A Comparison of 20 Free Breathing Versus AlignRT Based DIBH Breast Treatments
B Sintay*, C Yount, M Hawkins, S Wentworth, J Terrell, J Maurer, J Pursley, D Wiant, Cone Health Cancer Center, Greensboro, NCMO-F-WAB-1 Monday 4:30PM - 6:00PM Room: Wabash Ballroom
Purpose: Deep inspiration breath hold (DIBH) for treatment of left breast cancer is a technique that is rapidly gaining acceptance due to the possibility of reducing heart dose, particularly dose to the left anterior descending coronary artery. We report on the treatment of twenty patients using AlignRT (VisionRT, London, UK) to monitor breath hold.
Methods: Patients were simulated with a breath hold and free breathing CT scan. A treatment plan was created on each scan in the XiO treatment planning system (Elekta AB, Stockholm, Sweden). Plans consisted of two parent tangent fields and 1-2 reduced fields per side. The maximum point dose and volume receiving 30 Gy (V30) to the heart from each plan is compared. Patients were set-up using an AlignRT reference surface generated from the breath hold scan with a 3 mm / 3 degree tolerance. Patient position was evaluated by comparing boney landmarks, breast tissue, and heart position on port images prior to the first treatment, then once per week. We examine the number of port images retaken as compared to free breathing set-ups.
Results: For DIBH plans the maximum heart dose was reduced by an average of 39% and the V30 was reduced by an average of 78%. For 16 patients that had completed treatment at this time the number of retaken port images was 9.6%, which is in line with 8.5% of retaken port images previously reported for our free breathing patients.
Conclusion: Patients were generally able to complete each of the 4-6 fields in one breath hold per field. The number of port images was comparable to free breathing treatments. Treatment of left sided breast patients using DIBH is an effective way to reduce heart dose without impactful change in treatment time.