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The dependence of inhomogeneity correction factors on photon beam quality index performed with the Anisotropic Analytical Algorithm

Akhtaruzzaman Md, Kukołowicz Paweł

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 3

127--134

EN

The purpose of the study was to investigate the dependence of tissue inhomogeneity correction factors (ICFs) on the photon beam quality index (QI). Materials and Methods: Heterogeneous phantoms, comprising semi-infinite slabs of the lung (0.10, 0.20, 0.26 and 0.30 g/cm3), adipose tissue (0.92 g/cm3) and bone (1.85 g/cm3) in water, were constructed in the Eclipse treatment planning system. Several calculation models of 6 MV and 15 MV photon beams for quality index (TPR20,10) = 0.670±k*0.01 and TPR20,10 = 0.760±k*0.01, k = -3, -2, -1, 0, 1, 2, 3 respectively were built in the Eclipse. The ICFs were calculated with the anisotropic analytical algorithm (AAA) for several beam sizes and points lying at several depths inside of and below inhomogeneities of different thicknesses. Results: The ICFs increased for lung and adipose tissues with increasing beam quality (TPR20,10), while decreased for bone. Calculations with AAA predict that the maximum difference in ICFs of 1.0% and 2.5% for adipose and bone tissues, respectively. For lung tissue, changes of ICFs of a maximum of 9.2% (6 MV) and 13.8% (15 MV). For points where charged particle equilibrium exists, a linear dependence of ICFs on TPR20,10 was observed. If CPE doesn’t exist, the dependence became more complex. For points inside of the low-density inhomogeneity, the dependence of the ICFs on energy was not linear but the changes of ICFs were smaller than 3.0%. Measurements results carried out with the CIRS phantom were consistent with the calculation results. Conclusions: A negligible dependence of the ICFs on energy was found for adipose and bone tissue. For lung tissue, in the CPE region, the dependence of ICFs on different beam quality indexes with the same nominal energy may not be neglected, however, this dependence was linear. Where there is no CPE, the dependence of the ICFs on energy was more complicated.

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Monte Carlo simulation approaches to dose distributions for 6 MV photon beams in clinical linear accelerator

Tartar A.

Biocybernetics and Biomedical Engineering

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2014

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Vol. 34, no. 2

90--100

EN

Monte Carlo method is often used in radiation therapy as utilized in all the branches of science. For this purpose, various preset codes are used for the dose calculations in radiotherapy. In this study, a new Monte Carlo Simulation Program (MCSP) was developed for the dose distributions of a clinical linear accelerator (LINAC) in water phantom. MCSP was carried out by taking into account the interactions of photons with matter in MATLAB (The Mathworks, Inc.). In the study, 6 MeV (6 MV photon mode) energies of photons are examined. In order to validate the performance and accuracy of the simulation, the experimental measurements and MCSP calculations were compared for both percentage depth dose curves and beam profiles. The Monte Carlo results show good agreement with experimental results.

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Free Electron Laser in Poland

Romaniuk R. S.

Electronics and Telecommunications Quarterly

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2009

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Vol. 55, No 4

669-682

EN

The idea of building a new IVth generation of light sources of high luminosity, which use accelerators, arose in the 80ties of XXth century. Now, in a numerable synchrotron and laser laboratories in Europe, an intense applied research on free electron lasers has been carried out for a couple of years (FEL) [17,18]. Similarly, in this country, free electron laser in Poland - POLFEL [9] is in a design, a coherent light source of the IVth generation, characterized by very short pulses in the range of 10-100fs, of big power 0,2GW and UV wavelength of 27nm, of average power 1W, with effective high power third harmonic of 9nm. The laser consists of a linear superconducting accelerator 100m in length, undulator and experimental lines. It generates a monochromatic and coherent radiation and can be tuned from THz range via IR, visible to UV, and potentially to X-rays. The linac works in quasi-CW or real-CW mode. It is planned by IPJ [9,10] and XFEL-Poland Consortium [16] as a part of the ESFRI [1] priority Euro FEL infrastructure collaboration network [6], part of the European Research Area - ERA [2]. The paper discusses: FEL background in Poland as a part of EuroFEL infrastructure, FEL parameters and performance, FEL research and technical program and FEL networking in Europe and worldwide. Emphasis is put on the usage of superconducting RF TESLA technology and ties linking Polfel and the European X-Ray Free Electron Laser. The Polfel team of researchers is now dissipated worldwide among such projects as Flash and E-xfel in Desy, Cebaf in JLab, Alba in Barcelona, Elettra in Trieste, ILC in Fermilb, LCLS in SLAC. Polfel creates an unique, but quite transient chance to gather and solidly accumulate for a long time this expertise in this country again.

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A comparison of the basic photon and electron dosimetry data for Neptun 10PC linear accelerators

Shokrani P., Monadi S.

Nukleonika

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2008

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Vol. 53, No. 4

181-185

EN

. In recent years the similarity of dosimetric characteristics of modern linear accelerators with the same make, model and nominal energy, has become more common. The goal of this study was to quantitatively investigate the reproducibility of the basic photon and electron dosimetry data from Neptun 10PC accelerators across the institutions. In the current study, the photon and electron dosimetry data collected during acceptance and initial commissioning of six Neptun 10PC linear accelerators are analyzed. The dates of original installations of these six machines were evenly spread out over a 5 year period and the series of measurements were conducted during an average of 1-2 months after original installations. All units had identical energies and beam modifiers. For photon beams, the collected data include depth dose data, output factors and beam profile data in water. For electron beams, in addition to depth dose data and output factors, the effective source skin distance for 10 × 10 cm field size is also presented. For most beam parameters the variation (one standard deviation), was less than 1.0% (less than 2% for 2 parameters). A variation of this magnitude is expected to be observed during annual calibration of well-maintained accelerators. In conclusion, this study is presenting a consistent set of data for Neptun 10PC linear accelerators. This consistency implies that for this model, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes.

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A radiographic facility at the Soltan Institute for Nuclear Studies (SINS) at Świerk, Poland

Bigolas J., Drabik W., Pławski E., Wysocka-Rabin A.

Nukleonika

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2006

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Vol. 51, nr 2

131-135

EN

This paper describes the 6 MeV linac electron accelerator facility now operating at SINS, Świerk, Poland. The accelerator can work in both the electron or X-ray photon mode. The photon beam may be used for non-destructive radiographic investigations on a laboratory scale and, with some modifications, for industrial purposes, as well. As the accelerator's removable tungsten e/X converter is placed outside, the beam vacuum window, an external electron beam is also accessible. The design stages of the accelerator's construction are described, and examples of measurements and radiographic pictures are also presented.

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The photon beam characteristics of linear accelerator equipped with additional narrow beam collimator

Wysocka A., Maciszewski W.

Nukleonika

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2001

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Vol. 46, nr 3

91-93

EN

In this paper a laboratory set-up with an electron linac installed in this Institute, and an attached narrow-beam collimator for photon beam are presented. Characteristics of the circular photon beams of diameters ranging from 10 to 30 mm at the isocentre are reported. The specific quantities measured include: relative output factors, beam profiles (off axis factors), and a central axis attenuation of beams. Measurements of these parameters were performed in a water phantom using small cylindrical ionisation chambers.