Photoacoustic Imaging:from Theory To Practice Of Microscopy And Application On Surveillance And Estimation Of Burn Injury

Photoacoustic(PA)imaging,as an emerging imaging method,has the advantages of high contrast,high resolution and deep penetration depth.This paper focuses on PA imaging technology,and carries out two major scientific researches concerning the design and instrumentation of PA microscopy and the surveillance and evaluation of burn models using dual-scale PA imaging.The first part is to design and build a PA microscopy.By designing of the hardware structure and software components based on basical principle of PA iamging,the modulation of the optical path,the synchronous control of PA signal acquisition and the image reconstruction processing are realized.After the continuous debugging of the system,the instrumentation of the PA microscopy was successfully realized,and the system performance parameters were tested.The lateral resolution of the PA microscopy was tested to be about 11.08 ?m with an imaging depth of no less than 600?m.In the second part,the dual-scale PA imaging technique was applied to monitor and evaluate burns.A superficial second degree burn and a deep second degree burn model were established on dorsal skin of the mouse.Then,the burn depth,the structural and functional information,volume changes and angiogenesis of the burn region were studied from macroscale to microscale level through PA imaging.The experiment results showed that deep second degree burns showed deeper burn depth and larger burn area volume,while superficial second degree burns changed faster and had higher concentration in blood oxygen saturation.Quantitatively,the burn depth value of 1.6 mm was regarded as the boundary point to distinguish the two kinds of burns within post-burn three days.On the second and third day post-bum,the oxygen saturation percentage of 40%was also regarded as an important separating point for refference.Combining these two indicators can make a more accurate diagnosis in burn depth.In summary,photoacoustic imaging technology can perform well in structural and functional imaging of burns.This work have successfully employed macroscopic PA computed tomography and microscopic PA microscopy in burn imaging.This study performed systematic imaging and evaluation of the occurrence and development of burns,providing important references and research theory for future research of PA imaging in burns.