PDF(Pubmed)
Abstract：
Near-infrared fluorescence (NIRF) thermometry is an emerging method for the noncontact measurement of in vivo deep temperatures. Fluorescence-lifetime-based methods are effective because they are unaffected by optical loss due to excitation or detection paths. Moreover, the physiological changes in body temperature in deep tissues and their pharmacological effects are yet to be fully explored. In this study, we investigated the potential application of the NIRF lifetime-based method for temperature measurement of in vivo deep tissues in the abdomen using rare-earth-based particle materials. β-NaYF4 particles codoped with Nd3+ and Yb3+ (excitation: 808 nm, emission: 980 nm) were used as NIRF thermometers, and their fluorescence decay curves were exponential. Slope linearity analysis (SLA), a screening method, was proposed to extract pixels with valid data. This method involves performing a linearity evaluation of the semilogarithmic plot of the decay curve collected at three delay times after cutting off the pulsed laser irradiation. After intragastric administration of the thermometer, the stomach temperature was monitored by using an NIRF time-gated imaging setup. Concurrently, a heater was attached to the lower abdomens of the mice under anesthesia. A decrease in the stomach temperature under anesthesia and its recovery via the heater indicated changes in the fluorescence lifetime of the thermometer placed inside the body. Thus, NaYF4:Nd3+/Yb3+ functions as a fluorescence thermometer that can measure in vivo temperature based on the temperature dependence of the fluorescence lifetime at 980 nm under 808 nm excitation. This study demonstrated the ability of a rare-earth-based NIRF thermometer to measure deep tissues in live mice, with the proposed SLA method for excluding the noisy deviations from the analysis for measuring temperature using the NIRF lifetime of a rare-earth-based thermometer.
摘要：
近红外荧光（NIRF）测温是一种新兴的非接触式测量体内深层温度的方法。基于荧光寿命的方法是有效的,因为它们不受由于激发或检测路径引起的光学损失的影响。此外，深部组织中体温的生理变化及其药理作用尚待充分探索。在这项研究中,我们研究了基于NIRF寿命的方法在使用稀土基颗粒材料测量腹部体内深部组织温度的潜在应用。与Nd3和Yb3共掺杂的β-NaYF4颗粒（激发：808nm，发射：980nm）用作NIRF温度计，它们的荧光衰减曲线是指数的。斜率线性分析(SLA)，一种筛选方法，提出用有效数据提取像素。该方法涉及对在切断脉冲激光照射后的三个延迟时间处收集的衰减曲线的半对数图进行线性评估。胃内给药温度计后，采用NIRF时间门控成像装置监测胃温.同时,在麻醉下将加热器连接到小鼠的下腹部。麻醉下胃温度的降低及其通过加热器的恢复表明放置在体内的温度计的荧光寿命的变化。因此，NaYF4:Nd3+/Yb3+用作荧光温度计,其可以基于在808nm激发下在980nm处的荧光寿命的温度依赖性来测量体内温度。这项研究证明了基于稀土的NIRF温度计能够测量活体小鼠的深层组织，使用拟议的SLA方法，可以从使用稀土温度计的NIRF寿命测量温度的分析中排除噪声偏差。
