At the National Institute of Radiological Sciences (NIRS), more than 8,000 patients have been treated for various tumors with carbon-ion (C-ion) radiotherapy in the past 20 years based on a radiobiologically defined clinical-dose system. Through clinical experience, including extensive dose escalation studies, optimum dose-fractionation protocols have been established for respective tumors, which may be considered as the standards in C-ion radiotherapy. Although the therapeutic appropriateness of the clinical-dose system has been widely demonstrated by clinical results, the system incorporates several oversimplifications such as dose-independent relative biological effectiveness (RBE), empirical nuclear fragmentation model, and use of dose-averaged linear energy transfer to represent the spectrum of particles. We took the opportunity to update the clinical-dose system at the time we started clinical treatment with pencil beam scanning, a new beam delivery method, in 2011. The requirements for the updated system were to correct the oversimplifications made in the original system, while harmonizing with the original system to maintain the established dose-fractionation protocols. In the updated system, the radiation quality of the therapeutic C-ion beam was derived with Monte Carlo simulations, and its biological effectiveness was predicted with a theoretical model. We selected the most used C-ion beam with αr = 0.764 Gy(-1) and β = 0.0615 Gy(-2) as reference radiation for RBE. The C-equivalent biological dose distribution is designed to allow the prescribed survival of tumor cells of the human salivary gland (HSG) in entire spread-out Bragg peak (SOBP) region, with consideration to the dose dependence of the RBE. This C-equivalent biological dose distribution is scaled to a clinical dose distribution to harmonize with our clinical experiences with C-ion radiotherapy. Treatment plans were made with the original and the updated clinical-dose systems, and both physical and clinical dose distributions were compared with regard to the prescribed dose level, beam energy, and SOBP width. Both systems provided uniform clinical dose distributions within the targets consistent with the prescriptions. The mean physical doses delivered to targets by the updated system agreed with the doses by the original system within ± 1.5% for all tested conditions. The updated system reflects the physical and biological characteristics of the therapeutic C-ion beam more accurately than the original system, while at the same time allowing the continued use of the dose-fractionation protocols established with the original system at NIRS.
This retrospective study indicates that the annual incidence rate of HCC among Japanese NAFLD patients is low. Elderly NAFLD patients with diabetes, elevated serum AST, and especially thrombocytopenia (suggested to be associated with advanced liver fibrosis) should be monitored carefully during follow-up that includes using the APRI to ensure early diagnosis and treatment of HCC.
Carbon ion radiotherapy seems to be a safe and effective modality in the management of bone and soft tissue sarcomas not eligible for surgical resection, providing good local control and offering a survival advantage without unacceptable morbidity.
The effects of thermal annealing before and after Al deposition on poly͑3-hexylthiophene͒ ͑P3HT͒ / ͓6,6͔-phenyl-C 61 butyric acid methyl ester ͑PCBM͒ blend solar cells were investigated by current density-voltage measurements and x-ray photoelectron spectroscopy ͑XPS͒. Compared to the preannealed device, the postannealed device exhibited enhanced open-circuit voltage ͑V OC ͒, which is ascribed to the decrease in the reverse saturation current density J 0 . The XPS measurements demonstrated that P3HT is dominant at the Al interface in the preannealed device while PCBM is instead dominant in the postannealed device. This surface-segregated PCBM formed in the postannealed device can serve as a hole-blocking layer at the Al interface to reduce J 0 , and therefore improve V OC .
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