Prone left-sided whole-breast irradiation: Significant heart dose reduction using end-inspiratory versus end-expiratory gating

AbstractPurpose ntify the influence on heart dose metrics of prone left-sided whole-breast irradiation in an end-inspiratory phase (PrIN) versus an end-expiratory phase (PrEX). ts and methods patients underwent CT-simulation in PrIN and PrEX. Dynamic intensity-modulated radiotherapy was planned for whole-breast irradiation with a median prescription dose of 40.05 Gy in 15 fractions and maximal sparing of the organs at risk. Dose–volume parameters were analyzed for heart, left anterior descending coronary artery, ipsilateral lung and both breasts. s onsistently reduced (P < 0.001) heart and left anterior descending coronary artery dose metrics compared to PrEX. Population averages for maximum and mean heart dose were 6.2 Gy and 1.3 Gy for PrIN versus 21.4 Gy and 2.5 Gy for PrEX, respectively. Moreover, a maximum heart dose less than 10 Gy was achieved in 80% of patients for PrIN. Target dose distribution, ipsilateral lung and contralateral breast sparing by radiation dose were similar for both procedures. sions atory gating consistently reduced heart dose metrics pointing to a possible benefit of breathing-adapted radiotherapy for prone left-sided whole-breast irradiation.