Research on vein finder instrument design using twowavelength optical method

Nội dung text: Research on vein finder instrument design using twowavelength optical method

1. TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 15, SOÁ K1- 2012 RESEARCH ON VEIN FINDER INSTRUMENT DESIGN USING TWO- WAVELENGTH OPTICAL METHOD Tran Van Tien, Huynh Quang Linh, Nguyen Anh Hang University of Technology – VNUHCM (Manuscript Received on April 5 th , 2012, Manuscript Revised November 20 rd , 2012) ABSTRACT: In intravenous injection manipulation, popular visual method of fast and accurate finding of veins strongly depends on patient body and physician experience. Especially for geriatric, pediatric or obese patients, nurses or paramedics may fail in the first intravenous injection and have to repeat many times, which causes a lot of pains or discomforts for the patients. This paper will introduce some studies on imaging of vein using two-wavelength optical method, on basis of which a vein finder instrument can be optimally designed for supporting intravenous injection manipulation. Keywords: intravenous injection, vein finder, light tissue interaction, two-wavelength optical method. 1. INTRODUCTION intravenous injection manipulation. However, even skilled nurses or paramedics may be very Injection needles are the most common and often unsuccessful in such manipulation with greatest source of procedural pain for patients, obese, geriatric or pediatric patients, when their especially in pediatrics [1]. In quick veins are not palpable or visible for popular immunizations, glucose monitoring, visual finding. According to a recent study [5], intravenous injection, laceration repairs, it is estimated that there are nearly 500 million dermatologic procedures and even tattooing, vein injections done every year with 92.5 to needle pain is a major growing concern. These 97.3 percent successful in the first attempt, so effects may be amplified with age, children that around 14 million cases are failed on the avoid medical treatment, 16% to 75% of first try. The main reason is the vein invisibility surveyed adults refuse to donate blood and due to factors like obesity and small sized geriatric patients refuse flu shots due to fear of veins. So research design of vein finder devices needle pain [2,3]. The health implications of to support nurses in intravenous injection needle phobia extend beyond the affected manipulation is really necessary. Moreover, individuals, HIV patients continued to infect those devices can be useful for physicians for others while delaying blood tests and needle locating and mapping the abnormal veins in phobic parents are less likely to immunize their treating disorders or diagnosing related children [4]. It is important to minimize the diseases. discomfort associated with needle injection for patients more than once; especially in Trang 43
2. Science & Technology Development, Vol 15, No.K1- 2012 Recently several devices have been used for mapping veins in the body before developed to support physicians and nurses in surgery or treatment. Venography offers a wide finding veins for diagnosis or intravenous field of view and is used for identifying and manipulation. Their principle of working is treating numerous disorders. There is however based on different capability of scattering and a significant amount of radiation associated absorption of skin and vein to the light with with the procedure [9]. different wavelength to show peripheral veins The purpose of this research is firstly on the skin background [6, 7]. Mentioned quantitative study of the interaction of LED devices are very compact and cause no damage light with the tissue, on base of which optimal to patients but require the ambient lighting not combination of LED wavelength should be too bright in order to view the vein clearly. chosen and secondly experimental verification Some modern infrared imaging device with of optimal layout of LEDs to design low cost complex electronic system permits projecting vein finder instrument. of venous system contrast-enhanced images in 2. METHODS real-time but they are very expensive. With other physical principle, high-resolution 2.1. Simulation methods ultrasound scanner can provide good quality Photons transport in tissue may include images of the superficial and deep veins for mainly following processes: reflection, obese patients or small veins for pediatric refraction, scattering and absorption. In order patients in real-time as well. However, the to examine the photon penetration in skin and transducer has to be held in place during needle veins, the Monte Carlo code for photon insertion, which makes uncomfortable transport simulation MCML [12] has been used manipulation [8]. Venography provides an with the model of an infinitely narrow photon image of the veins after the patient is injected beam perpendicularly irradiating on the with a contrast dye. This x-ray image can be surveyed skins. Table 1. Biological structure of surveyed skins [11] Skins with veins Skins without veins Layer Thickness Layer Thickness Epidermis 0.06 mm Epidermis 0.06 mm Dermis 5 mm Dermis 5 mm Blood 1 mm Subcutaneous 7 mm Subcutaneous 7 mm Trang 44
3. TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 15, SOÁ K1- 2012 Model of skin (table 1) has 3-4 infinitely scattering width in the dark room etc. General wide plane layers, which have characteristic procedure is measuring intensity of reflecting parameters as the thickness, the refractive light at various positions in dependence on index n, the absorption coefficient µ a, the different configurations of LEDs. scattering coefficient µ , and the anisotropy s 3. RESULTS AND DISCUSSIONS factor g. The top ambient medium is air and bottom ambient medium is subcutaneous. 3.1. Simulation results Photon wavelength was selected in accordance Monte Carlo simulation was used to to LED sources used in experimental procedure evaluate quantitatively two tasks: i) at which including 5 types: blue (453.5nm), green photon wavelength the absorption of blood is (515.8nm), orange (593.4nm), red (635.4nm) the highest, this result will help to select the and IR (750nm). appropriate LED to optimally distinguish the areas of veins and without veins, and ii) the 2.2. Experimental procedure scattering radius (the radial distance at which In order to optimize geometric layout of the light drops to 1/e of its original intensity) LEDs to design appropriate projection area, and absorption depth (the vertical distance into some measurements were carried out to the material at which the light drops to 1/e of examine the effectiveness of human vision to its original intensity), mentioned results will above mentioned wavelengths, the relationship help to select optimal operating regime of between the angle of illumination and LED. 0 4 2 0.5 0 -2 z [cm] z -4 1 -6 -8 -1 -0.5 0 0.5 1 r [cm] Figure 1. Internal photons distribution in tissue without veins with incident wavelength 634.5 nm Fig. 1 shows the photon distribution with case, the scattering radius is approximately incident wavelength 634.5 nm when they 0.99 cm and the depth is about 1.21 cm. propagate in the tissue without veins. In this Trang 45
4. Science & Technology Development, Vol 15, No.K1- 2012 10 0 4 2 0.5 0 -2 z [cm] z -4 1 -6 -8 -1 -0.5 0 0.5 1 r [cm] Figure 2. Internal photons distribution in tissue with veins with incident wavelength 634.5 nm Fig. 2 shows the photon distribution with with no vein. In addition, the scattering radius incident wavelength 634.5 nm when they has no change and is a useful parameter to propagate in the tissue having veins. The design the vein finder instrument. photon distribution is clearly discontinued in For optimal selection of LED wavelength, the areas of depth from 0.506 cm to 0.606 cm, mentioned photon-tissue-vein configuration where is the vein area. It has been reported that was simulated for a set of wavelengths: blue the blood in the veins absorbed a considerable (453.5nm), green (515.8nm), orange part of photon beam. The reflected part on the (593.4nm), red (635.4nm) and IR (750nm). skin surface decreases and as a result, the vein Calculated results are showed in Tab. 3. area will be seen darker than the surrounding Tab.3. MC simulation results for different lights reaching in the skin with vein and skin without vein Skin with vein Skin without vein Wavelength zmax rmax R(r max ) A(z=0.506cm) zmax rmax R(r max ) (nm) (cm) (cm) (cm -2) (cm -1) (cm) (cm) (cm -2) 453.5 0.545 0.575 1.022 e -8 2.638 e -6 0.685 0.575 2.039 e -9 515.8 0.575 0.755 1.202 e -9 0.0001323 1.025 0.785 4.475 e -9 593.4 0.615 0.895 1.061 e -9 0.001074 1.215 0.945 1.397 e -9 635.4 1.315 0.945 2.72e -9 0.002109 1.215 0.995 1.134 e -9 750 1.315 1.265 3.35 e -9 0.004726 1.215 1.185 9.301 e -10 Where z max is the absorption depth , rmax is Note that the instrument to locate a vein the scattering radius, R(r max ) gives the must be achieved two conditions: the contrast reflectance at r max , A(z=0.506cm) gives the of a vein image can be viewed clearly and the photon probability of absorption in z layer of illuminating space around the vein is large material. enough for access it. Thus the appropriate light has to satisfy: i) the penetration must overcome Trang 46
5. TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 15, SOÁ K1- 2012 the depth of the vein under the skin, so that the light. The sensitivity to the orange light is blood can absorb a great part of photons, ii) the about five times higher than the sensitivity to scattering radius has to be large enough. the red and violet light [16]. Thus, using the Generally the veins are set up about 0.6 cm combination of orange and red light to below the skin surface, results in Tab. 3 show manufacture the vein finder instrument will that the light satisfying mentioned conditions considerably enhance the view contrast. are 750, 635 and 593.4 nm. 3.2. Experimental results Furthermore because the human vision can detect the lights from 350 to 760nm [15], the Firstly, the experiment was designed for red and orange light can be considered to use. measuring of scattering radius depending on Scattering radius and penetration of both operating current of LED (Fig. 3). With wavelengths are similar, but the absorption of circular black plastic rings around LED with blood for red light (A=0.002109 cm -1) is higher the radius increasing by 1mm, the scattering than orange light (A=0.001074 cm -1) and the radius in dependence on operating current of reflectance of skin without vein for red light LED light (635.4nm) irradiated perpendicularly (R=1.134 e -9 cm -2) is smaller than orange light to the skin with vein and without vein were (R=1.397 e -9 cm -2). In addition, human eyes are measured [Fig. 4]. more sensitive to the orange light than the red with vein, dark room without vein, dark room 1.2 without vein, dim light 1.0 0.8 0.6 scattering (cm) radius 0.4 10 20 30 40 50 60 70 current (mA) Figure 3. The optical system for measuring scattering radius Figure 4. The scattering radius in dependence on LED current in dark room and dim light In the dim light condition, the visible condition of normal light, so we need to shade scattering radius is considerably smaller then in the ambient light by any way to obtain optimal the dark room condition. In practice, the vein view of backscattering light from LED. finder instrument should be used in the Trang 47
6. Science & Technology Development, Vol 15, No.K1- 2012 635.4 1.8 1.2 593.4 515.8 453.5 1.0 1.5 0.8 1.2 0.6 scattering radius radius scattering(cm) scattering widthscattering(cm) 0.4 0.9 10 20 30 40 50 60 70 0 10 20 30 40 50 current (mA) angle (degree) Figure 6. The scattering radius in dependence on irradiation Figure 5. The scattering radius in dependence on angle of LED 653.4nm operating on 45mA current LED current for different wavelengths in dark room irradiated with different angles to the skin without vein. condition Fig.5 shows that, the scattering radius with optimal angle for LEDs layout in instrument the light with the wavelength 635.4 nm is design. considerably greater then the others (593 nm, A prototype of vein finder instrument, 515 nm, 453nm). Mentioned results are which was designed and manufactured consistent with simulation. For the purpose of according to above mentioned results, is shown enhancing detection capacity of human eye the on the figure 7. Vein image could be seen orange light with the wavelength 635.4 nm has clearly in normal ambient light. However, for been used as the optimal selection. the final product many aspects such as LED Figures 4 and 5 also shows, the optimal layout configuration, user-friendly flexible operating current of all measured LEDs to give usage, stability and lastingness etc. have to the maximum scattering radius is about 45 mA. considered more practically. The relationship between the angle of irradiation and scattering radius shown on figure 6 was examined for the selection of the Trang 48
7. TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 15, SOÁ K1- 2012 Figure 7. Prototype of vein finder instrument. 4. CONCLUSION irradiation angle of LED can be used for LEDs layout design optimization. With the Monte Carlo simulation of light- skin-vein interaction, experimental verification 3. There was found plausible scientific bases and prototype manufacturing, some for using the combination between red and conclusions can be drawn as follows: orange LEDs as an optimal solution for vein finding and imaging. This result 1. Simulation results of the interaction of similar as the design of foreign products LED light with the tissue by MCML are (VeinLite, TransLite) confirmed the ability consistent with experimental results. This of domestically manufacturing with lower procedure can be used for further price. biomedical research using LED technology. 2. The optimal operating current of all measured LEDs to give the maximum scattering radius is about 45 mA. The scattering radius in dependence on Trang 49
8. Science & Technology Development, Vol 15, No.K1- 2012 NGHIÊN C U CH TO THI T B TÌM T ĨNH M CH B NG PH ƯƠ NG PHÁP QUANG H C K T H P HAI B ƯC SÓNG Tr n V ăn Ti n, Hu ỳnh Quang Linh, Nguy n Ánh H ng B môn V t Lý K Thu t Y Sinh, Khoa Khoa h c ng d ng, Tr ưng ð i H c Bách Khoa - ðHQG TP.HCM TÓM T ẮT: Trong thao tác tiêm t ĩnh m ch, vi c xác ñ nh nhanh và chính xác v trí t ĩnh m ch th ưng ph thu c r t l n vào c ơ th b nh nhân c ũng nh ư kinh nghi m c a các y bác s ĩ. ð c bi t ñ i v i nh ng b nh nhân lão khoa, b nh nhi, hay b nh nhân béo phì , các y tá, y s ĩ hay th t b i trong l n tiêm ñu tiên, ph i tiêm l i nhi u l n gây ñau ñ n và c m giác s hãi cho b nh nhân. Bài vi t này s gi i thi u m t s nghiên c u trong vi c xác ñ nh v trí t ĩnh m ch b ng ph ươ ng pháp quang h c k t h p hai bưc sóng, trên c ơ s ñó ch t o thi t b t i ưu ñ h tr các thao tác tiêm t ĩnh m ch ñươ c nhanh chóng, d dàng và chính xác. REFERENCES [5]. Ludeman K, Nursing Made Incredibly Easy!, 6, 5 (2008). [1]. Schechter N.L , Zempsky W.T , Cohen L.L, McGrath P.J, Pain reduction during [6]. Lovhoiden G, Ph.D. Thesis, Design of a pediatric immunizations: evidence-based Prototype Vein Enhancing Illuminator, review and recommendations , Pediatr. U.Tenn, Health Sci. Ctr., (2004). Rev, 119, 1184 (2007). [7]. Zeman H.D, Lovhoiden G, Vrancken C, [2]. Vika M, Raadal M, Skaret E, Kvale G, Prototype vein contrast enhancer. SPIE, Dental and medical injections: Bellingham , WA, 3949 (2004). prevalence of self-reported problems [8]. Kremkau F.W, Diagnostic ultrasound: among 18-yr-old subjects in Norway , principles, instruments and exercises , Eur J Oral Sci, 114, 122 (2006). WB Saunders, Philadelphia, PA (2001). [3]. Harrington M, Sweeney M.R et. al, [9]. Jackson T.R, Snell J.W, Goble J.C, What would encourage blood donation Laws E.R, and Kassell N.F, Tissue in Ireland?, Vox Sang , 92, 361 (2007). Selective Magnetic Resonance [4]. Froehlich H, West D.J, Compliance with Subtraction Venography. Proc. Spie, hepatitis B virus vaccination in a high- Medical Imaging, 2434, 300-306 (1995). risk population, Aust. J. Physiother , 47, 179 (2001). Trang 50
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