This study examined the dose response of an optically stimulated luminescence dosemeter (OSLD) to megavoltage photon and electron beams. A nanoDot™ dosemeter was used to measure the dose response of the OSLD. Photons of 6-15 MV and electrons of 9-20 MeV were delivered by a Varian 21iX machine (Varian Medical System, Inc. Milpitas, CA, USA). The energy dependency was <1 %. For the 6-MV photons, the dose was linear until 200 cGy. The superficial dose measurements revealed photon irradiation to have an angular dependency. The nanoDot™ dosemeter has potential use as an in vivo dosimetric tool that is independent of the energy, has dose linearity and a rapid response compared with normal in vivo dosimetric tools, such as thermoluminescence detectors. However, the OSLD must be treated very carefully due to the high angular dependency of the photon beam.

PurposeTo evaluate and compare the risks of secondary cancers from therapeutic doses received by patients with hepatocellular carcinoma (HCC) during intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and tomotherapy (TOMO).MethodsTreatments for five patients with hepatocellular carcinoma (HCC) were planned using IMRT, VMAT, and TOMO. Based on the Biological Effects of Ionizing Radiation VII method, the excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) were evaluated from therapeutic doses, which were measured using radiophotoluminescence glass dosimeters (RPLGDs) for each organ inside a humanoid phantom.ResultsThe average organ equivalent doses (OEDs) of 5 patients were measured as 0.23, 1.18, 0.91, 0.95, 0.97, 0.24, and 0.20 Gy for the thyroid, lung, stomach, liver, small intestine, prostate (or ovary), and rectum, respectively. From the OED measurements, LAR incidence were calculated as 83, 46, 22, 30, 2 and 6 per 104 person for the lung, stomach, normal liver, small intestine, prostate (or ovary), and rectum.ConclusionsWe estimated the secondary cancer risks at various organs for patients with HCC who received different treatment modalities. We found that HCC treatment is associated with a high secondary cancer risk in the lung and stomach.

Purpose We evaluated the effects of diabetes mellitus (DM) and DM-related serologic factors (HbA1c and fasting glucose) on the development of radiation pneumonitis in patients with lung cancer. Methods We retrospectively analyzed the clinical data of 123 patients with lung cancer treated with radiotherapy. Radiation pneumonitis was scored according to the toxicity criteria of the Radiation Therapy Oncology Group. We used binary logistic regression analysis to find significant predictive factors for the development of grade ≥3 radiation pneumonitis. Results On univariable analysis, V20, mean lung dose, DM, HbA1c, and fasting glucose level were significantly associated with the development of grade ≥3 radiation pneumonitis. On multivariable analysis, V20, mean lung dose, DM, HbA1c, and fasting glucose level remained significant predictive factors for grade ≥3 radiation pneumonitis. The incidence of grade ≥3 radiation pneumonitis was 44.4% in patients with DM and 20.7% in patients without DM. The incidence of grade ≥3 radiation pneumonitis was 12.7% for HbA1c level ≤6.15% and 41.5% for HbA1c level >6.15%. The incidence of grade ≥3 radiation pneumonitis was 17.2% for fasting glucose level ≤121 mg/dL and 35.5% for fasting glucose level >121 mg/dL. Conclusion DM, HbA1c, and fasting glucose level are significant predictive factors for the development of grade ≥3 radiation pneumonitis in patients with lung cancer. Patients with DM, patients who have HbA1c >6.15%, and patients who have fasting glucose >121 mg/dL should be treated with greater caution.

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Spontaneously regulated in‐plane polarity inversion of a‐oriented GaN domains has been demonstrated for the first time. Crystallographic analysis revealed that each domain grown on circular‐hole‐patterned r‐plane sapphire substrates has basal faces with oppositely oriented in‐plane polarity. The inverted orientation of in‐plane polarity on the opposite basal faces is not due to merging between in‐plane polarity‐inverted domains nucleated on the patterned r‐plane sapphire substrate, but it was found to be due to spontaneous formation of an inversion domain boundary on the growth fronts of existing domains. This result provides new insights into controlling the in‐plane polarity of a‐oriented GaN, because the nucleation of in‐plane polarity‐inverted domains of a‐oriented GaN on r‐plane sapphire is symmetrically not allowed.