AUTHOR=Zhang Wei , Li Ruisheng , You Dong , Su Yi , Dong Wei , Ma Zhao 

TITLE=Dosimetry and Feasibility Studies of Volumetric Modulated Arc Therapy With Deep Inspiration Breath-Hold Using Optical Surface Management System for Left-Sided Breast Cancer Patients

JOURNAL=Frontiers in Oncology

VOLUME=Volume 10 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.01711

DOI=10.3389/fonc.2020.01711

ISSN=2234-943X

ABSTRACT=Background: During radiotherapy (RT) procedure of breast cancer, portions of the heart and lung will receive some radiation dose, which may result acute and late toxicities. In the current study, we report the experience of our single institution with organs at risk (OARs)-sparing RT with deep inspiration breath hold (DIBH) using an optical surface management system (OSMS) and compare the dosimetric parameters with that of free breathing (FB).
Patients and methods: Forty-eight cases diagnosed as early-stage left-sided breast cancer scheduled for postoperative RT were enrolled. The OSMS was used to monitor the breathing magnitude, and track the real-time respiratory status, which can control a stable lung and heart volume during radiotherapy delivery under DIBH. We did the dosimetric analysis of the heart, left anterior descending (LAD) coronary artery, lungs and contralateral breast under FB and DIBH plans.
Results: Compared with FB-volumetric-modulated arc therapy (FB-VMAT), DIBH-VMAT resulted in significantly changed volumes to the heart and lungs receiving irradiation dose. The average mean heart dose and average D2%, V5 and V10 showed significant differences between the DIBH and FB techniques. For the LAD coronary artery, we found significantly reduced average mean dose, D2% and V10 with DIBH. Similar results were also found in the lungs and contralateral breast. The use of FFF decreased treatment time compared with the flat beam mode in our VMAT (p<0.05). For the 48 patients, there was no significant differences in the lat, long and vert directions, between OSMS and CBCT. 
Conclusions: DIBH-VMAT with OSMS is very feasible in daily practice with excellent patient compliance in our single-center experience. Note that OSMS is an effective tool that may easier to achieve precise positioning, shorter position-verify time and better. Meanwhile, compared with FB, DIBH was characterized by lower doses to OARs, which may reduce the probability of cardiac and pulmonary complications in the future.