主动呼吸控制结合光学体表监测在左侧乳腺癌深吸气屏气放疗呼吸训练中的应用

目的 探讨左侧乳腺癌深吸气屏气(Deep Inspiration Breath-Hold,DIBH)放疗中使用主动呼吸控制(Active Breathing Coordinator,ABC)下光学体表监测DIBH的可行性以及幅度变化范围,比较两种呼吸状态下剂量学差异.方法 15例左侧乳腺癌保乳术后拟行全乳放疗患者,使用...

Application of Active Breathing Coordinator Combined with Optical Surface Monitoring in Breathing Training of Deep Inspiration Breath-Hold Radiotherapy for Left Breast Cancer

Objective To investigate the feasibility and range of optical surface monitoring of deep inspiration breath-hold(DIBH),under active breathing coordinator(ABC)in left breast cancer DIBH radiotherapy,and to compare the dosimetry difference between the two respiratory states.Methods A total of 15 patients with left breast cancer who were to receive whole breast radiotherapy after breast-conserving surgery were treated with an ABC device to control the inspiratory volume of the patients,and an optical surface monitoring device was used to monitor the changes in the respiratory amplitude of the patients.CT images were collected at the state of free breathing(FB)and 80%of the maximum inspiratory volume,respectively.Planning and design were carried out on two sets of images by using Pinnacle planning system.Paired t test was conducted for the difference between the two states of double lung volume and the threshold of ABC inspiratory volume on the CT image.The ratio of DIBH amplitude to the maximum breathing amplitude on the optical body surface were calculated,and the percentage of optical body surface amplitude decreased by more than 3 mm when the DIBH was controlled by ABC to show that the inspiratory volume did not change.Dosimetry differences between the two respiratory states were compared.Results There was no significant difference between volume difference of the two lungs and the ABC inspiratory volume threshold on the CT images of 15 patients with FB and DIBH(P>0.05).The 80% average maximum inspiratory volume range was 12.1 mm,and the 95% CI was(11.4~14.1)mm.The ratio of 80% maximum inspiratory volume to maximum inspiratory volume was 0.78±0.12,and the ratio of 80% maximum inspiratory volume to FB volume was 3.24±1.08.DIBH using ABC control showed no change in inspiratory volume,the optical body surface amplitude decreased by more than 3 mm,accounting for 10.8%.The mean cardiac dose,V₁₀,V₂₀,average dose to the left lung,and total lung V₂₀ were all significantly reduced compared with FB(P<0.001).Conclusion It is effective to use optical body surface monitoring to achieve high quality DIBH in left breast cancer postoperative radiotherapy.