Photoacoustic Mesoscopy For In Vivo Tumor Imaging In Small-animal Models

As a new non-invasive biomedical imaging technology,photoacoustic imaging(PAI)combines the low attenuation,high penetration of ultrasound imaging and the lossless and high contrast of pure optical imaging.PAI can present multi-scale images with different spatial resolution and penetration depth characteristics.Among them,photoacoustic mesoscopy(PAMe)can break through the limitation of optical diffusion depth while providing high spatial resolution images.It is suitable for researching on biological mechanisms of in vivo tumors,monitoring of tumor treatment processes,and prediction and evaluation of therapeutic effects.Combined with the current domestic and international research on the PAMe system and the status quo in oncology research,this paper proposes to combine the high sensitivity of focused single-ultrasonic detector with the multi-angle stereo scanning method to develop a new PAMe system.The hardware part of the system was designed and screended,and the hardware part was built.Through the software control part design,the semi-cylindrical stereo scanning scheme in discrete and continuous dual mode,as well as the data acquisition and storage of photoacoustic signals are realized.After obtaining the effective photoacoustic signal,the image reconstruction method based on virtual point detection technology and the parallel computing strategy are used to realize the rapid reconstruction of the image.In order to verify the performance of the system,a phantom experiment was first designed and implemented to evaluate the performance of the PAMe system.The experimental results show that the spatial resolution of the system can reach 77 microns and can realize three-dimensional imaging.In addition,the mouse kidney was imaged,the outline of the kidney and the internal vascular network were clearly visible in the experimental results.Finally,the mouse tumor model was imaged,and the PAMe method for living animal tumor model was developed.