Design And Realization Of Intravascular Photoacoustic Imaging Acquisition System

Intravascular photoacoustic(IVPA) imaging, based on the biological photoacoustic effect, is a newly emerged interventional imaging modality for the diagnosis of vascular diseases. As a powerful supplement to the intravascular ultrasound(IVUS) imaging, it combines advantages of ultrasonic and optical imaging. An efficient and stable data acquisition system is an important part of the IVPA imaging system. The main function is to transfer the photoacoustic signals to the host computer.In this dissertation, an IVPA signal acquisition system is designed, which includes an analog signal processing circuit and a digital signal processing circuit, according to the characteristics of IVPA signals and related literatures. The analog signal processing circuit, being used to adjustably amplify the signals, consists of a frequency-selective amplification circuit, an operational amplifier circuit and a TGC amplifier circuit. AVR MCU acts as the main control unit of the TGC circuit. The serial port circuit is used to modify the parameters. In addition, MCU programs are written in C language in the ICCAVR development environment to amplify the signal under control and modify data parameters of the serial port. The function of the digital signal processing circuit includes data cache, digital filtering and data transmission. A FPGA chip is adopted as the main control part. In addition, a high speed AD chip, two SRAM and USB interface are also included. The sampling procedures, ping-pong cache program and USB control program are written with hardware description language in Quartus II. The performance of the system has met the expected qualification through the module debugging and integral debugging.