https://www.selleckchem.com/products/n-acetyl-dl-methionine.html PURPOSE A relative biological effectiveness (RBE) of 1.1 is commonly used in clinical proton therapy, irrespective of tissue type and depth. This in-vitro study was conducted to quantify the RBE of scanned protons as a function of the dose-averaged linear energy transfer (LETd ) and the sensitivity factor (α/ß)X . Additionally, three phenomenological models (McNamara, Rørvik and Jones) and one mechanistic model (Repair-Misrepair-Fixation, RMF) were applied to the experimentally derived data. METHODS Four human cell lines (FaDu, HaCat, Du145, SKMel) with differential (α/ß)X ratios were irradiated in a custom-designed irradiation set-up with doses between 0 and 6 Gy at proximal, central and distal positions of a 80 mm spread-out Bragg peak (SOBP) centered at 80 mm (set-up A proton energies 66.5-135.6 MeV) and 155 mm (set-up B proton energies 127.2-185.9 MeV) depth, respectively. LETd values at the respective cell positions were derived from Monte Carlo simulations performed with the treatment planning system (Tsensitivity parameter (α/ß)X was observed to be a major influencing factor for the RBE of protons and its sensitivity towards LETd changes. RBE prediction models are applicable for high (α/ß)X cell lines but do not estimate RBE values with sufficient accuracy in low (α/ß)X cell lines. This article is protected by copyright. All rights reserved.A 10-year-old intact male Golden Retriever was presented to The Ohio State University Veterinary Medical Center for acute, non-painful facial swelling of the right mandibular region. On physical examination, the right mandibular swelling was found to represent marked lymphadenopathy of the submandibular lymph node. At this time, marked lymphadenopathy of the prescapular and popliteal lymph nodes was also appreciated. The CBC showed a moderate leukocytosis (38.4 × 109 cells/L, reference interval [RI] 4.8-13.9 × 109 cells/L) characterized by a moderate lymphocy