TY - JOUR T1 - Robust Treatment Planning in Intrafraction Motion Using TomoDirectâ„¢ Intensity-modulated Radiotherapy for Breast Cancer JF - In Vivo JO - In Vivo SP - 2655 LP - 2659 DO - 10.21873/invivo.12548 VL - 35 IS - 5 AU - HIDEYUKI HONGO AU - KOICHI TOKUUE AU - TAKEJI SAKAE AU - MISATO MASE AU - MOTOKO OMURA Y1 - 2021/09/01 UR - http://iv.iiarjournals.org/content/35/5/2655.abstract N2 - Background/Aim: To evaluate the robustness of radiotherapy treatment planning optimization for respiratory-moving breast cancer using fixed-angle beams planning TomoDirectâ„¢ intensity-modulated radiotherapy (IMRT). Materials and Methods: A minimax optimisation algorithm was applied to 10 breast cancer patients. Two sets of treatment plans with or without robust techniques were prepared considering anterior-posterior and head-tail movements due to respiration. Parameters were compared between treatment plans: 95% planned target volume (PTV) dose, conformal index and homogeneity index (HI), and organs at risk (OAR) parameters including the lung volume receiving 20 Gy or more (V20) and 5 Gy (V5). Results: Robust planning significantly improved parameters of 95% PTV dose and HI, without deteriorating V20 or V5 in the anterior-posterior movement, while it slightly improved 95% PTV and slightly deteriorated V20 in the head-tail movement. Conclusion: Robust treatment planning improves coverage of targets moving because of respiration in the treatment of breast cancer using TomoDirect; however, normal lung doses should be cautiously evaluated on a case-by-case basis. ER -