Research On 3D Photoacoustic Tomography Method And System Based On Sparse Sampling

In recent years,the incidence and death rate of malignant tumor diseases have been on the rise and become the biggest threat to human health.It has become a hot issue in the field of medical imaging and oncology to come up with effective methods for the diagnosis of malignant tumors.Using medical imaging technology to obtain structure and function information of tumor is one of the key methods to ensure effective follow-up treatment.Among the existing medical imaging technologies,ultrasound imaging has a low contrast,CT imaging has a strong radiation effect,and optical coherence tomography has a low penetration depth limited by the optical diffraction.All of these lead to its inability to obtain comprehensive information about the status of the tumor.While photoacoustic imaging is a new non-invasive and non-destructive multi-mode medical imaging technology,which possesses the advantages of high contrast in optical imaging and large penetration in ultrasonic imaging simultaneously.Nowadays,it's in a critical period from scientific research to clinical application.Therefore,it is of great practical significance and clinical value to develop the photoacoustic imaging system and methods suitable for molecular imaging of tumor.A 3D optoacoustic imaging method,includes the optoacoustic imaging system and the corresponding reconstruction method based on sparse sampling,is proposed in this paper.This paper includes following parts:First,the basic principle of photoacoustic tomography is studied,the process of photoacoustic imaging is analyzed in detail through theory inference and simulation model established by k-wave.Based on the above theory,the application of iterative reconstruction method to photoacoustic tomography is studied.After taking the characteristic of large receiving angle of ultrasonic transducer into full consideration,an accurate projection model based on detection sensitivity of array element is constructed.Based on the joint algebraic reconstruction method,the photoacoustic tomography image reconstruction with sparse sampling is realized.Then,a 3D photoacoustic tomography system under the sparse sample is designed and constructed.The research was carried out on new optical path and ultrasonic detection method,and the photoacoustic coplanar structure was proposed beneficial for extending imaging field of vision,improving laser illumination and photoacoustic detection efficiency.In addition,a human-computer interaction platform based on Lab VIEW was designed to effectively control the system.Finally,a series of corresponding experiments were designed to test the lateral resolution and imaging range of the system,and to verify its capability to achieve high performance photoacoustic imaging.Finally,the simulation and experiment of the photoacoustic imaging method with sparse sampling are carried out.On the one hand,the feasibility of the sparse imaging method and system were validated with simulation in the case of sparse sampling and photoacoustic phantom experiment.On the other hand,the sparse imaging method was applied to the 3D photoacoustic imaging of blood vessel and tumor phantom,and mice with breast cancer.The imaging performance of the system is quantitatively described by the structural similarity between the imaging target and the 3D optoacoustic image,which further demonstrates the effectiveness of the 3D optoacoustic imaging system and method based on sparse sampling.A three-dimensional photoacoustic imaging method with sparse sampling is proposed in this paper.Based on the two-dimensional photoacoustic tomography technology,this method can effectively collect the photoacoustic signal of the imaging section under the sparse sample with a new lighting path and ultrasonic detection mode,which greatly reduces the acquisition time of the photoacoustic data.Thought using the photoacoustic image reconstruction method based on sparse sampling,high-quality reconstruction of the light absorption distribution in tissue can be carried out,and the 3D photoacoustic image of the optical absorber within the tissue can be accurately obtained.