呼吸门控放疗中呼吸基线波动对呼吸预测滤波器性能的影响-《中国医学物理学杂志》

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Title:: Effects of respiratory baseline fluctuations on performance of breathing predictive filter in respiration-gated radiotherapy

文章编号:: 1005-202X（2022）02-0152-05

作者:: 郑佳俊; 孙丽; 汪琪; 牟忠德; 翟振宇; 江苏省肿瘤医院/江苏省肿瘤防治研究所/南京医科大学附属肿瘤医院放疗物理技术中心，江苏南京 210000

Author(s):: ZHENG Jiajun; SUN Li; WANG Qi; MU Zhongde; ZHAI Zhenyu; Department of Medical Physics and Technology, Jiangsu Cancer Hospital/Jiangsu Institute of Cancer Research/the Affiliated Cancer Hospital of Nanjing Medical University, Nanjing 210000, China

关键词:: 实时位置管理; 相位式呼吸门控; 呼吸预测滤波器; 呼吸基线; 基线波动; 残余呼吸信号

Keywords:: Keywords: real-time position management phase-based respiration gating breathing predictive filter respiratory baseline baseline fluctuation residual motion

分类号:: R815.6

DOI:: DOI:10.3969/j.issn.1005-202X.2022.02.004

文献标志码:: A

摘要:: 目的：评估基于瓦里安实时位置管理（RPM）系统的呼吸门控放疗中病人呼吸基线波动对呼吸预测滤波器（BPF）性能的影响。方法：分析20例RPM相位式呼吸门控放疗病例的参考呼吸波形和残余呼吸信号以及共146次治疗时的呼吸波形和残余呼吸信号，作以下处理：（1）将呼吸波形（包括参考和治疗时）经Savitsky-Golay平滑、峰值检测和异常点剔除后得到呼吸基线，计算其标准差做为衡量基线波动强弱的指标，计算各次治疗时基线波动相对于参考基线波动的相对偏差；（2）计算残余呼吸信号（包括参考和治疗时）标准差，将其作为衡量呼吸信号强弱的指标，同样计算各次治疗时残余呼吸相对于参考残余呼吸的相对偏差；（3）对基线波动偏差和残余呼吸信号偏差做Pearson相关性分析。结果：146次治疗中呼吸基线波动偏差最小值和最大值分别为-61.0%、752.3%，四分位数分别为42.8%、90.3%、161.7%；残余呼吸信号偏差最小值和最大值分别为-74.8%、174.0%，四分位数分别为-7.8%、15.1%、48.8%；残余呼吸信号偏差与基线波动偏差之间的相关系数为0.544，差异有统计学意义（P<0.01）；线性拟合系数为0.2。结论：当前RPM相位式呼吸门控技术条件下，治疗时病人实际残余呼吸信号偏差与呼吸基线波动偏差线性显著相关，每100%的基线波动偏差平均可导致20%的残余呼吸信号偏，表明BPF性能受到影响；临床工作中需要制定有效的质量控制方案以避免治疗时病人出现缓慢的呼吸基线波动偏差。

Abstract:: Abstract: Objective To evaluate the effect of baseline fluctuations of patients breathing on the performance of breathing predictive filter in respiration-gated radiotherapy based on Varian real-time position management (RPM) system. Methods The reference respiratory waveforms and residual motions of 20 cases of RPM phase-based respiration-gated radiotherapy were analyzed, as well as the respiratory waveforms and residual motions in a total of 146 treatments. (1) After Savitsky-Golay smoothing, peak detection and abnormal point elimination for the respiratory waveforms (including reference and treatment), the respiratory baseline was obtained. Standard deviation was calculated as an index to measure the strength of baseline fluctuations, and the relative deviation of baseline fluctuations relative to the reference baseline fluctuations during each treatment was calculated. (2) The standard deviation of residual motions (including reference and treatment) was used as an indicator to measure the strength of residual motion, and the relative deviation of residual motion relative to the reference residual motion during each treatment was calculated. (3) Pearson correlation analyses on the baseline fluctuation deviations and residual motion deviations were carried out. Results The minimum and maximum values ?#8203of the deviations of respiratory baseline fluctuations in 146 treatments were -61.0%, 752.3%, and the quartiles were 42.8%, 90.3%, 161.7%. For the deviations of residual motions, the minimum and maximum values were -74.8%, 174.0%, and the quartiles were -7.8%, 15.1%, 48.8%. The correlation coefficient between residual motion deviations and baseline fluctuation deviations was 0.544, and the P value was much less than 0.01, indicating statistical significance. The linear fitting coefficient was 0.2. Conclusion Under the current technical conditions of RPM phase-based respiration-gated technology, the actual residual motion deviation of the patient during treatment is significantly linearly related to the baseline respiratory fluctuation deviation. Every 100% baseline fluctuation deviation can lead to an average of 20% residual motion deviation. Therefore, an effective quality control program needs to be formulated in clinic for avoiding respiratory baseline deviations during treatment.

《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]

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