MR temperature monitoring applying the proton resonance frequency method in liver and kidney at 0.2 and 1.5 T: segment-specific attainable precision and breathing influence

OBJECT: The objective of this study was to evaluate breathing influence on precision in temperature determination by using the proton resonance frequency (PRF) shift method depending on the location in abdominal organs at 0.2 and 1.5 T. MATERIALS AND METHODS: Phase images were acquired with gradient echo sequences in a total of 12 volunteers at 1.5 and 0.2 T. Different examination protocols were performed (each 8 measurements with (1) in-/expiration, (2) free breathing, (3) under breathhold, (4) with breathing belt triggering, and (5) with navigator triggering (integrated in MR signal acquisition). Regions of interest were placed on liver and kidneys, and the resulting phase differences between the measurements were transformed into corresponding temperature differences. RESULTS: Precision significantly varied depending on the liver segment or location in the kidney. Gating techniques were found better than breathhold techniques and clearly better than non-gated examinations. The most precise approach reached a standard deviation of 2.0 degrees C under continuous breathing when navigator gating was used at 1.5 T. CONCLUSION: PRF temperature measurement is feasible even for moving organs in the abdomen at 0.2 and 1.5 T. The location of the target region and the required precision of the measurements should direct the choice of examination mode.     

基于互相关分析的约翰逊噪声测温法研究

约翰逊噪声是由在导体中的电子的随机热运动产生的基本的物理学结果。它的根本性质允许人们构建不要求周期性定标的温度测量系统。因而长期，无人值守的运行是可行的。分析了在采集、传输约翰逊噪声电压信号过程中消除外部干扰和各级放大器的噪声的信号处理问题，提出了采用间接互相关分析法来降噪的方法，同时给出了基于相关分析的测温系统设计。     

NIR emitting terephthalates(Sm_xDy_yGd_(1-x-y))_2(tph)_3(H_2O)_4 for luminescence thermometry in the physiological range

The first luminescence thermometer based on coordination compound of samarium and dysprosium is repo rted.High luminescence intensity and high signal resolution are reached thanks to the concentration quenching reduction due to the use of the trimetallic complexes of Sm-Dy-Gd.The best thermometric properties in a wide temperature range among the studied systems are demonstrated by(Sm_(0.2)Dy_(0.15)Gd_(0.65))_2(tph)3(H_2 O)_4.The sensitivity reaches 0.5%/K in visible range and 1.2%/K in NIR range at low temperatures and 0.5%/K and 0.8%/K in physiological range.     

Linear response fluorescent temperature-sensing properties based on Stark sublevels of Er3+-doped Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Yb1/2Nb1/2)O3 ceramics

The Er³⁺ doped 0.84(PMN-PT)?0.14PYN ceramics were employed as a temperature-sensing material. The obtained compounds exhibit strong visible upconversion (UC) fluorescence under a 980-nm diode laser excitation. On account of the Stark split effect, the ²H_11/2, ⁴S_3/2, and ⁴F_9/2 levels of Er³⁺ split into two Stark sublevels, respectively. The fluorescence intensity ratios (FIR) between these sublevels were calculated in a temperature range of 133–573?K, and a linear FIR vs. temperature relation has been found. FIR of A/B shows a wide temperature sensing range with a relatively low sensitivity of 0.003?K^?1. Meanwhile E/C illustrates the highest sensitivity of 0.0134?K^?1 but in the smallest temperature range 453–573?K. FIR technique provides us a optical thermometric method with constant sensitivity in a wide temperature range.     

New Fluoroptic Thermometer with Optical Fiber

A new optical fiber fluoroptic thermometer based on the temperature-fluoroptic characteristic of fluoroptic materials is presented.The ratio technique of intensities of fluorescent emission lines of certain rare earth phosphors is used,making the measurement of temperatures of the system to 0.5℃ precision.The characteristics of thermometer are discussed and the experiment results of temperature are given.     

比辐射率现场测试方法的理论和实验研究

以反射率归一化双向反射率分布函致为基础建立了红外测温普遍方程,并以此作为理论基础提出一种比辐射率现场测试方法。实验结果表明,理论与实践相符。     

Special Report on the International Temperature Scale of 1990: Report on the 17th Session of the Consultative Committee on Thermometry

This article summarizes the results of the 17th Session of the Consultative Committee on Thermometry of the International Committee of Weights and Measures (Comité Consultatif de Thermométrie of the Comité International des Poids et Mesures) that met in Sèvres, France, September 12–14, 1989. That session was devoted exclusively to the completion of the International Temperature Scale of 1990, described herein, and to the implications of its adoption.     

红外测温法研究延期药的燃烧温度

文章采用红外测温法研究延期药的燃烧温度,将延期药压制成延期体装入测试模具,然后分别用两种红外测温仪对燃烧温度进行测量,拟合燃烧温度曲线并分析。对延期药燃烧温度的研究结果表明,用红外测温法可以清楚地反映延期药从点燃到燃烧结束燃烧温度的动态变化规律。该方法对延期药的配方设计、寻找优良性能的添加剂、延期药的延期精度等方面的研究具有重要的意义。     

Optical Diffraction Corrections in Radiometric Thermodynamic Temperature Determination

One of the main components of uncertainty in high-temperature thermometry arises because of the size-of-source effect (SSE). This effect makes the temperature measurement sensitive to the geometry of the radiating environment. It is caused by optical diffraction and especially by light scattering off/from, and inter-reflections between, optical components inside the pyrometer. The LNE-INM/CNAM is involved in extending the thermometry temperature scale to very high temperatures (T > 2000 °C) and has developed eutectic-based fixed points (Sadli et al. (in: Zvizdic (ed.) Proceedings of TEMPMEKO 2004, 9th International Symposium on Temperature and Thermal Measurements in Industry and Science, 2004)) and a thermodynamic temperature measurement capability based on absolute radiometric methods (Briaudeau et al. (in: D. Zvizdic (ed.) Proceedings of TEMPMEKO 2004, 9th International Symposium on Temperature and Thermal Measurements in Industry and Science 2004)). A new measurement technique that uses an optical fiber has been developed and tested, allowing the determination of the SSE at any defocusing plane, with high resolution. A model based on optical diffraction has been developed to simulate the SSE in a real situation, considering the contribution to the pyrometer signal of the whole “3D” optical scene inside the blackbody furnace. Using the same approach, it has been demonstrated that optical scattering in a simple radiance meter can be estimated from accurate optical diffraction measurement.