Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China.
Radiat Oncol. 2021 Feb 18;16(1):35. doi: 10.1186/s13014-021-01763-z.
The Halcyon is a new machine from the Varian company. The purpose of this study was to evaluate the dosimetry of the Halcyon in treatment of bilateral breast cancer with volumetric modulated arc therapy.
On CT images of 10 patients with bilateral breast cancer, four Halcyon plans with different setup fields were generated, and dosimetric comparisons using Bonferroni's multiple comparisons test were conducted among the four plans. Whole and partial arc plans on the Trilogy and the Halcyon, referred to as T-4arc, T-8arc, H-4arc and H-8arc, were designed. The prescription dose was 50 Gy in 2-Gy fractions. All plans were designed with the Eclipse version 15.5 treatment planning system. The dosimetric differences between whole and partial arc plans in the same accelerator were compared using the Mann-Whitney U test. The better Halcyon plan was selected for the further dosimetric comparison of the plan quality and delivery efficiency between the Trilogy and the Halcyon.
Halcyon plans with high-quality megavoltage cone beam CT setup fields increased the D, D and V of the planning target volume (PTV) and the V and D of the heart, left ventricle (LV) and lungs compared with other Halcyon setup plans. The mean dose and low dose volume of the heart, lungs and liver were significantly decreased in T-8arc plans compared to T-4arc plans. In terms of the V, V, V, V and D of the heart, the V, V, V and D of the LV, the V, V, D and D of the left anterior descending artery (LAD), and the V and V of lungs, H-8arc was significantly higher than H-4arc (p < 0.05). Compared with the Trilogy's plans, the Halcyon's plans reduced the high-dose volume of the heart and LV but increased the mean dose of the heart. For the dose of the LAD and the V and V of lungs, there was no significant difference between the two accelerators. Compared with the Trilogy, plans on the Halcyon significantly increased the skin dose but also significantly reduced the delivery time.
For the Halcyon, the whole-arc plans have more dosimetric advantages than partial-arc plans in bilateral breast cancer radiotherapy. Although the mean dose of the heart and the skin dose are increased, the doses of the cardiac substructure and other OARs are comparable to the Trilogy, and the delivery time is significantly reduced.
Halcyon 是瓦里安公司的一款新设备。本研究旨在评估容积旋转调强弧形治疗双侧乳腺癌时 Halcyon 的剂量学。
对 10 例双侧乳腺癌患者的 CT 图像进行分析，生成了 4 种不同射野设置的 Halcyon 计划，并采用 Bonferroni 多重比较检验对 4 种计划进行了剂量比较。在 Trilogy 和 Halcyon 上设计了全弧和 4 弧、8 弧计划，分别称为 T-4arc、T-8arc、H-4arc 和 H-8arc。处方剂量为 50Gy/2Gy。所有计划均采用 Eclipse 版本 15.5 治疗计划系统设计。采用 Mann-Whitney U 检验比较同一加速器中全弧和部分弧计划的剂量学差异。选择更好的 Halcyon 计划，对 Trilogy 和 Halcyon 之间的计划质量和治疗效率进行进一步的剂量学比较。
高质量的兆伏锥形束 CT 射野设置的 Halcyon 计划增加了计划靶区（PTV）的 D、D 和 V，以及心脏、左心室（LV）和肺的 V 和 D。与 T-4arc 计划相比，T-8arc 计划的心脏、肺和肝脏的平均剂量和低剂量体积显著降低。在心脏、LV 的 V、V、V、D，左前降支（LAD）的 V、V、D、D 和肺的 V、V 方面，H-8arc 显著高于 H-4arc（p<0.05）。与 Trilogy 的计划相比，Halcyon 的计划降低了心脏和 LV 的高剂量体积，但增加了心脏的平均剂量。对于 LAD 的剂量和肺的 V 和 V，两种加速器之间没有显著差异。与 Trilogy 相比，Halcyon 上的计划显著增加了皮肤剂量，但也显著缩短了治疗时间。
对于 Halcyon，全弧计划在双侧乳腺癌放疗中比部分弧计划具有更多的剂量学优势。尽管心脏的平均剂量和皮肤剂量增加，但心脏亚结构和其他 OAR 的剂量与 Trilogy 相当，治疗时间显著缩短。
