Water Phantom Characterization of a Novel Optical Fiber Sensor for LDR Brachytherapy

Martyn, Michael; Kam, Wern; Woulfe, Peter; O'Keeffe, Sinéad

doi:10.1109/jsen.2022.3225007

Cited by 11 publications

(6 citation statements)

References 19 publications

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“…Because of the low-energy radiation typically emitted by LDR sources, energy correction is not expected to be required [27] and the data support this, as shown in Figure 13, where the ratios between the dose-rate-normalized PCR and the TG43-U1 predictions are displayed. Assessment of the system performance against the project specification was pursued following the approach outlined for HDR dosimetry, with the advantage that angular dependence did not need to be considered since all the data were recorded on the plane perpendicular to the source centre.…”

Section: Pre-clinical Campaign: Ldrmentioning

confidence: 73%

“…The results were obtained with the S13360-1375 SiPM and the Gadox fibre (0.5 mm diameter) irradiated by an 125 I source of 0.3 mCi activity. The measurements were carried out using a PTW MP3-XS water phantom system (PTW, Freiburg, Germany), coupled with a 3-D printed source and sensor holders made from polymer-like material with a density of 1.17 -1.18 g/cm 3 [27]. Figure 11 shows the schematic of the setup.…”

Section: Pre-clinical Campaign: Ldrmentioning

confidence: 99%

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Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter

Caccia,

Giaz,

Galoppo

et al. 2024

Sensors

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Source localisation and real-time dose verification are at the forefront of medical research in brachytherapy, an oncological radiotherapy procedure based on radioactive sources implanted in the patient body. The ORIGIN project aims to respond to this medical community’s need by targeting the development of a multi-point dose mapping system based on fibre sensors integrating a small volume of scintillating material into the tip and interfaced with silicon photomultipliers operated in counting mode. In this paper, a novel method for the selection of the optimal silicon photomultipliers to be used is presented, as well as a laboratory characterisation based on dosimetric figures of merit. More specifically, a technique exploiting the optical cross-talk to maintain the detector linearity in high-rate conditions is demonstrated. Lastly, it is shown that the ORIGIN system complies with the TG43-U1 protocol in high and low dose rate pre-clinical trials with actual brachytherapy sources, an essential requirement for assessing the proposed system as a dosimeter and comparing the performance of the system prototype against the ORIGIN project specifications.

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Section: Pre-clinical Campaign: Ldrmentioning

confidence: 73%

Section: Pre-clinical Campaign: Ldrmentioning

confidence: 99%

Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter

Caccia,

Giaz,

Galoppo

et al. 2024

Sensors

Self Cite

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“…Sensitivity to Dose from 5 mm to 30 mm Spatial Resolution 3 mm @ a distance of 30 mm Dose Rate Range 0.4-2 Gy/h Statistical Precision 5% in 0.5 s @ a distance of 30 mm Results obtained by irradiating with a 125 I source of 0.3 mCi activity the single-fibre prototype of the ORIGIN dosimeter, are reported in the work of M. Martyn et al [5] and M. Caccia et al [6]. These studies also compare the counting rate as a function of the sensor to source distance with the prediction from the TG43-U1 protocol [7] indicating that there is no need for an "energy correction" factor to account for the non-water equivalence of the scintillating material.…”

Section: Ldr -Specificationsmentioning

confidence: 99%

“…This work focuses on LDR-BT, employing a permanent implantation technique of different 125 I sources, called seeds, and it is mainly used to cure prostate cancer [3,4]. For LDR-BT (specifications in table 1), the ORIGIN project aims to design a multi-point dosimeter sensitive in a distance range from the source within 5 to 30 mm, where 5 mm corresponds to the spacing between the LDR-BT template grid and 30 mm is linked to the average dimensions of the prostate gland [5]. Sensitivity has to be guaranteed for the single seed, depositing a dose between 0.4 Gy/h to 2 Gy/h, and measurements have to provide a 5% statistical precision at 30 mm distance in 0.5 s, where the short time window is connected to the minimum time between two seed implants.…”

Section: Introductionmentioning

confidence: 99%

Design and commissioning of a Silicon Photomultiplier-based dosimeter for Low Dose Rate (LDR) oncological brachytherapy

Burdyko,

Caccia,

Giaz

et al. 2024

J. Inst.

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Brachytherapy is a radiotherapy procedure performed with radioactive sources implanted into the patient's body, close to the area affected by cancer. This is a reference procedure for the treatment of prostate and gynecologic cancer due to the reduction of the dose released close to organs at risk (e.g., rectum, bladder, colon). For this reason, real-time dose verification and source localisation are essential for an optimal treatment plan. The ORIGIN collaboration aims to achieve this goal through a 16-fibre sensor system, designed to house a small volume of scintillating material in a transparent fibre tip to enable point-like measurements. The selected scintillating materials feature a decay time of about 500 μs and the signal associated with the primary γ-ray interaction results in the emission of a sequence of single photons distributed over time. Therefore, the dosimeter requires a detector with single-photon sensitivity and a system designed to provide dose measurements by photon counting. Uniformity of fibre response, system stability and reproducibility of measurements are key features of the dosimeter. The characterisation of the 16-channel dosimeter system equipped with thermo-electrically cooled Silicon Photomultipliers, carried out in the laboratory using an X-ray cabinet, is discussed and the results are compared with an earlier version equipped with SiPMs operated at room temperature.

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“…Scintillator detectors, which produce optical photons in response to ionizing radiation, may be an alternative which avoid the previously mentioned problems. Combining fast response times (and the ability for real-time readout), with sub-mm spatial resolution, and dose rate independence for a variety of radiation types and sources [14]- [20], radioluminescent detectors are excellent dosimeters for use across the spectrum of dose rates em-ployed in preclinical studies and radiotherapy [21]- [23]. There are a wide range of scintillating materials including organic (polystyrene and polyvinyltoluene-based plastics), and inorganic scintillators.…”

Section: Introductionmentioning

confidence: 99%

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

Hart,

Giguére,

Bateman

et al. 2024

Preprint

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Very high energy electron (VHEE) beams with energies greater than 100 MeV may be promising candidates for FLASH radiotherapy due to their favourable dose distributions and accessibility of ultrahigh dose-rates (UHDR). Combining VHEE with the normal tissue-sparing FLASH effect of UHDR radiotherapy could improve patient outcomes. The standard dosimeters used for conventional radiotherapy, including ionization chambers and film, have limited application to UHDR radiotherapy due to deficits in dose rate independence and temporal resolution. Plastic scintillator detectors (PSDs) are a potential alternative. PSDs connected to a Medscint Hyperscint RP-100 were used to measure the response to 200 MeV electrons produced by the CERN Linear Electron Accelerator for Research (CLEAR). The dose-response linearity and radiation hardness of PSDs under UHDR VHEE conditions was investigated, using dose rates up to 1.21 × 10 Gy/s. Two scintillators were investigated: a polystyrene-based BCF-12 and a proprietary polyvinyltoluene (PVT)-based material. The BCF-12 probe exhibited linear light output with dose per train from 4.9 to 125.2 Gy, and dose rates up to 1.16 × 10 Gy/s within a single pulse. The output of the PVT-based probe was linear from 3.9 to 59.5 Gy per train, and dose rates up to 9.92 × 10 Gy/s. While output linearity was retained (R > 0.998) after delivering 26.2 and 13.8 kGy to the BCF-12 and PVT-based probe, respectively, the light output was reduced by < 1.5%/kGy. The performance of PSDs in this work suggest they may be useful real-time dosimeters for applications in UHDR VHEE radiotherapy.

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Water Phantom Characterization of a Novel Optical Fiber Sensor for LDR Brachytherapy

Cited by 11 publications

References 19 publications

Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter

Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter

Design and commissioning of a Silicon Photomultiplier-based dosimeter for Low Dose Rate (LDR) oncological brachytherapy

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

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