Efficiency of modulated and dose rate altered flattening filter free beams in high dose per fraction radiotherapy applications on the survival of prostate cancer cell lines


Ceylan C., Ozturk A., GUNGOR G. , Karabey A. U. , Sahin S., DURUKSU G., ...More

INTERNATIONAL JOURNAL OF RADIATION RESEARCH, vol.19, no.4, pp.879-889, 2021 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 19 Issue: 4
  • Publication Date: 2021
  • Doi Number: 10.29242/ijrr.19.4.879
  • Title of Journal : INTERNATIONAL JOURNAL OF RADIATION RESEARCH
  • Page Numbers: pp.879-889
  • Keywords: Flattening filter free, Cell survival, Radiosurgery, Radiobiology, RADIATION-THERAPY, IN-VITRO, DELIVERY TIMES, X-RAYS, IMRT, ARC, DEPENDENCE, IMPACT, PULSE, VIVO

Abstract

Background: The radiobiological effect of high dose rate FFF beams on the DU-145 cells was investigated with SBRT plans which have >10 Gy. Methods and Materials: To compare the radiobiological effect on DU-145 cell line four experiments designed: (1) the constant dose rate of 6 MV and 6 MV FFF with increased dose per pulse (2) the effect of dose per pulse while increasing instantaneous dose rate for 6 MV and 6 MV FFF, (3) the effect of increased average dose rate for 6 MV FFF and (4) the effect of protracted treatment time and modulation of 6 MV FFF beams. The survival fraction was counted with WST. Results: FF and FFF for 6 MV with same dose rate and treatment time has no effect on cell survival. Significant differences was observed on survival which were irradiated with 6 MV 600 MU/min and 6 MV FFF 1400 MU/min (p=0.024). There was no difference between 6 MV FFF 600 MU/min and 6 MV FFF 1400 MU/min for 10 Gy. The significant survival difference obtained for 20 Gy. The survival percentages for both 10 Gy and 20 Gy with Cyberknife were obtained higher than FFF. Conclusion: Our in-vitro study presented here show that higher dose rate and reduced treatment time might become a crucial factor for SBRT especially which has >10 Gy fraction dose.