Advantages of simulating thoracic cancer patients in an upright position
Advantages of simulating thoracic cancer patients in an upright position
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DOI：
10.1016/j.prro.2013.04.005
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发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Court, Laurence E.
中科院分区：
文献类型：
--
作者：
Yang, Jinzhong;Chu, David;Court, Laurence E.
目的：比较平卧位和直立位的肺容量和呼吸运动，以评估直立位治疗胸部肿瘤患者的潜在优势。方法与材料：采用多体位MRI扫描仪（FONAR, Melville， NY）对5名处于仰卧位和直立位的健康志愿者进行MRI成像。在每个病例中，在正常呼吸期间进行一系列矢状面磁共振扫描，然后在正常呼气结束时屏气期间进行体积扫描。利用可变形图像配准技术和主成分分析模型对肺内点的运动轨迹进行自动检测和跟踪。呼气量图像被输入到治疗计划系统中，描绘并比较不同设置位置下的肺体积。结果：肺容积的一组标志点在上下方向上的运动幅度从2 mm（距离膈肌远）到29 mm（靠近膈肌）不等。对每个志愿者的呼吸运动幅度与离横膈膜距离的线性回归表明，直立姿势的呼吸运动比仰卧姿势的呼吸运动平均小3毫米，尽管个体之间存在差异。与仰卧位相比，志愿者在直立位时平均呼出气量增加27% (751 cm(3))（范围：9%-53%，250-1390 cm(3)）。结论：与仰卧位相比，直立位患者肺内运动幅度更小，肺绝对体积更大，提示直立位治疗胸椎患者可降低平均肺剂量。(C) 2014年美国放射肿瘤学会。Elsevier Inc.出版。版权所有。
Purpose: To compare lung volume and respiratory motion in supine and upright positions to assess the potential advantages of treating thoracic cancer patients in an upright position.Methods and Materials: A multi-position MRI scanner (FONAR, Melville, NY) was used to take MRI images of 5 healthy volunteers in both supine and upright setup positions. In each case, a series of sagittal cine MR scans were acquired during normal respiration, followed by a volumetric scan taken during breath-hold at end of normal expiration. The trajectory of points inside the lung was automatically detected and tracked in the cine images and then analyzed using a deformable image registration technique together with a principal component analysis model. The exhale volume images were imported into a treatment planning system and lung volumes were delineated and compared for different setup positions.Results: The amplitude of motion for a set of landmark points in the lung volume ranged from 2 mm (distant from the diaphragm) to 29 mm (close to the diaphragm) in the superior-inferior direction. A linear regression to the amplitude of respiratory motion versus distance from the diaphragm for each volunteer showed that the motion was 3 mm less on average in the upright position than in the supine position, although there was variability among individuals. The average exhale lung volume was 27% (751 cm(3)) larger (range: 9%-53%, 250-1390 cm(3)) when volunteers were in the upright position compared with the supine position.Conclusions: The magnitude of motion inside the lung was smaller and the absolute lung volumes were much larger in the upright position than in the supine position, which suggests that treating thoracic patients in the upright position may allow for a reduction in the mean lung dose. (C) 2014 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.