Kuru Okan, Ozan Goksel Evren, Volkan Demircan Niyazi, Sengoz Meric
Eastern Mediterranean University, School of Health Services, Radiotherapy Program, Famagusta, North Cyprus, via Mersin 10, Turkey.
Acibadem MAA University, Vocational School of Health Services, Radiotherapy Program, Istanbul, Turkey.
Tech Innov Patient Support Radiat Oncol. 2024 Aug 6;31:100268. doi: 10.1016/j.tipsro.2024.100268. eCollection 2024 Sep.
The aim of this study is to investigate, from a dosimetric perspective, whether helical Tomotherapy (HT) during free breathing (FB) can serve as an alternative technique for treating left-sided breast cancer patients who are unable to comply with the deep inspiration breath hold (DIBH) technique.
For this purpose, the CT images of 20 left breast-only cancer patients acquired in both FB and DIBH phases were utilized. The left breast was contoured as the target volume, while the heart, LAD, ipsilateral and contralateral lungs, and contralateral breast were contoured as organs at risk on the CT images obtained in both DIBH and FB. Planning with the volumetric modulated arc therapy (VMAT) technique was performed on the CT scans obtained in the DIBH (VMAT-DIBH), while planning with the HT technique was carried out on the CT scans obtained in the FB (HT-FB). Subsequently, dosimetric comparison of the plans were done in terms of target coverage and preservation of normal tissues.
Both techniques achieved the desired target coverage; however, in terms of D2, Vpres values, Conformity Number (CN), and Homogeneity Index (HI), the HT-FB technique was found to be superior. While the mean doses to the heart were similar for both techniques, doses to the LAD and left lung were found to be superior in plans generated with the HT-FB technique. When compared in terms of contralateral breast and right lung protection, VMAT-DIBH technique was found to be significantly superior.
The treatment of left breast-only patients with the HT-FB technique has been observed to provide similar heart protection and better LAD and ipsilateral lung protection compared to the VMAT-DIBH technique without compromising target coverage. However, when the HT-FB technique is used, doses to the contralateral lung and contralateral breast should be carefully evaluated.
本研究旨在从剂量学角度研究自由呼吸（FB）状态下的螺旋断层放射治疗（HT）能否作为一种替代技术，用于治疗无法配合深吸气屏气（DIBH）技术的左侧乳腺癌患者。
为此，利用了20例仅左侧乳腺癌患者在FB和DIBH阶段采集的CT图像。将左侧乳腺勾勒为靶区，而在DIBH和FB获取的CT图像上，将心脏、左前降支、同侧和对侧肺以及对侧乳腺勾勒为危及器官。在DIBH获取的CT扫描图像上采用容积调强弧形治疗（VMAT）技术进行计划（VMAT-DIBH），而在FB获取的CT扫描图像上采用HT技术进行计划（HT-FB）。随后，从靶区覆盖和正常组织保护方面对计划进行剂量学比较。
两种技术均实现了预期的靶区覆盖；然而，在D2、Vpres值、适形数（CN）和均匀性指数（HI）方面，发现HT-FB技术更具优势。虽然两种技术对心脏的平均剂量相似，但在HT-FB技术生成的计划中，对左前降支和左肺的剂量更高。在对侧乳腺和右肺保护方面进行比较时，发现VMAT-DIBH技术明显更具优势。
观察发现，与VMAT-DIBH技术相比，采用HT-FB技术治疗仅左侧乳腺的患者在不影响靶区覆盖的情况下，能提供相似的心脏保护以及更好的左前降支和同侧肺保护。然而，使用HT-FB技术时，应仔细评估对侧肺和对侧乳腺的剂量。
