Hostname: page-component-76fb5796d-qxdb6 Total loading time: 0 Render date: 2024-04-29T13:36:59.538Z Has data issue: false hasContentIssue false
  • English
  • Français

Preclinical studies for implementing flattening filter-free beams in hypofractionated volumetric-modulated arc therapy (VMAT) for prostate cancer radiotherapy

Published online by Cambridge University Press:  01 September 2017

Baochang Liu ,
Johnson Darko  and
Ernest Osei
Baochang Liu
Affiliation:
Department of Medical Physics, British Columbia Cancer Agency, Centre for the North, Prince George, BC, Canada
Johnson Darko
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Center, Kitchener, ON, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
Ernest Osei*
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Center, Kitchener, ON, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada Department of Systems Design, University of Waterloo, Waterloo, ON, Canada
*
Correspondence to: Ernest Osei, Department of Medical Physics, Grand River Regional Cancer Centre, 835 King Street West, Kitchener, ON, Canada N2G1G3. Tel: +1 519 749 4300, ext 5407. E-mail: ernest.osei@grhosp.on.ca
Get access Rights & Permissions [Opens in a new window]

Abstract

Background

Volumetric-modulated arc therapy (VMAT) has emerged as one of the most favourable techniques for radiotherapy treatment in recent years because of its conformal dose distribution to the planning target volume (PTV), lower doses to adjacent normal organs at risk (OARs) and faster and easier dose delivery. A typical conventional VMAT protocol for low-intermediate risk prostate cancer uses a flattened 6 MV photon beam to deliver 78 Gy in 39 fractions, however, a recent Radiation Therapy Oncology Group study investigated prostate cancer radiotherapy with a hypofractionated dose scheme of 36·25 Gy in 5 fractions. One advantage of flattening filter-free (FFF) beams in radiotherapy is the higher doses in the central region on the dose profile and much higher dose delivery rates.

Methods and materials

This paper reports the investigation of preclinical studies for implementing FFF beams in hypofractionated VMAT for prostate cancer radiotherapy. All treatment planning were accomplished using Varian EclipseTM treatment planning system version 11 and delivered on Varian Truebeam linear accelerators. The studies compared the biological-effective dose–volume histograms and dose–volume histograms of PTV and OARs for 20 patients using conventional and hypofractionated dose schemes. The study also evaluated the 6 and 10 MV FFF by comparing 6 and 10 MV VMAT plans with the FFF beams. The treatment time was investigated using plans with 6 MV beams and doses of 2, 4, 5, 6, 7·25 Gy/fraction and plans with 10 MV FFF with a dose of 7·25 Gy/fraction. We also investigated an angular monitor unit (MU) quantity (MU/deg) and its threshold value for RapidArcTM plans, beyond which FFF beams can be considered superior to flattened beams in terms of treatment time increased caused by higher dose per fraction.

Results

The results show that the hypofractionated plans resulted in greater biological equivalent doses to PTV and lower doses to OARs. The 10 MV FFF plans have statistically lower mean doses to all the OARs, whereas PTV homogeneity index remains the same compared with other beam energies. The mean body integral dose for the 20 patients is 8·7% lower using 10 MV FFF compared with 6 MV FFF mainly because of the higher energy and less required MUs with the 10 MV FFF beam. The hypofractionated scheme with 10 MV FFF plan has the same treatment time as that of the 6 MV plan at 2 Gy/fraction, as the higher dose delivery rates at 10 MV FFF can compensate for the higher prescribed dose per fraction without the need of extra treatment time.

Conclusion

In this study, we observed that the 10 MV FFF beam is better for hypofractionated prostate cancer VMAT plan delivery. The threshold value of MU/deg is found to be 2·083 MU/deg based on our machine configurations.

Keywords

flattening filter freehypofractionationprostate cancerradiotherapyVMAT
Type
Original Articles
Information
Journal of Radiotherapy in Practice , Volume 16 , Issue 3 , September 2017 , pp. 286 - 302
Copyright
© Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Canadian Cancer Society’s Advisory Committee on Cancer Statistics. Canadian Cancer Statistics 2015. Toronto, ON: Canadian Cancer Society, 2015.Google Scholar
2. Palma, D, Vollans, E, James, K et al. Volumetric modulated arc therapy for delivery of prostate radiotherapy: comparison with intensity-modulated radiotherapy and three-dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys 2008; 72 (4): 996–1001.Google Scholar
3. Meier, R. Dose-escalated robotic SBRT for stage I-II prostate cancer. Front Oncol 2014; 5: 48.Google Scholar
4. Benedict, S H, Yenice, K M, Followill, D et al. Stereotactic body radiation therapy: the report of AAPM Task Group 101. Med Phys 2010; 37 (8): 4078–4101.Google Scholar
5. Han, K, Cheung, P, Basran, P S, Poon, I, Yeung, L, Lochray, F. A comparison of two immobilization systems for stereotactic body radiation therapy of lung tumors. Radiother Oncol 2010; 95: 103–108.Google Scholar
6. Kruis, M F, van de Kamer, J B, Sonke, J J, Jansen, E P, van Herk, M. Registration accuracy and image quality of time averaged mid-position CT scans for liver SBRT. Radiother Oncol 2013; 109: 404–408.Google Scholar
7. Grills, I S, Mangona, V S, Welsh, R et al. Outcomes after stereotactic lung radiotherapy or wedge resection for stage I non-small-cell lung cancer. J Clin Oncol 2010; 28: 928–935.Google Scholar
8. Tuzer, M, Brustugun, O T, Waldeland, E, Helland, A. Stereotactic body radiation therapy is effective and safe in patients with early-stage non-small cell lung cancer with low performance status and severe comorbidity. Case Rep Oncol 2011; 4: 25–34.Google Scholar
9. Zhang, Y, Xiao, J P, Zhang, H Z et al. Stereotactic body radiation therapy favors long-term overall survival in patients with lung metastases: five-year experience of a single-institution. Chin Med J (Engl) 2011; 124: 4132–4137.Google Scholar
10. Baldwin, D R. Improving outcomes in lung cancer patients. Practitioner 2011; 255: 19–22.Google Scholar
11. Goyal, K, Einstein, D, Yao, M et al. Cyberknife stereotactic body radiation therapy for nonresectable tumors of the liver: preliminary results. HPB Surg 2010; 2010: 309780.Google Scholar
12. Dewas, S, Bibault, J E, Mirabel, X et al. Prognostic factors affecting local control of hepatic tumors treated by stereotactic body radiation therapy. Radiat Oncol 2012; 7: 166.Google Scholar
13. Pan, H Y, Allen, P K, Wang, X S et al. Incidence and predictive factors of pain flare after spine stereotactic body radiation therapy: secondary analysis of phase 1/2 trials. Int J Radiat Oncol Biol Phys 2014; 90: 870–876.CrossRefGoogle ScholarPubMed
14. Freeman, D E, King, C R. Stereotactic body radiotherapy for low-risk prostate cancer: five-year outcomes. Radiat Oncol 2011; 6: 3.Google Scholar
15. Katz, A J, Santoro, M, Diblasio, F, Ashley, R. Stereotactic body radiotherapy for localized prostate cancer: disease control and quality of life at 6 years. Radiat Oncol 2013; 8: 118.Google Scholar
16. King, C R, Brooks, J D, Gill, H, Pawlicki, T, Cotrutz, C, Presti, J. Stereotactic body radiotherapy for localized prostate cancer: interim results of a prospective phase II clinical trial. Int J Radiat Oncol Biol Phys 2009; 73 (4): 1043–1048.Google Scholar
17. Matuzak, M M, Yan, D, Grills, I, Martinez, A. Clinical applications of volumetric modulated arc therapy. Int J Radiat Oncol Biol Phys 2010; 77: 608–616.CrossRefGoogle Scholar
18. Navarria, P, Ascolese, A M, Mancosu, P et al. Volumetric modulated arc therapy with flattening filter free (FFF) beams for stereotactic body radiation therapy (SBRT) in patients with medically inoperable early stage non-small cell lung cancer (NSCLC). Radiother Oncol 2013; 107: 414–418.Google Scholar
19. Alongi, F, Cozzi, L, Arcangeli, S et al. Linac based SBRT for prostate cancer in 5 fractions with VMAT and flattening filter free beams: preliminary report of a phase II study. Radiat Oncol 2013; 8: 171.CrossRefGoogle ScholarPubMed
20. King, C R, Lehmann, J, Adler, J R, Hai, J. Cyberknife radiotherapy for localized prostate cancer: rationale and technical feasibility. Technol Cancer Res Treat 2003; 2 (1): 25–29.Google Scholar
21. Chung, J-B, Kim, J-S, Eom, K-Y et al. Comparison of VMAT-SABR treatment plans with flattening filter (FF) and flattening filter-free (FFF) beam for localized prostate cancer. J Appl Clin Med Phys 2015; 16 (6): 302–313.Google Scholar
22. 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: 1005–1011.Google Scholar
23. Lukka, H, Bahary, J P, Lawton, C et al RTOG 0938: a randomized phase II trial of hypofractionated radiotherapy for favorable risk prostate cancer. RTOG, Hamilton, Canada, 2015.Google Scholar
24. Bentzen, S M, Constine, L S, Deasy, J O et al. Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC): an introduction to the scientific issues. Int J Radiat Oncol Biol Phys 2010; 76 (3): S3–S9.Google Scholar
25. Emami, B, Lyman, J, Brown, A et al. Tolerance of normal tissue to therapeutic irradiation. Int J Radiat Oncol Biol Phys 1991; 21 (1): 109–122.Google Scholar
26. Almond, P R, Biggs, P J, Coursey, B M et al. AAPM’s TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams. Med Phys 1999; 26 (9): 1847–1870.CrossRefGoogle ScholarPubMed