ICTR-PHE 2016 S63 analyze these effects based on synthetic datasets of anthropomorphic phantoms and suggest an extended optimization scheme which explicitly accounts for these effects. Performance of the method is been tested for various simulated irradiation parameters. We also investigate the use of a special optimization method to enhance the spatial resolution and the WET accuracy of proton radiographies prior to the HU-RSP re-calibration. The optimization method is designed for imaging systems measuring only the residual range of protons without relying on tracker detectors to determine the beam trajectory before and after the target. The ultimate purpose of the optimization is to minimize uncertainties in the HU-RSP calibration curve. We therefore suggest and perform a thorough statistical treatment to quantify the accuracy of the optimized HU-RSP curve. Resul t s: We demonstrate that without extending the optimization scheme, spatial blurring (equivalent to FWHM=3mm convolution) in the proton radiographies can cause up to 10% deviation between the optimized and the ground truth HU-RSP calibration curve. Instead, results obtained with our extended method reach 1% or better correspondence, as shown in Figure 1. We have further calculated gamma index maps for different acceptance levels. With DTA=0.5mm and RD=0.5%, a passing ratio of 100% is obtained with the extended method, while an optimization neglecting effects of spatial blurring only reach ~90%. Conclusions: Our contribution underlines the potential of a single optimized proton radiography to generate a patient- specific calibration curve and to improve dose delivery by optimizing the HU-RSP calibration curve as long as all sources of systematic incongruence are properly modeled. Figure 1: Comparison of optimized conversion curves. Keywords: proton therapy, proton radiography, image processing References: [1] Krah, N. et al. 2015, An advanced image processing met hod to improve t he spat ial resolution of ion radiographies, Physics in medicine and biology, 60(21), pp.8525–8547 [2] U. Schneider et al. 2005, Patient specific optimization of the relation between CT-Hounsfield units and proton stopping power with proton radiography, Med Phys 32 195 [3] P. J. Doolan et al. 2015, Patient-specific stopping power calibration for proton therapy planning based on single- detector proton radiography, PMB 60 1901 128 Overcoming Cancer Radioresistance Factors of radioresistance in prostate cancer M. Krause 1,2,3,4 , A. Dubrovska 1,2,3 , M. Baumann 1,2,3,4 1 German Cancer Consortium (DKZK) Dresden and German Cancer Research Center (DKFZ) Heidelberg 2 Dept. of Radiation Oncology, Faculty of medicine and University Hospital C. G. Carus, Technische Universität Dresden 3 OncoRay – National Center for Radiation Research in Oncology (NCRO), Faculty of medicine and University Hospital C.G. Carus, Technische Universität Dresden and 4 Helmholtz- Zentrum Dresden – Rossendorf Prostate Cancer is one of the leading cancer entities in men, however. In this disease, radiotherapy leads to comparable cure rates compared to surgery. Overall, survival and cure rates of patients with prostate cancer are on average much higher than in many other cancers. Despite this fact, biological individualization of treatment is also an important research topic in this disease. Specifically in the field of personalized radiation oncology important research questions include: 1) pre-treatment identification of patient subgroups with individually very radioresistant tumours that would have a high risk of recurrence after standard radiotherapy alone. 2) pre-treatment identification of subgroups that have a high chance of tumour cure after radiotherapy alone 3) identification of subgroups with a high risk of distant metastasis after local treatment Definition of biomarkers to identify such patient subgroups need to consider biochemical failure, local recurrences and distant metastases. Biomarkers will in future help to individualize radiation dose, but also combined radiation and systemic treatments. All endpoints need to be compared with surgical patient groups, with the mid-term aim to find decision parameters between the two treatment approaches. The talk will give an overview over current candidate biomarkers in preclinical and translational research. Keywords: prostate cancer, radiotherapy, personalized treatment, biomarker 129 Front-end electronics and hit position reconstruction methods for the J-PET scanner W. Krzemień 1* , D. Alfs 2 , T. Bednarski 2 , P. Białas 2 , E. Czerwiński 2 , A. Gaj os 2 , B. Głowacz 2 , M. Gorgol 3 , B. Jasińska 3 , D. Kamińska 2 , Ł. Kapłon 2,4 , G. Korcyl 2 , P. Kowalski 5 , T. Kozik 2 , E. Kubicz 2 , M. Mohammed 2 , Sz. Niedźwiecki 2 , M. Pałka 2 , L. Raczyński 5 , Z. Rudy 2 , O. Rundel 2 , N. G. Sharma 2 ,M. Silarski 2 , A. Słomski 2 , A. Strzelecki 2 , A. Wieczorek 2,4 , W. Wiślicki 5 , B. Zgardzińska 3 , M. Zieliński 2 , P. Moskal 2 1 High Energy Physics Division, National Centre for Nuclear Research, A. Soltana 7, 05-400 Otwock- Świerk, Poland 2 Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, S.Łojasiewicza 11, 30-348 Kraków, Poland 3 Department of Nuclear Methods, Institute of Physics, Maria Curie Sklodowska University, Pl. M. Curie- Skłodowskiej 1, 20- 031 Lublin, Poland 4 Institute of Metallurgy and Materials Science of Polish Academy of Sciences, W. Reymonta 25, 30-059 Kraków, Poland 5 Świerk Computing Centre, National Centre for Nuclear Research, A. Soltana 7, 05-400 Otwock- Świerk, Poland email: wojciech.krzemien@ncbj.gov.pl t el: +48 22 5532265 f ax: +48 22 5532265 Purpose: The J-PET collaboration is developing a novel TOF- PET, whole-body tomography scanner based on polymer scintillators [1-4]. The scanner barrel is made of long scintillators, axially positioned, which are readout from both sides by photomultipiers. This novel approach relies mainly on the timing of the signals instead of their amplitudes for the reconstruction of the Lines-of-Response, therefore a very precise time resolution is one of the main challenges of the project. Material and methods: For this purpose, novel ultrafast front- end electronics (FFE) allowing for sampling in the voltage domain of the signals with a duration of few nanosecond was developed [5]. The FEE solution is a purely digital implementation, based solely on a FPGA (Field Programmable