Russo Stefania, Ricotti Rosalinda, Molinelli Silvia, Patti Filippo, Barcellini Amelia, Mastella Edoardo, Pella Andrea, Paganelli Chiara, Marvaso Giulia, Pepa Matteo, Comi Stefania, Zaffaroni Mattia, Avuzzi Barbara, Giandini Tommaso, Pignoli Emanuele, Valdagni Riccardo, Baroni Guido, Cattani Federica, Ciocca Mario, Jereczek-Fossa Barbara Alicja, Orlandi Ester, Orecchia Roberto, Vischioni Barbara
Medical Physics Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy.
Bioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy.
Front Oncol. 2021 Sep 28;11:740661. doi: 10.3389/fonc.2021.740661. eCollection 2021.
Rectum and bladder volumes play an important role in the dose distribution reproducibility in prostate cancer adenocarcinoma (PCa) radiotherapy, especially for particle therapy, where density variation can strongly affect the dose distribution. We investigated the reliability and reproducibility of our image-guided radiotherapy (IGRT) and treatment planning protocol for carbon ion radiotherapy (CIRT) within the phase II mixed beam study (AIRC IG 14300) for the treatment of high-risk PCa. In order to calculate the daily dose distribution, a set of synthetic computed tomography (sCT) images was generated from the cone beam computed tomography (CBCT) images acquired in each treatment session. Planning target volume (PTV) together with rectum and bladder volume variation was evaluated with sCT dose-volume histogram (DVH) metric deviations from the planning values. The correlations between the bladder and rectum volumes, and the corresponding DVH metrics, were also assessed. No significant difference in the bladder, rectum, and PTV median volumes between the planning computed tomography (pCT) and the sCT was found. In addition, no significant difference was assessed when comparing the average DVHs and median DVH metrics between pCT and sCT. Dose deviations determined by bladder and rectum filling variations demonstrated that dose distributions were reproducible in terms of both target coverage and organs at risk (OARs) sparing.
直肠和膀胱体积在前列腺癌腺癌（PCa）放疗的剂量分布可重复性中起着重要作用，特别是对于粒子治疗，密度变化会强烈影响剂量分布。在治疗高危PCa的II期混合束研究（AIRC IG 14300）中，我们研究了图像引导放疗（IGRT）和碳离子放疗（CIRT）治疗计划方案的可靠性和可重复性。为了计算每日剂量分布，从每个治疗疗程采集的锥形束计算机断层扫描（CBCT）图像生成一组合成计算机断层扫描（sCT）图像。使用sCT剂量体积直方图（DVH）与计划值的度量偏差评估计划靶体积（PTV）以及直肠和膀胱体积变化。还评估了膀胱和直肠体积与相应DVH度量之间的相关性。在计划计算机断层扫描（pCT）和sCT之间，膀胱、直肠和PTV的中位体积没有显著差异。此外，比较pCT和sCT之间的平均DVH和中位DVH度量时，未评估到显著差异。由膀胱和直肠充盈变化确定的剂量偏差表明，在靶区覆盖和危及器官（OARs） sparing方面，剂量分布是可重复的。
