Validation of Monte Carlo simulation of 6 MV photon beam produced by Varian Clinac 2100 linear accelerator using BEAMnrc code and DOSXYZnrc code

Bencheikh, Mohamed; Maghnouj, Abdelmajid; Tajmouati, Jaouad; Didi, Abdessamad; Ezzati, Ahad Ollah

doi:10.1134/s154747711705003x

Cited by 17 publications

(13 citation statements)

References 41 publications

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“…1540 [19,20]. The Monte Carlo simulation validation of Varian Clinac 2100 is a subject of one of our previous scientific publications [21]. It is more accurate by approximately 99 % for PDD and dose profile in comparison with previous studies [22].…”

Section: Resultsmentioning

confidence: 99%

Monte Carlo-based analysis of the photon beam fluence with air gap thickness between Linac head exit window and patient’s skin in radiotherapy treatments

Bencheikh¹,

Maghnouj²,

Tajmouati³

2020

Nucl. Phys. At. Energy

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Linear accelerators (Linac) are used in radiation therapy treatment and its technology improvement ensures high dosimetry quality that should be conserved for high radiotherapy efficiency. However, does the air gap between the exit window of Linac head and patient’s skin alters the physical properties of the photon beam? The objective of this study is to assess the physical properties changes of photon beam fluence according to air gap thickness under the Linac head. The air gap under the Linac head is the last material in the photon beam path; it induces alterations in the beam quality before reaching the patient’s skin. The Varian Clinac 2100 head and the air gap up to the phantom surface are modelled using Monte Carlo BEAMnrc code; the nominal beam energy is 6 MV. The BEAMDP code is used to extract the photon fluence. The photon beam fluence is affected by the air gap under Linac head and decreases by six times due to the photon beam attenuation with air gap thickness; in addition to increasing of beam contamination by scattered photons and electrons. Thus, the air gap induces the beam quality deterioration which is evaluated in terms of photon fluence with air gap thickness. To remove the particles contaminations and conserve integrally the photon beam quality, the number of the photon interactions with air atoms should be as low as possible under Linac head up to patient’s skin and ensure a higher quality of the radiotherapy treatment of deep tumour.

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Section: Resultsmentioning

confidence: 99%

Monte Carlo-based analysis of the photon beam fluence with air gap thickness between Linac head exit window and patient’s skin in radiotherapy treatments

Bencheikh¹,

Maghnouj²,

Tajmouati³

2020

Nucl. Phys. At. Energy

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“…The Monte Carlo simulation of Linac head was validated by using the gamma index method with criteria of 3 % for dose deviation (DD) and 3 mm for distance to agreement (DTA). The simulation validation is ensured by the gamma index acceptance rate of 99 % for percentage depth dose (PDD) and of 98 % for beam dose profiles [6].…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

“…The Monte Carlo geometry was built for Varian Clinac 2100 by BEAMnrc code [5]. The Linac head was modeled as realistically as possible and the simulation validation was done in our previous study [6]. The photon beam energy was 6 MV, the field size was 10 × 10 cm 2 and the source-to-surface distance (SSD) was 100 cm.…”

Section: Introductionmentioning

confidence: 99%

Analysis and evaluation of secondary photons originated in jaws as contamination particles at the phantom surface

Bencheikh¹,

Maghnouj²,

Tajmouati³

2020

Nucl. Phys. At. Energy

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The present work is focused on the study of the geometry and material of a beam modifier (jaws), which is crucial for Linac improvement by reducing secondary photons emergent from it. They have negative effects when the cancer was treated and especially in the deep tumor because their energy is deposited in shallower depth and could destroy the healthy cells that surround the treatment volume. The purpose of this study is to investigate and evaluate the characterizations of secondary photons originated in jaws in terms of fluence profile, energy fluence profile, energy fluence distribution, spectral distribution, and angular spread distribution. This work was performed by using the BEAMnrc Monte Carlo and BEAMDP codes. The jaws are a potential source of secondary photons nearest to the phantom. The number of secondary photons emergent from X-jaw (in-plan jaw) is higher and they are more energetic in comparison to secondary photons of Y-jaw (cross-plan jaw). Therefore, the most significant result is on the angular spread distribution of secondary photons for each pair jaw. For Y-jaw, the majority of photons are scattered and spread with high angle degree that means these photons can fall out of the irradiation field and affect the healthy cells but for the X-jaw, most of the secondary photons are within the irradiation field and they can affect healthy cells mainly only at the entrance of treatment volume.

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“…Varian Clinac 2100 Monte Carlo simulation validation was performed using gamma index method as a technique for quantitative evaluation of comparison of calculated dose distributions to measured dose distributions [15]. The Monte Carlo simulation validation is done in our previous work using gamma index criteria of 3%/3mm and the acceptance rate was approximately 99% for percentage depth dose (PDD), and approximately 98% for beam dose profiles [11]. Thus, Varian Clinac 2100 Monte Carlo geometry was validated according to tolerance limit recommended by IAEA in TRS430 [16] and in IAEA-TECDOC-1583 [17].…”

Section: Monte Carlo Simulation Validationmentioning

confidence: 99%

“…Monte Carlo simulation is a technique that provides both accurate and detailed energetic and dosimetric calculation of a medical linear accelerator head. It has been used extensively in the medical physics for modeling this device and radiation transport [10,11]. In this work, the Monte Carlo geometry is built for 6 MV photon beam produced by Varian Clinac 2100 using BEAMnrc code [12].…”

Section: Introductionmentioning

confidence: 99%

Study of the volume reduction impact on secondary photons emergent from flattening filter for high radiotherapy quality

Bencheikh

Maghnouj

Tajmouati

et al. 2019

Polish Journal of Medical Physics and Engineering

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This study aims to investigate and evaluate the secondary photons characterizations under flattening filter (FF) for high radiotherapy quality in terms of fluence, energy fluence, energy fluence distribution, spectral distribution and angular spread distribution of secondary photons, which are mainly coming from primary collimator originated in the whole Linac head. However, the flattening filter illuminates the photons of low energy. After this component, the secondary photons of low energy are coming from flattening filter and secondary collimators that contaminate the dosimetry for deep tumor treatment. Fluence profile, energy profile and angular spread of secondary photons decreased with FF volume reduction percent but energy distribution and spectral distribution kept almost constant with FF volume reduction. The FF volume reduction allows reducing the secondary photons emergent from FF in number and in energy and it permits to increase the radiotherapy efficiency by decreasing the photons contamination when the cancer is treating.

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Validation of Monte Carlo simulation of 6 MV photon beam produced by Varian Clinac 2100 linear accelerator using BEAMnrc code and DOSXYZnrc code

Cited by 17 publications

References 41 publications

Monte Carlo-based analysis of the photon beam fluence with air gap thickness between Linac head exit window and patient’s skin in radiotherapy treatments

Monte Carlo-based analysis of the photon beam fluence with air gap thickness between Linac head exit window and patient’s skin in radiotherapy treatments

Analysis and evaluation of secondary photons originated in jaws as contamination particles at the phantom surface

Study of the volume reduction impact on secondary photons emergent from flattening filter for high radiotherapy quality

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