Tsai Pingfang, Tseng Yu-Lun, Shen Brian, Ackerman Christopher, Zhai Huifang A, Yu Francis, Simone Charles B, Choi J Isabelle, Lee Nancy Y, Kabarriti Rafi, Lazarev Stanislav, Johnson Casey L, Liu Jiayi, Chen Chin-Cheng, Lin Haibo
New York Proton Center, New York, NY 10035, USA.
Proton Center, Taipei Medical University, Taipei 11031, Taiwan.
Cancers (Basel). 2023 Oct 22;15(20):5101. doi: 10.3390/cancers15205101.
The study evaluates the efficacy of cone-beam computed tomography (CBCT)-based synthetic CTs (sCT) as a potential alternative to verification CT (vCT) for enhanced treatment monitoring and early adaptation in proton therapy.
Seven common treatment sites were studied. Two sets of sCT per case were generated: direct-deformed (DD) sCT and image-correction (IC) sCT. The image qualities and dosimetric impact of the sCT were compared to the same-day vCT.
The sCT agreed with vCT in regions of homogeneous tissues such as the brain and breast; however, notable discrepancies were observed in the thorax and abdomen. The sCT outliers existed for DD sCT when there was an anatomy change and for IC sCT in low-density regions. The target coverage exhibited less than a 5% variance in most DD and IC sCT cases when compared to vCT. The D of serial organ-at-risk (OAR) in sCT plans shows greater deviation from vCT than small-volume dose metrics (D0.1cc). The parallel OAR volumetric and mean doses remained consistent, with average deviations below 1.5%.
The use of sCT enables precise treatment and prompt early adaptation for proton therapy. The quality assurance of sCT is mandatory in the early stage of clinical implementation.
本研究评估基于锥形束计算机断层扫描（CBCT）的合成CT（sCT）作为验证CT（vCT）的潜在替代方法，用于在质子治疗中加强治疗监测和早期适应性调整的效果。
研究了七个常见的治疗部位。每个病例生成两组sCT：直接变形（DD）sCT和图像校正（IC）sCT。将sCT的图像质量和剂量学影响与同日的vCT进行比较。
sCT在脑和乳腺等均匀组织区域与vCT一致；然而，在胸部和腹部观察到明显差异。当解剖结构发生变化时，DD sCT存在sCT异常值，而在低密度区域IC sCT存在异常值。与vCT相比，大多数DD和IC sCT病例中靶区覆盖的差异小于5%。sCT计划中系列危及器官（OAR）的剂量与vCT相比，显示出比小体积剂量指标（D0.1cc）更大的偏差。并行OAR的体积和平均剂量保持一致，平均偏差低于1.5%。
sCT的使用能够实现质子治疗的精确治疗和及时的早期适应性调整。在临床实施的早期阶段，sCT的质量保证是必不可少的。
