Application of deep inspiration breath hold in postoperative radiotherapy for left-side breast cancer

Abstract

Objective To investigate the dosimetric differences among three types of breath hold mode (free breath: FB, thoracic deep inspiration breath hold: T-DIBH, abdomen deep inspiration breath hold: A-DIBH) and to explore the optimal breath hold method in the postoperative radiotherapy of left-side breast cancer patients with minimum dose to normal tissues and organs at risk. Methods A total of eighteen patients with left-side breast cancer patients who underwent postoperative radiotherapy were enrolled in this study. Three CT simulation scans with three different breath hold method (FB, T-DIBH, and A-DIBH) were performed for each patient. Dosimetric differences were compared among plans generated on these three different CT image sets. Results There was no significant difference in the volume, mean dose, and homogeneity of planning target volume (PTV) among plans generated from three different image sets (P>0.05). The mean heart dose, mean LAD dose and mean ipsilateral lung dose in plans generated from CT image sets with FB, T-DIBH and A-DIBH were (3.21±1.02), (1.74±0.51), (1.31±0.41) Gy (W=171, P<0.05), (34.61±13.51), (14.38±10.20), (9.21±6.53) Gy (W=171, P<0.05), and (8.31±2.75), (7.46±1.96), (6.89±1.79) Gy (W=171, P<0.05), respectively. Conclusions Compared with plans with FB, plans with DIBH (T-DIBH and A-DIBH) achieved lower cardiac, LAD and pulmonary doses. A-DIBH achieved a better normal dose reduction than T-DIBH. Trial registration Chinese clinical trial registry, ChiCTR-INR-17012551 Key words: Breast cancer; Radiotherapy; Deep inspiration breath hold; Organs at risk; Radiation dose