동일 기종 선형가속기간 8 MV 광자선에 대한 빔 매칭 정확도 평가

• 영문명: Evaluation of Beam-Matching Accuracy for 8 MV Photon Beam between the Same Model Linear Accelerator
• 발행기관: 대한방사선과학회(구 대한방사선기술학회)
• 저자명: 김연래(Yon-Lae Kim) 정진범(Jin-Beom Chung) 강성희(Seong-Hee Kang)
• 간행물 정보: 『방사선기술과학』방사선기술과학 제43권 제2호, 105~114쪽, 전체 10쪽
• 주제분류: 의약학 > 방사선과학
• 파일형태: PDF
• 발행일자: 2020.04.30

영문 초록

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 ㎜ criteria and 99% for the 2%/3 ㎜ 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.

목차

Ⅰ. Introduction

Ⅱ. Materials and methods

Ⅲ. Results

Ⅳ. Discussion

Ⅴ. Conclusion

키워드

심부선량백분율(Percentage depth dose) 선량분포(Dose profile) 사용준비(Commissioning) 선량체적히스토그람(Dose volume histogram) 전달 정확성(Delivery accuracy)