Development Of A Near-infrared Induced Abortion Operation System

Induced abortion is a method of termination of pregnancy by using the surgery. So far, China has used it for nearly 50 years, vacuum aspiration has a simple and effective, less bleeding and other characteristics, its completely abortion rate is still the highest. Vacuum aspiration applies to the termination of 5 to 10 weeks of gestation. However, the traditional vacuum aspiration abortion is a intrauterine surgical operation with the operator’s experience; it can not accurately determine the location of intrauterine gestational sac inside and determine whether embryonic tissue is cleaned, surgical procedure is in non-direct visual conditions, with a certain blindness.An endoscopic medical instrument is used to examine the internal disease of the human organs, including intestinal endoscopy, stomach endoscopic, uterus endoscopy, abortion endoscopic, ENT endoscopic, laparoscopic, bladder endoscopic, etc. With the development of modern medical and health services, Endoscope backend with universal applicability generally takes a CCD camera or a camera, it can be more convenient to observe, sample and save the image to achieve clinical data visualization images, systematic, network and intelligence management. CCD pixels are more than 410,000, far greater than the fiber bundle of 50,000 pixels. CCD has clear image, vivid color and higher resolution than ordinary optical fiber endoscope image, CCD can provide more people to watch at the same time. However, when using a straight or fiber mirror, it still be not guaranteed to see the whole picture of the uterine cavity.In large-area operation, a lot of blood will flow, especially during pregnancy, the distribution of blood vessels is more and more, if some actions are not taken, surgery can not get on because of poor visibility infected blood. Endoscopic technology has solved the two problems above currently. The method of the uterine cavity filling with the expansion substances can get a good view. Due to expansion of substances that can cause air embolism or thrombosis, this method can not be good for abortion.As a result, endoscopic visualization abortion gradually developed.The uterus is a hollow muscular organ, which is potentially empty lacuna, the external force in the uterine cavity surface can occur in two biomechanical effects: uterine wall is elastically deformed and uterine smooth muscle gets contraction and relaxation changes; this can make intrauterine lacunar corresponding deformation, thereby causing changes in intrauterine pressure. Depending on the flow mechanics, intrauterine pressure aspiration is a relatively large positive pressure, and intraperitoneal is generally negative, both can formate a large pressure difference, when the pressure difference has the ability to overcome the resistance of the fallopian tubes and tubal cannot stop intrauterine blood backflow along the fallopian tube into the abdominal cavity, it will cause endometriosis and other complications.In order to overcome the shortcomings of the existing abortion visualization systems, It provides a full observation during surgery to the entire surgical site plan, proposes a abortion system design based on near-infrared light. Near infrared LED instead of conventional visible light LED is illuminated, CMOS camera in the case with blood occlusion has better imaging results; The CMOS module which is accurately assembled in the attraction channel can make physician observe surgical site clearly and attract gestational sac accurately to void blindness. A decompression pipe is designed to reduce the pressure inside the uterine cavity in the form of fluid mechanics to avoid complications such as uterine blood reflux; In addition, it can promote blood sinus closed, reduce bleeding and reduce pain.Blood absorbance in the near infrared region is less than the region in the visible. At 200～1300nm band, absorption spectrum of human blood and animal blood are measured, comparing the absorbance level of ultraviolet region, visible region and near-infrared light region, human and animal blood absorbance is minimal in the near infrared region of 700～1300nm. In the near-infrared light, due to blood absorbance of the near-infrared light is lower than the visible light, near-infrared light intensity of the light transmitted through the blood is relatively more than visible, the transmitted light intensity that CMOS camera is receiving is relatively more, CMOS camera imaging is very better. To do near infrared light simulation experiments in a blood environment to verify the CMOS camera is with better resolution under conditions of near-infrared light conditions than visible light.The visible light、850nm、940nm infrared LED were selected directly as the main wave lighting.Three cuvettes filled of blood were selected, the size of three cuvettes with different optical path (0.3mm,0.5mm, lmm) represent the thickness of blood.Throughing the blood of 0.3 mm thickness, CMOS camera can distinguish line spacing of 1 mm under the condition of visible light, but the imaging result is bad;At 850 nm、940 nm infrared light conditions, CMOS can distinguish line spacing of 0.5 mm, the imaging effect is good. Throughing the blood of 0.5 mm thickness, CMOS camera can not distinguish line spacing of 1 mm under the condition of visible light, so the imaging result is bad;At 850 nm、940 nm infrared light conditions, CMOS can distinguish line spacing of 1mm, the imaging effect is worse. Throughing the blood of 1 mm thickness, CMOS camera can not distinguish line spacing of 1 mm under the condition of visible light and 850 nm、940 nm infrared light conditions, so the imaging result is worst.Experiments above proved that CMOS camera can penetrate through the blood of 0.3 mm thickness under the condition of infrared lighting, and imaging effect was better than visible light. The spectral range of the CMOS image sensor is 350-1100nm, the peak response wavelength is near 700nm, and the CMOS image sensor has its own cut-off wavelength. With infrared wavelength increases the responsivity and quantum efficiency of CMOS sensors are changed, this will have certain effects on imaging. Therefore,under the condition of imaging through blood, a reasonable choice of the wavelength of the infrared light becomes the key.So,we need do the following experiments to further determine the best infrared wavelengths.A tungsten halogen light source (wavelength range 360～2000nm), and 10nm narrowband filter (800,900,925,975,1000,1025,1050,1075nm) consists of a single wavelength of infrared light, it is as a light source using the beam light illumination.The following experiment conditions are same with the above except the illumination light source.Throughing the blood of 0.3 mm thickness, CMOS camera can distinguish line spacing, the imaging result of 800 and 900 nm wavelength of infrared light is better; the imaging result of 925 and 975 nm wavelength of infrared light is good; the imaging result of 1000、1025、1050 and 1075 nm wavelength of infrared light is bad.Throughing the blood of 0.5 mm thickness, CMOS camera can distinguish line spacing badly. Throughing the blood of 1.0mm thickness, CMOS camera can not distinguish line spacing. Throughing the blood of 0.5mm or 1.0mm thickness, the imaging result of CMOS camera at different monochromatic light wavelengths is worse.The experiments determine the best infrared wavelength is near 900nm throughing the blood of 0.3mm thickness.CMOS camera analog signal is acquired through the WDM acquisition card application completes the video signal acquisition by manipulating the DirectShow filter with characteristics of seamless docking of application and WDM and DirectShow video acquisition card driver. In the case of visual abortion surgery, realize visualization in the whole process of the real abortion. CMOS image sensor adopts OmniVision company 1/18 of an inch OV6922 medical sensor, low power consumption is very suitable for small disposable cameras used in medical imaging applications, better application in artificial abortion in the system. OV622 become required diameter less than ideal choice of 4 mm camera application. Due to the special physiological structure of the cervix and asked to attract pipe diameter can’t more than 9 mm, use OV6922 CMOS chip module can meet the above requirement. The CMOS module includes CMOS image sensor, the imaging lens in the front, lighting source, FPC flexible circuit board. CMOS image sensor placed on the FPC flexible circuit board, the power line placed in CMOS module power signal line cavity. Lighting source using near infrared LED replace the traditional visible light leds. CMOS imaging lens module attracted towards the direction of the window to observe the situation when intrauterine gestational sac inside the location and intraoperative suction evacuation accurately. CMOS module followed by a wedge and played the role of fixed CMOS module to prevent CMOS imaging module shaking impact in attracting tube. CMOS camera with wide-angle camera, the camera can be observed that the maximum range of the angle β,β≥90°. The angle between the axial direction and attracting CMOS imaging objective of the central axis of the tube is α,100≤α≤135°. A transparent partition is placed in the front of CMOS module to prevent bleeding contamination of CMOS camera modules during surgery.DirectShow on application layer provides a unified specification of COM interface, thus to separate the underlying hardware equipment and high-level application, which can be easily programmed using multimedia data from a device or equipment playback multimedia data, without consideration of specific hardware features. To construct a proper filter graph, and then build a filter graph of each filter, and connect them; Through the application again to control the filter graph manager to complete the function of video acquisition. The use of vc++ MFC to achieve the video acquisition interface. Run the software, click on the "video preview", "video video", "image processing","video formats " and other buttons, which can realize video preview video, video, video image processing and other functions. Video image processing functions including brightness, contrast, saturation, chroma, etc. After test, all the above functions.