A Single-Particle Trigger for Time-of-Flight Measurements in Prompt-Gamma Imaging

Martins, P. J. Magalhaes; Bello, Riccardo Dal; Seimetz, M.; Hermann, G.; Kihm, T.; Seco, Joao

doi:10.3389/fphy.2020.00169

Cited by 9 publications

(14 citation statements)

References 49 publications

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“…Detector 1 collects a higher signal for the 90 angle, while detector 2 collects a higher signal for the 270 angle. To increase the signal at a 0 angle, we used the timing information of the arrival time of the protons provided by the scintillating fibres placed between the nozzle and the target 60 . The trigger was not further used in the treatment plans due to the strong impact in the statistics and due to the intensity constraints (increasing pile-up above p/s).…”

Section: Resultsmentioning

confidence: 99%

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Towards real-time PGS range monitoring in proton therapy of prostate cancer

Martins

Freitas

Tessonnier

et al. 2021

Sci Rep

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Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Endorectal balloons (ERBs) are used to stabilize prostate movement during radiotherapy. These ERBs are usually filled with water. However, other water solutions containing elements with higher atomic numbers, such as silicon, may enable the use of PGS to monitor the radiation exposure of the rectum. Protons hitting silicon atoms emit prompt gamma rays with a specific energy of 1.78 MeV, which can be used to monitor whether the ERB is being hit. In a binary approach, we search the silicon energy peaks for every irradiated prostate region. We demonstrate this technique for both single-spot irradiation and real treatment plans. Real-time feedback based on the ERB being hit column-wise is feasible and would allow clinicians to decide whether to adapt or continue treatment. This technique may be extended to other cancer types and organs at risk, such as the oesophagus.

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Section: Resultsmentioning

confidence: 99%

“…These detectors are scintillation detectors with very good time and energy resolution. They feature a measured energy resolution of 3.49% 55 and a measured time resolution of 0.85 ns 60 . They are mainly used for range verification of the proton and ion beams in a patient.…”

Section: Methodsmentioning

confidence: 99%

Towards real-time PGS range monitoring in proton therapy of prostate cancer

Martins

Freitas

Tessonnier

et al. 2021

Sci Rep

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“…Therefore, a beam tagging system can be used advantageously to detect the time of arrival of ions on the patient, provided it is able to cope with high counting rates, either in clinical-intensity bunch modes, or in single particle counting regime. For bunch detection, secondary particle detectors can be used [20,41], whereas scintillator-based hodoscopes are generally proposed for single particle counting, with timing resolutions of several hundred picoseconds [39,42]. Thin ultra-fast silicon detectors (UFSD) have been explored for such purpose [43].…”

Section: Need For a Beam Tagging Systemmentioning

confidence: 99%

On the Role of Single Particle Irradiation and Fast Timing for Efficient Online-Control in Particle Therapy

et al. 2020

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Within the frame of the CLaRyS collaboration, we discuss the assets of using a reduced-intensity in vivo treatment control phase during one or a few beam spots at the beginning of a particle therapy session. By doing so we can improve considerably the conditions for secondary radiation detection and particle radiography. This also makes Time-of-Flight (ToF) resolutions of 100 ps rms feasible for both the transmitted particles and secondary radiations, by means of a single-projectile counting mode using a beam-tagging monitor with time and position registration. This opens up new perspectives for prompt-gamma timing and Compton imaging for range verification. ToF-based proton computed tomography (CT) and ToF-assisted secondary proton vertex imaging in carbon therapy are also discussed, although for the latter, no evidence of any benefit at small observation angles is anticipated. The reduction of the beam intensity during one or a few spots on the various accelerators for particle therapy should not significantly reduce the patient workflow.

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“…Therefore, fast and accurate monitoring of the time structure of the beam is vital for FLASH treatments, which challenges existing solutions. Bunch monitors are also crucial for some range verification techniques in particle therapy that rely on the prompt‐gamma ray production within the patient 6 …”

Section: Introductionmentioning

confidence: 99%

“…Some previous work has been done with singular sensors capable of ultra‐fast beam diagnosis in real time. However, most of them rely on an indirect measurement of the beam, which is based on the scattered photons, 20 prompt gamma rays 6 or neutrons 24…”

Section: Introductionmentioning

confidence: 99%

Technical note: Measurement of the bunch structure of a clinical proton beam using a SiPM coupled to a plastic scintillator with an optical fiber

et al. 2023

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Background: Recent proposals of high dose rate plans in protontherapy as well as very short proton bunches may pose problems to current beam monitor systems. There is an increasing demand for real-time proton beam monitoring with high temporal resolution, extended dynamic range and radiation hardness. Plastic scintillators coupled to optical fiber sensors have great potential in this context to become a practical solution towards clinical implementation. Purpose: In this work,we evaluate the capabilities of a very compact fast plastic scintillator with an optical fiber readout by a SiPM and electronics sensor which has been used to provide information on the time structure at the nanosecond level of a clinical proton beam. Materials and methods: A 3 × 3 × 3 mm 3 plastic scintillator (EJ-232Q Eljen Technology) coupled to a 3 × 3 mm 2 SiPM (MicroFJ-SMA-30035, Onsemi) has been characterized with a 70 MeV clinical proton beam accelerated in a Proteus One synchrocyclotron. The signal was read out by a high sampling rate oscilloscope (5 GS/s). By exposing the sensor directly to the proton beam, the time beam profile of individual spots was recorded. Results: Measurements of detector signal have been obtained with a time sampling period of 0.8 ns. Proton bunch period (16 ns), spot (10 µs) and interspot (1 ms) time structures could be observed in the time profile of the detector signal amplitude. From this, the RF frequency of the accelerator has been extracted, which is found to be 64 MHz. Conclusions: The proposed system was able to measure the fine time structure of a clinical proton accelerator online and with ns time resolution.

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A Single-Particle Trigger for Time-of-Flight Measurements in Prompt-Gamma Imaging

Cited by 9 publications

References 49 publications

Towards real-time PGS range monitoring in proton therapy of prostate cancer

Towards real-time PGS range monitoring in proton therapy of prostate cancer

On the Role of Single Particle Irradiation and Fast Timing for Efficient Online-Control in Particle Therapy

Technical note: Measurement of the bunch structure of a clinical proton beam using a SiPM coupled to a plastic scintillator with an optical fiber

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