隨著台灣人口的高齡化，老年人得到糖尿病的比例越來越高，據統計平均65歲以上每五個人就有一個是糖尿病患；糖尿病患足部及其相關感染更是最大的隱憂之一，約有四成七的截肢病患是因為糖尿病；因此歐美等先進國家對糖尿病足部病變研究不虞遺力，反觀國內相關危險因素之研究仍非常匱乏。本研究主要目的在利用光電技術，建立一套以光體積變化描述波形（PPG）與雷射都卜勒流速計（LDF）為基礎的非侵入式微循環量測系統，並透過此系統來監控糖尿病患足部血管流量與流速的變化。由於微循環的訊號易受外在環境，如溫度、探頭壓力及受試者內在情緒，如脈搏、呼吸的影響，因此很少採用微循環流量的絕對大小，作為循環功能是否有異樣的參考標準。但微循環訊號所呈現之相對變化，在生理意義上卻能提供許多有價值的參考性指標。本研究主要可分為兩個部份，第一個部分為雙通道微循環量測系統之硬體架設，欲藉由此系統量測左右兩側足部微循環流量與流速的變化。結果顯示，流速計的流速指標<ω>與實際血液仿體流速的關係，已可達到不錯的相關性（R2=0.97）。第二部份是實際應用於人體手指與足部末梢微循環量測，利用自行設計的近紅光系統，可以穩定擷取血量與血流變化的訊號；並在利用壓脈袋給予壓力模擬周邊血管阻塞下，本系統也能在左右兩側同部位，所擷取之血量與血流訊號中反映出明顯之差異。在實際病患量測結果分析上發現，利用左右兩腳PPG波形產生的時間差，可以明顯地判斷出足部末梢是否有血管病變的現象（P＜0.05）。

Diabetes mellitus is a highly prevalent disease among the elderly of Taiwan and worldwide. Reportedly, one out of five persons aged 65 years and older suffers this illness, a constellation of chronic disorders, diabetic vasculopathy including diabetic foot and a resultant osteomyelitis is one of the most common one; approximately 47% of the amputation are due to diabetes. Thus, medical care of diabetic foot and infections on diabetics has become an important clinic issue in our ageing society. Most of western countries including United States and European Union have devoted to much research on the pathogenesis and relevant infections in diabetic feet; by comparison, there are very few in Taiwan. The aim of this study is to apply the photo-electronic technology to develop a non-invasive measurement system for microcirculation measurement system based on photoplethesmography (PPG) and laser Doppler flowmetry (LDF) techniques. With the system, we could monitor the changes of blood volume and blood velocity in the diabetic lower limbs. The research was mainly divided into two parts. The first part was the setup of the dual-channels measurement system. We expected it to monitor the changes of blood volume and blood velocity both collected simultaneously from the right and left lower limbs. At present, the correlation coefficient R2 between the indexes of the flow meter's velocity <ω> and practically velocity of blood mimicking fluids had reached a high linear relation of 0.97. In the second part, we measured the human microcirculation signals. Till now, the self-designing non-invasive measurement system for microcirculation could acquire the changes of blood volume and blood velocity in human’s fingers and lower limbs. In addition, there were significant differences in blood volume and blood velocity signals between bilateral sites of fingers or lower limbs by using this system, when applying a pressure to cuff one site of upper arm or leg by using a pressure cuff. In the clinical data analyzing, we found out that the pulse timing differences between pulse peaks in the bilateral lower limbs’ great toe PPG pulses could figure out whether patients has vascular diseases in the lower limbs (P < 0.05).

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