Prospective study comparing heart dose using conventional free breathing technique and Voluntary Deep Inspiration Breath Holding (vDIBH) technique in post-operative radiotherapy for patients with left breast cancer / Roa Abdulrahim Hassan Eltagy ; Supervised Hanaa Attiya , Samy Elbadawy , Mohammed Mahmoud

Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Oncology (Clinical )

Aim:This is a prospective dosimetric study including patients with left sided breast cancer to compare doses delivered to critical organs at risk (mean heart dose, V10-heart, V20-heart, V25-heart, Left Anterior Descending (LAD) artery, and lungs between conventional free-breathing simulation technique and deep-inspiration breath holding (DIBH) technique, to assess feasibility of DIBH technique in lowering radiation exposure to the heart and lungs without compromising coverage of left breast or chest wall, and to evaluate effect of cardiac rotation on LAD artery dose. Patients and methods:Sixty-six women with left breast cancer needing post-operative radiotherapy were accrued from Radiotherapy department, National Cancer Institute, Cairo from November 2015 to December 2016. All patients were coached on proper method of breath holding and underwent CT simulation during free breathing and DIBH techniques. All patients were planned by 3D conformal technique. Results:Using DIBH technique, all patients, with the exception of one, had lower heart, LAD artery, and left lung doses with statistically significant difference whether they underwent CBS or MRM compared with free breathing technique. Patients who had a unilateral disease, had highly significant lower heart, LAD artery, and left lung doses (p-value <0.001) using DIBH, however, patients who received bilateral breast/chest wall irradiation didn{u2019}t have statistically significant lower doses.Patients who received left axillary/SCV irradiationhad highly significant lower ipsilateral (left) lung doses using DIBH technique than free breathing technique. Patients who received IM nodal irradiation, with wide tangential fields, showed statistically significant lower doses regarding heart and LAD artery between both techniques. In our study, cardiac rotation played a significant role only during DIBH technique, where patients with clockwise rotation had the lowest LAD artery doses and patients with counterclockwise rotation had the highest doses

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