Vein Pattern Locating Technology for Cannulation: A Review of the Low-Cost Vein Finder Prototypes Utilizing near Infrared (NIR) Light to Improve Peripheral Subcutaneous Vein Selection for Phlebotomy <s> Site for venipuncture. <s> Intravenous (IV) procedures are often difficult due to the poor visualization of subcutaneous veins. Because existing vein locators lack the ability to assess depth, and also because mis-punctures and poor vascular access remain problematic, we propose an imaging system that employs diffuse reflectance images at three isosbestic wavelengths to measure both the depth and thickness of subcutaneous veins. This paper describes the proposed system as well as proof-of-principle experimental demonstrations. We initially introduce the working principle and structure of the system. All measurements were based on the Monte Carlo (MC) method and accomplished by referring an optical density (OD) ratio to a multi-layer diffuse reflectance model. Results were all validated by comparative ultrasound measurements. Experimental trials included 11 volunteers who were subjected to both ultrasound measurements and the proposed optical process to validate the system's applicability. However, the unreliability of the "thickness" measurement of the vein may be due to the fact that the veins have collapsible walls - so excess pressure by the transducer will give a false thickness. <s> BIB001 </s> Vein Pattern Locating Technology for Cannulation: A Review of the Low-Cost Vein Finder Prototypes Utilizing near Infrared (NIR) Light to Improve Peripheral Subcutaneous Vein Selection for Phlebotomy <s> Site for venipuncture. <s> Poor quality of the images captured by a conventional vein viewer or finder renders it to be un-useful as a diagnostic tool. This is a result of an insufficient amount of venous blood in the superficial veins and the low resolution of the near-infrared (NIR) cameras used in the traditional vein viewers. In this paper, we propose using a high resolution NIR camera, vein warmer and image contrast enhancer (CLAHE) to improve the view of the superficial veins. This approach effectively produces a diagnostic medical superficial vein images. <s> BIB002
The preferred venipuncture sites include the antecubital fossa and the back of the hand that has the superficial vein. Veins are blood vessels that aim to return the blood to the heart. It has a higher percentage of deoxygenated blood (deoxyhemoglobin) as compared to arteries that have higher level of oxygenated blood (oxyhemoglobin) BIB002 . Hemoglobin (Hb) is the primary component of the blood, specifically; of the red blood cells that have the oxygen carrying capacity  . There are three veins that can be selected. Among the three are the veins in the median aspect (center of the arm) must be the first choice followed by the veins in the lateral aspect (outer thumb side), i.e., the cephalic vein, and last are the veins in the medial aspect (inner little finger side), i.e., the basilic vein  . Figure 5 shows the main veins of the antecubital fossa (a) median cubital vein, (b) cephalic vein, and (c) the basilic vein. The median cubital vein is considered as the best site for venipuncture. It lies over the cubital fossa and serves as a branching between the cephalic and basilic veins  . Compared to the two other sites it is well anchored vein, usually large and prominent  . Moreover, there were studies that include the determination of the veins' properties such as the depth and its diameter as a parameter, which affects its visibility with the use of a vein finder device. The said two parameters were quantitatively measured by the ultrasound method. In the study of Ganesh, S., the ultrasound images were obtained using techniques, such as dot and tick-mark methods, and were analyzed with the software Corel Draw Graphics Suite 12. The diameter of the veins was an average value of the diameter measured in the horizontal and vertical directions reported in (mm) millimeters. This study stated that there is a linear correlation between depth and diameter of veins.  Another study by Goh, C. et al. in 2017, which proposed a new measurement system that, infers both the depth and thickness of subcutaneous veins to improve the success rate of venous access. The principle is based on the diffuse reflectance images at three isosbestic wavelengths to measure both the depth and thickness of subcutaneous veins. Measurements were based on the Monte Carlo (MC) method and accomplished by referring an optical density (OD) ratio to a multilayer diffuse reflectance model. The results of their study were all validated using comparative ultrasound measurements. It shows that the inference of depth and thickness by OD ratio determination, the melanosome (Cm) have to be calculated. A 'characteristic angle', as obtained during this process, was then determined and used to select the appropriate Cm group for the Moreover, there were studies that include the determination of the veins' properties such as the depth and its diameter as a parameter, which affects its visibility with the use of a vein finder device. The said two parameters were quantitatively measured by the ultrasound method. In the study of Ganesh, S., the ultrasound images were obtained using techniques, such as dot and tick-mark methods, and were analyzed with the software Corel Draw Graphics Suite 12. The diameter of the veins was an average value of the diameter measured in the horizontal and vertical directions reported in (mm) millimeters. This study stated that there is a linear correlation between depth and diameter of veins.  Another study by Goh, C. et al. in 2017, which proposed a new measurement system that, infers both the depth and thickness of subcutaneous veins to improve the success rate of venous access. The principle is based on the diffuse reflectance images at three isosbestic wavelengths to measure both the depth and thickness of subcutaneous veins. Measurements were based on the Monte Carlo (MC) method and accomplished by referring an optical density (OD) ratio to a multi-layer diffuse reflectance model. The results of their study were all validated using comparative ultrasound measurements. It shows that the inference of depth and thickness by OD ratio determination, the melanosome (Cm) have to be calculated. A 'characteristic angle', as obtained during this process, was then determined and used to select the appropriate Cm group for the determination of the vein depth and thickness. Segmented vein imaging is utilized to specify the location of veins and extract the OD ratio values. The obtained OD ratio is referred to the 3000 diffuse reflectance models to produce depth and thickness, as shown in Figure 6 BIB001 . The said determinations of the veins depth and its diameter can be considered as a useful parameter for future studies. It can help to improve the capabilities of a vein finder, as a guiding device for cannulation or phlebotomy, performed by medical practitioners. Sensors 2018, 18, x FOR PEER REVIEW 13 of 18 determination of the vein depth and thickness. Segmented vein imaging is utilized to specify the location of veins and extract the OD ratio values. The obtained OD ratio is referred to the 3000 diffuse reflectance models to produce depth and thickness, as shown in Figure 6 [71]. The said determinations of the veins depth and its diameter can be considered as a useful parameter for future studies. It can help to improve the capabilities of a vein finder, as a guiding device for cannulation or phlebotomy, performed by medical practitioners. 