Dose rate measurements with a ruby-based fiber optic radioluminescent probe

Teichmann, T.; Sommer, M.; Henniger, J.

doi:10.1016/j.radmeas.2013.03.027

Cited by 15 publications

(24 citation statements)

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“…Using external beam radiotherapy sources, Jordan (Jordan 1996) measured a ~3 ms half-time, and Teichmann et al (Teichmann et al 2013) measured 2 half-times of 2.54 ±0.03 ms and 46.6 ±0.6 ms. However, both our measurements and the results of Teichmann et al (Teichmann et al 2013) demonstrate that some ruby crystals possess luminescence mechanisms with decay kinetics on the order of seconds (for example, Ruby #2 in figures 6 and 7), while others do not (Ruby #1 in figures 6 and 7). Bessonova et al (Bessonova et al 1979) measured a significant ruby radioluminescence intensity buildup during constant dose rate exposure for ruby specimens that contained no specially introduced impurities.…”

Section: Discussionmentioning

confidence: 99%

“…First, a wide variety of scintillator materials emit in the red wavelength region, i.e., 600–750 nm (Jordan 1996, Molina et al 2012, Veronese et al 2014, McCarthy et al 2013, Teichmann et al 2013, Martinez et al 2015). Scintillation in longer wavelengths is advantageous for dosimetry because it greatly simplifies the removal of the most important sources of measurement uncertainty for scintillation detectors—the Cerenkov and fluorescence effects (Beddar et al 1992a, Therriault-Proulx et al 2013a), which exhibit a continuous emission spectrum most prominent in the blue region.…”

Section: Introductionmentioning

confidence: 99%

“…The photoluminescence signal is proportional to the absorbed dose in the fiber-optic cable and can therefore distort the desired radioluminescence signal induced in the ruby crystal, which is proportional to the absorbed dose in the detector volume. Teichmann et al (Teichmann et al 2013) further investigated ruby-based ISDs for external beam radiation sources and highlighted that ruby crystals can exhibit unwanted time-dependent luminescence properties that probably depend on the admixture of impurities other than Cr 3+ in the crystal lattice (Bessonova et al 1979). Both Jordan and Teichmann et al used the temporal gating technique to suppress the stem signal.…”

Section: Introductionmentioning

confidence: 99%

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Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy

Kertzscher

Beddar

2016

Phys. Med. Biol.

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We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from > 5% to < 1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was < 3% as long as the source distance from the scintillator was < 7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by > 5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy

Kertzscher

Beddar

2016

Phys. Med. Biol.

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“…72 The RL light was transmitted through an optical bandpass filter with 689 nm centre wavelength and 29.5 nm bandwidth. The remaining light signal was measured using a Hamamatsu H7421-50 detector (Hamamatsu Protonics KK, Shizuka, Japan).…”

mentioning

confidence: 99%

“…The sensor is stable for larger doses up to at least 500 Gy. 72 Although the system seems very sensitive, it is not clear how it might perform in the typical clinical radiotherapy dosimetry environment.…”

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confidence: 99%

A review of recent advances in optical fibre sensors forin vivodosimetry during radiotherapy

O'Keeffe¹,

McCarthy²,

Woulfe³

et al. 2015

BJR

109

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This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The article outlines the principal sensor design systems along with some of the main strengths and weaknesses associated with the development of these techniques. The successful demonstration of these sensors in a range of different clinical environments is also presented.

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Real‐time in vivo dosimetry system based on an optical fiber‐coupled microsized photostimulable phosphor for stereotactic body radiation therapy

et al. 2020

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Purpose: To develop an in vivo dosimeter system for stereotactic body radiation therapy (SBRT) that can perform accurate and precise real-time measurements, using a microsized amount of a photostimulable phosphor (PSP), BaFBr:Eu 2+. Methods: The sensitive volume of the PSP was 1.26 9 10 À5 cm 3. The dosimeter system was designed to apply photostimulation to the PSP after the decay of noise signals, in synchronization with the photon beam pulse of a linear accelerator (LINAC), to eliminate the noise signals completely using a time separation technique. The noise signals included stem signals, and radioluminescence signals generated by the PSP. In addition, the dosimeter system was built on a storage-type dosimeter that could read out a signal after an arbitrary preset number of photon beam pulses were incident. First, the noise and photostimulated luminescence (PSL) signal decay times were measured. Subsequently, we confirmed that the PSL signals could be exclusively read out within the photon beam pulse interval. Finally, using a water phantom, the basic characteristics of the dosimeter system were demonstrated under SBRT conditions, and the feasibility for clinical application was investigated. The reproducibility, dose linearity, dose-rate dependence, temperature dependence, and angular dependence were evaluated. The feasibility was confirmed by measurements at various dose gradients and using a representative treatment plan for a metastatic liver tumor. A clinical plan was created with a two-arc beam volumetric modulated arc therapy using a 10 MV flattening filter-free photon beam. For the water phantom measurements, the clinical plan was compiled into a plan with a fixed gantry angle of 0°. To evaluate the energy dependence during SBRT, the percent depth dose (PDD) was measured and compared with those calculated via Monte Carlo (MC) simulations. Results: All the PSL signals could be read out while eliminating the noise signals within the minimum pulse interval of the LINAC. Stable real-time measurements could be performed with a time resolution of 56 ms (i.e., number of pulses = 20). The dose linearity was good in the dose range of 0.01-100 Gy. The measurements agreed within 1% at dose rates of 40-2400 cGy/min. The temperature and angular dependence were also acceptable since these dependencies had only a negligible effect on the measurements in SBRT. At a dose gradient of 2.21 Gy/mm, the measured dose agreed with that calculated using a treatment planning system (TPS) within the measurement uncertainties due to the probe position. For measurements using a representative treatment plan, the measured dose

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Dose rate measurements with a ruby-based fiber optic radioluminescent probe

Cited by 15 publications

References 8 publications

Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy

Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy

A review of recent advances in optical fibre sensors forin vivodosimetry during radiotherapy

Real‐time in vivo dosimetry system based on an optical fiber‐coupled microsized photostimulable phosphor for stereotactic body radiation therapy

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Dose rate measurements with a ruby-based fiber optic radioluminescent probe

Cited by 15 publications

References 8 publications

Ruby-based inorganic scintillation detectors for192Ir brachytherapy

Ruby-based inorganic scintillation detectors for192Ir brachytherapy

A review of recent advances in optical fibre sensors forin vivodosimetry during radiotherapy

Real‐time in vivo dosimetry system based on an optical fiber‐coupled microsized photostimulable phosphor for stereotactic body radiation therapy

Contact Info

Product

Resources

About

Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy

Ruby-based inorganic scintillation detectors for¹⁹²Ir brachytherapy