ESTRO 2023 - Abstract Book

S185

Saturday 13 May

ESTRO 2023

Results Figure 1 shows a comparison between the automatic and manual plan of test patient A. Gradient-optimized beam dose distributions are achieved with good target coverage and sparing of OARs.

For automatic plans, the target coverage is robust with respect to setup and range uncertainty (3mm/3%). Table 1 shows that in the high dose region of the prostate (CTV 70) the goal of 95% coverage at 70 Gy(RBE) is fulfilled in the worst scenario for all patients. The same is true for the goal of 95% coverage at 47.88 Gy(RBE) in the low dose target (CTV 50.4). The sparing of OARs is similar for both automatic and manual plans. Clinical goals for the bladder, rectum and femur heads are fulfilled for all test patients with three exceptions, marked red in Table 1. For the bowel, three of the five automatic plans and two of the five manual plans fail to keep the dose at 1% volume below 49 Gy(RBE). The mimic optimization problem has not been set up to emphasize strict max dose constraints of the OARs.

Conclusion The deep learning model predicts gradient-optimized beam doses, matched to yield uniform target coverage, despite a limited training set of only 30 patients. Deliverable plans with robust target coverage and OAR sparing on par with manual plans are achieved using mimic optimization. The results show the benefits of a promising method, needed for fully automated PBS proton therapy. PD-0250 Intrafraction tumor motion monitoring and dose reconstruction for liver spot scanning proton therapy S. Nankali 1,3 , E. Worm 2 , J. Thomsen 1 , L. Stick 1 , M. Høyer 1 , B. Weber 1,2 , H. Mortensen 1 , P. Poulsen 1,2 1 Aarhus University Hospital, Danish Centre for Particle Therapy, Aarhus, Denmark; 2 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark; 3 Aarhus University, Department of Clinical Medicine, Aarhus, Denmark Purpose or Objective To develop intra-treatment tumor motion monitoring during pencil beam scanning (PBS) proton therapy and combine it with motion-including tumor dose reconstruction for individual hepatocellular carcinoma (HCC) treatment fractions. Materials and Methods