PMID- 32037543 OWN - NLM STAT- MEDLINE DCOM- 20210126 LR - 20210126 IS - 2473-4209 (Electronic) IS - 0094-2405 (Linking) VI - 47 IP - 4 DP - 2020 Apr TI - Refinement of the Hounsfield look-up table by retrospective application of patient-specific direct proton stopping-power prediction from dual-energy CT. PG - 1796-1806 LID - 10.1002/mp.14085 [doi] AB - BACKGROUND AND PURPOSE: Proton treatment planning relies on an accurate determination of stopping-power ratio (SPR) from x-ray computed tomography (CT). A refinement of the heuristic CT-based SPR prediction using a state-of-the-art Hounsfield look-up table (HLUT) is proposed, which incorporates patient SPR information obtained from dual-energy CT (DECT) in a retrospective patient-cohort analysis. MATERIAL AND METHODS: SPR datasets of 25 brain-tumor patients, 25 prostate-cancer patients, and three nonsmall cell lung-cancer (NSCLC) patients were calculated from clinical DECT scans with the comprehensively validated DirectSPR approach. Based on the median frequency distribution of voxelwise correlations between CT number and SPR within the irradiated volume, a piecewise linear function was specified (DirectSPR-based adapted HLUT). Differences in dose distribution and proton range were assessed for the nonadapted and adapted HLUT in comparison to the DirectSPR method, which has been shown to be an accurate and reliable SPR estimation method. RESULTS: The application of the DirectSPR-based adapted HLUT instead of the nonadapted HLUT reduced the systematic proton range differences from 1.2% (1.1 mm) to -0.1% (0.0 mm) for brain-tumor patients, 1.7% (4.1 mm) to 0.2% (0.5 mm) for prostate-cancer patients, and 2.0% (2.9 mm) to -0.1% (0.0 mm) for NSCLC patients. Due to the large intra- and inter-patient tissue variability, range differences to DirectSPR larger than 1% remained for the adapted HLUT. CONCLUSIONS: The incorporation of patient-specific correlations between CT number and SPR, derived from a retrospective application of DirectSPR to a broad patient cohort, improves the SPR accuracy of the current state-of-the-art HLUT approach. The DirectSPR-based adapted HLUT has been clinically implemented at the University Proton Therapy Dresden (Dresden, Germany) in 2017. This already facilitates the benefits of an improved DECT-based tissue differentiation within clinical routine without changing the general approach for range prediction (HLUT), and represents a further step toward full integration of the DECT-based DirectSPR method for treatment planning in proton therapy. CI - (c) 2020 American Association of Physicists in Medicine. FAU - Wohlfahrt, Patrick AU - Wohlfahrt P AUID- ORCID: 0000-0002-2121-0934 AD - OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. AD - Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany. FAU - Mohler, Christian AU - Mohler C AUID- ORCID: 0000-0001-8053-4843 AD - German Cancer Research Center (DKFZ), Heidelberg, Germany. AD - National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany. FAU - Enghardt, Wolfgang AU - Enghardt W AD - OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. AD - Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany. AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - German Cancer Consortium (DKTK), Partner Site, Dresden, Germany. FAU - Krause, Mechthild AU - Krause M AD - OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. AD - Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany. AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - German Cancer Consortium (DKTK), Partner Site, Dresden, Germany. AD - National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany. AD - German Cancer Research Center (DKFZ), Heidelberg, Germany. AD - Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - Helmholtz Association/Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. FAU - Kunath, Daniela AU - Kunath D AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. FAU - Menkel, Stefan AU - Menkel S AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. FAU - Troost, Esther G C AU - Troost EGC AD - OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. AD - Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany. AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - German Cancer Consortium (DKTK), Partner Site, Dresden, Germany. AD - National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany. AD - German Cancer Research Center (DKFZ), Heidelberg, Germany. AD - Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - Helmholtz Association/Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. FAU - Greilich, Steffen AU - Greilich S AUID- ORCID: 0000-0001-6237-7936 AD - German Cancer Research Center (DKFZ), Heidelberg, Germany. AD - National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany. FAU - Richter, Christian AU - Richter C AUID- ORCID: 0000-0003-4261-4214 AD - OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. AD - Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany. AD - Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universitat Dresden, Dresden, Germany. AD - German Cancer Consortium (DKTK), Partner Site, Dresden, Germany. LA - eng PT - Journal Article DEP - 20200229 PL - United States TA - Med Phys JT - Medical physics JID - 0425746 RN - 0 (Protons) SB - IM MH - Humans MH - *Protons MH - Radiometry MH - Retrospective Studies MH - Tomography, X-Ray Computed/*methods OTO - NOTNLM OT - Hounsfield look-up table OT - clinical translation OT - dual-energy CT OT - proton range prediction OT - proton stopping power OT - proton therapy EDAT- 2020/02/11 06:00 MHDA- 2021/01/27 06:00 CRDT- 2020/02/11 06:00 PHST- 2019/09/01 00:00 [received] PHST- 2020/02/03 00:00 [revised] PHST- 2020/02/05 00:00 [accepted] PHST- 2020/02/11 06:00 [pubmed] PHST- 2021/01/27 06:00 [medline] PHST- 2020/02/11 06:00 [entrez] AID - 10.1002/mp.14085 [doi] PST - ppublish SO - Med Phys. 2020 Apr;47(4):1796-1806. doi: 10.1002/mp.14085. Epub 2020 Feb 29.