Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908-0375, USA.
Int J Radiat Oncol Biol Phys. 2011 Nov 15;81(4):e569-76. doi: 10.1016/j.ijrobp.2011.01.044. Epub 2011 Apr 29.
Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table.
Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planning Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy.
Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0-3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 ± 3 mm inferior, 1 ± 2 mm right, and 1 ± 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008).
We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.
自愿深吸气屏气（VDIBH）可降低左乳房放疗中心脏的剂量。我们介绍了第一项研究的结果，该研究旨在通过骨性解剖结构、心脏位置和心脏剂量来量化 VDIBH 患者在治疗台上屏气的可重复性。
对 10 例接受 VDIBH 全乳照射的左乳腺癌患者的数据进行了分析。采集了两次 CT 扫描，即自由呼吸（FB）和 VDIBH，以比较关键结构的剂量。在治疗前每周采集 kV 正交图像和切线端口。在核心注册数字重建射线照片（DRR）和骨性胸部的 kV 成像之间，从脊髓到胸骨的位移差异是衡量屏气可重复性的指标。如果患者按照骨性解剖结构进行定位，则骨性配准与心脏配准之间的差异即为所测量的心脏移位。
从 FB 到 VDIBH 的剂量减少百分比：平均心脏剂量（48%，SD 19%，p = 0.002）、平均左前降支（LAD）剂量（43%，SD 19%，p = 0.008）和最大左前降支（LAD）剂量（60%，SD 22%，p = 0.008）。使用骨性解剖结构在沿前后（AP）平面穿过等中心的整个屏气过程中的平均呼吸可重复性为 1（范围为 0-3；SD，1）mm。在不同的呼吸保持期间，相对于骨性解剖结构的平均心脏移位为下 2 ± 3mm、右 1 ± 2mm 和后 1 ± 3mm。从计划到交付的剂量变化百分比：平均心脏剂量（7%，SD 6%）；平均 LAD 剂量，（9%，SD 7%），最大 LAD 剂量，（11%，SD 11%），p = 0.008。
我们观察到计划与治疗前成像之间存在出色的三维骨性配准。在整个 VDIBH 治疗过程中，心脏和 LAD 的剂量都保持降低。
