Entity

Time filter

Source Type


Terashima K.,Hyogo Ion Beam Medical Center
Japanese Journal of Clinical Radiology | Year: 2016

Focal liver reaction was observed corresponding to particle therapy (PT) using proton or carbon-ion beam for liver tumor, presented with significant low intensity at hepatobiliary phase on gadoxetate acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging. The imaging findings appeared 8 weeks after PT with threshold dose of 19.9 and 24.3 gray equivalents (GyE) at 10 and 20 fractions for proton beam, 21.9 and 25.5 GyE at 10 and 20 fractions for carbon-ion beam. These results could serve as a basis for an optimal management of radiation induced liver disease. © 2016, Kanehara Shuppan Co. Ltd. All rights reserved. Source


Yamashita T.,Hyogo Ion Beam Medical Center | Akagi T.,Hyogo Ion Beam Medical Center | Aso T.,Nagaoka University of Technology | Kimura A.,Ashikaga Institute of Technology | Sasaki T.,High Energy Accelerator Research Organization
Physics in Medicine and Biology | Year: 2012

The pencil beam algorithm (PBA) is reasonably accurate and fast. It is, therefore, the primary method used in routine clinical treatment planning for proton radiotherapy; still, it needs to be validated for use in highly inhomogeneous regions. In our investigation of the effect of patient inhomogeneity, PBA was compared with Monte Carlo (MC). A software framework was developed for the MC simulation of radiotherapy based on Geant4. Anatomical sites selected for the comparison were the head/neck, liver, lung and pelvis region. The dose distributions calculated by the two methods in selected examples were compared, as well as a dose volume histogram (DVH) derived from the dose distributions. The comparison of the off-center ratio (OCR) at the iso-center showed good agreement between the PBA and MC, while discrepancies were seen around the distal fall-off regions. While MC showed a fine structure on the OCR in the distal fall-off region, the PBA showed smoother distribution. The fine structures in MC calculation appeared downstream of very low-density regions. Comparison of DVHs showed that most of the target volumes were similarly covered, while some OARs located around the distal region received a higher dose when calculated by MC than the PBA. © 2012 Institute of Physics and Engineering in Medicine. Source


Demizu Y.,Hyogo Ion Beam Medical Center
Japanese Journal of Clinical Radiology | Year: 2013

Particle therapy, such as proton therapy and carbon ion therapy, is capable of delivering high-dose radiation to tumors while minimizing the dose delivered to organs at risk because of its precise dose distribution, as compared with conventional photon therapy. Little is known about particle therapy for oligometastases and oligo-recurrence, however, published reports and our unpublished data suggest that particle therapy can achieve favorable local control with acceptable toxicities. More data accumulation is warranted. Source


Nihei K.,National Cancer Center | Ogino T.,National Cancer Center | Onozawa M.,National Cancer Center | Murayama S.,Proton Therapy | And 3 more authors.
International Journal of Radiation Oncology Biology Physics | Year: 2011

Purpose: Proton beam therapy (PBT) is theoretically an excellent modality for external beam radiotherapy, providing an ideal dose distribution. However, it is not clear whether PBT for prostate cancer can clinically control toxicities. The purpose of the present study was to estimate prospectively the incidence of late rectal toxicities after PBT for organ-confined prostate cancer. Methods and Materials: The major eligibility criteria included clinical Stage T1-T2N0M0; initial prostate-specific antigen level of ≤20 ng/mL and Gleason score ≤7; no hormonal therapy or hormonal therapy within 12 months before registration; and written informed consent. The primary endpoint was the incidence of late Grade 2 or greater rectal toxicity at 2 years. Three institutions in Japan participated in the present study after institutional review board approval from each. PBT was delivered to a total dose of 74 GyE in 37 fractions. The patients were prospectively followed up to collect the data on toxicities using the National Cancer Institute-Common Toxicity Criteria, version 2.0. Results: Between 2004 and 2007, 151 patients were enrolled in the present study. Of the 151 patients, 75, 49, 9, 17, and 1 had Stage T1c, T2a, T2b, T2c, and T3a, respectively. The Gleason score was 4, 5, 6, and 7 in 5, 15, 80 and 51 patients, respectively. The initial prostate-specific antigen level was <10 or 10-20 ng/mL in 102 and 49 patients, respectively, and 42 patients had received hormonal therapy and 109 had not. The median follow-up period was 43.4 months. Acute Grade 2 rectal and bladder toxicity temporarily developed in 0.7% and 12%, respectively. Of the 147 patients who had been followed up for >2 years, the incidence of late Grade 2 or greater rectal and bladder toxicity was 2.0% (95% confidence interval, 0-4.3%) and 4.1% (95% confidence interval, 0.9-7.3%) at 2 years, respectively. Conclusion: The results of the present prospective study have revealed a valuable piece of evidence that PBT for localized prostate cancer can achieve a low incidence of late Grade 2 or greater rectal toxicities. © 2011 Elsevier Inc. Source


Someya M.,Sapporo Medical University | Yamamoto H.,St. Marianna University School of Medicine | Nojima M.,Tokyo Medical University | Hori M.,Sapporo Medical University | And 7 more authors.
Radiotherapy and Oncology | Year: 2015

Background and purpose: Late rectal bleeding is one of the severe adverse events after radiotherapy for prostate cancer. New biomarkers are needed to allow a personalized treatment. Materials and methods: Four patients each with grade 0-1 or grade 2-3 rectal bleeding were randomly selected for miRNA array to examine miRNA expression in peripheral blood lymphocytes (PBLs). Based on results of miRNA array, 1 of 348 miRNAs was selected for microRNA assays. Then, expression of DNA-dependent protein kinase mRNA and miR-99a was analyzed in the PBLs of 97 patients. PBLs were exposed to 4 Gy of X-ray ex-vivo. Results: In the discovery cohort, grade 2-3 rectal bleeding was significantly higher in the Ku80 <1.09 expression group compared with ≥1.09 group (P = 0.011). In radiation-induced expression of miR-99a, grade 2-3 rectal bleeding was significantly higher in the miR-99a IR(+)/IR(-) >0.93 group compared with ≤0.93 group (P = 0.013). Most patients with grade 2-3 rectal bleeding were in the group with low Ku80 and high miR-99a expression. In the validation cohort, similar results were obtained. Conclusion: A combination of low Ku80 expression and highly-induced miR-99a expression could be a promising marker for predicting rectal bleeding after radiotherapy. © 2015 Elsevier Ireland Ltd. All rights reserved. Source

Discover hidden collaborations