Register Steven, Takita Cristiane, Reis Isildinha, Zhao Wei, Amestoy William, Wright Jean
Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL.
Department of Public Health Sciences, University of Miami, Miami, FL.
Med Dosim. 2015 Spring;40(1):89-95. doi: 10.1016/j.meddos.2014.10.005. Epub 2014 Dec 17.
To identify anatomic and treatment characteristics that correlate with organ-at-risk (OAR) sparing with deep inspiration breath-hold (DIBH) technique to guide patient selection for this technique. Anatomic and treatment characteristics and radiation doses to OARs were compared between free-breathing and DIBH plans. Linear regression analysis was used to identify factors independently predicting for cardiac sparing. We identified 64 patients: 44 with intact breast and 20 postmastectomy. For changes measured directly on treatment planning scans, DIBH plans decreased heart-chest wall length (6.5 vs 5.0cm, p < 0.001), and increased lung volume (1074.4 vs 1881.3cm(3), p < 0.001), and for changes measured after fields are set, they decreased maximum heart depth (1.1 vs 0.3cm, p < 0.001) and heart volume in field (HVIF) (9.1 vs 0.9cm(3), p < 0.001). DIBH reduced the mean heart dose (3.4 vs 1.8Gy, p < 0.001) and lung V20 (19.6% vs 15.3%, p < 0.001). Regression analysis found that only change in HVIF independently predicted for cardiac sparing. We identified patients in the bottom quartile of the dosimetric benefits seen with DIBH and categorized the cause of this "minimal benefit." Overall, 29% of patients satisfied these criteria for minimal benefit with DIBH and the most common cause was favorable baseline anatomy. Only the reduction in HVIF predicted for reductions in mean heart dose; no specific anatomic surrogate for the dosimetric benefits of DIBH technique could be identified. Most patients have significant dosimetric benefit with DIBH, and this technique should be planned and evaluated for all patients receiving left-sided breast/chest wall radiation.
确定与深吸气屏气（DIBH）技术下危及器官（OAR）保留相关的解剖学和治疗特征，以指导该技术的患者选择。比较了自由呼吸和DIBH计划之间的解剖学和治疗特征以及OAR的辐射剂量。采用线性回归分析确定独立预测心脏保留的因素。我们纳入了64例患者：44例乳房完整，20例乳房切除术后。对于在治疗计划扫描上直接测量的变化，DIBH计划缩短了心脏-胸壁长度（6.5 vs 5.0cm，p<0.001），增加了肺体积（1074.4 vs 1881.3cm³，p<0.001），对于在设野后测量的变化，DIBH计划降低了最大心脏深度（1.1 vs 0.3cm，p<0.001）和野内心脏体积（HVIF）（9.1 vs 0.9cm³，p<0.001）。DIBH降低了平均心脏剂量（3.4 vs 1.8Gy，p<0.001）和肺V20（19.6% vs 15.3%，p<0.001）。回归分析发现，只有HVIF的变化独立预测心脏保留。我们确定了DIBH剂量学获益处于最低四分位数的患者，并对这种“最小获益”的原因进行了分类。总体而言，29%的患者符合DIBH最小获益的这些标准，最常见的原因是基线解剖结构有利。只有HVIF的降低预测了平均心脏剂量的降低；无法确定DIBH技术剂量学获益的特定解剖学替代指标。大多数患者通过DIBH有显著的剂量学获益，对于所有接受左侧乳腺/胸壁放疗的患者都应规划和评估该技术。
