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BackgroundThe lower neck and upper mediastinum are the major regions for postoperative radiotherapy (PORT) in thoracic esophageal squamous cell carcinoma (TESCC). However, there is no uniform standard regarding the delineation of nodal clinical target volume (CTVnd). This study aimed to map the recurrent lymph nodes in the cervical and upper mediastinal regions and explore a reasonable CTVnd for PORT in TESCC.MethodsWe retrospectively reviewed patients in our hospital with first cervical and/or upper mediastinal lymph node recurrence (LNR) after upfront esophagectomy. All of these recurrent lymph nodes were plotted on template computed tomography (CT) images with reference to surrounding structures. The recurrence frequency at different stations was investigated and the anatomic distribution of recurrent lymph nodes was analyzed.ResultsA total of 119 patients with 215 recurrent lymph nodes were identified. There were 47 (39.5%) patients with cervical LNR and 102 (85.7%) patients with upper mediastinal LNR. The high-risk regions were station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. LNR in the external group of station 104L/R was not common, and LNR was not found in the narrow spaces where the trachea was in close contact with the innominate artery, aortic arch and mediastinal pleura. LNR below the level of the cephalic margin of the superior vena cava was also not common for upper TESCC.ConclusionsThe CTVnd of PORT in the cervical and upper mediastinal regions should cover station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. Based on our results, we proposed a useful atlas for guiding the delineation of CTVnd in TESCC.

Background: The lower neck and upper mediastinum are the major regions for postoperative radiotherapy (PORT) in thoracic esophageal squamous cell carcinoma (TESCC). However, there is no uniform standard regarding the delineation of nodal clinical target volume (CTVnd). This study aimed to map the recurrent lymph nodes in the cervical and upper mediastinal regions and explore a reasonable CTVnd for PORT in TESCC. Methods: We retrospectively reviewed patients in our hospital with first cervical and/or upper mediastinal lymph node recurrence (LNR) after upfront esophagectomy. All of these recurrent lymph nodes were plotted on template computed tomography (CT) images with reference to surrounding structures. The recurrence frequency at different stations was investigated and the anatomic distribution of recurrent lymph nodes was analyzed. Results: A total of 119 patients with 215 recurrent lymph nodes were identified. There were 47 (39.5%) patients with cervical LNR and 102 (85.7%) patients with upper mediastinal LNR. The high-risk regions were station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. LNR in the external group of station 104L/R was not common, and LNR was not found in the narrow spaces where the trachea was in close contact with the innominate artery, aortic arch and mediastinal pleura. LNR below the level of the cephalic margin of the superior vena cava was also not common for upper TESCC. Conclusions: The CTVnd of PORT in the cervical and upper mediastinal regions should cover station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. Based on our results, we proposed a useful atlas for guiding the delineation of CTVnd in TESCC. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to examine long‐term outcomes in patients who received salvage radiotherapy (SRT) for biochemical recurrence (BRec) of prostate cancer after radical prostatectomy (RP). One hundred and twenty patients with prostate cancer who underwent SRT for BRec after RP without evidence of clinical disease were identified in our institution from 2002 to 2014. Prescription doses to prostate beds were 64.8 Gy with a fractional dose of 1.8 Gy in 96.7% of the patients. In three‐dimensional conformal radiation therapy (3D‐CRT), the seminal vesicle bed (SVB) was not included in the radiation fields. The prognostic factors for BRec‐free survival (BRFS) and incidence of acute and late toxicities were investigated. Median follow‐up duration after SRT was 64.9 months. The 5‐year rates of BRFS, overall survival (OS), cause‐specific survival (CSS), and clinical recurrence‐free survival (CRFS) were 39.2%, 98.3%, 97.0%, and 91.9%, respectively. Only two patients experienced late grade 3 toxicity of hematuria. Multivariate analysis revealed that BRFS was significantly favorable in patients with prostate‐specific antigen (PSA) values

Abstract: The aim of this study was to examine long‐term outcomes in patients who received salvage radiotherapy (SRT) for biochemical recurrence (BRec) of prostate cancer after radical prostatectomy (RP). One hundred and twenty patients with prostate cancer who underwent SRT for BRec after RP without evidence of clinical disease were identified in our institution from 2002 to 2014. Prescription doses to prostate beds were 64.8 Gy with a fractional dose of 1.8 Gy in 96.7% of the patients. In three‐dimensional conformal radiation therapy (3D‐CRT), the seminal vesicle bed (SVB) was not included in the radiation fields. The prognostic factors for BRec‐free survival (BRFS) and incidence of acute and late toxicities were investigated. Median follow‐up duration after SRT was 64.9 months. The 5‐year rates of BRFS, overall survival (OS), cause‐specific survival (CSS), and clinical recurrence‐free survival (CRFS) were 39.2%, 98.3%, 97.0%, and 91.9%, respectively. Only two patients experienced late grade 3 toxicity of hematuria. Multivariate analysis revealed that BRFS was significantly favorable in patients with prostate‐specific antigen (PSA) values <0.5 ng/mL at the initiation of SRT and pathological Gleason score not including Gleason grade 5. In patients treated with 3D‐CRT, a positive surgical margin at the base of the prostate influenced BRFS unfavorably in comparison with positive surgical margins at other sites. SRT for patients with BRec after RP was performed very safely in our institution. However, to improve BRFS, adequate inclusion of the SVB appears mandatory, especially in cases of positive surgical margins at the base of the prostate. [ABSTRACT FROM AUTHOR]

We evaluate the neutron and muon fluxes produced in the ILC beam dumps by Monte Carlo simulations and discuss their potential use in irradiation fields. We show that the beam dumps can provide high-intensity neutron and muon fluxes with spectra quite similar to secondary cosmic rays, which are suitable for soft error studies. The beam dumps deliver neutrons about 1 0 11 times the secondary cosmic rays on spaces perpendicular to the beam axis and muons 1 0 8 times downstream of the beam dumps in the initial phase of the ILC. Large-area irradiation of 1 m 2 or more is possible. Differences in the energy distribution of muons in electron and positron beam dumps are also discussed for particle physics experiments. [ABSTRACT FROM AUTHOR]

Introduction: X-ray penumbral width depends on the size of the detector in the off-axis ratio of medical linear accelerators. The use of detectors with appropriate sizes according to the irradiation field is recommended. However, when measuring dose distributions, the shape of the off-axis ratio differs depending on detectors even if the dose distribution remains unchanged. This study aims to calculate the penumbral width using multiple detectors and obtain the independent penumbral width according to irradiation size., Materials and Methods: Using the X-ray output from a medical linear accelerator, off-axis ratios in water were measured using nine types of detectors. Penumbral width was calculated from each measured off-axis ratio by linear approximation and determining the intercept for analysis. The experimental irradiation fields were square areas (1×1 cm 2 to 10×10 cm 2 ). Penumbral widths were obtained from three types of detectors with different sensitive region widths of at least 1.2 mm., Results: The values estimated from the nine detectors were 2.51-4.07 and 2.93-4.70 mm for 6 and 10 MV X-rays, respectively. The penumbral width and variation due to detector size increased with the irradiation field. The results estimated from the three selected detectors varied within ±0.5 mm compared with those from the nine detectors and were generally consistent. The reliability of the results was evaluated by comparing with the results from past studies and Monte Carlo simulations., Conclusion: Calculation of the penumbral width can be done regardless of size for various detectors. Thus, dose distributions can be compared for the linear accelerator at different facilities.

Abstract: The characteristics of moderator assembly dimension was investigated for the usage of 7Li(p,n) neutrons by 2.3–2.8MeV protons and W(p,n) neutrons by 50MeV protons. The indexes were the treatable protocol depth (TPD) and advantage depth (AD). Consequently, a configuration for W target with the Fe filter, Fluental moderator, Pb reflector showed the TPD of 5.8cm and AD of 9.3cm. Comparable indexes were found for the Li target in a geometry with the MgF2 moderator and Teflon reflector. [Copyright &y& Elsevier]

Abstract: In order to measure the spatial distributions of neutrons and gamma rays separately using the imaging plate, the requirement for the converter to enhance specific component was investigated with the PHITS code. Consequently, enhancing fast neutrons using recoil protons from epoxy resin was not effective due to high sensitivity of the imaging plate to gamma rays. However, the converter of epoxy resin doped with 10B was found to have potential for thermal and epithermal neutrons, and graphite for gamma rays. [Copyright &y& Elsevier]

Abstract: Spectroscopic experiments were conducted to characterise commercial side emission optical fibres regarding their emission spectra and the intensity of emitted radiation in the spectral range from UV-A to visible blue. For fibres with silica core and scattering particles embedded in the cladding, the emission spectra are determined by the material of the scattering particles. While Al2O3 particles allow emission of UV-A and visible blue light, ZnO filters most of the UV-A light up to wavelengths of 380nm. The emitted intensity ideally decays exponentially along the fibre with a decay constant that is correlated to the particle concentration. The absolute values of the emitted intensity increase with increasing fibre radius. For fibres with PMMA core and surface perforation, relatively weak background emission of UV-A and blue light and additional local emission peaks due to the surface treatment were observed. The background emission can be explained by scattering due to the intrinsic non-uniformity of the PMMA core. The surface defects cause highly non-uniform and directional emission at a relatively high intensity. Compared to the silica core fibres, higher emission intensity in the UV-A and visible blue spectrum, albeit at a non-uniform distribution, was observed although the transmission along the fibre over longer distances is significantly lower for PMMA core fibres than for fibres with silica core. [Copyright &y& Elsevier]

Basic research related to heavy-ion cancer therapy has been done at the Institute of Modern Physics (IMP), Chinese Academy of Sciences since 1995. Now a plan of clinical trial with heavy ions has been launched at IMP. First, superficially placed tumor treatment with heavy ions is expected in the therapy terminal at the Heavy Ion Research Facility in Lanzhou (HIRFL), where carbon ion beams with energy up to 100 MeV/u can be supplied. The shallow-seated tumor therapy terminal at HIRFL is equipped with a passive beam delivery system including two orthogonal dipole magnets, which continuously scan pencil beams laterally and generate a broad and uniform irradiation field, a motor-driven energy degrader and a multi-leaf collimator. Two different types of range modulator, ripple filter and ridge filter with which Guassian-shaped physical dose and uniform biological effective dose Bragg peaks can be shaped for therapeutic ion beams respectively, have been designed and manufactured. Therefore, two-dimensional and three-dimensional conformal irradiations to tumors can be performed with the passive beam delivery system at the earlier therapy terminal. Both the conformal irradiation methods have been verified experimentally and carbon-ion conformal irradiations to patients with superficially placed tumors have been carried out at HIRFL since November 2006. [ABSTRACT FROM AUTHOR]

Due to the favorable characteristics of heavy-ion beams such as dose localization as well as high relative biological effectiveness, heavy-ion cancer therapy is attracting growing interests all over the world. The application of β-delayed particle decay beams like 9C ions in cancer therapy is expected to further improve the treatment efficacy of the modality of heavy-ions. For the first time 9C beams were produced in the secondary beam line (SBL) of the HIMAC facility with a primary 12C beam of 430 MeV/n. The production conditions providing a 9C beam with higher production rate and purity were optimized using different thick production targets and degraders. The results show setting the momentum acceptance to the full value of 5% the production rate is 9.07 × 10−6 and the purity is 82.88% for the produced 9C beam under the optimal condition. Because of the large momentum spread for a secondary beam, the momentum distribution of the produced 9C beam at the optimal condition was measured. The momentum among the beam had a nearly Gaussian profile with a standard deviation of 26.1 MeV/c/n and the largest component of the momenta appeared around 838.9 MeV/c/n. In order to form a relatively large uniform irradiation field being appropriate to further biological experiments for the produced 9C beam, the scanning magnets in the irradiation system of the SBL, operating in a wobbling mode, was used. A uniform irradiation field of 20 mm in diameter could be achieved with homogeneity of 93.8%. The work presented in this paper provides a substantial basis for the further studies with 9C beams for the therapeutic purpose. [Copyright &y& Elsevier]