Respiratory motion management with breath hold for patients with hepatobiliary cancers remain a challenge in the precise positioning for radiotherapy. We compared different image-guided alignment markers for estimating positional errors, and investigated the factors associated with positional errors under breath-hold control. Spirometric motion management system (SDX) for breath holds was used in 44 patients with hepatobiliary tumor. Among them, 28 patients had a stent or embolized materials (lipiodol) as alignment markers. Cone-beam computed tomography (CBCT) and kV-orthogonal images were compared for accuracy between different alignment references. Breath-hold level (BHL) was practiced, and BHL variation (ΔBHL) was defined as the standard deviation in differences between actual BHLs and baseline BHL. Mean BHL, ΔBHL, and body-related factors were analyzed for the association with positional errors. Using the reference CBCT, the correlations of positional errors were significantly higher in those with stent/lipiodol than when the vertebral bone was used for alignment in three dimensions. Patients with mean BHL > 1.4 L were significantly taller (167.6 cm vs. 161.6 cm, p = 0.03) and heavier (67.1 kg vs. 57.4 kg, p = 0.02), and had different positional error in the craniocaudal direction (− 0.26 cm [caudally] vs. + 0.09 cm [cranially], p = 0.01) than those with mean BHL < 1.4 L. Positional errors were similar for patients with ΔBHL< 0.03 L and > 0.03 L. Under rigorous breath-hold respiratory control, BHL correlated with body weight and height. With more accurate alignment reference by stent/lipiodol, actual BHL but not breath-hold variation was associated with craniocaudal positional errors.

中文翻译：

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屏气水平对采用屏气呼吸控制的肝胆放疗中支架/脂质碘对准的位置误差的影响。

肝胆癌患者屏住呼吸的呼吸运动仍然是放射治疗精确定位的挑战。我们比较了不同的图像引导对准标记来估计位置误差，并研究了屏气控制下与位置误差相关的因素。用于屏气的肺活量管理系统（SDX）用于44例肝胆肿瘤患者。其中28例患者以支架或栓塞材料（碘油）作为对准标记。比较了锥形束计算机断层扫描（CBCT）和kV正交图像在不同对准基准之间的准确性。实行屏气水平（BHL），将BHL变化（ΔBHL）定义为实际BHL与基线BHL之间差异的标准偏差。平均BHL，ΔBHL，分析与身体相关的因素与位置错误的关系。使用参考CBCT时，与支架/碘油相比，位置误差的相关性显着高于将椎骨用于三维对准时的位置误差。平均BHL> 1.4 L的患者明显更高（167.6 cm vs. 161.6 cm，p = 0.03）和更重（67.1 kg vs. 57.4 kg，p = 0.02），并且在颅尾方向上存在不同的位置误差（-0.26 cm与平均BHL <1.4 L的患者相比[尾部] vs. + 0.09 cm [颅骨]，p = 0.01）。ΔBHL<0.03 L和> 0.03 L的患者的位置误差相似。在严格屏气呼吸控制下，BHL与体重和身高相关。借助支架/碘油更精确的对准参考，