Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Hueso-González, F.; Bortfeld, Thomas

doi:10.1109/trpms.2019.2930362

Cited by 16 publications

(5 citation statements)

References 79 publications

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“…27 Furthermore, the obtained result is in agreement with the reported analytical estimation in the literature as the number of emitted PGs, which partially contribute to the background, are linearly proportional to the beam range. 59 In our study, the background was defined as scattered and penetrated gammas produced already with primary PGs and neutrons during irradiation. We did not consider treatment room, couch, and beam nozzle.…”

Section: Discussionmentioning

confidence: 99%

Design and performance evaluation of a slit‐slat camera for 2D prompt gamma imaging in proton therapy monitoring: A Monte Carlo simulation study

et al. 2023

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Purpose We investigated the design of a prompt gamma camera for real‐time dose delivery verification and the partial mitigation of range uncertainties. Methods A slit slat (SS) camera was optimized using the trade‐off between the signal‐to‐noise ratio and spatial resolution. Then, using the GATE Monte Carlo package, the camera performances were estimated by means of target shifts, beam position quantification, changing the camera distance from the beam, and air cavity inserting. A homogeneous PMMA phantom and the air gaps induced PMMA phantom were used. The air gaps ranged from 5 mm to 30 mm by 5 mm increments were positioned in the middle of the beam range. To reduce the simulation time, phase space scoring was used. The batch method with five realizations was used for stochastic error calculations. Results The system's detection efficiency was 1.1×10−4PGsEmitted0.33emPGs(1.8×10−5$1.1 \times {10}^{-4}\frac{{\rm PGs}}{{\rm Emitted}\ {\rm PGs}}\ (1.8 \times {10}^{-5}$ PGs/proton) for a 10 × 20 cm2 detector (source‐to‐collimator distance = 15.0 cm). Axial and transaxial resolutions were 23 mm and 18 mm, respectively. The SS camera estimated the range as 69.0 ± 3.4 (relative stochastic error 1‐sigma is 5%) and 67.6 ± 1.8 mm (2.6%) for the real range of 67.0 mm for 107 and 108 protons of 100 MeV, respectively. Considering 160 MeV, these values are 155.5 ± 3.1 (2%) and 152.2 ± 2.0 mm (1.3%) for the real range of 152.0 mm for 107 and 108 protons, respectively. Considering phantom shift, for a 100 MeV beam, the precision of the quantification (1‐sigma) in the axial and lateral phantom shift estimation is 2.6 mm and 1 mm, respectively. Accordingly, the axial and lateral quantification precisions were 1.3 mm and 1 mm for a 160 MeV beam, respectively. Furthermore, the quantification of an air gap formulated as gapdet=0.98×gapreal${{\rm gap}}_{det}=0.98 \times {{\rm gap}}_{{\rm real}}$, where gapdet${{\rm gap}}_{det}$ and gapreal are the estimated and real air gap, respectively. The precision of the air gap quantification is 1.6 mm (1 sigma). Moreover, 2D PG images show the trajectory of the proton beam through the phantom. Conclusion The proposed slit‐slat imaging systems can potentially provide a real‐time, in‐vivo, and non‐invasive treatment monitoring method for proton therapy.

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Section: Discussionmentioning

confidence: 99%

Design and performance evaluation of a slit‐slat camera for 2D prompt gamma imaging in proton therapy monitoring: A Monte Carlo simulation study

et al. 2023

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“…by in-beam PET [10], and prompt gamma rays (PGs), e.g. by the prompt-gamma imaging [11], spectroscopy [12], timing [13] and peak-integration [14] methods. It has also been shown that the spatial distribution of fast neutrons (FNs) generated during treatment delivery is correlated to the proton range, and could reveal complementary information to PGs about the proton range [15,16].…”

Section: Introductionmentioning

confidence: 99%

Characterization of organic glass scintillator bars and their potential for a hybrid neutron/gamma ray imaging system for proton radiotherapy range verification

Turko,

Beyer,

Junghans

et al. 2024

J. Inst.

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For accurate and simultaneous imaging of fast neutrons (FNs) and prompt gamma rays (PGs) produced during proton therapy, the selection of a highly performant detector material is crucial. In this work, a promising candidate material known as organic glass scintillator (OGS) is characterized for this task. To this end, a precisely-timed source of neutrons and Bremsstrahlung radiation produced by the nELBE facility was used to study the light output and neutron/gamma ray pulse shape discrimination (PSD) properties of a 1 × 1 × 20 cm3 OGS bar with double-sided readout. Furthermore, the energy, timing, and depth-of-interaction (DOI) resolutions of 1 × 1 × 10 cm3 and 1 × 1 × 20 cm3 OGS and EJ-200 bars were characterized with radioactive sources. For electron-equivalent energies above 0.5 MeVee, OGS was found to have excellent PSD capabilities (figure-of-merit above 1.27), energy resolution (below 12%), coincident time resolution (below 500 ps), and DOI resolution (below 10 mm). This work establishes the data analysis methods required for hybrid FN/PG imaging using OGS, and demonstrates the materials' excellent performance for this application.

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“…Some imaging devices have been proposed in the past to monitor the proton range in vivo , which are modified versions of classical nuclear medicine imaging modalities 4 – 10 , while other more original approaches do not provide the full PG profile (e.g. prompt gamma spectroscopy 11 , PG integral counts 12 , 13 ). The existing methods have been extensively described in multiple reviews 3 , 14 , 15 .…”

Section: Introductionmentioning

confidence: 99%

A high sensitivity Cherenkov detector for prompt gamma timing and time imaging

Jacquet

Ansari

Gallin-Martel

et al. 2023

Sci Rep

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We recently proposed a new approach for the real-time monitoring of particle therapy treatments with the goal of achieving high sensitivities on the particle range measurement already at limited counting statistics. This method extends the Prompt Gamma (PG) timing technique to obtain the PG vertex distribution from the exclusive measurement of particle Time-Of-Flight (TOF). It was previously shown, through Monte Carlo simulation, that an original data reconstruction algorithm (Prompt Gamma Time Imaging) allows to combine the response of multiple detectors placed around the target. The sensitivity of this technique depends on both the system time resolution and the beam intensity. At reduced intensities (Single Proton Regime—SPR), a millimetric proton range sensitivity can be achieved, provided the overall PG plus proton TOF can be measured with a 235 ps (FWHM) time resolution. At nominal beam intensities, a sensitivity of a few mm can still be obtained by increasing the number of incident protons included in the monitoring procedure. In this work we focus on the experimental feasibility of PGTI in SPR through the development of a multi-channel, Cherenkov-based PG detector with a targeted time resolution of 235 ps (FWHM): the TOF Imaging ARrAy (TIARA). Since PG emission is a rare phenomenon, TIARA design is led by the concomitant optimisation of its detection efficiency and Signal to Noise Ratio (SNR). The PG module that we developed is composed of a small PbF$$_{2}$$ 2 crystal coupled to a silicon photoMultiplier to provide the time stamp of the PG. This module is currently read in time coincidence with a diamond-based beam monitor placed upstream the target/patient to measure the proton time of arrival. TIARA will be eventually composed of 30 identical modules uniformly arranged around the target. The absence of a collimation system and the use of Cherenkov radiators are both crucial to increase the detection efficiency and the SNR, respectively. A first prototype of the TIARA block detector was tested with 63 MeV protons delivered from a cyclotron: a time resolution of 276 ps (FWHM) was obtained, resulting in a proton range sensitivity of 4 mm at 2$$\sigma$$ σ with the acquisition of only 600 PGs. A second prototype was also evaluated with 148 MeV protons delivered from a synchro-cyclotron obtaining a time resolution below 167 ps (FWHM) for the gamma detector. Moreover, using two identical PG modules, it was shown that a uniform sensitivity on the PG profiles would be achievable by combining the response of gamma detectors uniformly distributed around the target. This work provides the experimental proof-of-concept for the development of a high sensitivity detector that can be used to monitor particle therapy treatments and potentially act in real-time if the irradiation does not comply to treatment plan.

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Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Cited by 16 publications

References 79 publications

Design and performance evaluation of a slit‐slat camera for 2D prompt gamma imaging in proton therapy monitoring: A Monte Carlo simulation study

Design and performance evaluation of a slit‐slat camera for 2D prompt gamma imaging in proton therapy monitoring: A Monte Carlo simulation study

Characterization of organic glass scintillator bars and their potential for a hybrid neutron/gamma ray imaging system for proton radiotherapy range verification

A high sensitivity Cherenkov detector for prompt gamma timing and time imaging

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