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TLD calibration and absorbed dose measurement in a radiation-induced liver injury model under a linear accelerator

Nuclear Science and Techniques 2023年第4期34卷 69-78页

作者： Hui-Hui Xiao Ling-Ling Liu Wen-Yi Li Bing-Bing Li Xiang-Li Cui Jie Li Tao-Sheng Li Zong-Tao Hu School of Basic Medical Sciences Anhui Medical UniversityHefei 230000China Hefei Cancer Hospital Chinese Academy of SciencesHefei 230000China Institute of Health and Medical Technology Hefei Institute of Materials ScienceChinese Academy of SciencesHefei 230000China University of Science and Technology of China Hefei 230000China Hefei Institute of Materials Science Chinese Academy of SciencesHefei 230000China

The application of a thermoluminescent detector(TLD) for dose detection at the liver irradiation site in mice under linear accelerator precision radiotherapy and the use of a single high dose to irradiate the mouse liver to construct a biological model of a radiation-induced liver injury(RILD) in mice were to determine the feasibility of constructing a precision radiotherapy model in small animals under a linear accelerator. A 360° arc volumetric rotational intensity-modulated radiotherapy(VMAT) plan with a prescribed dose of 2 Gy was developed for the planned target volume(PTV) at the location of the TLD within solid water to compare the difference between the measured dose of TLD and the assessed parameters in the TPS system. The TLD was implanted in the livers of mice, and VMAT was planned based on TLD to compare the measured and prescribed doses. C57BL/6 J mice were randomly divided into control and 25-Gy radiation groups and were examined daily for changes in body weight. They were euthanized at 3 and 10 weeks after radiation, and the levels of liver serum enzymes such as alanine aminotransferase(ALT), aspartate aminotransferase(AST), and alkaline phosphatase(ALP) were measured to observe any pathological histological changes in the irradiated areas of the mouse liver. The measured values of solid underwater TLD were within ± 3% of the Dmean value of the evaluation parameter in the TPS system. The mice in the 25-Gy radiation group demonstrated pathological signs of radiation-induced liver injury at the site of liver irradiation. The deviation in the measured and prescribed doses of TLD in the mouse liver ranged from-1.5 to 6%;construction of an accurate model of RILD using the VMAT technique under a linear accelerator is feasible.

关键词： Thermoluminescent detector Radiation-induced liver injury linear accelerator Volumetric rotational intensity-modulated radiotherapy

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Beam dynamics studies on the 100 MeV/100 kW electron linear accelerator for NSC KIPT neutron source

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Chinese Physics C 2012年第7期36卷 653-660页

作者：裴士伦池云龙王书鸿裴国玺周祖圣侯汨 Mykola Ayzatskiy Ivan Karnaukhov Volodymyr Kushnir Viktor Mytrochenko Andrey Zelinsky Institute of High Energy Physics Chinese Academy of Sciences Kharkov Institute of Physics and Technology National Science Center

We designed a 100 MeV/100 kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the basis of subcritical assembly. Beam dynamics studies have been conducted to reach the design requirements （E=100 MeV, P=100 kW, dE/E 〈1% for 99% particles）. In this paper, we will present the progress of the design and the dynamic simulation results. For high intensity and long beam pulse linear accelerators, the BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at a low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced downstream of the 1st accelerating section; the unwanted particles will be collimated there.

关键词： beam dynamics linear accelerator BBU collimation system neutron source

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Monte Carlo Modeling and Verification of 6 MV linear accelerator

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World Journal of Engineering and Technology 2022年第2期10卷 213-223页

作者： Shixiong Lu Haijun Deng College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu China Department of Oncology Sichuan Mianyang 404 Hospital Mianyang China

Purpose: To model the ELEKTA COMPACT accelerator head by using EGSnrc/BEAMnrc/DOSXYZnrc and to validatethe simulation according to the depth-dose and lateral profiles of different radiation fields measured by the water phantom. Methods: IBA Blue Water Phantom2 and CC13 Ionization Chamber were used to measure the depth-dose curves at 10 cm × 10 cm field and profile curves at 10 cm depth underwater. In BEAMnrc, the main components of accelerator head and the initial electron beam are established based on the specifications file, and the phase space file containing the photon beam information is generated. In DOXYZnrc, phase space files were used to irradiate a homogeneous water phantom of the same size as the IBA water phantom, and the simulated percentage depth dose curves and lateral profiles were outputted. The accuracy of the model was evaluated by mean square error (MSE) compared with the measured data. PDD curves are used to determine the energy of the initial electron beam. Dose profile curves are used to adjust the flattening filter. The penumbra on lateral profiles is used to adjust the full-width half-maximum (FWHM) of the electron source. Result: The electron energy of 5.8 MeV was considered the best match after comparing the PDD curves of 5.6 - 6.2 MeV electron beams. The flattening filter can only be adjusted by trial. In the final result, the maximum fluctuation of profile curve within 80% of the maximum field size is less than 3%, which meets the requirements of field flatness. The optimum FWHM for different fields is not consistent due to the Transmission penumbra. But a match can be approached by adjusting the FWHM every 10 cm field size.

关键词： EGSnrc/BEAMnrc/DOSXYZnrc linear accelerator Initial Electron Beam PDD Lateral Profiles

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Measurement of the Energy Spectrum of a 6 MV linear accelerator Using Compton Scattering Spectroscopy and Monte Carlo-Generated Corrections

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2020年第4期9卷 186-200页

作者： Sameer Taneja Laura J. Bartol Wesley Culberson Larry A. De Werd School of Medicine and Public Health University of Wisconsin-Madison Madison USA

Purpose: The energy spectrum of a linear accelerator used for dose calculations is determined during beam commissioning by iteratively adjusting the spectrum and comparing calculated and measured percent depth-dose curves. Direct measurement of the energy spectrum using pulse mode detectors is particularly challenging because of the high-energy, high fluence nature of these beams and limitations of the detector systems. This work implements a Compton scattering (CS) spectroscopy setup and presents detector corrections and spectral unfolding techniques to measure the spectrum of a 6 MV linear accelerator using a pulse mode detector. Methods: Spectral measurements were performed using a Varian Clinac 21EX linear accelerator and a high-purity germanium (HPGe) detector. To reduce fluence to the detector, a custom-built lead shield and a CS spectrometry setup were used. The detector was placed at CS angles of 46°, 89°, and 125°. At each of these locations, a detector response function was generated to account for photon interactions within the experimental geometry. Gold’s deconvolution algorithm was used to unfold the energy spectrum. The measured spectra were compared to simulated spectra, which were obtained using an experimentally benchmarked model of the Clinac 21EX in MCNP6. Results: Measurements were acquired and detector response corrections were calculated for all three CS angles. A comparison of spectra for all CS angles showed good agreement with one another. The spectra for all three angles were averaged and showed good agreement with the MCNP6 simulated spectrum, with all points above 400 keV falling w

关键词： linear accelerator Energy Spectrum Spectrometry High Purity Germanium Detectors Monte Carlo

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A Study of the TPS Based Beam-Matching Concept for Medical linear accelerators at a Tertiary Hospital

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2024年第1期13卷 16-25页

作者： Ntombela N. Lethukuthula Rovetto J. Nicolas Nethwadzi C. Lutendo Mpumelelo Nyathi Department of Radiation Oncology Steve Biko Academic Hospital Pretoria South Africa Department of Medical Physics University of Pretoria Pretoria South Africa Department of Medical Physics Sefako Makgatho Health Sciences University Ga-Rankuwa South Africa

The flexibility in radiotherapy can be improved if patients can be moved between any one of the department’s medical linear accelerators (LINACs) without the need to change anything in the patient’s treatment plan. For this to be possible, the dosimetric characteristics of the various accelerators must be the same, or nearly the same. The purpose of this work is to describe further and compare measurements and parameters after the initial vendor-recommended beam matching of the five LINACs. Deviations related to dose calculations and to beam matched accelerators may compromise treatment accuracy. The safest and most practical way to ensure that all accelerators are within clinical acceptable accuracy is to include TPS calculations in the LINACs matching evaluation. Treatment planning system (TPS) was used to create three photons plans with different field sizes 3 × 3 cm, 10 × 10 cm and 25 × 25 cm at a depth of 4.5 cm in Perspex. Calculated TPS plans were sent to Mosaiq to be delivered by five LINACs. TPS plans were compared with five LINACs measurements data using Gamma analyses of 2% and 2 mm. The results suggest that for four out of the five LINACs, there was generally good agreement, less than a 2% deviation between the planned dose distribution and the measured dose distribution. However, one specific LINAC named “Asterix” exhibited a deviation of 2.121% from the planned dose. The results show that all of the LINACs’ performance were within the acceptable deviation and delivering radiation dose consistently and accurately.

关键词： Radiotherapy Beam-Matching linear accelerator Dosimetry

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Development and testing of a high-power S-band klystron at BINP SB RAS

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Nuclear Science and Techniques 2024年第7期35卷 58-67页

作者： A.Levichev A.Barnyakov S.Samoylov D.Nikiforov V.Ivanov M.Arsentyeva D.Chekmenev O.Pavlov I.Pivovarov Budker Institute of Nuclear Physics Lavrentyeva Av.11NovosibirskRussia630090 Novosibirsk State University Pirogova Str.2NovosibirskRussia630090

This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP SB RAS).Upon testing,the klystron demonstrated the following parameters:an operating frequency of 2856 MHz and a peak power output of 50 *** paper presents the klystron's design,its constituent units,and pertinent processing procedures,along with discussions on the measurement of its parameters.

关键词： Klystron linear accelerator Electron beam

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Development of S-Band High Power Klystron

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Chinese Journal of Electronics 2020年第4期29卷 772-778页

作者： WANG Shengchang DONG Dong PEI Shilun ZHOU Zusheng FUKUDA Shigeki ZHENG Kai Institute of High Energy Physics Chinese Academy of Sciences High Energy accelerator Research Organization Hubei Hanguang Technology Co. Ltd

A 2998 MHz, 60 MW klystron has been developed for future linear accelerators of synchrotron radiation *** order to save development and construction time, the 2998 MHz, 60 MW klystron is a modified version of an existing 2856 MHz klystron used in linear accelerator of Beijing Electron-Positron Collider Ⅱ.Based on the simulations, it was shown that the scaled version klystron was able to produce more than 60 MW at a 350 kV beam voltage.A prototype was built and *** successfully produced 50 MW output power with an RF pulse width of 4.0μs, which exceeded the operating requirement of China’s High Energy Photon *** also produced 62 MW with an RF pulse width of 1.6μs, which proved the validity of new RF circuit *** paper describes the details of the progresses of this klystron and advantages of this tube development.

关键词： Klystron linear accelerator Radio-frequency(RF) source

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Comparison of two methods for assessing leakage radiation dose around the head of the medical linear accelerators

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The Chinese-German Journal of Clinical Oncology 2013年第9期12卷 435-438页

作者： Ehab M. Attalla Department of Radiotherapy and Nuclear Medicine National Cancer Institute Cairo University Children Cancer Hospital

Objective:The aim of this study was to measure the leakage by two methods with ion chamber and ready packs film,and to investigate the feasibility and the advantages of using two dosimetry methods for assessing leakage radiation around the head of the linear ***:Measurements were performed using a 30 cm3ion chamber;the gantry at 0°,the X-ray head at 0°,the field size at between the central axis and a plane surface at a FSD of 100 as a reference,a series of concentric circles having radii of 50,75,and 100 cm with their common centre at the reference *** absorbed dose was measured at the reference point,and this would be used as the reference *** the diaphragm closed,the measurements were taken along the circumference of the three circles and at 45°***:Leakage radiations while the treatment head was in the vertical position varied between 0.016%–0.04%.With the head lying horizontally,leakage radiation was the same order magnitude and varied between 0.02%–0.07%.In the second method,the verification was accomplished by closing the collimator jaws and covering the head of the treatment unit with the ready pack *** films were marked to permit the determination of their positions on the machine after exposed and *** the diaphragm closed,and the ready packs films around the linear accelerator the beam turned on for 2500 cGy(2500 MU).The optical density of these films was measured and compared with this of the reference *** radiation varied according to the film positions and the magnitude of leakage was between 0.005%–0.075%.Conclusion:The differences between the values of the leakage radiation levels observed at different measurement points do not only reflect differences in the effective shielding thickness of the head wall,but are also related to differences in the distances between the target and the measurement *** experimental errors involved in dosimetric measurement also contribute to such d

关键词： leakage radiation acceptance testing linear accelerator ion chamber ready packs film

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Molybdenum sputtering film characterization for high gradient accelerating structures

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Chinese Physics C 2013年第9期37卷 73-79页

作者： S.Bini B.Spataro A.Marcelli S.Sarti V.A.Dolgashev S.Tantawi A.D.Yeremian Y.Higashi M.G.Grimaldi L.Romano F.Rufno R.Parodi G.Cibin C.Marrelli M.Migliorati C.Caliendo INFN - LNF Via E. Fermi 40Frascati (RM) 00044 Italy NSRL University of Science and Technology of China Chinese Academy of Sciences University of Rome-Sapienza Dipartimento di FisicaPiazzale Aldo Moro 5Rome 00185Italy SLAC National accelerator Laboratory 2575 Sand Hill RoadMenlo ParkCA 94025USA KEK 1-1 Oho TsukubaIbaraki 305Japan University of Catania Dipartimento di Fisica e Astronomia & MATIS-IMM-CNRVia S. Sofia 64Catania 95123Italy INFN-Genova Via Dodecaneso 33Genova 16146Italy Diamond Light Source ChiltonDidcotOxford OX110DEUK University of Roma-Sapienza Dipartimento di Scienze di Base e Applicate per l’IngegneriaVia A. ScarpaRoma 14-00161-Italy Istituto dei Sistemi Complessi ISC-CNRArea della Ricerca di Roma 1Via Salaria km 29.300MonterotondoRome 00040Italy

Technological advancements are strongly required to fulfill the demands of new accelerator devices with the highest accelerating gradients and operation reliability for the future colliders. To this purpose an extensive R^zD regarding molybdenum coatings on copper is in progress. In this contribution we describe chemical composition, deposition quality and resistivity properties of different molybdenum coatings obtained via sputtering. The deposited films are thick metallic disorder layers with different resistivity values above and below the molibdenum dioxide reference value. Chemical and electrical properties of these sputtered coatings have been characterized by Rutherford backscattering, XANES and photoemission spectroscopy. We will also consider multiple cells standing wave section coated by a molybdenum layer designed to improve the performance of X-Band accelerating systems.

关键词： linear accelerator cavities X-band coatings XANES resistivity

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Preliminary study of a niobium quarter-wave prototype cavity for a heavy-ion superconducting linac

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Chinese Physics C 2010年第11期34卷 1757-1761页

作者：张聪赵红卫何源许哲张周礼孙列鹏梅立荣丛严 Institute of Modern Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Superconducting quarter-wave resonators,due to their compactness and their convenient shape for tuning and coupling,are very attractive for low-β beam *** this paper,two types of cavities with different geometry have been numerically simulated the first type with larger capacitive load in the beam line and the second type of lollipop-shape for 100 MHz,β=0.06 beams then the relative electromagnetic parameters and geometric sizes have been *** is found that the second type,whose structural design is optimized with the conical stem and shaping drift-tube,can support the better accelerating *** the end of the paper,some structural deformation effects on frequency shifts and appropriate solutions have been discussed.

关键词： quarter-wave resonator superconductivity numerical simulation electromagnetic field frequency shift linear accelerator

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