DOI QR코드

DOI QR Code

Evaluation of Beam-Matching Accuracy for 8 MV Photon Beam between the Same Model Linear Accelerator

동일 기종 선형가속기간 8 MV 광자선에 대한 빔 매칭 정확도 평가

  • Kim, Yon-Lae (Department of Radiologic Technology, Choonhae College of Health Science) ;
  • Chung, Jin-Beom (Department of Radiation Oncology, Seoul National Univ. Bundang Hospital) ;
  • Kang, Seong-Hee (Department of Radiation Oncology, Seoul National Univ. Bundang Hospital)
  • 김연래 (춘해보건대학교 방사선과) ;
  • 정진범 (분당서울대학교병원 방사선종양학과) ;
  • 강성희 (분당서울대학교병원 방사선종양학과)
  • Received : 2020.03.30
  • Accepted : 2020.04.20
  • Published : 2020.04.30

Abstract

This study aimed to assess of beam-matching accuracy for an 8 MV beam between the same model linear accelerators(Linac) commissioned over two years. Two models were got the customer acceptance procedure(CAP) criteria. For commissioning data for beam-matched linacs, the percentage depth doses(PDDs), beam profiles, output factors, multi-leaf collimator(MLC) leaf transmission factors, and the dosimetric leaf gap(DLG) were compared. In addition, the accuracy of beam matching was verified at phantom and patient levels. At phantom level, the point doses specified in TG-53 and TG-119 were compared to evaluate the accuracy of beam modelling. At patient level, the dose volume histogram(DVH) parameters and the delivery accuracy are evaluated on volumetric modulated arc therapy(VMAT) plan for 40 patients that included 20 lung and 20 brain cases. Ionization depth curve and dose profiles obtained in CAP showed a good level for beam matching between both Linacs. The variations in commissioning beam data, such as PDDs, beam profiles, output factors, TF, and DLG were all less than 1%. For the treatment plans of brain tumor and lung cancer, the average and maximum differences in evaluated DVH parameters for the planning target volume(PTV) and the organs at risk(OARs) were within 0.30% and 1.30%. Furthermore, all gamma passing rates for both beam-matched Linacs were higher than 98% for the 2%/2 mm criteria and 99% for the 2%/3 mm criteria. The overall variations in the beam data, as well as tests at phantom and patient levels remains all within the tolerance (1% difference) of clinical acceptability between beam-matched Linacs. Thus, we found an excellent dosimetric agreement to 8 MV beam characteristics for the same model Linacs.

Keywords

References

  1. Hrbacek J, Depuydt T, Nulens A, Swinnen A, Heuvel FV. Quantitative evaluation of a beam-mathcing procedure using one-dimensional gamma analysis. Med Phys. 2007;34:2917-27. https://doi.org/10.1118/1.2745239
  2. Beyer GP. Commissioning measurements for photon beam data on three TrueBeam linear accelerators, and comparison with Trilogy and Clinac 2100 linear accelerators. J Appl Clin Med Phys. 2013;14:273-88. https://doi.org/10.1120/jacmp.v14i1.4077
  3. Glide-Hurst C, Bellon M, Foster R, Altunbas C, Speiser M, et al. Commissioning of the Varian TrueBeam linear accelerator: a multi-institutional study. Med Phys. 2013;40(3).
  4. SjSstrSm D, Bjelkengren U, Ottosson W, Behrens CF. A beam-matching concept for medical linear accelerators. Acta Oncol. 2009;48:192-200. https://doi.org/10.1080/02841860802258794
  5. Kang S, Chung JB, Eom KY, Song C, Kim IA, et al. Possibility of Interchanging Patients for Beam-Matched Linear Accelerators from the Same Vendor. J Korean Phys Soc. 2019;75:628-35. https://doi.org/10.3938/jkps.75.628
  6. Fraass B, Doppke K, Hunt M, Kutcher G, Starkschall G, Stern R, Dyke RV. American Association of Physicist in medicine radiation therapy committee task group 53: quality assurance for clinical treatment planning. Med Phys. 1998;25:1773-829. https://doi.org/10.1118/1.598373
  7. Ezzell GA, Burmeister JW, Dogan N, LoSassoJ TJ, Mechalakos JG, et al. IMRT commissioning: multiple institution planning and dosimetry comparison. Med Phys. 2009;36:5359-83. https://doi.org/10.1118/1.3238104
  8. Nithya L, Raj NA, Rathinamuthu S, Pandey MB. Analyzing the performance of the planning system by u se o f AAPM T G119 t est cases. Radiol Phys Technol. 2016;9:22-9. https://doi.org/10.1007/s12194-015-0328-z
  9. Kim YL, Chung JB, Kim JS, Lee JW, Choi KS. Comparison of the performance between portal dosimetry and a commercial two-dimensional array system on pretreatment quality assurance for volumetric-modulated arc and intensity-modulated radiation therapy. J Korean Phys Soc. 2014;64:1207-12. https://doi.org/10.3938/jkps.64.1207
  10. Ashokkumar S, Ganesh KM, Ramalingam K, Karthikeyan K, Jagadheeskumar N. Dosimetric validation of volumetric modulated arc therapy with three 6 MV beam-matched linear accelerators. Asian Pacific Journal of Cancer Prevention. 2017;18:3439-44.
  11. Xu Z, Warrell G, Lee S, et al. Assessment of beammatched Linacs quality/accuracy for interchanging SBRT or SRT patient using VMAT without replanning. J Appl Clin Med Phys. 2019; 20:1:68-75. https://doi.org/10.1002/acm2.12492
  12. Watts RJ. Comparative measurements on a series of accelerators by the same vendor. Med Phys. 1999;26:2581-5. https://doi.org/10.1118/1.598796
  13. Attalla EM, Abou-Elenein HS, Ammar H, et al. Dosimetric evaluation of a beam matching procedure. Chinese-German J Clin Oncol. 2014;13:89-93.
  14. Bhangle JR, Narayanan VKS, Kumar NK, et al. Dosimetric analysis of beam-matching procedure of two similar linear accelerators. J Med Phys. 2011;36:176-80. https://doi.org/10.4103/0971-6203.83497
  15. Krishnappan C, Radha CA, Balaji K, et al. Evaluation of beam matching accuracy among six Linacs from the same vendor. Radiol Phys Technol. 2018;11:423-33. https://doi.org/10.1007/s12194-018-0480-3
  16. Baek TS, Chung EJ, Son J, Yoon M. Feasibility study of patient specific quality assurance using transit dosimetry based on measurement with an electronic portal Imaging Device. Prog Med Phys. 2017;28:54-60. https://doi.org/10.14316/pmp.2017.28.2.54
  17. Son SY, Choi KW, Kim JM, et al. Evaluation of image quality for various electronic portal imaging devices in radiation therapy. Journal of Radiological Science and Technology. 2015;38(4):451-61. https://doi.org/10.17946/JRST.2015.38.4.16