System Implementation of Time Domain Breast Cancer Detection System Prototype

Abstract

한국유방암학회가 발표한 유방암 현황분석 자료에 따르면 우리나라 유방암 발생 증가율은 OECD 국가 중 최고수준이다. 유방암은 조기발견 시 완치율이 90% 이상으로 조기검진 활성화가 중요하다고 할 수 있다. 본 논문에서는 초기 유방암 검진에 주로 사용되고 있는 x-ray mammography의 단점을 보완하는 대안으로 활발히 연구되고 있는 Microwave Imaging 기법의 유효성을 검증하기 위해 benign과 malignant tumor model의 모양적 특성을 반영한 model을 제작하였다. 이 model을 FDTD 방식을 이용하여 제안된 breast cancer detection system 내에 배치 후 시뮬레이션을 수행하여 tumor를 찾아내는 것을 확인하였다. 제안되는 시스템의 동작을 확인하기 위해 FPGA board를 이용하여 simulation을 수행하여 MATLAB Simulink의 simulation 결과와 비교하였다. 이를 통하여 simulink에서 생성된 shifted된 clock과 동일한 clock인 FPGA board의 clock을 가지고 ETS(Equivalent Time Sampling)를 수행할 수 있음을 확인하였다. 또한, 실제 FPGA board와 연결할 4개의 안테나와 low noise amplifier, analog/digital converter로 이루어진 board를 제작하고 이를 FPGA board와 연결하여 시스템의 동작을 확인하였다.;Microwave Imaging is a promising method for early-stage breast cancer detection. It is based on the large contrast of electric properties between the tumor and the normal breast tissue. In aspect of distinguishing between malignant tumor and benign tumor, there are some factors to be considered. In this paper, we focus on the shape of a tumor and make corresponding models – malignant and benign tumors. Both benign and malignant tumor models are implanted in the simple breast model and we performed simulation and analyze these two models. Also, we performed the implementation of proposed time domain breast cancer system especially focused on master controller’s behavior and control. Proposed system includes 16 UWB transceivers and a master controller.[16] In this paper, for prototyping, master controller’s role goes to FPGA board and 4 50MHz antennas are used instead of 16 UWB transceivers. By phase shifting, FPGA board generates 200MHz clock from on-board 50MHz and 5ns shifted 200MHz. With these clocks, 8 shifted clocks are generated and it plays an ETS(Equivalent time sampling). We compare the result of these PLL outputs and antenna control signal which was simulated in MATLAB Simulink. The simulation results show that it is the same with the result from Simulink simulation. So, it would be expected that it will work properly as ETS when it is working for the real system with those shifted clocks. Also, to perform with the FPGA board for implementation of the proposed system, we make the analog board with 50MHz antenna, LNA(Low noise amplifier), ADC(Analog/Digital converter). The data which measured by analog board shows that FPGA board can generate the pulse signal and control signals properly.