Dosimetric evaluation of a novel electron–photon mixed beam, produced by a medical linear accelerator

AbstractAimThis study deals with the characteristics of simultaneous photon and electron beams in homogenous and inhomogeneous phantoms by experimental and Monte Carlo dosimetry, for therapeutic purposes. Materials and methods: Both 16 and 20 MeV high-energy electron beams were used as the original beam to strike perforated lead sheets to produce the mixed beam. The dosimetry results were achieved by measurement in an ion chamber in a water phantom and film dosimetry in a Perspex nasal phantom, and then compared with those calculated through a simulation approach. To evaluate two-dimensional dose distribution in the inhomogeneous medium, the dose–area histogram was obtained.ResultsThe highest percentage of photon contribution in mixed beam was found to be 36% for 2-mm thickness of lead layer with holes diameter of 0·2 cm for a 20 MeV primary electron energy. For small fields, the percentage depth dose parameters variations were found to be similar to pure electron beam within ±2%. The most feasible flatness in beam profile was 11% for pure electron and 7% for the mixed beam. Penumbra changes as function of depth was about ten times better than in pure electron field.ConclusionsThe results present some dosimetric advantages that can make this study a platform for the production of simultaneous mixed beams in future linear accelerators (LINACs), which through redesign of the LINAC head, which could lead to setup error reduction and a decrease of intra-fractional tumour cells repair.

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Dosimetric Characterization of Small Radiotherapy Electron Beams Collimated by Circular Applicators with the New Microsilicon Detector

Applied Sciences ◽

10.3390/app12020600 ◽

2022 ◽

Vol 12 (2) ◽

pp. 600

Author(s):

Serenella Russo ◽

Silvia Bettarini ◽

Barbara Grilli Leonulli ◽

Marco Esposito ◽

Paolo Alpi ◽

...

Keyword(s):

Radiation Therapy ◽

Electron Beams ◽

High Energy ◽

Field Size ◽

The Novel ◽

Linear Accelerators ◽

Depth Dose ◽

Dosimetric Data ◽

Output Factors ◽

Dose Measurements

High-energy small electron beams, generated by linear accelerators, are used for radiotherapy of localized superficial tumours. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector compared to other available dosimeters. Relative dose measurements of circular fields with 20, 30, 40, and 50 mm aperture diameters were performed for electron beams generated by an Elekta Synergy linac, with energy between 4 and 12 MeV. Percentage depth dose, transverse profiles, and output factors, normalized to the 10 × 10 cm2 reference field, were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom, at SSD of 100 cm, by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam apertures for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber. Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by circular applicators.

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Dosimetric Characterization of Small Radiation Therapy Electron Beams Collimated by Tubular Applicators With the New Micro-Silicon Detector

10.20944/preprints202112.0245.v1 ◽

2021 ◽

Author(s):

Serenella Russo ◽

Silvia Bettarini ◽

Barbara Grilli Leonulli ◽

Marco Esposito ◽

Paolo Alpi ◽

...

Keyword(s):

Radiation Therapy ◽

Electron Beams ◽

Silicon Detector ◽

High Energy ◽

Field Size ◽

The Novel ◽

Linear Accelerators ◽

Depth Dose ◽

Dosimetric Data ◽

Output Factors

High-energy small electron beams generated by linear accelerators are used for radiotherapy of localized superficial tumors. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector by comparison with commercially available dosimeters. Relative dose measurements of circular fields with 20, 30, 40 and 50 mm aperture diameters were performed for 4 to 12 MeV energy range of electron beams generated by an Elekta Synergy linac. Percentage depth dose, transverse profiles and output factors normalized to the 10 × 10 cm2 reference field were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom at SSD of 100cm by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam aperture for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber.Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies, within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by tubular applicators.

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Quadrupole field geometries for intense electron beam acceleration

Laser and Particle Beams ◽

10.1017/s0263034600010193 ◽

1996 ◽

Vol 14 (3) ◽

pp. 519-528

Author(s):

Stanley Humphries

Keyword(s):

Electron Beams ◽

Low Frequency ◽

High Energy ◽

Linear Accelerators ◽

Quadrupole Field ◽

Magnetic Focusing ◽

Current Electron ◽

Intense Electron Beam ◽

Intense Electron ◽

High Current Electron

High-intensity electron beams could be focused in low-frequency RF accelerators and induction linear accelerators by adding transverse components to the accelerating electric field. Calculations with a 3D code show that quasielectrostatic focusing is sufficient to transport kiloampere electron beams in RF accelerators and the high-energy sections of induction accelerators. The elimination of conventional magnetic focusing systems could lead to reductions in the volume and weight of high-current electron accelerators. Two novel quadrupole geometries are investigated: a periodic array of spherical electrodes with alternating displacements and a set of plate electrodes with elliptical apertures.

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Backscatter towards the monitor ion chamber in high-energy photon and electron beams: charge integration versus Monte Carlo simulation

Physics in Medicine and Biology ◽

10.1088/0031-9155/45/11/304 ◽

2000 ◽

Vol 45 (11) ◽

pp. 3159-3170 ◽

Cited By ~ 38

Author(s):

F Verhaegen ◽

R Symonds-Tayler ◽

H H Liu ◽

A E Nahum

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Electron Beams ◽

High Energy ◽

High Energy Photon ◽

Energy Photon ◽

Ion Chamber ◽

Charge Integration

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Electron Beam Measurements Employing Electron Montecarlo Algorithm on TrueBeam STx® and Clinac iX® Linear Accelerators

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2021.7564 ◽

2021 ◽

Vol 9 (B) ◽

pp. 1730-1738

Author(s):

Kamal Saidi ◽

Othmane Kaanouch ◽

Hanae El Gouach ◽

Mohamed Reda Mesradi ◽

Mounir Mkimel ◽

...

Keyword(s):

Electron Beam ◽

Electron Beams ◽

Measured Data ◽

Field Size ◽

Large Field ◽

Linear Accelerators ◽

Tolerance Intervals ◽

Depth Dose ◽

Large Water ◽

Good Agreement

Electron beam measurement comparison between TrueBeam STx® and Clinac iX® established. Data evaluation of eMC-calculated and measured for TrueBeam STx® performed. Dosimetric parameters measured including depth dose curves for each applicator, percentage depth dose (PDDs) curves without applicator, the profile in-air for a large field size 40×40 cm2, and the Absolute Dose (cGy/MU) for each applicator using a large water phantom (PTW, Freiburg, Germany), employing Roos and Markus plane-parallel ionization chambers. The data were examined for five electron beams of Varian’s TrueBeam STx® and Clinac iX® machines. A comparison between measurement PDDs and calculated by the Eclipse electron Monte Carlo (eMC) algorithm was performed to validate Truebeam STx® commissioning. The measured data indicated that electron beam PDDs from the TrueBeam STx® machine are well matched to those from Clinac iX® machine. The quality index R50 for applicator 15×15 cm2 was in the tolerance intervals. However, Surface dose (Ds) increases with increasing energy for both accelerators. Comparisons between the measured and eMC-calculated values revealed that the R100, R90, R80, and R50 values mostly agree within 5 mm. Measured and calculated bremsstrahlung tail Rp correlates well statistically. Ds agrees mostly within 2%. Electron beams were successfully validated for TrueBeam STx®, a good agreement between modeled and measured data was observed.

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