Implementation of Beam Tracking and Dose Compensation in TRiP4D

Scanned particle beams are used since 1997 for treatment of stationary tumors [1]. One current field of research aims at transferring this highly tumor conformal treatment technique to moving tumors. Therefore, techniques to mitigate dose deteriorations caused by interference between beam scanning and tumor motion are needed [2]. Technical feasibility of different motion mitigation techniques has already been shown in phantom measurements [3–5]. Simulations incorporating patient data (e.g. 4D-CT) are important to bring scanned particle therapy of moving tumors closer to clinical practice. Therefore, the GSI treatment planning software TRiP98 is currently extended to be able to cope with moving tumors [8]. In this work the implementation of beam tracking (BT) and real-time dose compensation (RD) has been done. While BT adapts the beam position to the moving tumor position [5], RD is an extension of BT improving dose homogeneity in the presence of non-translational motion components [6, 7].