摘要
目的:探讨锥形束CT的验收与质量保证;方法 :CBCT的验收主要包括系统与机械的安全验收。利用承球模体验收CBCT的中心与加速器的治疗中心的一致性。使用Catphan模体验收CBCT的图像质量,包括刻度的精度,灰度值均匀性,最低可见对比度,最高空间分辨率等。结果:CBCT的系统与机械相关联锁工作正常。CBCT中心与加速器中心的偏差在左右,前后与垂直方向分别为0.25 mm、0.16 mm,和0.19 mm。灰度值均匀度为1.35%。刻度精确度在垂直,水平与长轴方向上的误差分别为0.2 mm,0.5 mm和0.4 mm。最高空间分辨为11 lp/cm,最低可见对比度为1.07%。结论:CBCT的验收与质量保证对其在图像引导的放射治疗中的正确使用,发挥其最大的临床优势至关重要。本文所探讨的对KV级CBCT的验收与质量保证方法步骤,将为CBCT在临床的安全应用提供指导。
Objective： To investigate the commissioning and quality assurance procedures for cone beam CT （CBCT）. Meth- ods： Commissioning on system and mechanical safety of CBCT was conducted. Alignment of CBCT isocenter with linear ac- celerator isocenter was commissioned with ball-bearing phantom. The image quality of CBCT, including the 3D scale and dis- tance accuracy, uniformity, low contrast and spatial resolution, was commissioned with Catphan phantom. Results： system and mechanical safety related interlock function correctly for CBCT. After commissioning, the deviation of kV isocenter from MV isocenter in lateral, longitudinal, and vertical direction was 0.25 mm, 0.16 mm, and 0.19 mm, respectively. Scale and dis- tance accuracy in vertical, lateral, and longitudinal direction was 0.2 mm, 0.5 mm, and 0.4 mm, respectively. The 3D uniformi- ty of CBCT was 1.35%. Low contrast visibility was 1.07%. The highest spatial resolution was 11 lp/cm. Conclusion： Im- age-guided radiotherapy is an exciting new chapter for radiation oncology. While, at the same time, it requires more effort from medical physicist in order to make sure the performance of CBCT system meets the high expectation consistent with patient care. The described procedures in this study allow for sate clinical implementation of CBCT systems in a modem radiotherapy department.
出处
《中国医学物理学杂志》
CSCD
2013年第1期3854-3858,共5页
Chinese Journal of Medical Physics
