Apparatus for visualizing the energy release in a water phantom irradiated with the proton beam of the radiotherapeutic accelerator

AbstractPurposeThis exploration is intended to analyse the dosimetric characteristics of proton beams of multiple energies using different snout sizes.Materials and methodsA synchrotron was used for the extraction of eight proton beam energies (100–250 MeV). Dosimetric measurements were taken in a water phantom that was irradiated with a proton beam emanating from the gantry system at angles 0, 90, 180 and 270 degree using a large and a medium snout. The range of beam energies in the phantom, their corresponding centre modulation depth (CMD) and the width of spread out Bragg peak (SOBP) were measured by Markus chamber. Double scattering technique was employed for the creation of SOBPs.ResultsThe range of proton beams varied from 4·3 cm for 100 MeV beam to 28·5 cm for 250 MeV beam with the medium snout and from 4·3 cm for 100 MeV to 25 cm for 250 MeV beam with large snout in the water phantom. SOBP width showed a variation from 4 to 10 cm with medium and large snout. While determining the output with medium snout, the discrepancy of 1·1% was observed between the maximum and minimum mean values of output for all the given set of energies and angles. There occurred a difference of 0·9% between the maximum and minimum mean values of output with the large snout. Beam output at SOBP centre was 12% higher with large snout as compared to that with medium snout for all the given beam energies. Flatness and symmetry were found within ±2·5% tolerance limits with medium and large snouts.ConclusionFlatness and symmetry were found within explicit limits with both medium and large snouts. Large snout produced higher beam output than that of medium snout at the centre of SOBP. This exploration can be extended to the determination of beam output, flatness and symmetry with a small snout.

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Characterization of angular detection dependence of prompt gamma-rays with respect to the Bragg peak in a water phantom using proton beam irradiations

2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD) ◽

10.1109/nssmic.2016.8069539 ◽

2016 ◽

Author(s):

M. Zarifi ◽

S. Guatelli ◽

D. Bolst ◽

B. Hutton ◽

A. Rosenfeld ◽

...

Keyword(s):

Proton Beam ◽

Gamma Rays ◽

Bragg Peak ◽

Prompt Gamma ◽

Water Phantom

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MCNPX’S Water Equivalent Thickness Simulation of Material with Different Density via Proton Beam Irradiation

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.35.23088 ◽

2018 ◽

Vol 7 (4.35) ◽

pp. 678

Author(s):

M.A Khattak ◽

Abdoulhdi. A. Borhana ◽

Lailatul Fitriyah A. Shafii ◽

Rustam Khan

Keyword(s):

Proton Beam ◽

Computing Time ◽

Analytical Calculation ◽

High Dose ◽

Beam Irradiation ◽

Equivalent Thickness ◽

Proton Beam Irradiation ◽

Approximation Techniques ◽

Method Of Calculation ◽

Water Phantom

The radiological thickness of materials and beam penetration range is often referred as the water equivalent thickness (WET). In the clinical application of radiotherapy it is mandatory to obtain a WET calculation with high accuracies to ensure the beam that penetrated the human tissues is capable to deliver high dose of radiation into the deep-rooted tumors and kill the malignant cancerous cell without any major damages to the healthy tissues. Nevertheless, the present method of calculation that is available needs either intensive numerical method or approximation techniques with unknown precision. Hence, the purpose of this research is to study the depth of proton beam irradiation penetration range of materials with arbitrary density & elemental composition and modeled the water equivalent thickness (WET) calculation by using the Monte Carlo N Particle Transport Code Extension (MCNPX). There are several type of material with different density that are utilize in this project which are water phantom (ρ =1.0 g cm-3), PMMA (ρ =1.19 g cm-3) aluminum (ρ = 2.70 g cm-3 lead (ρ =11.3g cm-3). The water phantom represent reference material whilst PMMA, Aluminum and Lead each represent low, medium and high density respectively. Based from the result produced in output file, Bragg curves for each material were reproduced, analyzed and compared with the Bragg curve of water phantom. The WET of water phantom was successfully modelled by using MCNPX. Apart from the short computing time, modelling WET via MCNPX was more efficient compare to analytical calculation

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“Warm liquid” detector for measuring dose profiles from ionizing radiation

Izvestiya Vysshikh Uchebnykh Zavedenii Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering ◽

10.17073/1609-3577-2019-3-228-236 ◽

2020 ◽

Vol 22 (3) ◽

pp. 228-236

Author(s):

V. V. Siksin

Keyword(s):

Proton Beam ◽

Proton Therapy ◽

Dose Distribution ◽

Bragg Peak ◽

Beam Width ◽

Great Accuracy ◽

Therapy Session ◽

High Dose ◽

Water Phantom ◽

Accuracy Measure

The use of “warm liquid” tetramethylsilane (TMS) in ionization chambers for measuring dose profiles in water phantoms to prepare the accelerator for a proton therapy session is relevant. One of the promising areas of radiation therapy is proton therapy. To increase the conformality of proton therapy, it is important to know exactly the dose distributions from the energy release of the proton beam in the water phantom before conducting a proton therapy session. A television-type detector (TTD), which measures the profiles of the Bragg peak by the depth of the beam in the water phantom, helps to increase the accuracy of the dose distribution knowledge. To accurately determine the profile of the Bragg peak by the beam width in the water phantom, an additional method is proposed that will allow TTD to quickly determine the profile by the width of the Bragg peak in on-line mode. This prefix to the TTD will improve the quality of summing up the therapeutic beam-thanks to accurate knowledge of the profile by width, and therefore the formed high-dose distribution field will correspond to the irradiated volume in the patient and will increase the conformality of irradiation. The additional prefix to the TTD is designed on an organosilicon “warm liquid” and represents a high-precision ionization chamber with coordinate sensitivity along the width of the water phantom. The fully developed technology for obtaining “warm liquid” TMS allows creating both microdosimeters for proton therapy and detectors for measuring “dose profiles” in water phantoms during accelerator calibration. The considered prefix to the TTD detector - the calibrator meter of the dose field (KIDP) - can also be used independently of the TTD and with great accuracy measure the dose profiles of the Bragg peak in the water phantom, both in depth and width. KIDP can also be used to measure the outputs of secondary “instantaneous” neutrons and gamma quanta emitted from the water phantom orthogonally to the direction of the proton beam.

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