A Simple Approach for Experimental Characterization and Validation of Proton Pencil Beam Profiles

Stasica, Paulina; Baran, Jakub; Granja, Carlos; Krah, Nils; Korcyl, G.; Oancea, Cristina; Pawlik-Niedźwiecka, M.; Niedźwiecki, Szymon; Rydygier, Marzena; Schiavi, A.; Ruciński, Antoni; Gajewski, J.

doi:10.3389/fphy.2020.00346

Cited by 8 publications

(5 citation statements)

References 48 publications

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“…To translate the proposed method into the clinic, future works should focus on increasing the efficiency of the proposed method either by acquiring larger sensor detector or automating the motion of the small sensor on a precision motion stage. Furthermore, use of pinhole to reduce flux rate is not required when the commercial proton delivery system can reduce dose rate (Stasica et al 2020). Since each acquisition typically last a few seconds, multiple acquisitions can be done within a couple of minutes with motorized detectors and synchronized motion of pinhole if needed.…”

Section: Discussionmentioning

confidence: 99%

A novel proton counting detector and method for the validation of tissue and implant material maps for Monte Carlo dose calculation

et al. 2021

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The presence of artificial implants complicates the delivery of proton therapy due to inaccurate characterization of both the implant and the surrounding tissues. In this work, we describe a method to characterize implant and human tissue mimicking materials in terms of relative stopping power (RSP) using a novel proton counting detector. Each proton is tracked by directly measuring the deposited energy along the proton track using a fast, pixelated spectral detector AdvaPIX-TPX3 (TPX3). We considered three scenarios to characterize the RSPs. First, in-air measurements were made in the presence of metal rods (Al, Ti and CoCr) and bone. Then, measurements of energy perturbations in the presence of metal implants and bone in an anthropomorphic phantom were performed. Finally, sampling of cumulative stopping power (CSP) of the phantom were made at different locations of the anthropomorphic phantom. CSP and RSP information were extracted from energy spectra at each beam path. To quantify the RSP of metal rods we used the shift in the most probable energy (MPE) of CSP from the reference CSP without a rod. Overall, the RSPs were determined as 1.48, 2.06, 3.08, and 5.53 from in-air measurements; 1.44, 1.97, 2.98, and 5.44 from in-phantom measurements, for bone, Al, Ti and CoCr, respectively. Additionally, we sampled CSP for multiple paths of the anthropomorphic phantom ranging from 18.63 to 25.23 cm deriving RSP of soft tissues and bones in agreement within 1.6% of TOPAS simulations. Using minimum error of these multiple CSP, optimal mass densities were derived for soft tissue and bone and they are within 1% of vendor-provided nominal densities. The preliminary data obtained indicates the proposed novel method can be used for the validation of material and density maps, required by proton Monte Carlo Dose calculation, provided by competing multi-energy computed tomography and metal artifact reduction techniques.

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Section: Discussionmentioning

confidence: 99%

A novel proton counting detector and method for the validation of tissue and implant material maps for Monte Carlo dose calculation

et al. 2021

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“…Second, the holder with the detector was positioned so that β = 45°, and the phantom was filled with water. Such angular position is preferred as it is an optimum between maximizing registration of elongated clusters and minimizing the scattering of protons on an aluminum case of Timepix as it was proved before (Stasica et al 2020b).…”

Section: Measurementsmentioning

confidence: 99%

“…This contribution implements a method based on a Timepix detector (see figure 1 energy-sensitive single particle tracking (Granja et al 2013, Heijne et al 2013, Ballabriga et al 2018 and quantumdosimetry imaging (Granja and Pospisil 2014) into the physical sciences with applications in space (Turecek et al 2011, Kroupa et al 2015, Stoffle et al 2015, Granja et al 2016 and medicine (Bisogni et al 2009, Jakubek et al 2010, Loo et al 2011, Martisikova et al 2011. Timepix was also applied to measure the relative dose with a wide dynamic range in clinical proton radiation fields (Stasica et al 2020b).…”

Section: Introductionmentioning

confidence: 99%

Single proton LET characterization with the Timepix detector and artificial intelligence for advanced proton therapy treatment planning

et al. 2023

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Objective: Protons have advantageous dose distributions and are increasingly used in cancer therapy. At the depth of the Bragg peak range, protons produce a mixed radiation field consisting of low- and high-linear energy transfer (LET) components, the latter of which is characterized by an increased ionization density on the microscopic scale associated with increased biological effectiveness. Prediction of the yield and LET of primary and secondary charged particles at a certain depth in the patient is performed by Monte Carlo simulations but is difficult to verify experimentally. Approach: Here, the results of measurements performed with Timepix detector in the mixed radiation field produced by a therapeutic proton beam in water are presented and compared to Monte Carlo simulations. The unique capability of the detector to perform high-resolution single particle tracking and identification enhanced by artificial intelligence allowed to resolve the particle type and measure the deposited energy of each particle comprising the mixed radiation field. Based on the collected data, biologically important physics parameters, the LET of single protons and dose-averaged LET, were computed.Main results: An accuracy over 95% was achieved for proton recognition with a developed neural network model. For recognized protons, the measured LET spectra generally agree with the results of Monte Carlo simulations. The mean difference between dose-averaged LET values obtained from measurements and simulations is 17%. We observed a broad spectrum of LET values ranging from a fraction of keV/um to about 10 keV/um for most of the measurements performed in the mixed radiation fields.Significance: It has been demonstrated that the introduced measurement method provides experimental data for validation of LET_D or LET spectra in any treatment planning system. The simplicity and accessibility of the presented methodology make it easy to be translated into a clinical routine in any proton therapy facility.

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“…the initial energy, energy spread, and Twiss parameters describing the lateral propagation of the beam (Twiss and Frank 1949), have been recalculated to the corresponding GATE parameters, giving an equivalent beam model in GATE. The equivalent beam models implemented in FRED and GATE have been previously used for dosimetric and radiation quality characterisation by Stasica et al (2020).…”

Section: Simulationsmentioning

confidence: 99%

GPU accelerated Monte Carlo scoring of positron emitting isotopes produced during proton therapy for PET verification

et al. 2022

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Objective Verification of delivered proton therapy treatments is essential for reaping the many benefits of the modality, with the most widely proposed in vivo verification technique being the imaging of positron emitting isotopes generated in the patient during treatment using positron emission tomography (PET). The purpose of this work is to reduce the computational resources and time required for simulation of patient activation during proton therapy using the GPU accelerated Monte Carlo code FRED, and to validate the predicted activity against the widely used Monte Carlo code GATE. Approach We implement a continuous scoring approach for the production of positron emitting isotopes within FRED version 5.59.9. We simulate treatment plans delivered to 95 head and neck patients at Centrum Cyklotronowe Bronowice using this GPU implementation, and verify the accuracy using the Monte Carlo toolkit GATE version 9.0. Main results We report an average reduction in computational time by a factor of 50 when using a local system with 2 GPUs as opposed to a large compute cluster utilising between 200 to 700 CPU threads, enabling simulation of patient activity within an average of 2.9 minutes as opposed to 146 minutes. All simulated plans are in good agreement across the two Monte Carlo codes. The two codes agree within a maximum of 0.95σ on a voxel-by-voxel basis for the prediction of 7 different isotopes across 472 simulated fields delivered to 95 patients, with the average deviation over all fields being 6.4·10-3σ. Significance The implementation of activation calculations in the GPU accelerated Monte Carlo code FRED provides fast and reliable simulation of patient activation following proton therapy, allowing for research and clinical applications of range verification for this treatment modality using PET to proceed at a rapid pace.

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A Simple Approach for Experimental Characterization and Validation of Proton Pencil Beam Profiles

Cited by 8 publications

References 48 publications

A novel proton counting detector and method for the validation of tissue and implant material maps for Monte Carlo dose calculation

A novel proton counting detector and method for the validation of tissue and implant material maps for Monte Carlo dose calculation

Single proton LET characterization with the Timepix detector and artificial intelligence for advanced proton therapy treatment planning

GPU accelerated Monte Carlo scoring of positron emitting isotopes produced during proton therapy for PET verification

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