Characterization of a scintillating fibre detector for small animal imaging and irradiation dosimetry

Deroff, C. Le; Frelin-Labalme, A.M.; Ledoux, X.

doi:10.1259/bjr.20160454

Cited by 6 publications

(7 citation statements)

References 28 publications

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“…We previously developed and evaluated a prototype named DosiRat, specifically adapted to preclinical millimeter and orthovoltage beams. 16,17 This dosimeter showed a highly repeatable, reproducible and linear response with dose and dose rate in treatment beams. 9 It was also successfully used in preclinical relative dosimetry to measure percentage depth dose distributions in a 4  4 cm² irradiation field and to measure relative output factors at the surface of a phantom for irradiation fields as small as 2.5 mm diameter.…”

Section: Introductionmentioning

confidence: 95%

“…The dose measurements were performed with DosiRat scintillating fiber dosimeter, previously fully described by Le Deroff et al 16,17 In all this study, we used a BCF-12 (polystyrene based, Saint-Gobain Crystal, Paris, France) scintillating probe of 2 mm length and 1 mm diameter, presenting an effective measurement point at about 0.5 mm from its surface. DosiRat was calibrated in absorbed dose to water in a 4  4 cm² irradiation field at 225 kVp.…”

Section: Scintillating Fiber Dosimetrymentioning

confidence: 99%

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In vivosurface dosimetry with a scintillating fiber dosimeter in preclinical image‐guided radiotherapy

et al. 2019

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In vivo surface dosimetry with a scintillating fiber dosimeter in preclinical image-guided radiotherapy Abstract Purpose. New preclinical image-guided irradiators and treatment planning systems represent a huge progress in radiobiology. Nevertheless, quality control of preclinical treatments is not as advance as in clinical radiotherapy and in vivo dosimetry is little developed. In this study, we evaluate the use of a scintillating fiber dosimeter called DosiRat to verify the agreement between the doses planned with SmART-Plan and the measured doses during small animal irradiations. Methods. In vivo dosimetry was first evaluated with DosiRat through dose measurements performed at the surface of a 3  9  3 cm 3 phantom. Measured and planned doses were compared for different irradiation conditions (prescription point, anterior and posterior beams, 5 mm and 10 mm irradiation fields). In a second phase, measured and planned doses were compared for rat brain irradiations performed with anterior beams, with DosiRat positioned at the beam entrance. Comparisons were performed for different tube currents (1.3 and 13 mA), collimations (5, 10 and 25 mm diameter) and planned doses (0.1, 0.5, 2 and 10 Gy). Results.In the case of the phantom irradiations, planned and measured doses showed discrepancies smaller than the 5 % accuracy of the TPS, except in cases in which the dosimeter was not centered in the irradiation field. The differences were larger for animal irradiations (from -3.3 % to 8.8 %) because of variations of the beam energy spectrum and the non-equivalence between materials at medium and low energy. Conclusions.This study highlighted the complexity to implement one-dimension in vivo dosimetry in orthovoltage millimetric beams. Nevertheless, DosiRat is well adapted to in vivo dosimetry because of its small volume and its direct reading and allowed in vivo control of planned doses for anterior beams down to 5 mm diameter.

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Section: Introductionmentioning

confidence: 95%

Section: Scintillating Fiber Dosimetrymentioning

confidence: 99%

In vivosurface dosimetry with a scintillating fiber dosimeter in preclinical image‐guided radiotherapy

et al. 2019

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“…Plastic scintillators have been used in megavoltage therapy, with a growing interest in examining their properties for kilovoltage energies [65][66][67]. Recently, plastic scintillators have been characterized and successfully validated for use in the 40 to 220 kVp tube voltage energy range within multiple small animal irradiators [49,[68][69][70][71][72]. Due to an energy dependence that is present for energies below 250 kVp, output must be corrected for by using a combination of mass-energy absorption coefficients, Monte Carlo (MC) obtained beam spectra information, and quenching corrections [66,71].…”

Section: Plastic Scintillator Detectorsmentioning

confidence: 99%

A review of small animal dosimetry techniques: image-guided and spatially fractionated therapy

Johnstone,

Bazalova-Carter

2023

J. Phys.: Conf. Ser.

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Research in small animal radiotherapy is a crucial step in clinical translation of novel radiotherapy techniques, either delivered as stand-alone treatment or in combination with other treatments, such as chemotherapy and immunotherapy. In order to efficiently translate preclinical findings to the clinical setting, preclinical radiotherapy must replicate clinical therapy in terms of mode of delivery as well as dose delivery accuracy as closely as possible. In this review article, we focused on the description of dosimetry tools for radiotherapy of small animals delivered with kilovoltage x-ray beams on image-guided irradiators and in a spatially-fractionated manner by means of microbeam therapy. The specifics of dosimetry of kilovoltage x-ray beam deliveries with small, often sub-millimeter, beams are highlighted, and suitable dosimeters, phantoms, and dose measurement and calculation techniques are reviewed. Future directions for accurate real-time high spatial resolution dosimetry of small animal irradiations are also discussed.

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“…As the dosimeter design incorporates a PMMA optical fiber, it was necessary to consider the stem effect contributions to the fiber output signal. Many attempts have been made to quantify or discriminate such signals in optical fiber dosimeters for both kV and MV beam energies [8], [15]- [17]. Le Deroff et al [17] irradiated 194 cm of PMMA optical fiber lacking an active scintillating volume with beam energies set at 225, 100 and 40 kVp while applying maximum tube currents to maximize the stem effect signal (13, 30 and 45 mA for 225, 100 and 40 kVp, respectively).…”

Section: Introductionmentioning

confidence: 99%

“…Many attempts have been made to quantify or discriminate such signals in optical fiber dosimeters for both kV and MV beam energies [8], [15]- [17]. Le Deroff et al [17] irradiated 194 cm of PMMA optical fiber lacking an active scintillating volume with beam energies set at 225, 100 and 40 kVp while applying maximum tube currents to maximize the stem effect signal (13, 30 and 45 mA for 225, 100 and 40 kVp, respectively). The negligible signal generated in this experiment was indicative of the inability of beam energies ≤225 kV to produce secondary electrons capable of causing detectable Cerenkov effects within the optical fiber.…”

Section: Introductionmentioning

confidence: 99%

Initial Evaluation of the Performance of Novel Inorganic Scintillating Detectors for Small Animal Irradiation Dosimetry

et al. 2020

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The purpose of this study was to design and evaluate the performance of four novel inorganic scintillating detectors (ISDs) on the Small Animal Radiation Research Platform (SARRP). Relative scintillator output, measurement repeatability, setup uncertainty, linearity with dose rate, and signal reproducibility over time were investigated. The Gd2O2S:Tb detector had the highest relative signal output, generating up to 219 times more charge than a previously characterized BCF-60based plastic scintillating detector (PSD). The Gd2O2S:Tb detector was then used to measure 220 kVp therapy beam profiles of 10 x 10 and 5 x 5 mm 2 fields. Beam profiles using the ZnS-based phosphor were also obtained and compared to investigate the performance of a lower density inorganic scintillator. 10 x 10 and 5 x 5 mm 2 therapy beam profile measurements made with the Gd2O2S:Tb and BCF-60 detectors differed, on average, by 1.1% and 1.9%, respectively. The ZnS:Ag measurements differed, on average, by 2.5% and 6% relative to BCF-60 measurements of the 10 x 10 and 5 x 5 mm 2 beam profiles, respectively. MicroCT imaging of the detector volumes was also performed, revealing poor packing of the ZnS:Ag crystalline phosphor in the deepest region of the cylindrical cavity. The Gd2O2S:Tb detector, in particular, has proven to be a promising candidate for real-time dosimetry of small fields in small animal irradiators, primarily because of the very large signal intensities observed, along with good repeatability, dose rate linearity, reproducibility and agreement with beam profile measurements made with a previously validated detector.

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Characterization of a scintillating fibre detector for small animal imaging and irradiation dosimetry

Cited by 6 publications

References 28 publications

In vivosurface dosimetry with a scintillating fiber dosimeter in preclinical image‐guided radiotherapy

In vivosurface dosimetry with a scintillating fiber dosimeter in preclinical image‐guided radiotherapy

A review of small animal dosimetry techniques: image-guided and spatially fractionated therapy

Initial Evaluation of the Performance of Novel Inorganic Scintillating Detectors for Small Animal Irradiation Dosimetry

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