ESTRO 2021 Abstract Book

S664

ESTRO 2021

Results The mean difference between all points on each plane of the captured surfaces was 0.2mm (SD 0.8mm, max 2.2mm). The differences in volumes following conversion to DICOM are shown in Table 1. The absolute difference in volume of the created bolus was within 0.1cm 3 for all surface captures. After 3D printing the fit was verified (Figure 1F).

Conclusion The use of a low-cost surface capture device has been shown to be feasible for producing DICOM files for use in radiotherapy without the requirement for a CT scan. The 3D printed moulds produced with the proposed workflow fulfil the required accuracy for radiotherapy. References [1] Kinect Developer Toolkit. 1.8.0.572 ed.: Microsoft. 2013 [2] 3D Slicer. 4.11.0 ed.: 3D Slicer. 2020 [3] HUOTILAINEN, E. et al. 2014. Journal of Cranio-Maxillofacial Surgery, 42 , e259-e265. PD-0829 Multimodal anthropomorphic abdomen phantom with real-time breathing motion for IGRT C. Stengl 1 , A. Weidner 1,2 , F. Dinkel 1 , S. Dorsch 1 , A. Runz 1,3 , G. Echner 1,4 1 German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany; 2 Heidelberg University, Faculty of Medicine, Heidelberg, Germany; 3 Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany; 4 Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany Purpose or Objective Respiratory motion causes tumors in abdominal organs to move serveral centimeters in craniocaudal direction and therefore presents challenges for accurate and precise delivery of radiotherapy [1]. Improvements in image-guided radiotherapy have revolutionized the management of moving targets being effective in tumor treatment while sparing healthy tissue. However, end-to-end studies to validate the treatment workflow for newly developed hybrid devices such as MR-Linac becomes challenging due to respiratory-induced organ shifts. Therefore, the developed abdominal phantom is capable of inducing anthropomorphic organ shifts by breathing motion in real-time to be used for applications in MR- and CT-guided radiotherapy. Materials and Methods An abdominal phantom was designed consisting of two conically shaped polypropylene containers that contain