Dosimetric Considerations in Respiratory-Gated Deep Inspiration Breath-Hold for Left Breast Irradiation
Dosimetric Considerations in Respiratory-Gated Deep Inspiration Breath-Hold for Left Breast Irradiation
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DOI：
10.1177/1533034615624311
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发表时间：
2017-02-01
影响因子：
2.8
通讯作者：
Rong, Yi
中科院分区：
文献类型：
--
作者：
Walston, Steve;Quick, Allison M.;Rong, Yi
目的：介绍我们将AlignRT用于左乳房深吸气屏气治疗的临床工作流程以及深吸气屏气方案的剂量学考虑。材料和方法：接受乳房肿瘤切除术或乳房切除术的I至III期左侧乳腺癌患者被认为是深吸气屏气技术用于体外放射治疗的候选者。根据每例患者的自由呼吸和深吸气屏气计算机断层扫描创建治疗计划，以根据剂量测定比较确定深吸气屏气是否有益。AlignRT系统用于患者设置和监测。研究了自由呼吸和深吸气屏气计划的剂量测量及其与胸壁偏移和左肺容量增加的相关性。结果：与自由呼吸相比，深吸气屏气计划显著增加了胸壁偏移。这种几何形状的变化导致平均和最大心脏剂量降低，但不影响肺V-20或平均剂量。胸壁偏移与心脏或肺剂量绝对减少之间的相关性不显著，但左肺容积与心脏剂量之间的相关性呈线性相关。还发现，较高水平的胸壁偏移可能会矛盾地增加心脏或肺剂量。结论：对于许多左侧乳房和胸壁患者，使用深吸气屏气可以减少心脏剂量。胸壁偏移以及左肺容积与心脏剂量减少无关，仍需确定何种指标将提供最佳和最可靠的剂量测定优势。
Purpose: To present our clinical workflow of incorporating AlignRT for left breast deep inspiration breath-hold treatments and the dosimetric considerations with the deep inspiration breath-hold protocol. Material and Methods: Patients with stage I to III left-sided breast cancer who underwent lumpectomy or mastectomy were considered candidates for deep inspiration breath-hold technique for their external beam radiation therapy. Treatment plans were created on both free-breathing and deep inspiration breath-hold computed tomography for each patient to determine whether deep inspiration breath-hold was beneficial based on dosimetric comparison. The AlignRT system was used for patient setup and monitoring. Dosimetric measurements and their correlation with chest wall excursion and increase in left lung volume were studied for free-breathing and deep inspiration breath-hold plans. Results: Deep inspiration breath-hold plans had significantly increased chest wall excursion when compared with free breathing. This change in geometry resulted in reduced mean and maximum heart dose but did not impact lung V-20 or mean dose. The correlation between chest wall excursion and absolute reduction in heart or lung dose was found to be nonsignificant, but correlation between left lung volume and heart dose showed a linear association. It was also identified that higher levels of chest wall excursion may paradoxically increase heart or lung dose. Conclusion: Reduction in heart dose can be achieved for many left-sided breast and chest wall patients using deep inspiration breath-hold. Chest wall excursion as well as left lung volume did not correlate with reduction in heart dose, and it remains to be determined what metric will provide the most optimal and reliable dosimetric advantage.