Impact of Flattening Filter Free Photon Beam on Rapidarc Radiotherapy for Gynaecological Malignancies: A Comparative Study

Document Type : Original Paper

Authors

1 Rajiv Gandhi Cancer Institute & Research Center, New Delhi, India

2 Department of Applied Science & Humanities, Bundelkhand Institute of Engineering & Technology, Jhansi, India

3 Medical Physics Division, Radiation Oncology Department, Rajiv Gandhi Cancer Institute & Research Centre, Sector-5, Rohini, Delhi-110085

4 Department of Medical Physics, Rajiv Gandhi Cancer Research Center Delhi

5 Medical Physics Division & Radiation Oncology Department,Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India

6 Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi,India

Abstract

Introduction: To compare the dosimetric outcomes of 6 and 10 MV flattening filter free beam (FFFB) energies in gynaecological malignancies RapidArc (RA) planning.
Material and Methods: The RA plans were generated for a cohort of 20 patients using 6 and 10 MV FFFBs. The plans aimed to deliver a dose of 50.4Gy in 28 fractions to planning target volume (PTV); moreover, planning objectives were kept as low as reasonably achievable for organs at risk (OARs). Dosimetric analysis was performed in terms of PTV coverage, conformity index (CI), homogeneity index (HI), dose to OAR’s, integral dose to normal tissue (NTID), and total number of monitor units (MU’s).
Results: According to the results, volumes of PTV receiving prescription dose and CI values were 95.03±0.10% and 95.02±0.18%, as well as 1.018±0.028 and 1.024±0.027, respectively. Moreover, HI values were estimated at 1.063±0.008 and 1.068±0.010. Additionally, the corresponding values of mean NTID and MUs were 280.3±42.5 and 267.9±39.1 (liter-Gy), as well as 610.3±30.3 and 630.6±39.7 for FFFB using 6 and 10 MV, respectively. The 6 and 10 MV FFFBs were statistically similar in terms of mean dose to bladder, rectum and both femoral heads, while comparison yielded significant difference (p <0.05) in terms of HI, CI, MUs and NTID.
Conclusion: The FFFB of 6MV was found superior, compared to 10MV, for RA planning in case of gynaecological malignancies. Moreover, it offers better HI and CI values, as well as fewer numbers of MUs (3.33%). In addition, it delivers more NTID (4.42%) for similar target coverage and OAR’s sparing.

Keywords

Main Subjects

References

  1. Swaminathan S, KatochVM.Consolidated report of hospital based cancer registries 2001-3, national cancer registry program. New Delhi: Indian Council of Medical Research.2007.
  2. Uma Devi K. Current status of gynecological cancer care in India. Journal of Gynecologic Oncology. 2009; 20(2): 77–80.
  3. Sunil Dutt Sharma. Unflattened photon beams from the standard flattening filter free accelerators for radiotherapy: Advantages, limitations and challenges. J Med Phys. 2011; 36(3): 123–5.
  4. Vassiliev ON, Titt U, Ponisch F, Kry SF, Mohan R, Gillin MT. Dosimetric properties of photon beams from a flattening filter free clinical accelerator. Phys Med Biol. 2006; 51: 1907–17.
  5. Cashmore J. The characterization of unflattened photon beams from a 6 MV linear accelerator. Phys Med Biol. 2008; 53: 1933.
  6. Kry SF, Vassiliev ON, Mohan R. Out-of-field photon dose following removal of the flattening filter from a
  7. medical accelerator. Phys Med Biol. 2010; 55: 2155–66.
  8. Georg D, Knoos T, McClean B. Current status and future perspective of flattening filter free photon beams.Med Phys. 2011; 38:1280–93.
  9. Ponisch F, Titt U, Vassiliev ON, Kry SF, Mohan R. Properties of unflattened photon beams shaped by a multileaf collimator. Med Phys. 2006; 33:1738–46.
  10. Vassiliev ON, Titt U, Kry SF, Mohan R, Gillin MT. Radiation safety survey on a flattening filter-free medical accelerator. RadiatProtDosimetry. 2007; 124:187–90.
  11. Vassiliev ON, Titt U, Kry SF, Ponisch F, Gillin MT, Mohan R. Monte Carlo study of photon fields from a flattening filter-free clinical accelerator. Med Phys. 2006; 33:820–7.
  12. Spruijt KH, Dahele M, Cuijpers JP, Jeulink M, Rietveld D, Slotman BJ, et al. Flattening filter free vs flattened beams for breast irradiation. International Journal of Radiation Oncology* Biology* Physics. 2013;85(2):506-13.
  13. Hrbacek J, Lang S, Graydon SN, Klock S, Riesterer O. Dosimetric comparison of flattened and unflattened beams for stereotactic ablative radiotherapy of stage I non-small cell lung cancer. Med Phys. 2014; 41: 031709.
  14. Vasssiliev ON, KrySF,Kuban DA, Salehpour M, Mohan R, Titt U. Treatment-Planning Study of Prostate Cancer Intensity-Modulated Radiotherapy With a Varian Clinac Operated Without a Flattening Filter. Int. J. Radiation Oncology Biol. Phys. 2007; 68(5): 1567–71
  15. Nicolini G, Ghosh-Laskar S, Shrivastava SK, Banerjee S, Chaudhary S, Agarwal JP, et al. Volumetric modulation arc radiotherapy with flattening filter-free beams compared with static gantry IMRT and 3D conformal radiotherapy for advanced esophageal cancer: a feasibility study. Int J RadiatOncolBiol Phys. 2012; 84: 553–60.
  16. Zwahlen DR, Lang S, Hrbacek J, Glanzmann C, Kloeck S, Najafi Y, et al. The use of photon beams of a flattening filter-free linear accelerator for hypofractionated volumetric modulated arc therapy in localized prostate cancer. Int J RadiatOncolBiol Phys. 2012; 83: 1655–60.
  17. Yadav G, Bhushan M, Dewan A, Saxena U, Kumar L, Chauhan D, et al. Dosimetric influence of photon beam energy and number of arcs on volumetric modulated arc therapy in carcinoma cervix: A planning study. Rep PractOncolRadiother. 2017;22(1):1-9.
  18. Kumar L, Yadav G, Kishore V, Bhushan M, Gairola M, Tripathi D. Validation of the RapidArc delivery system using a volumetric phantom as per task group report 119 of the American association of physicists in medicine.  J Med Phys. 2019; 44:126-34.
  19. Kumar L, Yadav G, Raman K, Bhushan M, Pal M. The dosimetric impact of different photon beam energy on RapidArc radiotherapy planning for cervix carcinoma. J Med Phys. 2015; 40:207-13.
  20. Kumar L, Yadav G, Samuvel KR, Bhushan M, Kumar P, Suhail M, et al. Dosimetric influence of filtered and flattening filter free photon beam on rapid arc (RA) radiotherapy planning in case of cervix carcinoma. Rep PractOncolRadiother. 2017;22(1):10-8.
  21. Lang S, Reggiori G, PuxeuVaquee J, Calle C, Hrbacek J, Klock S, et al. Pre-treatment quality assurance of flattening filter free beams on 224 patients for intensity modulated plans: a multicentric study. Med Phys.2012;39(3):1351–6.
  22. Gasic D, Ohlhues L, Brodin NP, Fog LS, Pommer T, Bangsgaard JP, 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. ActaOncol. 2014; 53(8):1005-11.
  23. Vassiliev ON, Kry SF, Kuban DA, Salehpour M, Mohan R, Titt U. Treatment-planning study of prostate cancer intensity-modulated radiotherapy with a Varian Clinac operated without a flattening filter. Int J RadiatOncolBiol Phys. 2007;68(5):1567-71.
  24. Cashmore J, Ramtohul M, Ford D. Lowering whole-body doses in pediatric intensity-modulated radiotherapy through the use of unflattened photon beams. Int J RadiatOncolBiol Phys. 2011; 80(4):1220-7.
  25. Kragl G, Baier F, Lutz S, Albrich D, Dalaryd M, Kroupa B, et al. Flattening filter free beams in SBRT and IMRT: Dosimetric assessment of peripheral doses. Z Med Phys. 2011; 21(2):91-101.
  26. Gurjar OP, Jha VK, Sharma SD. Radiation dose to radiotherapy technologists due to induced activity in high energy medical electron linear accelerators. RadiatProt Environ. 2014; 37:25‑9.
  27. Akkurt I, Adler JO, Annand JR, Fasolo F, Hansen K, Isaksson L, et al. Photoneutron yields from tungsten in the energy range of the giant dipole resonance. Phys Med Biol. 2003; 48(20):3345-52.
  28. Kry SF, Titt U, Ponisch F, Vassiliev ON, Salehpour M, GillinM,etal.Reduced neutron production through use of a flattening-filter-free accelerator. Int J RadiatOncolBiol Phys. 2007; 68:1260-4.
  29. Mesbahi A. A Monte Carlo study on neutron and electron contamination of an unflattened 18-MV photon beam. ApplRadiatIsot. 2009; 67(1):55-60.
  30. NCRP. NCRP Report No. 79: Neutron Contamination for Medical Electron Accelerators. Bethesda, Maryland: NCRP; 1987.
  31. Haas JA, Witten MR, Clancey O, Episcopia K, Accordino D, Chalas E. CyberKnife Boost for Patients with Cervical Cancer Unable to Undergo Brachytherapy. Front Oncol. 2012; 2:25.

 

Iranian Journal of Medical Physics
Volume 18, Issue 1
January and February 2021
Pages 23-29

Files

History

  • Receive Date: 10 September 2019
  • Revise Date: 04 January 2020
  • Accept Date: 12 January 2020

Share

How to cite

Statistics