radiosurgery in the UK. Br J Radiol 2016; 89: 20150452.CrossRefGoogle ScholarPubMed
Rieber, J, Tonndorf-Martini, E, Schramm, O et al. Radiosurgery with flattening-filter-free techniques in the treatment of brain metastases. Strahlenther Onkol 2016; 192: 789796.CrossRefGoogle ScholarPubMed
Youqun, L, Shanyu, C, Changdong, X et al. Dosimetric superiority of flattening filter free beams for single-fraction stereotactic radiosurgery in single brain metastasis. Oncotarget 2017; 8 (21): 3527235279.Google Scholar
Stieler, F, Fleckenstein, J, Simeonova, A, Wenz, F, Lohr, F. Intensity modulated radiosurgery of brain metastases with flattening filter-free beams. Radiother Oncol 2013; 109: 448451.CrossRefGoogle ScholarPubMed
Abacioglu, U, Ozen, Z, Yilmaz, M et al. Critical appraisal of RapidArc radiosurgery with flattening filter free photon beams for benign brain lesions in comparison to GammaKnife: a treatment planning study. Radiat Oncol 2010; 9: 119.CrossRefGoogle Scholar
Gasic, D, Ohlhues, L, Brodin, N P et al. A treatment planning and delivery comparison of volumetric modulated arc therapy with or without flattening filter for gliomas, brain metastases, prostate, head/neck and early stage lung cancer. Acta Oncol 2014; 53 (8): 10051011.CrossRefGoogle ScholarPubMed
Minniti, G, Capone, L, Alongi, F et al. Initial Experience With Single-Isocenter Radiosurgery to Target Multiple Brain Metastases Using an Automated Treatment Planning Software: Clinical Outcomes and Optimal Target Volume Margins Strategy. Adv Radiat Oncol 2020; 5 (5): 856864.CrossRefGoogle ScholarPubMed
Kirkpatrick, J P, Wang, Z, Sampson, J H et al. Defining the optimal planning target volume in image-guided stereotactic radiosurgery of brain metastases: results of a randomized trial. Int J Radiat Oncol Biol Phys 2015; 91 (1): 100108.CrossRefGoogle ScholarPubMed
Lawrence, Y R, Li, XA, Naqa el, I et al. Quantitative analyses of normal tissue effects in the clinic (QUANTEC): radiation dose-volume effects in the brain. Int J Radiat Oncol Biol Phys 2010; 76: S20S27.CrossRefGoogle Scholar
Mayo, C, Martel, M K, Marks, L B, Flickinger, J, Nam, J, Kirkpatrick, J. Radiation dose-volume effects of optic nerves and chiasm, Int J Radiat Oncol Biol Phys 2010; 76; S28S35.CrossRefGoogle ScholarPubMed
Mayo, C, Yorke, E, Merchant, T E. Radiation associated brainstem injury. Int J Radiat Oncol Biol Phys 2010; 76: S36S41.CrossRefGoogle ScholarPubMed
Paddick, I. A simple scoring ratio to index the conformity of radiosurgical treatment plans. Technical note. J Neurosurg 2000; 93 (3): 219222.CrossRefGoogle ScholarPubMed
Paddick, I, Lippitz, B. A simple dose gradient measurement tool to complement the conformity index. J Neurosurg 2006; 105: S194S201.CrossRefGoogle ScholarPubMed
Dang, T M, Peters, M J, Hickey, B, Semciw, A. Efficacy of flattening-filter-free beam in stereotactic body radiation therapy planning and treatment: a systematic review with meta-analysis. J Med Imaging Radiat Oncol 2017; 61: 379387.CrossRefGoogle ScholarPubMed
Mohamed Yoosuf, A B, Jeevandram, P, Whitten, G, Workman, G, McGarry, C K. Verification of high-dose-rate brachytherapy treatment planning dose distribution using liquid filled ionisation chamber array. J Contemp Brachytherapy 2018; 10 (2): 142154.CrossRefGoogle Scholar
Lang, S, Shrestha, B, Graydon, S et al. Clinical application of flattening filter free beams for extracranial stereotactic. Radiotherapy. Radiother Oncol 2013; 106: 255259.CrossRefGoogle ScholarPubMed
Hsu, S M, Lai, Y C, Jeng, C C, Tseng, C Y. Dosimetric comparison of different treatment modalities for stereotactic radiotherapy. Radiat Oncol 2017; 16:12 (1): 155.CrossRefGoogle ScholarPubMed
Blonigen, B J, Steinmetz, R D, Levin, L, Lamba, M A, Warnick, R E, Breneman, J C. Irradiated volume as a predictor of brain radionecrosis after linear accelerator stereotactic radiosurgery. Int J Radiat Oncol Biol Phys 2010; 77: 9961001.CrossRefGoogle ScholarPubMed
Kragl, G, af Wetterstedt, S, Knäusl, B et al. Dosimetric characteristics of 6 and 10MV unflattened photon beams. Radiother Oncol 2009; 93 (1): 141146.CrossRefGoogle ScholarPubMed
Dzierma, Y, Nuesken, F G, Palm, J, Licht, N P, Ruebe, C. Planning study and dose measurements of intracranial stereotactic radiation surgery with a flattening filter free linac. Pract Radiat Oncol 2014; 4: e109e116.CrossRefGoogle ScholarPubMed
Wang, J Z, Rice, R, Mundt, A J, Sandhu, A, Murphy, K T. Feasibility and advantages of using flattening filter-free mode for radiosurgery of multiple brain lesions. Pract Radiat Oncol 2012; 2 (4): e165e171.CrossRefGoogle ScholarPubMed