Multi-channel electronic parallel scanning photoacoustic real-time tomo graphic-imaging method and apparatus thereof

Abstract

The present invention provides a multichannel electronic parallel scanning real-time optoacoustic chromatographic image formation method and its equipment. Said method includes the following steps: making pulse laser light be come into biological tissue to produce optoacoustic signal; utilizing high-density array ultrasonic transducer to parallelly receive optoacoustic signal, utilizing multichannel electronic parallel scanning circuit to make synchronous acquisition and processing; after the digital signal processing and multiple-beam digital synthesis based on dynamic focusing utilizing USB interface to input the frame image data into computer. Said equipment for implementing above-mentioned method includes laser, high-density array ultrasonic transducer, multichannel electronic parallel scanning circuit and computer.

Description

technical field [0001] The invention relates to photoacoustic tomography technology, in particular to a multi-channel electronic parallel scanning photoacoustic real-time tomography method and device thereof. Background technique [0002] When the light absorber is irradiated with a short-pulse laser, the absorber absorbs the light energy to cause a temperature rise, and the temperature rise causes thermal expansion to generate a pressure wave. This is the photoacoustic effect. The photoacoustic effect gives the relationship between the light absorption distribution of the sample and the photoacoustic signal. , so the light absorption distribution of the sample can be reconstructed by measuring the photoacoustic pressure in all directions, which is the basic principle of photoacoustic imaging. Photoacoustic signals can realize tomographic imaging of samples or biological tissues with different light absorption, because the photoacoustic signals genera...

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Problems solved by technology

On the other hand, when ultrasonic transducers are generally used for measurement at present, ultrasonic transducers are basically placed on the end face of the sample or biological tissue to measure the photoacoustic signal transmitted from the sample or biological tissue; the signal obtained in this way is generally It is the superposition of the signals generated by each sound point of the body acoustic field at the measurement point. Therefore, it is difficult to reconstruct the photoacoustic image in the measured body or judge the signal of the exact point inside it. It requires multi-point measurement and complex algorithm to process data, and the amount of calculation is very high. Large; and for the application of samples or biological tissue with complex structure, such as biological tissue, because it is a strong scatterer of light, the incident laser light diverges quickly, and biological tissue is generally not an isotropic optical and acoustic body , so the sound field generated by the laser and the reflection, transmission and absorption of the sound field are very complicated, and it is difficult to obtain the exact photoacoustic signal of each point

The Chinese invention patent application with the patent application number 03126896.X discloses a "method and device for multi-element array electronic scanning photoacoustic tomography of biological tissue". Part of the group unit receives the photoacoustic signal, and then quickly synthesizes a scan line through the phase control algorithm; but a frame of image is composed of many scan lines, and this method requires repeated laser firing many times to reconstruct a frame of image. According to the method proposed in the article, it takes at least 2 seconds, and it is impossible to perform real-time imaging when the emission repetition frequency of lasers suitable for photoacoustic imaging is only tens of hertz.

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