Benkhaled Sofian, Gomes da Silveira Cauduro Carolina, Jullian Nicolas, Desmet Antoine, Rodriguez Diana, Jourani Younes, Van Gestel Dirk, De Caluwé Alex
Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium.
Department of Medical-Physics, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium.
Front Oncol. 2022 Aug 18;12:936088. doi: 10.3389/fonc.2022.936088. eCollection 2022.
PURPOSE/OBJECTIVE: Deep Inspiration Breath Hold (DIBH) is now considered as the standard of care for many breast cancer patients. However, there are still uncertainties about the dose given to the heart, and it is unknown if patients may improve voluntary DIBH depth by gaining experience during treatment. In this study, we will examine the interfractional three-dimensional (3D) heart displacement throughout voluntary DIBH (vDIBH) radiotherapy by means of daily cone-beam computed tomography (CBCT).
Two hundred twenty-five unique CBCTs from 15 patients treated in 15 fractions were analyzed. During CBCT, a vDIBH was conducted without any visual feedback. Patients performed their DIBH freely after receiving explanations and training. After daily CBCT matching to the chest wall (CW), surface-guided radiation therapy (SGRT) tracked DIBH depth to ensure that the CW position was the same as the daily acquired CBCT. The CBCTs were retrospectively registered to the DIBH planning-CT to calculate daily changes in heart displacement relative to the CW.
The mean displacement of the heart during DIBH treatment relative to the DIBH planning-CT was as follows: 1.1 mm to the right, interquartile range (IQR) 8.0; 0.5 mm superiorly, IQR 4.8; and 0 mm posteriorly, IQR 6.4. The Spearman correlation coefficients (r) were -0.15 (p=0.025), 0.04 (p=0.549), and 0.03 (p=0.612) for the X, Y, and Z directions, respectively. The differences in median heart displacement were significant: Friedmann rank sum test p=0.031 and pairwise comparison using the Wilcoxon rank-sum test were p=0.008 for X and Y; p=0.33 for X and Z; and p=0.07 for Y and Z. The total median heart motion was δ= 7.26 mm, IQR= 6.86 mm.
During DIBH, clinicians must be aware of the wide range of intra- and inter-individual heart position variations. The inter-individual heterogeneity shown in our study should be investigated further in order to avoid unexpected cardiac overexposure and to develop a more accurate heart dose-volume model.
目的/目标：深吸气屏气（DIBH）目前被视为许多乳腺癌患者的护理标准。然而，给予心脏的剂量仍存在不确定性，并且患者是否可以通过在治疗过程中积累经验来提高自主DIBH深度尚不清楚。在本研究中，我们将通过每日锥形束计算机断层扫描（CBCT）检查在自主DIBH（vDIBH）放疗期间心脏的分次间三维（3D）位移。
分析了15例患者15个分次的225次独特CBCT。在CBCT期间，在没有任何视觉反馈的情况下进行vDIBH。患者在接受解释和培训后自由进行DIBH。在每日CBCT与胸壁（CW）匹配后，表面引导放射治疗（SGRT）跟踪DIBH深度，以确保CW位置与每日获取的CBCT相同。将CBCT回顾性地注册到DIBH计划CT，以计算相对于CW的心脏位移的每日变化。
在DIBH治疗期间，心脏相对于DIBH计划CT的平均位移如下：向右1.1毫米，四分位数间距（IQR）8.0；向上0.5毫米，IQR 4.8；向后0毫米，IQR 6.4。X、Y和Z方向的Spearman相关系数（r）分别为-0.15（p = 0.025）、0.04（p = 0.549）和0.03（p = 0.612）。心脏位移中位数的差异具有统计学意义：Friedmann秩和检验p = 0.031，使用Wilcoxon秩和检验的成对比较中，X和Y方向为p = 0.008；X和Z方向为p = 0.33；Y和Z方向为p = 0.07。心脏总位移中位数为δ = 7.26毫米，IQR = 6.86毫米。
在DIBH期间，临床医生必须意识到个体内和个体间心脏位置变化的广泛范围。我们研究中显示的个体间异质性应进一步研究，以避免意外的心脏过度照射，并开发更准确的心脏剂量体积模型。
