Fiberoptic infrared radiometer for real time in situ thermometry inside an MRI system

Sade, Sharon; Katzir, Abraham

doi:10.1016/s0730-725x(01)00298-3

Cited by 18 publications

(9 citation statements)

References 7 publications

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“…Next, to measure IR signals induced by temperature, an embedded-type thermometer probe (CH 2) of a FOT was also constructed. As an IR fiber, we selected a silver halide optical fiber (PIR 900/1000, Art Photonics, Berlin, Germany) that can serve as a sensing element and an IR waveguide at the same time [ 17 , 18 , 19 , 20 , 21 , 22 ]. Diameters are 0.9 mm for the core only and 1 mm including the cladding.…”

Section: Materials and Experimental Setupmentioning

confidence: 99%

“…Next, in the cases of FOTs, they normally use a silver halide optical fiber as an infrared optical fiber (IR fiber) to measure temperature by transmitting IR signals emitted from a heat source [ 17 , 18 , 19 , 20 , 21 , 22 ]. As a non-contact temperature sensor, those based on IR fibers have been fabricated to use in examination or treatment rooms where magnetic resonance imaging (MRI) or radiofrequency ablation (RFA) devices are installed [ 20 , 21 ]. Previous reports demonstrated that IR fiber-based FOTs have immunity to high EMI and RFI.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber

Lee

Shin

Jang

et al. 2015

Sensors

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In this study, we have studied the effects of temperature and X-ray energy variations on the light output signals from two different fiber-optic sensors, a fiber-optic dosimeter (FOD) based on a BCF-12 as a plastic scintillating fiber (PSF) and a fiber-optic thermometer (FOT) using a silver halide optical fiber as an infrared optical fiber (IR fiber). During X-ray beam irradiation, the scintillating light and IR signals were measured simultaneously using a dosimeter probe of the FOD and a thermometer probe of the FOT. The probes were placed in a beaker with water on the center of a hotplate, under variation of the tube potential of a digital radiography system or the temperature of the water in the beaker. From the experimental results, in the case of the PSF, the scintillator light output at the given tube potential decreased as the temperature increased in the temperature range from 25 to 60 °C. We demonstrated that commonly used BCF-12 has a significant temperature dependence of −0.263 ± 0.028%/°C in the clinical temperature range. Next, in the case of the IR fiber, the intensity of the IR signal was almost uniform at each temperature regardless of the tube potential range from 50 to 150 kVp. Therefore, we also demonstrated that the X-ray beam with an energy range used in diagnostic radiology does not affect the IR signals transmitted via a silver halide optical fiber.

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Section: Materials and Experimental Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber

Lee

Shin

Jang

et al. 2015

Sensors

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“…The intensity of emitted IR radiation depends on the temperature of the heat source, as delineated in Equation (2), called the Stefan-Boltzmann law [6,8,17,19]:

I = {ɛ σ}_{e} T^{4} [W / {cm}^{2}]

where ɛ is the emissivity of the heat source (0 ≤ ɛ ≤ 1) and σ e is the Stefan-Boltzmann constant for radiant exitance, that is, 5.67 × 10 −12 W/(cm 2 ·K 4 ). The wavelength of peak exitance ( λ max ) is related to the temperature of the heat source by the Wien displacement law, as also shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Development of a 2-Channel Embedded Infrared Fiber-Optic Temperature Sensor Using Silver Halide Optical Fibers

Yoo

Jang

Seo

et al. 2011

Sensors

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A 2-channel embedded infrared fiber-optic temperature sensor was fabricated using two identical silver halide optical fibers for accurate thermometry without complicated calibration processes. In this study, we measured the output voltages of signal and reference probes according to temperature variation over a temperature range from 25 to 225 °C. To decide the temperature of the water, the difference between the amounts of infrared radiation emitted from the two temperature sensing probes was measured. The response time and the reproducibility of the fiber-optic temperature sensor were also obtained. Thermometry with the proposed sensor is immune to changes if parameters such as offset voltage, ambient temperature, and emissivity of any warm object. In particular, the temperature sensing probe with silver halide optical fibers can withstand a high temperature/pressure and water-chemistry environment. It is expected that the proposed sensor can be further developed to accurately monitor temperature in harsh environments.

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“…However, monitoring of respiratory activity such as respiratory rate, depth and gas exchange in an MR room with conventional electrical sensors or transducers is challenging, as the strong gradients of magnetic fields and the radiofrequency (RF) pulse induce interactive noise on the physiological signals during MR image acquisition. Thus, it is necessary to develop medical devices that can monitor the respiratory signal with other biomedical signals such as temperature and photo-plethysmograph (PPG) even in the presence of strong electro-magnetic interference [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Development of Respiration Sensors Using Plastic Optical Fiber for Respiratory Monitoring Inside MRI System

Yoo¹,

Jang²,

Seo³

et al. 2010

Journal of the Optical Society of Korea

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In this study, we have fabricated two types of non-invasive fiber-optic respiration sensors that can measure respiratory signals during magnetic resonance (MR) image acquisition. One is a nasal-cavity attached sensor that can measure the temperature variation of air-flow using a thermochromic pigment. The other is an abdomen attached sensor that can measure the abdominal circumference change using a sensing part composed of polymethyl-methacrylate (PMMA) tubes, a mirror and a spring. We have measured modulated light guided to detectors in the MRI control room via optical fibers due to the respiratory movements of the patient in the MR room, and the respiratory signals of the fiber-optic respiration sensors are compared with those of the BIOPAC ® system. We have verified that respiratory signals can be obtained without deteriorating the MR image. It is anticipated that the proposed fiber-optic respiration sensors would be highly suitable for respiratory monitoring during surgical procedures performed inside an MRI system.

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Fiberoptic infrared radiometer for real time in situ thermometry inside an MRI system

Cited by 18 publications

References 7 publications

Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber

Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber

Development of a 2-Channel Embedded Infrared Fiber-Optic Temperature Sensor Using Silver Halide Optical Fibers

Development of Respiration Sensors Using Plastic Optical Fiber for Respiratory Monitoring Inside MRI System

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