The physical characteristics of the 15MV Varian Clinac 2100C unflattened beam

Najem, M.A.; Spyrou, N. M.; Podolyák, Zs.; Abolaban, Fouad A.

doi:10.1016/j.radphyschem.2013.04.035

Cited by 10 publications

(3 citation statements)

References 18 publications

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“…1a, where the main details relevant to the electron beam transport simulation as implemented in the Monte Carlo MCNPX geometry of the LINAC are described. The geometry aims at approximately describe the Varian Truebeam Stx© starting from the Varian Clinac©2100 model description freely obtained from the scientific literature (Najem et al, 2014;Ovalle, 2013;Nedaje et al, 2015;Bezoubiri et al, 2014). The presence of a lead cake has also been considered on the basis of functional needs.…”

Section: The Bunker Geometry the Treatment Room And The Measurement S...mentioning

confidence: 99%

A Monte Carlo model for photoneutron generation by a medical LINAC

Sumini

Isolan

Cucchi

et al. 2017

Radiation Physics and Chemistry

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Section: The Bunker Geometry the Treatment Room And The Measurement S...mentioning

confidence: 99%

A Monte Carlo model for photoneutron generation by a medical LINAC

Sumini

Isolan

Cucchi

et al. 2017

Radiation Physics and Chemistry

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“…Several studies have reported the concept of freeflattening filter (FFF) beams at various energies [6,7]. The removal of the FF has been reported to decrease head scatter and increase the dose rate [8,9], as well as reduce electron and neutron contamination [10,11], penumbra, and out-of-field doses [6,12]. The presence of contaminant particles in the FF beam stems from the interaction of bremsstrahlung photons from the x-ray target with electrons and nuclei of the copper, resulting in particle contamination (electrons and neutrons) beyond the FF [10,11].…”

Section: Introductionmentioning

confidence: 99%

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Hashemizadeh,

Zabihzadeh,

Shahbazian

et al. 2024

Biomed. Phys. Eng. Express

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Dosimetric characteristics of the flattening filter (FF) and flattening filter free (FFF) modes of 18 MV therapeutic photon beam were investigated with and without the magnetic deflector (MD) and lead filter. MCNP version 6.1.0 Monte Carlo (MC) code was used to simulate the 18 MV photon beam of 2100 C/D-Varian linear accelerator (LINAC) for the FF and FFF modes. The MD (uniform magnetic flux density of 1 Tesla) and lead filter (thickness of 1 mm) were modeled to remove contaminant electrons. The dosimetric parameters for different scenarios of LINAC’s head were calculated. Removing the flattening filter in the FFF mode increased the dose rate, electron contamination, skin dose, out-of-field dose and un-flatness compared to the FF mode. While the lead filter decreased the contaminant electrons significantly, using the MD removed all secondary electrons from the beam line. The surface dose was decreased by 8.3 % and 11.2 % for the magnetic deflector (MD) and lead filter in the FF mode, respectively. The surface dose was decreased by 16.8 % and 20.3 % for the MD and lead filter scenarios in the FFF mode, respectively. The MD and lead filter decreased surface penumbra by 15.5 % and 11.5 % compared to the FFF mode. Removing the flattening filter from the LINAC’s head improves most of the dosimetric characteristics of the 18MV therapeutic beam. The use of a lead filter and magnetic deflector preserves the skin-sparing property of megavoltage beams that deteriorate in FFF mode. However, using a magnetic deflector does not reduce photon fluence and dose rate.

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“…Several studies related to flattening filter free (FFF) have been conducted at different energies [10,11]. They reported that removing the FF increased the dose rate and reduce the head scatter [12][13][14], electrons and neutrons contamination [15,16], out-of-field and penumbra doses [11,17,18]. The increase in particle contaminants in the FFF beam is caused by the bremsstrahlung photon from the X-ray target interacting with the electrons and nucleus of Cu and producing particle contamination (electron and neutron) after the FF [15,16].…”

Section: Introduction mentioning

confidence: 99%

Investigation of Electron Contamination on Flattened and Unflattened Varian Clinac iX 6X and 15X Photon Beam Based on Monte Carlo Simulation

et al. 2022

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The aim of this study was to characterize electron contamination of a flattened (FF) and an unflattened (FFF) Varian Clinac iX 6X and 15X photon beams using Monte Carlo (MC) simulation. EGSnrc MC technique was used to model the flattened and unflattened head and simulate dose distribution of 6X and 15X of FF and FFF photon beam in water phantom. The materials and geometrical data of FF linac were provided by Tan Tock Seng Hospital (TTSH) Singapore. The FFF linac was modeled by removing the flattening filter component in the FF linac. Phase space files were scored after flattening filter and in the phantom surface. The phsp files were analyzed to characterize the particles produced by the linac head using BEAMDP. The contaminants contribute around 1 % and 2 % in the phsp1 for flattened and unflattened beams, respectively. The photons are scattered in smallangle in the range of 0 -4 o . The contaminant electron contributes up to one hundredth compared to the photons. The increase of field area affects the increase in contaminants and penumbra width due to the increasing number of particle scattered out of the field area. The unflattened beam affects the increase in the number of electron contamination and surface dose. The penumbra width of the flattened beams was smaller than the unflattened beams for the same field size and energy.

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The physical characteristics of the 15MV Varian Clinac 2100C unflattened beam

Cited by 10 publications

References 18 publications

A Monte Carlo model for photoneutron generation by a medical LINAC

A Monte Carlo model for photoneutron generation by a medical LINAC

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Investigation of Electron Contamination on Flattened and Unflattened Varian Clinac iX 6X and 15X Photon Beam Based on Monte Carlo Simulation

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