ESTRO 2020 Abstract Book

S79 ESTRO 2020

using the S4A bra in both right and left sided cases (mean improvement 1.13Gy, and 0.391Gy respectively).

Association (AHA) 20-segment model. Dosimetric indices of heart, 20 segments of LV, pre-RT and post-RT myocardial perfusion parameters of SPECT were analyzed. Summed stress score (SSS), summed rest score (SRS), summed difference score (SDS) and cardiac defects were the parameters in SPECT. Results This retrospective study included 31 left BC patients. Of 31 patients, the MHD was 3.36 Gy and mean LV dose was 4.94 Gy. Comparing the patients with cardiac defects (n=16) and those without defects (n=15), the mean LV dose and mean segment dose of patients with cardiac defects were higher. There were significant differences in dose of segment 2, 3, 4 and 9 between the patients with cardiac defects and the patients without defects. (Table 1) Table 1.The dose of patients with cardiac defects and without cardiac defects

Conclusion This study showed mean ipsilateral lung dose was lower for women treated with the S4A bra. Mean heart dose was no different. Differences in systematic and random errors were not clinically significant. Skin reactions indicated no clinically detectable adverse effect of the bra material, and no serious adverse events were reported. There was improved modesty and dignity, and improved empowerment, (higher mean empowerment questionnaire scores) in the S4A bra arm. PH-0165 Integration of radiation doses and myocardial function in radiotherapy plans for breast cancer S. Yang 1,2 , K. Lin 1,2 , C. Yu 1,2 , C. Hsu 1,2 , S. Wang 2,3 , P. Shueng 1,4 , T. Wu 2 1 Far Eastern Memorial Hospital, Department of Radiation Oncology, New Taipei City, Taiwan ; 2 National Yang-Ming University, Department of Biomedical Imaging and Radiological Sciences, Taipei, Taiwan ; 3 Far Eastern Memorial Hospital, Department of Nuclear Medicine Center, New Taipei City, Taiwan ; 4 National Yang-Ming University, Department of Medicine, Taipei, Taiwan Purpose or Objective Radiotherapy for breast cancer can reduces breast cancer mortality, but also increase the side effects. Recent study shows that there is an increased risk of cardiac toxicities in the first 5 years after treatment in breast cancer. However, the MHD cannot represent the doses of segments of the left ventricle. This study aims to evaluate the mean segment dose and cardiac function using myocardial perfusion imaging (MPI) with Thallium-201 (Tl-201) single photon emission computer tomography (SPECT) in left breast cancer (BC) patients who receive radiotherapy (RT). Material and Methods This retrospective study included left BC patients who received Tl-201 SPECT scans before RT and 1 years after RT. Then SPECT MPI images were integrated and fused with the simulation CT images in the radiotherapy treatment planning system. The fused images discrete subvolumes of the left ventricle as defined by the American Heart

Conclusion This study successfully integrated radiation doses to the subvolumes and cardiac function index of SPECT MPI. PH-0166 Bilateral breast treatment comparative: mono and bi-isocentric VMAT treatment plan. A. Coral 1 , N. Espinosa López 2 , S. Bermejo Martinez 3 , G. Gomez De Segura Melcon 2 , X. Nolla Nieto 2 , M. Mancera Soto 2 , M. Lizondo Gisbert 4 1 Hospital de la Santa Creu i Sant Pau, Department of Medical Physics- Dosimetrist, Barceloana, Spain ;