J.R. Terrall, J.C. Slater. / "May 31, 1948." / Bibliography: p. 4. / Army Signal Corps Contract No. W-36-039 sc-100 Project No. 8-102B-0. Dept. of the Army Project No. 3-99-10-022.

The BEAMnrc and DOSXYZnrc codes from EGSnrc Monte Carlo (MC) system are considered to be the gold standards for simulating radiotherapy linear accelerators and resulting dose depositions (Rogers, Faddegon et al. 1995). The aim of this project was to setup the EGSnrc system for the simulation of the linear accelerator (linac) head and a Scanning Liquid Ionisation Chamber (SLIC) Electronic Portal Imaging Device (EPID) for calculations of transmitted dose in the EPID. The project was divided into two parts. The head of a 6 MV Varian 600C/D photon linac was first simulated by BEAMnrc. The modelling parameters such as the electron beam energy and the Full Width at Half Maximum (FWHM) of the electron spatial distribution were adjusted until the absorbed dose profiles and the Percentage Depth Dose (PDD) curves, in general agreed better than the measured profiles and PDDs by 2%. The X-ray beam obtained from the modelled linac head was used for the simulation of the transmitted dose in the EPID in the second part of the project. The EPID was simulated by DOSXYZnrc based on the information obtained from Spezi and Lewis 2002 (Spezi and Lewis 2002), who also modelled the Varian SLIC EPID (MK2 Portal Vision system, Varian Inc., Palo Alto, CA, USA). The comparisons between the measured and the simulated transmitted doses were carried out for three different phantom setups consisting of an open field, homogeneous water equivalent phantom and a humanoid phantom (RANDO). These phantom setups were designed so that the accuracy of the MC method for simulating absorbed dose in air, homogeneous and inhomogeneous phantoms could be assessed. In addition, the simulated transmitted dose in an EPID was also compared with values obtained from the Pinnacle treatment planning system (v6.2b, Phillips Medical Systems). In the process of selecting the electron beam energy and FWHM, it was confirmed (Sheikh-Bagheri and Rogers 2002; Keall, Siebers et al. 2003) that the variation of the electron beam FWHM and energy influenced the beam profiles strongly. The PDD was influenced by the electron beam energy less strongly. The increase in the energy led to the increase in the depth of maximum dose. However, the effect could not be observed until the energy change of 0.2 MeV was made. Based on the analysis of the results, it was found that the combination of FWHM and energy of 1.3 mm and 5.7 MeV provided the best match between the measured and MC simulated beam profiles and PDDs. It can be concluded that an accuracy of 1.5% can be achieved in the simulation of the linac head using Monte Carlo method. In the comparison between the Monte Carlo and the measured transmitted dose maps, agreements of 2% were found for both the open field and homogeneous water equivalent phantom setups. The same agreements were also found for the comparison between Monte Carlo and Pinnacle transmitted dose maps for these setups. In the setup where the humanoid phantom RANDO was introduced in between the radiation field and the EPID, a general agreement of about 5% found for the comparison between Monte Carlo and measured transmitted dose maps. Pinnacle and measured transmitted dose map was also compared for this setup and the same agreement was found. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352973 / Thesis (M.Sc.) - University of Adelaide, School of Chemistry and Physics, 2009

Thesis (Ph.D.)--Michigan State University. Dept. of Physics and Astronomy, 2007. / Title from PDF t.p. (viewed on August 18, 2009) Includes bibliographic references (p. 175-179). Also issued in print.

A utilização da técnica de teleterapia para tratamento de câncer tem sido usada por anos com bons resultados clínicos. Em meados da década de 90, a remoção do filtro aplainador, item que compõe o cabeçote de um acelerador linear de uso clínico, tem sido objeto de estudos por demonstrar bons resultados no tratamento de alguns tipos de câncer. Técnicas utilizadas como Radioterapia de Intensidade Modulada (IMRT) e Radioterapia Estereotáxica (SRT), mostram-se mais eficazes quando não se utiliza o filtro aplainador. A empresa Varian Oncology lançou em 2012 um acelerador linear de uso clínico capaz de operar com o filtro aplainador (FF) e sem o filtro aplainador (FFF), o TrueBeam. Os objetivos desse trabalho são avaliar a homogeneidade de dois importantes parâmetros utilizados para o cálculo de dose nos pacientes submetidos ao tratamento com esse modelo de acelerador linear, a porcentagem de dose profunda (PDP) e índice de qualidade do feixe (TPR20/10). Os dados fornecidos para a análise foram cedidos pelo Hospital Israelita Albert Einstein (HIAE), Real Hospital Português (RHP) e 3 instituições norte-americanas. Através de uma análise estatística dos dados das instituições citadas pode-se observar melhor o comportamento desses parâmetro que demonstraram-se muito homogêneos e com erros menores que 1% na maioria dos casos, confirmando desse modo que os aceleradores lineares do modelo TrueBeam mantém na maioria das vezes uma boa concordância dos parâmetros analisados. / Teletherapy, radiation therapy with linear accelerators, for cancer treatment has being used for years with good clinical results.Since the 90\'s the removal of the flattening filter, item placed at the gantry of the machine, has shown better results for the treatment of some cancers thus being extensively studied. Treatments with Intensity Modulated RadioTherapy (IMRT) and Sthereotaxic RadioTherapy (SRT) were more efficient without the flattening filter. Varian Oncology released the TrueBeam in 2012, a accelerator capable of operating with or without the flattening filter. The aim of this work is to access homogeneity of the percentage depth dose (PDP) and beam quality index (TPR20/10), two important parameters used in patient dose calculations. The data used for analysis were obtained with the Israelita Albert Einstein Hospital (HIAE), Real Português Hospital (RHP) and 3 more institutions located in the United States. The statistical data analysis allowed to observe the parameters behaviors. In general, they were very homogeneous, with errors smaller than 1% confirming the conformance of the TrueBeam accelerators.

One of the most promising devices to provide accurate measurement of the longitudinal bunch profile at the tens of femtosecond level is based on electro-optic techniques. In this thesis, a bunch profile monitor, based on electro-optic spectral decoding (EOSD), is currently developed for the CLIC Test Facility 3 at CERN. The monitor is optimised for bunch lengths over 3.5 ps with effective window of 16 ps, and sub-picosecond resolution. The measurement results from the EO monitor are compared with measurements by coherent transition radiation on a streak camera. The measurement on bunch charge dependence is studied. Timing resolution of the bunch profile monitor is studied in both theory and numerical calculation. This thesis summarises a frequency analysis approach of electro-optic effect based on $\chi^{(2)}$ frequency mixing process. From the theory analysed in frequency domain, a non-crossed polarization measurement includes all three of the probe laser background term, the linear term to Coulomb field and the quadratic term to Coulomb field. Three methods are induced based on this frequency analysis result to retrieve Coulomb field value which is emitted from electron beam. The measured 1.3 MV/m field strength agrees with calculation result. An experiment is designed to study the role of incident beam sizes and non-collinear incident beams in EO technique. Due to the phase matching process, the non-collinear angle of the incident beams induces a frequency dependent angular chirp in the beams emitted after the EO crystal. This frequency offset may lead to frequency loss in fibre coupling, and thus lead to bunch length broadening in a measurement for short electron bunch.

The focus of this thesis is to improve upon the existing neutron cross section data for rhenium (Re) in the energy range 0.01 eV to 1 keV. Neutron transmission and capture yield measurements were performed using natural rhenium samples at the Rensselaer Polytechnic Institute Gaerttner Linear Accelerator Center. Measurements were performed using the time of flight method, in which neutron energies are differentiated using the elapsed times between neutron emission from a pulsed neutron source and the subsequent detector interactions. Transmission measurements were performed using ⁶Li glass scintillation detectors. Capture measurements were performed utilizing a 16-segment NaI(Tl) multiplicity detector. Most measurements were performed at a flight path length of 25 meters, with one set of experiments (thermal transmission) performed at 15 meters. The experiments used several metallic, elemental rhenium samples of various thicknesses, ranging from 1 mil to 100 mils. (1 mil = 0.001 inch = 0.0254 mm) Following the reduction of the experimental data, SAMMY was used to perform the data analysis. SAMMY is a shape-fitting Bayesian analysis code that determines resonance parameters by fitting neutron time of flight data using the Reich-Moore approximation of R-matrix theory. The combined transmission and capture yield data analysis determined resonance parameters for rhenium resonances in the energy range of 0.01 eV to 1 keV. The updated rhenium resonance parameters are compared to previously published parameters and ENDF/B-VII.1. / text

Thesis (M.A.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 116-123). Also available on the World Wide Web.

A utilização da técnica de teleterapia para tratamento de câncer tem sido usada por anos com bons resultados clínicos. Em meados da década de 90, a remoção do filtro aplainador, item que compõe o cabeçote de um acelerador linear de uso clínico, tem sido objeto de estudos por demonstrar bons resultados no tratamento de alguns tipos de câncer. Técnicas utilizadas como Radioterapia de Intensidade Modulada (IMRT) e Radioterapia Estereotáxica (SRT), mostram-se mais eficazes quando não se utiliza o filtro aplainador. A empresa Varian Oncology lançou em 2012 um acelerador linear de uso clínico capaz de operar com o filtro aplainador (FF) e sem o filtro aplainador (FFF), o TrueBeam. Os objetivos desse trabalho são avaliar a homogeneidade de dois importantes parâmetros utilizados para o cálculo de dose nos pacientes submetidos ao tratamento com esse modelo de acelerador linear, a porcentagem de dose profunda (PDP) e índice de qualidade do feixe (TPR20/10). Os dados fornecidos para a análise foram cedidos pelo Hospital Israelita Albert Einstein (HIAE), Real Hospital Português (RHP) e 3 instituições norte-americanas. Através de uma análise estatística dos dados das instituições citadas pode-se observar melhor o comportamento desses parâmetro que demonstraram-se muito homogêneos e com erros menores que 1% na maioria dos casos, confirmando desse modo que os aceleradores lineares do modelo TrueBeam mantém na maioria das vezes uma boa concordância dos parâmetros analisados. / Teletherapy, radiation therapy with linear accelerators, for cancer treatment has being used for years with good clinical results.Since the 90\'s the removal of the flattening filter, item placed at the gantry of the machine, has shown better results for the treatment of some cancers thus being extensively studied. Treatments with Intensity Modulated RadioTherapy (IMRT) and Sthereotaxic RadioTherapy (SRT) were more efficient without the flattening filter. Varian Oncology released the TrueBeam in 2012, a accelerator capable of operating with or without the flattening filter. The aim of this work is to access homogeneity of the percentage depth dose (PDP) and beam quality index (TPR20/10), two important parameters used in patient dose calculations. The data used for analysis were obtained with the Israelita Albert Einstein Hospital (HIAE), Real Português Hospital (RHP) and 3 more institutions located in the United States. The statistical data analysis allowed to observe the parameters behaviors. In general, they were very homogeneous, with errors smaller than 1% confirming the conformance of the TrueBeam accelerators.

The aim of this diploma thesis is the design of linear accelerator for oncology treatment. The design focuses on the improvement of the aesthethical side of the accelator, but also comes up with inventional solutions how to improve the radiation treatment of oncology patients to higher the chances of successful treatment of cancer.

There is a present and future need for the medical isotope Actinium-225, currently in short supply worldwide.  Only a couple manufacturers produce it in very low quantities.  In roughly the past 10 years the medical community has explored the use of Ac-225 and its daughter Bismuth-213 for targeting a number of differing cancers by way of Targeted Alpha Therapy (TAT). This method utilizes the alpha-decay of both Ac-225 (half-life 10 days) and Bi-213 (half-life 46 min) to kill cancerous cells on a localized basis.  Maximum energy is delivered to the cancer cells thereby greatly minimizing healthy tissue damage. This research proposes a production method using a high-energy photon spectrum (generated by a linear accelerator or LINAC) to irradiate a sample of Radium-226 (half-life 1600yrs).  The photo-neutron reaction liberates neutrons from Ra-226 atoms leaving behind Radium-225 (half-life 14.7 days).  Ra-225 decays naturally through beta emission to Ac-225.  Previous research demonstrated it is possible to produce Ac-225 using a LINAC; however, very low yields resulted which questioned the feasibility of this production method.  This research proposes a number of LINAC and radium sample modifications that could be greatly increase yield amounts for practical use. Additionally, photo-neutron cross-section data for Ra-226 was used, which led to improved yield calculations for Ra-225.  A MATLAB® model was also created, which enables users to perform quick yield estimates given several key model parameter inputs.  Obtaining a sufficient supply of radium material is also of critical importance to this research.  Therefore information was gathered regarding availability and inventory of Radium-226.  This production method would serve as a way to not only eliminate many hazardous radium sources destined for interim storage, but provide a substantial supply of Ac-225 for future cancer treatment. / Master of Science