An analysis of beam parameters on proton-acoustic waves through an analytic approach

Kipergil, Esra Aytac; Erkol, Hakan; Kaya, Serhat; Gülşen, Gültekin; Ünlü, Mehmet

doi:10.1088/1361-6560/aa642c

Cited by 16 publications

(18 citation statements)

References 52 publications

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“…PGs are high energy gamma rays created by inelastic interactions between incident proton and target nuclei. PGs are emitted with decay time less than 1 ps and a broad energy spectrum (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). This approach faces two main challenges: (a) low detection efficiency due to the high energy of gamma rays; and (b) discrimination of PG signals from background noise originating from secondary neutrons.…”

Section: Introductionmentioning

confidence: 99%

Simulation studies of time reversal‐based protoacoustic reconstruction for range and dose verification in proton therapy

Yu¹,

Li²,

Zhang³

et al. 2019

Medical Physics

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Purpose In vivo range verification in proton therapy is a critical step to help minimize range and dose uncertainty. We propose to employ a time reversal (TR)‐based approach using proton‐induced acoustics (protoacoustics) to reconstruct pressure/dose distribution in heterogeneous tissues. Methods The dose distribution of mono‐energetic proton pencil beam in a CT‐based patient phantom was calculated by Monte Carlo simulation. K‐wave toolbox was used to investigate protoacoustic pressurization, propagation and reconstruction in 2D. To address the tissue heterogeneity effect, a number of physical parameters, including mass density (ρ), speed of sound (c), volumetric thermal expansion coefficient (αV), isobaric specific heat capacity (Cp) and attenuation power law prefactor (α0), were empirically converted from CT number. The performance was evaluated using two figures of merit: mean square error (MSE) of pressure profiles and Bragg peak localization error (ΔBP). The impact of six parameters of the TR inversion was examined, including number of sensors, sampling duration, sampling timestep, spill time, noise level and number of iterations. Results The quantitative accuracy of TR reconstruction and its dependency on the selected parameters is presented. Under optimum conditions, the positioning accuracy of the Bragg peak can be controlled below 1 mm. For instance, MSE is 0.0123 and ΔBP is 0.59 mm under the following conditions (32 sensors, sampling duration: 600 µs, sampling timestep: 40 ns, spill time: 1 µs, no noise). Conclusions The feasibility of TR‐based protoacoustic reconstruction in 2D for proton range verification was first demonstrated. The approach is not only applicable to pencil beam, but also has potential to be extended to passive scattering systems.

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Section: Introductionmentioning

confidence: 99%

Simulation studies of time reversal‐based protoacoustic reconstruction for range and dose verification in proton therapy

Yu¹,

Li²,

Zhang³

et al. 2019

Medical Physics

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“…In this study, we assume that the proton beam is injected in a short period of time ( σ p = 30–500 ns), which is within the output range of fast-extraction synchrotron, fixed-field alternating gradient, dielectric wall and laser-driven accelerators 19 . Figure 2(a,b) show the transferred energy distributions on the z-x plane without and with the gold marker, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The width of beam pulse σ p was varied from 30 to 500 ns. To obtain a clear signal, the pulse width was chosen in the < μs range 18,19 , which fulfils the confinement conditions. Moreover, Z m was varied from 16 to 38 mm, which corresponds to a residual range of 15 mm and −7 mm for 60-MeV protons, respectively; the marker was therefore positioned at both pre- and post-Bragg peak regions in the tests.…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, acoustic-signal detection does not require bulky equipment for implementation. So far, several simulation studies have focused on waveform analysis in a simple water medium 14,17–19 and in prostate- and liver-cancer patients 20 . Experimental observations of acoustic emissions have been performed with a linac 9 , a synchrotron 10–13 , a tandem accelerator 14 , a hospital-based isochronous cyclotron 15 and a synchrocyclotron 16 , with positive results.…”

Section: Introductionmentioning

confidence: 99%

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A novel range-verification method using ionoacoustic wave generated from spherical gold markers for particle-beam therapy: a simulation study

Takayanagi

Uesaka

Kitaoka

et al. 2019

Sci Rep

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This study proposes a novel alternative range-verification method for proton beam with acoustic waves generated from spherical metal markers. When proton beam is incident on metal markers, most of the resulting pressure waves are confined in the markers because of the large difference in acoustic impedance between the metal and tissue. However, acoustic waves with frequency equal to marker’s resonant frequency escape this confinement; the marker briefly acts as an acoustic transmitter. Herein, this phenomenon is exploited to measure the range of the proton beam. We test the proposed strategy in 3-D simulations, combining the dose calculations with modelling of acoustic-wave propagation. A spherical gold marker of 2.0 mm diameter was placed in water with a 60 MeV proton beam incident on it. We investigated the dependence of pressure waves on the width of beam pulse and marker position. At short beam pulse, specific high-frequency acoustic waves of 1.62 MHz originating from the marker were observed in wave simulations, whose amplitude correlated with the distance between the marker and Bragg peak. Results indicate that the Bragg peak position can be estimated by measuring the acoustic wave amplitudes from the marker, using a single detector properly designed for the resonance frequency.

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“…Note that the amplitude and temporal behavior of the resulting pressure field not only depend on the amplitude but also on the spatial distribution and temporal profile of the dose distribution. [8] To image the dose distribution, a set of 900 point receivers is homogeneous distributed in the plane z = 0. An example of a synthetically measured A-scan is displayed in Fig.…”

Section: Resultsmentioning

confidence: 99%

Modelling the Iono-Acoustic Wave Field for Proton Beam Range Verification

Dongen

Blécourt

Lens

et al. 2018

2018 IEEE International Ultrasonics Symposium (IUS)

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In proton therapy, cancer patients are irradiated with high energy protons. For a successful treatment it is important that the location with the highest energy deposition, the so-called Bragg-peak, is located inside the tumor and not in the healthy surrounding tissue. Here, we investigate if the iono-acoustic wave field generated by the protons can be used to monitor the Bragg-peak location during treatment. To this end we present a new numerical method to model the pressure field generated by a clinical proton pencil beam. To compute the field, we convolve a 3-D Greens function, representing the impulse response of the medium, with a volume density of injection rate source. This source describes the expansion of the medium due to a local temperature increase caused by the energy deposited by the protons. To image the proton dose distribution, we first measure the pressure field synthetically by a matrix transducer positioned below the Bragg peak in a plane parallel to the beam. Next, we use these measurements to solve the linear inverse problem iteratively. To regularize the inversion, we take the temporal behavior of the dose deposition as prior knowledge. For the presented example, where the pencil beam has a proton range of 63 mm we are able to reconstruct the location of the Bragg peak within 4 mm accuracy.

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An analysis of beam parameters on proton-acoustic waves through an analytic approach

Cited by 16 publications

References 52 publications

Simulation studies of time reversal‐based protoacoustic reconstruction for range and dose verification in proton therapy

Simulation studies of time reversal‐based protoacoustic reconstruction for range and dose verification in proton therapy

A novel range-verification method using ionoacoustic wave generated from spherical gold markers for particle-beam therapy: a simulation study

Modelling the Iono-Acoustic Wave Field for Proton Beam Range Verification

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