■在脑转移的放射治疗领域,通常采用全脑海马回避治疗。本研究旨在研究不同头部倾斜角度对全脑靶区和危险器官剂量分布的影响.它还旨在确定头部倾斜角度以实现最佳放射治疗结果。
■收集了8例脑转移患者在5个不同组的头部倾斜角度的CT图像。使用体积调节电弧疗法(VMAT)技术设计治疗计划。5组倾斜角如下:[0°,10°),[10°,20°),[20°,30°),[30°,40°),和[40°,45°].分析涉及评估参数,如均匀性指数,合格指数,输送到目标的平均剂量,目标的剂量覆盖,目标区域内的热点,最大剂量,和危险器官接受的平均剂量。此外,该研究评估了海马剂量与其他因素之间的相关性,建立了线性回归模型。
■在[40°,45°和[0°,10°)头部倾斜角度。[40°,45°角与[0°,10°)目标区域平均剂量的角度(31.49±0.29Gyvs.31.99±0.29Gy,p=0.016),剂量均匀性(1.20±0.03vs.1.24±0.03,p=0.016),目标区域的热点(33.64±0.35Gyvs.34.42±0.49Gy,p=0.016),最大海马剂量(10.73±0.36Gyvs.11.66±0.59Gy,p=0.008),晶状体中的最大剂量(2.82±1.10Gyvs.4.99±0.16Gy,p=0.016),和晶状体中的平均剂量(1.93±0.29Gyvs.4.22±0.26Gy,p=0.008)。海马的最大剂量与PTV长度之间存在中等相关性(r=0.49,p=0.001)。同样,海马平均剂量与海马长度显著相关(r=0.34,p=0.04)。
■头部倾斜角度为[40°,45°]满足所有剂量限制,并证明了目标区域的均匀性得到改善,同时减少了对有风险器官的剂量。此外,线性回归模型表明,在当前范围[0°,45°]可能导致平均海马剂量的减少。
UNASSIGNED: In the field of radiation therapy for brain metastases, whole-brain hippocampus-avoidance treatment is commonly employed. this study aims to examine the impact of different head tilt angles on the dose distribution in the whole-brain target area and organs at risk. It also aims to determine the head tilt angle to achieve optimal radiation therapy outcomes.
UNASSIGNED: CT images were collected from 8 brain metastases patients at 5 different groups of head tilt angle. The treatment plans were designed using the volumetric modulated arc therapy (VMAT) technique. The 5 groups of tilt angle were as follows: [0°,10°), [10°,20°), [20°,30°), [30°,40°), and [40°,45°]. The analysis involved assessing parameters such as the uniformity index, conformity index, average dose delivered to the target, dose coverage of the target, hot spots within the target area, maximum dose, and average dose received by organs at risk. Additionally, the study evaluated the correlation between hippocampal dose and other factors, and established linear regression models.
UNASSIGNED: Significant differences in dosimetric results were observed between the [40°,45°] and [0°,10°) head tilt angles. The [40°,45°] angle showed significant differences compared to the [0°,10°) angle in the average dose in the target area (31.49 ± 0.29 Gy vs. 31.99 ± 0.29 Gy, p=0.016), dose uniformity (1.20 ± 0.03 vs. 1.24 ± 0.03, p=0.016), hotspots in the target area (33.64 ± 0.35 Gy vs. 34.42 ± 0.49 Gy, p=0.016), maximum hippocampal dose (10.73 ± 0.36 Gy vs. 11.66 ± 0.59 Gy, p=0.008), maximum dose in the lens (2.82 ± 1.10 Gy vs. 4.99 ± 0.16 Gy, p=0.016), and average dose in the lens (1.93 ± 0.29 Gy vs. 4.22 ± 0.26 Gy, p=0.008). There is a moderate correlation between the maximum dose in the hippocampi and the PTV length (r=0.49, p=0.001). Likewise, the mean dose in the hippocampi is significantly correlated with the hippocampi length (r=0.34, p=0.04).
UNASSIGNED: The VMAT plan with a head tilt angle of [40°,45°] met all dose constraints and demonstrated improved uniformity of the target area while reducing the dose to organs at risk. Furthermore, the linear regression models suggest that increasing the head tilt angle within the current range of [0°,45°] is likely to lead to a decrease in the average hippocampal dose.