Monte carlo model and output factors of elekta infinity™ 6 and 10 MV photon beam

Yani, Sitti; Budiansah, Indra; Rhani, Mohamad Fahdillah; Haryanto, Freddy

doi:10.1016/j.rpor.2020.03.021

Cited by 11 publications

(6 citation statements)

References 36 publications

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“…Both energy levels show the difference between local dose of PDDs to be less than 2%. The output factors measured with different detectors are in good agreement with simulation within less than 2% for field sizes (40).…”

Section: Discussionsupporting

confidence: 64%

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Can

Şahi̇ner

Karaçetin³

et al. 2022

Preprint

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The aim of this study is to develop in-house Monte Carlo (MC) algorithm as an alternative tool to simulate all mechanisms of interactions for dose calculation in radiation therapy. Additionally, evaluating the MC-SCAN algorithm with beam modeling of Elekta VersaHD Linac was aimed. Mohan 6 MV photon spectrum was used and the source was modeled as a point source. The absorbed dose is calculated via modeling all interaction mechanisms to gain energy deposition. TPR20/10, PDD, photon profile of different field sizes as well as point dose was calculated after that, a comparison of all the achieved results with experimental measurements went through. The difference between calculated mean energy and theoretical one was obtained < 1%. The calculated TPR20/10 value was (0.685 ± 0.03). The difference between experimental PDD and photon profile, and the calculated ones by new model was < 3% for all field sizes. A new MC algorithm can be used as an alternative tool to simulate virtual source model on an Elekta VersaHD Linac. All calculated values turned out to present the difference between experimental measurements to be < 3% for homogeneous mediums. Nonetheless, further research was needed to be done for the better improvement.

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Section: Discussionsupporting

confidence: 64%

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Can

Şahi̇ner

Karaçetin³

et al. 2022

Preprint

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“…That said, the correlation between out-of-field doses with distance, depth, and energy beam levels in our study was largely consistent with previous reports [ 9 , 21 , 27 , 31 ]. Crucially, higher beam energy leads to higher electron contamination [ 32 ]. Although out-of-field electron doses may appear to be less significant than those observed with photon beams, the deposition of radiation in sensitive volumes is evident and may cause unwanted damage to healthy tissues, just as occurs with photon beam energy.…”

Section: Discussionmentioning

confidence: 99%

Nontarget and Out-of-Field Doses from Electron Beam Radiotherapy

Matuszak

Kruszyna-Mochalska

Skrobała

et al. 2022

Life

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In clinical radiotherapy, the most important aspects are the dose distribution in the target volume and healthy organs, including out-of-field doses in the body. Compared to photon beam radiation, dose distribution in electron beam radiotherapy has received much less attention, mainly due to the limited range of electrons in tissues. However, given the growing use of electron intraoperative radiotherapy and FLASH, further study is needed. Therefore, in this study, we determined out-of-field doses from an electron beam in a phantom model using two dosimetric detectors (diode E and cylindrical Farmer-type ionizing chamber) for electron energies of 6 MeV, 9 MeV and 12 MeV. We found a clear decrease in out-of-field doses as the distance from the field edge and depth increased. The out-of-field doses measured with the diode E were lower than those measured with the Farmer-type ionization chamber at each depth and for each electron energy level. The out-of-field doses increased when higher energy megavoltage electron beams were used (except for 9 MeV). The out-of-field doses at shallow depths (1 or 2 cm) declined rapidly up to a distance of 3 cm from the field edge. This study provides valuable data on the deposition of radiation energy from electron beams outside the irradiation field.

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“…found that the calculated S cp in the EGSnrc MC simulation for field size 3 cm × 3 cm, 5 cm × 5 cm, and 10 cm × 10 cm was in the range between 0.86 and 1.00 and the percentage difference between the measured and calculated S cp were within 2%. [ 22 ] The S cp measurement and calculation were done at 10 cm water depth in this study to avoid the effect of electron contamination from the Elekta linac treatment head, and the results had proved a good agreement between the measured and calculated S cp . [ 22 23 ] Thus, the measured S cp using the IC avoided the issue of electron contamination when the IC was placed at 10 cm depth.…”

Section: R Esults and Discussionsmentioning

confidence: 99%

“…[ 22 ] The S cp measurement and calculation were done at 10 cm water depth in this study to avoid the effect of electron contamination from the Elekta linac treatment head, and the results had proved a good agreement between the measured and calculated S cp . [ 22 23 ] Thus, the measured S cp using the IC avoided the issue of electron contamination when the IC was placed at 10 cm depth. Apart from that, the MC simulation acted as an alternative method to calculate the S cp as it can overcome the issue of electron contamination during the simulation process.…”

Section: R Esults and Discussionsmentioning

confidence: 99%

Determination of the small-field output factor for 6 MV photon beam using EGSnrc Monte Carlo

2022

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Accuracy of ionization chamber (IC) to measure the scatter output factor (S cp ) of a linear accelerator (linac) is crucial, especially in small field (<4 cm × 4 cm). The common IC volume of 0.6 cc is not adequate for small-field measurement and not all radiotherapy centers can afford to purchase additional IC due to the additional cost. This study aimed to determine the efficiency of the EGSnrc Monte Carlo (MC) to calculate the S cp for various field sizes including small field in Elekta Synergy (Agility multileaf collimator) linac. The BEAMnrc and DOSXYZnrc user codes were used to simulate a 6 MV linac model for various field sizes and calculate the radiation dose output in water phantom. The modeled linac treatment head was validated by comparing the percentage depth dose (PDD), beam profile, and beam quality (Tissue Phantom Ratio (TPR) 20,10 ) with the IC measurement. The validated linac model was simulated to calculate the S cp consisting of collimator scatter factor (S c ) and phantom scatter factor (S p ). The PDD and beam profile of the simulated field sizes were within a good agreement of ±2% compared with the measured data. The TPR 20,10 value was 0.675 for field size 10 cm × 10 cm. The S cp , S c , and S p simulated values were close to the IC measurement within ±2% difference. The simulation for S c and S p in 3 cm × 3 cm field size was calculated to be 0.955 and 0.884, respectively. In conclusion, this study validated the efficiency of the MC simulation as a promising tool for the S cp calculation including small-field size for linac.

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Monte carlo model and output factors of elekta infinity™ 6 and 10 MV photon beam

Cited by 11 publications

References 36 publications

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Nontarget and Out-of-Field Doses from Electron Beam Radiotherapy

Determination of the small-field output factor for 6 MV photon beam using EGSnrc Monte Carlo

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Monte carlo model and output factors of elekta infinity™ 6 and 10 MV photon beam

Cited by 11 publications

References 36 publications

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Developing a New Monte Carlo Algorithm as an Alternative Tool to Simulate Virtual Source Model on an Elekta Versa Hd Linac

Nontarget and Out-of-Field Doses from Electron Beam Radiotherapy

Determination of the small-field output factor for 6 MV photon beam using EGSnrc Monte Carlo

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Monte carlo model and output factors of elekta infinity™ 6 and 10 MV photon beam