The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)

Korean Society for Radiation Therapy (대한방사선치료학회)
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A Study on Superficial Dose of 6MV-FFF in HalcyonTM LINAC: Phantom Study

HalcyonTM 선형가속기 6MV-FFF 에너지의 표재 선량에 대한 고찰: Phantom Study

  • Choi, Seong Hoon (Department of Radiation Oncology, Asan Medical Center) ;
  • Um, Ki Cheon (Department of Radiation Oncology, Asan Medical Center) ;
  • Yoo, Soon Mi (Department of Radiation Oncology, Asan Medical Center) ;
  • Park, Je Wan (Department of Radiation Oncology, Asan Medical Center) ;
  • Song, Heung Kwon (Department of Radiation Oncology, Asan Medical Center) ;
  • Yoon, In Ha (Department of Radiation Oncology, Asan Medical Center)
  • 최성훈 (서울아산병원 방사선종양학과) ;
  • 엄기천 (서울아산병원 방사선종양학과) ;
  • 유순미 (서울아산병원 방사선종양학과) ;
  • 박제완 (서울아산병원 방사선종양학과) ;
  • 송흥권 (서울아산병원 방사선종양학과) ;
  • 윤인하 (서울아산병원 방사선종양학과)
  • Published : 2020.12.27
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Abstract

Purpose: The aims of this study were to compare the superficial dose with Optically Stimulated Luminescence Dosimeter(OSLD) measurement and Treatment Planning System(TPS) calculation for 6MV-Flattening Filter Free(FFF) energy using HalcyonTM and TrueBeamTM. Materials and methods: Phantom study was performed using the CT images of human phantom. In the treatment planning system, the Planning Target Volume(PTV) was contoured which is similar to Glottic cancer. Furthermore, Point(M), Point(R), and Point(L) were contoured at the iso-center of head and neck region and 5mm bolus was applied to the body contour. Each treatment plans using 6MV-FFF energy from HalcyonTM and TrueBeamTM with static Intensity Modulated Radiation Therapy(IMRT) and Volumetric Modulated Arc Therapy(VMAT) were established with eclipse. To reproduce the same position as the TPS, OSLDs were placed at the iso-center point and 5mm bolus was applied to compare the error rate after the dose delivery. Result: The results of the study using human phantom are as follows. In case of HalcyonTM, the mean absolute error rates of the point dose using the treatment planning system and the dose measured by OSLD were 1.7%±1.2% for VMAT and 4.0±2.8% for IMRT. Also TrueBeamTM was identified as 2.4±0.4% and 8.6±1.8% respectively for VMAT and IMRT. Conclusion: Through the results of this study, TrueBeamTM confirmed that the average error rate was 2.4 times higher for VMAT and 3.6 times higher for IMRT than HalcyonTM. Therefore, based on the results of this study, If we need a more accurate dose assessment for the superficial dose, It is expected that using HalcyonTM would be better than TrueBeamTM.

목 적: 본 연구는 HalcyonTM과 TrueBeamTM에서 사용하는 6MV-FFF(Flattening Filter Free) 에너지를 이용하여 전산화치료계획시스템(Treatment Planning System, TPS)에서 계산된 선량과 광자극형광선량계(Optically Stimulated Luminescence Dosimeter, OSLD)로 측정된 표재 선량(Superficial dose)을 비교하고자 한다. 재료 및 방법: 팬텀연구를 위해 인체모형 팬텀(Human Phantom)의 CT 영상을 이용하여 치료계획시스템에서 성문암(Glottic cancer)과 유사한 치료계획용적(Planning Target Volume, PTV)과 두경부위의 등 중심점(Iso-center) 위치에 측정을 위한 Point(M), Point(R), Point(L)의 구조물을 설정하고 체표윤곽(Body contour)에 5mm Bolus를 적용하였다. 그 후 전산화치료계획은 HalcyonTM과 TrueBeamTM의 6MV-FFF 에너지를 이용하여 정적(Static) 세기변조방사선치료(Intensity Modulated Radiation Therapy, IMRT)와 용적변조회전치료(Volumetric Modulated Arc Therapy, VMAT)계획을 각각 수립하였다. 전산화치료계획과 동일하게 재현하기 위해 OSLD를 등 중심점에 위치시키고 5mm Bolus를 적용하여 선량 전달 후 오차율을 비교하였다. 결 과: 인체모형 팬텀을 사용한 실험 결과 HalcyonTM의 전산화치료계획시스템에서의 점 선량과 OSLD를 이용한 선량 측정의 오차율의 절댓값의 평균은 VMAT, IMRT 각각 1.7±1.2%, 4.0±2.8%로 확인되었으며, TrueBeamTM의 오차율의 절댓값의 평균은 VMAT, IMRT 각각 2.4±0.4%, 8.6±1.8%로 확인되었다. 결 론: 실험결과 HalcyonTM을 기준으로 TrueBeamTM에서 VMAT과 IMRT 각각 2.4배, 3.6배 더 큰 오차가 발생하는 것을 확인할 수 있었다. 따라서 본 연구의 결과를 토대로 표재 선량에 대한 정확한 선량평가가 이루어져야 하는 경우, TrueBeamTM보다 HalcyonTM에서 정확한 선량 평가가 이루어질 수 있을 것으로 사료된다.

Keywords

References

  1. Korea central cancer Registry, National cancer center. Annual report of cancer statistics in korea in 2017, Ministry of Health and welfare (2020).
  2. Steven Michiels, Kenneth Poels, Wouter Crijns et al.: Volumetric modulated arc therapy of head-and-neck cancer on a fast-rotating O-ring linac: plan quality and delivery time comparison with a Carm linac. Radiotherapy and Oncology. Vol 128(3) 2018:479-484 https://doi.org/10.1016/j.radonc.2018.04.021
  3. H.Kim, M.S.Huq, C.J. Houser et al: Early clinical experience with varian halcyon V2 linear accelerator: Dual-isocenter IMRT planning and delivery with portal dosimetry for gynecological cancer treatments. Int J Radiation Oncol Biol Physics, Vol 125(1) 2019:E705
  4. Michele M.Kim, Douglas Bollinger, Chris Kennedy et al: Dosimetric Characterization of the Dual Layer MLC system for an O-Ring Linear Accelerator. Technology in Cancer Research & Trearment. Vol 18 2019:1-7
  5. Mikoto Tamura, Kenji Matsumoto, Masakazu Otsuka et al: Plan complexity quantification of dual-layer multi-leaf collimator for volumetric modulated arc therapy with Halcyon linac. Phys Eng Sci Med. Vol 43(3) 2020:947-957 https://doi.org/10.1007/s13246-020-00891-2
  6. Molham M. Eyadeh, Marcin Wierzbicki, Kevin R. Diamond: Measurements of superficial dose distributions in radiation therapy using translucent cryogel dosimeters. J.Appl.Clin.Med.Phys.,VOl 18(3) 2017:153-162 https://doi.org/10.1002/acm2.12087
  7. Cashmore J.: The characterization of unflattened photon beams from a 6MV linear accelerator. Phys. Med. Biol. Vol 53(7) 2008:1933-1946 https://doi.org/10.1088/0031-9155/53/7/009
  8. Fionnbarr O'Grady, Andrew R Barsky, Shibu Anamalyil.: Increase in Superficial Dose in Whole-Breast Irradiation With Halcyon Straight-Through Linac Compared With Traditional C-arm Linac With Flattening Filter: In vivo Dosimetry and planning Study. Advances in Radiation Oncology. Vol 5(1) 2020:120-126 https://doi.org/10.1016/j.adro.2019.07.011
  9. An-Cheng Shiau M.S, Tung-Ho Chen M.S, JengFong Chiou M.D.: Surface and superficial dose dosimetric verification for postmastectomy radiotherapy. Medical Dosimetry. Vol 37(4) 2012:417-424 https://doi.org/10.1016/j.meddos.2012.03.005
  10. S Mutic, D A Low: Superficial doses from serial tomotherapy delivery. Med Phys. Vol 27(1) 2000:163-165 https://doi.org/10.1118/1.598880
  11. Tien C.J., R.Ebeling, HiattJ.R., Curran B et al: Optically Stimulated Luminescent Dosimetry for High Dose Rate Brachytherapy. frontiers in Oncology. Vol91(2) 2012:1-7
  12. Audrey H Zhuang, Arthur J Olch: Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments. Med Phys. VOl 41(8) 2014: 081720-1-081720-8 https://doi.org/10.1118/1.4890795
  13. Zhenia Gopalakrishnanm, Raghuram K.Nair, Saju Bhasi et al: Verification of treatment planning algorithms using optically stimulated luminescent dosimeters in a breast phantom. J med Phys. Vol 43(4) 2018:264-269 https://doi.org/10.4103/jmp.jmp_112_18
  14. Su Chul Han, Kum Bae Kim, Sang Hyoun Choi et al: Changes of Optically Stimulated Luminescence Dosimeter Sensitivity with High Dose. Vol 27(2) 2016:98 https://doi.org/10.14316/pmp.2016.27.2.98
  15. Ugur AKBAS, Nazmiye DONMEZ KESEN, Canan KOKSAL et al: Investigation of Surface Dose Using Film Dosimetry and Commercial Treatment Planning System for Larynx Cancer Treatment with Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy. Turk J Oncol. Vol 33(1) 2018:12-17
  16. Taoran Li, Alexander Lin, Wei Zou et al: Impact of Multi-leaf Collimator Parameters on Head and Neck Plan Quality and Delivery: A Comparison between HalcyonTM and TruebeamTM Delivery Systems. Cureus. Vol 10(11) 2018:3648