基于锥形束CT的深吸气屏气技术在左侧乳腺癌患者放射治疗危及器官保护中的应用

The Application of Deep Inspiration Breath Holding Technique Based on Cone Beam CT in the Protection of Organs Endangered by Radiotherapy for Patients with Left Breast Cancer

目的探讨基于锥形束CT(CBCT)的深吸气屏气(DIBH)技术在左侧乳腺癌患者放射治疗危及器官保护中的应用。方法回顾性分析2019年1月至2022年10月于医院采用DIBH技术行放射治疗的46例左侧乳腺癌患者的临床资料,比较治疗前CBCT图像与定位CT图像胸骨角水平横断面和胸骨体与剑突交界处横断面肺轮廓的一致性。结果46例患者共进行552次CBCT扫描。其中,CBCT胸骨角水平横断面肺轮廓大于定位CT 432次(占78.26%),小于定位CT 120次(占21.74%),且120次中5次差异大于呼吸门控阈值(占0.91%);CBCT胸骨体与剑突交界处横断面肺轮廓大于定位CT 428次(占77.54%),小于定位CT 124次(占22.46%),且124次中10次差异大于呼吸门控阈值(占1.81%)。结论采用基于CBCT的DIBH技术行左侧乳腺癌放射治疗时,治疗前CBCT肺轮廓多数大于定位CT,而在小于定位CT的治疗分次中,相差大于呼吸门控阈值的占比小于2%。因此,基于CBCT的DIBH技术对患者危及器官的保护准确性较高,但仍需进一步寻找适宜人群及建立呼吸训练指标。

Objective To explore the application of deep inspiratory breath holding(DIBH)technique based on cone beam CT(CBCT)in the protection of organs endangered by radiotherapy for patients with left breast cancer.Methods With the retrospective analysis of the clinical data of 46 patients with left breast cancer who were treated with DIBH technology in the hospital from January 2019 to October 2022,the consistency of the horizontal cross section of the sternal angle and the cross section of the lung contour at the junction of the sternal body and the xiphoid in CBCT images before treatment was compared with that in localization CT images.Results A total of 552 CBCT scans were performed on 46 patients.Among them,the horizontal cross-sectional lung contour of CBCT sternal angle was greater than that of localization CT 432 times(accounted for 78.26%)and less than localization CT 120 times(accounted for 21.74%),and the difference in 5 out of 120 times was greater than the gated respiratory threshold(accounted for 0.91%);The cross-sectional lung contour at the junction of the sternum and xiphoid in CBCT was greater than that in localization CT 428 times(accounted for 77.54%)and smaller than that in localization CT 124 times(accounted for 22.46%),and the difference in 10 out of 124 times was greater than the gated respiratory threshold(accounted for 1.81%).Conclusions When DIBH technology based on CBCT is used for radiotherapy of left breast cancer,before treatment,the lung contour of CBCT is mostly larger than that of localization CT,and in the treatment grades smaller than localization CT,the difference greater than the threshold of respiratory gating is less than 2%.Therefore,the CBCt-based DIBH technology has high accuracy in protecting patients'organs at risk,but it is still necessary to further find suitable population and establish respiratory training indicators.