Study Of The Fault Diagnosis System For Electrical Impedance Scanning (EIS) Hardware And Image Post-Processing

Breast cancer is a kind of the malignant tumors which imperil women's health badly. Early diagnoses are crucial to improve the survival rate of the patients with breast cancer. Institutions concerned at home and abroad are advocating general investigation on it for the women of the right age. However, common methods for breast examination are not competent for early general investigation. Electrical Impedance Scanning (EIS) is a new method for breast cancer examination. Since conductance between tumors and normal breast tissues is significantly different, the distributing of current can be detected by electrodes placed on the breast surface to judge if there are abnormal blocks with exceptional conductance in the breast. It has been proved that EIS is an effective measure for early diagnoses of breast cancer as an adjunct to many other imaging devices, such as X-ray mammography. It is especially applicable for early general examination of breast cancer because it has so many advantages such as non-injury, nonradiation, easy operation, low price for devices, low charge for examination and so on.In 2002, the first EIS prototype in China was developed based on EIS theory by the electrical impedance research group in the Biomedical Engineering Department, Fourth Military Medical University. After that, they carried out clinical trials. The device got good appraisement and it showed that EIS technology has a bright future. Meanwhile, the clinical trials put forward new requirements and advice for the device. In order to make EIS more suitable for clinical general investigation, it is necessary to do further research and betterment work on the existing EIS system.First, many kinds of factors can make EIS hardware have some faults so the EIS system can't run rightly. By analyzing the circuit of the existing EIS system, this study determined the key testing points and designed the hardware and software of the fault diagnosis system. The DAQ board is used to acquire the analog voltage signals and the DIO board is used to acquire the digital voltage signals of the testing points. The software of the fault diagnosis system is used to control the measuring flow and process the signals of the testing points. Then, faults can be located at the module of every chip. The fault diagnosis system for EIS hardware can make EIS system more complete. And users can remove faults with this system efficiently so that EIS system can run rightly. The fault diagnosis system can make EIS more suitable for clinical general investigation.Second, our research group is developing the new EIS imaging system and we use the USB interface for data transferring between the computer and EIS Host. Since EIS Host is a special USB device, we must provide an appropriate USB device driver for our application so that the application can use device access functions of drivers to communicate with the device. Therefore, with three softwares: DriverStudio, DDK and Visual C++, we developed the USB device driver, the application and the USB firmware for the new EIS system. By debugging them, we succeeded in data transferring between the computer and the EIS Host.Third, in order to enhance the abilities of EIS to distinguish the abnormal tissues, this study has done some improvements on the algorithm of the existing EIS software: analyzing the data of the dark blocks in EIS images to determine the criterion of space and threshold and using image enhancement to display the dark blocks prominently. The dark blocks recognition module was programmed and used to recognize the dark blocks in the images of 40 patients in 2006. The result showed that all the typical dark blocks was recognized.Fourth, when examined by EIS, the breast is divided into 9 sections and they are scanned respectively, so there are 9 images according to every breast. The study tried to stitch the 9 images and give a whole image of the breast. Therefore, this study determined the stitching points and stitched the images. Then, we processed the sutures of the stitched image based on fade-in and fade-out theory and stitched the EIS scanning images with no sutures.The aim of this study is to improve EIS system and make it serve on clinical work with more facility. The fault diagnosis system can secure the device and the persons. The USB interface developed by ourselves can make the data transfer between the computer and EIS Host conveniently. The dark blocks recognition module enhances the abilities of EIS to distinguish the abnormal tissues. Stitching the EIS scanning images make the information of these images clearer and more obvious and it is beneficial to the judgment of the clinicians.