Placidi Lorenzo, Cusumano Davide, Boldrini Luca, Votta Claudio, Pollutri Veronica, Antonelli Marco Valerio, Chiloiro Giuditta, Romano Angela, De Luca Viola, Catucci Francesco, Indovina Luca, Valentini Vincenzo
Dipartimento di Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, UOC Radioterapia Oncologica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Roma, Italy.
Università Cattolica del Sacro Cuore, Rome, Italy.
J Appl Clin Med Phys. 2020 Nov;21(11):70-79. doi: 10.1002/acm2.13030. Epub 2020 Oct 22.
Magnetic Resonance-guided radiotherapy (MRgRT) systems allow continuous monitoring of therapy volumes during treatment delivery and personalized respiratory gating approaches. Treatment length may therefore be significantly affected by patient's compliance and breathing control. We quantitatively analyzed treatment process time efficiency (T ) using data obtained from real-world patient treatment logs to optimize MRgRT delivery settings.
Data corresponding to the first 100 patients treated with a low T hybrid MRI-Linac system, both in free breathing (FB) and in breath hold inspiration (BHI) were collected. T has been computed as the percentage difference of the actual single fraction's total treatment time and the predicted treatment process time, as computed by the TPS during plan optimization. Differences between the scheduled and actual treatment room occupancy time were also evaluated. Finally, possible correlations with planning, delivery and clinical parameters with T were also investigated.
Nine hundred and nineteen treatment fractions were evaluated. T difference between BHI and FB patients' groups was statistically significant and the mean T were 42.4%, and -0.5% respectively. No correlation was found with T for BHI and FB groups. Planning, delivering and clinical parameters classified BHI and FB groups, but no correlation with T was found.
The use of BHI gating technique can increase the treatment process time significantly. BHI technique could be not always an adequate delivery technique to optimize the treatment process time. Further gating techniques should be considered to improve the use of MRgRT.
磁共振引导放疗（MRgRT）系统可在治疗过程中持续监测治疗体积，并采用个性化呼吸门控方法。因此，治疗时长可能会受到患者依从性和呼吸控制的显著影响。我们使用从实际患者治疗记录中获取的数据，对治疗过程时间效率（T）进行了定量分析，以优化MRgRT的交付设置。
收集了使用低T值混合MRI直线加速器系统治疗的前100例患者在自由呼吸（FB）和屏气吸气（BHI）状态下的数据。T值计算为实际单次分割总治疗时间与计划优化期间TPS计算的预测治疗过程时间的百分比差异。还评估了预定治疗室占用时间与实际治疗室占用时间之间的差异。最后，还研究了T值与计划、交付和临床参数之间可能存在的相关性。
共评估了919个治疗分割。BHI组和FB组患者的T值差异具有统计学意义，平均T值分别为42.4%和-0.5%。BHI组和FB组与T值均未发现相关性。计划、交付和临床参数对BHI组和FB组进行了分类，但未发现与T值相关。
使用BHI门控技术可显著增加治疗过程时间。BHI技术不一定总是优化治疗过程时间的合适交付技术。应考虑进一步的门控技术以改善MRgRT的使用。
