Progress in Medical Physics (한국의학물리학회지:의학물리)

Korean Society of Medical Physics (한국의학물리학회)
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Commissioning Experience of Tri-Cobalt-60 MRI-guided Radiation Therapy System

자기공명영상유도 Co-60 기반 방사선치료기기의 커미셔닝 경험

  • Park, Jong Min (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Park, So-Yeon (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Wu, Hong-Gyun (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Kim, Jung-in (Department of Radiation Oncology, Seoul National University Hospital)
  • 박종민 (서울대학교병원 방사선종양학과) ;
  • 박소연 (서울대학교병원 방사선종양학과) ;
  • 우홍균 (서울대학교병원 방사선종양학과) ;
  • 김정인 (서울대학교병원 방사선종양학과)
  • Received : 2015.11.23
  • Accepted : 2015.12.03
  • Published : 2015.12.31
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Abstract

The aim of this study is to present commissioning results of the ViewRay system. We verified safety functions of the ViewRay system. For imaging system, we acquired signal to noise ratio (SNR) and image uniformity. In addition, we checked spatial integrity of the image. Couch movement accuracy and coincidence of isocenters (radiation therapy system, imaging system and virtual isocneter) was verified. Accuracy of MLC positioing was checked. We performed reference dosimetry according to American Association of Physicists in Medicine (AAPM) Task Group 51 (TG-51) in water phantom for head 1 and 3. The deviations between measurements and calculation of percent depth dose (PDD) and output factor were evaluated. Finally, we performed gamma evaluations with a total of 8 IMRT plans as an end-to-end (E2E) test of the system. Every safety system of ViewRay operated properly. The values of SNR and Uniformity met the tolerance level. Every point within 10 cm and 17.5 cm radii about the isocenter showed deviations less than 1 mm and 2 mm, respectively. The average couch movement errors in transverse (x), longitudinal (y) and vertical (z) directions were 0.2 mm, 0.1 mm and 0.2 mm, respectively. The deviations between radiation isocenter and virtual isocenter in x, y and z directions were 0 mm, 0 mm and 0.3 mm, respectively. Those between virtual isocenter and imaging isocenter were 0.6 mm, 0.5 mm and 0.2 mm, respectively. The average MLC positioning errors were less than 0.6 mm. The deviations of output, PDDs between mesured vs. BJR supplement 25, PDDs between measured and calculated and output factors of each head were less than 0.5%, 1%, 1% and 2%, respectively. For E2E test, average gamma passing rate with 3%/3 mm criterion was $99.9%{\pm}0.1%$.

본 연구는 뷰레이 시스템의 커미셔닝 결과에 대한 보고이다. 먼저, 시스템 안전장치의 적절한 작동을 확인했다. 영상시스템에 대한 평가를 위해 신호 대 잡음비와 영상의 균질도, 공간적 무결성을 확인했다. 카우치 동작의 정확성 및 축교점의 일치성을 평가했다. 미국의학물리학회 특별업무단51규약 프로토콜에 따라 절대선량을 측정했다. BJR supplement 25에서 제공하는 심부선량백분율과 측정한 값의 차이, 치료계획에서 계산한 값과 측정한 심부선량백분율의 차이를 확인했다. 더불어, 출력인수에 대하여, 측정값과 계산값의 차이를 구했다. 최종 검증 단계로, 8개의 세기변조방사선치료계획을 사용하여 감마평가를 수행하였다. 커미셔닝을 수행한 결과, 모든 안전장치는 적절히 구동함을 확인했다. 신호 대 잡음비 값과 영상 균질도 값은 허용범위 이내임을 확인했다. 공간적 무결성 확인 결과, 반지름 10 cm 및 17.5 cm 안의 모든 지점에 대하여 각각 1 mm 및 2 mm 이내의 오차를 확인했다. 카우치는 x, y, z 방향으로 각각 0.2 mm, 0.1 mm, 0.2 mm의 오차를 보였다. 방사선 축교점과 가상 축교점 사이에는 x, y, z 방향으로 0 mm, 0 mm, 0.3 mm의 오차를 보였다. 영상 시스템의 축교점과 가상 축교점 사이에는 0.6 mm, 0.5 mm, 0.2 mm의 오차를 보였다. 다엽콜리메이터의 평균적 구동 오차는 0.6 mm였다. 측정한 출력의 오차는 0.5% 이내, 심부선량백분율 오차는 1% 이내, 출력인수 오차는 2% 이내였다. 세기조절방사선치료 감마평가 결과값이 $99.9%{\pm}0.1%$였다.

Keywords

References

  1. Stam MK, van Vulpen M, Barendrecht MM, et al: Kidney motion during free breathing and breath hold for MR-guided radiotherapy. Phys Med Biol 58(7):2235-2245 (2013) https://doi.org/10.1088/0031-9155/58/7/2235
  2. Seierstad T, Hole KH, Saelen E, et al: MR-guided simultaneous integrated boost in preoperative radiotherapy of locally advanced rectal cancer following neoadjuvant chemotherapy. Radiother Oncol 93(2):279-284 (2009) https://doi.org/10.1016/j.radonc.2009.08.046
  3. Mutic S, Dempsey JF: The ViewRay system: magnetic resonance-guided and controlled radiotherapy. Semin Radiat Oncol 24(3):196-199 (2014) https://doi.org/10.1016/j.semradonc.2014.02.008
  4. Wooten HO, Green O, Yang M, et al: Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a Co-60 Magnetic Resonance Image Guidance Radiation Therapy System. Int J Radiat Oncol Biol Phys 92(4):771-778 (2015) https://doi.org/10.1016/j.ijrobp.2015.02.057
  5. Wooten HO, Rodriguez V, Green O, et al: Benchmark IMRT evaluation of a Co-60 MRI-guided radiation therapy system. Radiother Oncol 114(3):402-405 (2015) https://doi.org/10.1016/j.radonc.2015.01.015
  6. Kishan AU, Cao M, Wang PC, et al: Feasibility of magnetic resonance imaging-guided liver stereotactic body radiation therapy: A comparison between modulated tri-cobalt-60 teletherapy and linear accelerator-based intensity modulated radiation therapy. Pract Radiat Oncol 5(5):330-337 (2015) https://doi.org/10.1016/j.prro.2015.02.014
  7. Rajiv L, Gopi K, Sathish K: Acceptance Test Procedure for MRIdian System. ViewRay Inc., Cleveland, OH (2015)
  8. Attix FH: Introduction to radiological physics and radiation dosimetry. 1st ed, Wiley, New York, NY (1986)
  9. Day M, EGA A: Central axis depth dose data for use in radiotherapy: A survey of depth doses and related data measured in water or equivalent media. Brit J Radiol Suppl 17:1-147 (1983)
  10. Ezzell GA, Burmeister JW, Dogan N, et al: IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys 36(11): 5359-5373 (2009) https://doi.org/10.1118/1.3238104
  11. Almond PR, Biggs PJ, Coursey BM, et al: AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams. Med Phys 26(9):1847-1870 (1999) https://doi.org/10.1118/1.598691
  12. Klein EE, Hanley J, Bayouth J, et al: Task Group 142 report: quality assurance of medical accelerators. Med Phys 36(9):4197-4212 (2009) https://doi.org/10.1118/1.3190392
  13. Kutcher GJ, Coia L, Gillin M, et al: Comprehensive QA for radiation oncology: report of AAPM Radiation Therapy Committee Task Group 40. Med Phys 21(4):581-618 (1994) https://doi.org/10.1118/1.597316

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