光学体积描记术

The amplitude ratio of the photoplethysmography waveform of red light and infrared light varies with the oxygen saturation of blood. 脉搏血氧仪具有连续、无创、快速、准确监测人体动脉血氧饱和度和心率的功能，现已在临床上发挥重要作用[1]。

In the present article, the approach of dynamic spectrum （DS） is in troduced, which is based on the principle of photoplethysmography. 在近红外光谱检测法所面临的诸多问题中，个体差异和检测条件对光谱测量的影响，是突出的技术问题。

How to eliminate the effects of the noises while correctly extract the photoplethysmography is one of the key tasks to improve the accuracy and reliability of the instrument. 消除测量系统中各种干扰的影响,设法正确地检出光电容积脉搏波信号是关系到测量系统准确性及其精度的关键问题之一。

Objectives To assess the scope of photoplethysmography (PPG), color duplex ultrasonography, percutaneous transpopliteal venography for evaluating chronic venous disease. 目的了解双功彩超、经皮腘静脉穿刺造影、光电容积描记（PPG）在检测下肢静脉倒流中的优缺点及相对适应证。

Objective To analyse pulse transit time variability (PTTV) in frequency domain and to study the physiological interpretation of PTTV. Methods Pulse transit time (PTT) was obtained by ECG and PPG (photoplethysmography) from 187 subjects. 目的分析脉搏波传导时间变异性(pulse transit time variability,PTTV),研究PTTV的生理意义。