Reduction of the Bremsstrahlung component of clinical electron beams: implications for electron arc therapy and total skin electron irradiation

El‐Khatib, Ellen; Scrimger, John W.; Murray, Brian W.

doi:10.1088/0031-9155/36/1/010

Cited by 15 publications

(7 citation statements)

References 11 publications

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“…[90][91][92][93][94][95][96][97][98][99][100][101] Electron contamination cannot be generally scaled by any SSD except that it can be minimized with proper techniques adopted by the manufacturer. 102,103 The relative amount of electron contamination changes with the length of the air column ͑standard versus extended SSD͒ as head scattered electrons decrease with increased scattering in air. • Primary dose: It is well behaved and can be scaled for different SSDs just by applying the inverse square law, except for small field sizes close to what is required for lateral electron equilibrium.…”

Section: Iva1 Depth Dosementioning

confidence: 99%

Accelerator beam data commissioning equipment and procedures: Report of the TG‐106 of the Therapy Physics Committee of the AAPM

Das

Cheng

Watts³

et al. 2008

Medical Physics

422

424

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For commissioning a linear accelerator for clinical use, medical physicists are faced with many challenges including the need for precision, a variety of testing methods, data validation, the lack of standards, and time constraints. Since commissioning beam data are treated as a reference and ultimately used by treatment planning systems, it is vitally important that the collected data are of the highest quality to avoid dosimetric and patient treatment errors that may subsequently lead to a poor radiation outcome. Beam data commissioning should be performed with appropriate knowledge and proper tools and should be independent of the person collecting the data. To achieve this goal, Task Group 106 (TG-106) of the Therapy Physics Committee of the American Association of Physicists in Medicine was formed to review the practical aspects as well as the physics of linear accelerator commissioning. The report provides guidelines and recommendations on the proper selection of phantoms and detectors, setting up of a phantom for data acquisition (both scanning and no-scanning data), procedures for acquiring specific photon and electron beam parameters and methods to reduce measurement errors (<1%), beam data processing and detector size convolution for accurate profiles. The TG-106 also provides a brief.discussion on the emerging trend in Monte Carlo simulation techniques in photon and electron beam commissioning. The procedures described in this report should assist a qualified medical physicist in either measuring a complete set of beam data, or in verifying a subset of data before initial use or for periodic quality assurance measurements. By combining practical experience with theoretical discussion, this document sets a new standard for beam data commissioning.

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Section: Iva1 Depth Dosementioning

confidence: 99%

Accelerator beam data commissioning equipment and procedures: Report of the TG‐106 of the Therapy Physics Committee of the AAPM

Das

Cheng

Watts³

et al. 2008

Medical Physics

422

424

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“…[1][2][3][4][5][6][7][8][9][10] The bremsstrahlung tail in the electron beam contributes to the dose far beyond the electron practical range and therefore is a concern in TSET. 11 At low incident electron energy of 6 MeV, the bremsstrahlung dose is negligible (<1%) at standard source to surface distance (SSD) of 100 cm. At SSD = 300 cm, the results published in the AAPM Report #23 1 showed the bremsstrahlung dose for a dual field technique increased from about 0.5% at center to about 1% on the vertical distance of 100 cm from the center.…”

Section: Introductionmentioning

confidence: 99%

“…Low energy electron beams produced from linear accelerators are commonly used to treat the entire body with a relatively uniform dose to a shallow depth (∼3 mm) by avoiding dose to deep tissues 1–10 . The bremsstrahlung tail in the electron beam contributes to the dose far beyond the electron practical range and therefore is a concern in TSET 11 . At low incident electron energy of 6 MeV, the bremsstrahlung dose is negligible (<1%) at standard source to surface distance (SSD) of 100 cm.…”

Section: Introductionmentioning

confidence: 99%

Technical note: Bremsstrahlung dose in the electron beam at extended distances in total skin electron therapy

2022

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Electron beam from a linear accelerator is commonly used in total skin electron therapy (TSET) at extended distances. Since Das et al (Med Phys 21, p.1733, 1994 reported 5% bremsstrahlung dose for a 6 MeV electron beam at extended distance of 500 cm it has been accepted as common knowledge. However, measurements by Chen et al (Int J. Rad Onc Biol Phys 59 p.872, 2004) and Monte Carlo simulations by Ding et al (Phys. Med. Biol. 66, 075010, 2021) were unable to reproduce such high bremsstrahlung dose. As bremsstrahlung dose contributes to whole-body dose, which could produce bone marrow toxicity with serious complications for the outcome of the TSET, it is important to reevaluate the magnitude of bremsstrahlung dose accurately. Methods: The EGSnrc Monte Carlo system is used to investigate bremsstrahlung doses from 6 MeV high dose rate total skin electron (HDTSe) beams from Varian TrueBeam and Clinac Accelerators. The measurements were carried out at a depth of d max and 5 cm in Solid Water and Acrylic phantoms at extended distances using a parallel-plate chamber and a cylindrical ion chamber. Results: We were able to reproduce previously reported high bremsstrahlung dose at extended distances by using a parallel plate ionization chamber. However, both the measurements made by using a cylindrical chamber and Monte Carlo simulations showed an insignificant bremsstrahlung dose (∼1%) even at SSD = 500 cm. Conclusion:The bremsstrahlung doses of a 6 MeV electron beam are 0.5% to 1% for SSD from 100 to 700 cm, although it increases with the increasing extended distance. The common belief of up to 5% bremsstrahlung dose at large extended distances is incorrect. Previously reported high bremsstrahlung doses might be due to poor signal-to-noise ratio of using a parallel plate chamber for measuring very low dose or particular setup. K E Y W O R D Sbremsstrahlung dose, cylindrical ion chamber, Monte Carlo simulation, parallel plate ion chamber, total skin electron therapy

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“…Dose enhancement by nanoparticles in combination with brachytherapy sources, or external beams from medical linacs, has been the subject of various studies [2][3][4][5][6]. Zhang et al [4] have evaluated dose enhancement by gold nanoparticles.…”

mentioning

confidence: 99%

A Monte Carlo study on dose enhancement and photon contamination production by various nanoparticles in electron mode of a medical linac

Toossi

Ghorbani

Sabet³

et al. 2015

Nukleonika

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The aim of this study is the evaluation of electron dose enhancement and photon contamination production by various nanoparticles in the electron mode of a medical linac. MCNPX Monte Carlo code was used for simulation of Siemens Primus linac as well as a phantom and a tumor loaded with nanoparticles. Electron dose enhancement by Au, Ag, I and Fe2O3 nanoparticles of 7, 18 and 30 mg/ml concentrations for 8, 12 and 14 MeV electrons was calculated. The increase in photon contamination due to the presence of the nanoparticles was evaluated as well. The above effects were evaluated for 500 keV and 10 keV energy cut-offs defined for electrons and photons. For 500 keV energy cut-off, there was no significant electron dose enhancement. However, for 10 keV energy cut-off, a maximum electron dose enhancement factor of 1.08 was observed for 30 mg/ml of gold nanoparticles with 8 MeV electrons. An increase in photon contamination due to nanoparticles was also observed which existed mainly inside the tumor. A maximum photon dose increase factor of 1.07 was observed inside the tumor with Au nanoparticles. Nanoparticles can be used for the enhancement of electron dose in the electron mode of a linac. Lower energy electron beams, and nanoparticles with higher atomic number, can be of greater benefit in this field. Photons originating from nanoparticles will increase the photon dose inside the tumor, and will be an additional advantage of the use of nanoparticles in radiotherapy with electron beams.

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Reduction of the Bremsstrahlung component of clinical electron beams: implications for electron arc therapy and total skin electron irradiation

Cited by 15 publications

References 11 publications

Accelerator beam data commissioning equipment and procedures: Report of the TG‐106 of the Therapy Physics Committee of the AAPM

Accelerator beam data commissioning equipment and procedures: Report of the TG‐106 of the Therapy Physics Committee of the AAPM

Technical note: Bremsstrahlung dose in the electron beam at extended distances in total skin electron therapy

A Monte Carlo study on dose enhancement and photon contamination production by various nanoparticles in electron mode of a medical linac

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