Study On Quantitative Photoacoustic Spectroscopic Imaging Method For Interventional Application

The photoacoustic imaging technique can achieve high contrast structural imaging in a large depth.Further combined with photoacoustic spectroscopy,it can also identify and quantify components to achieve high-sensitivity imaging.It is expected to help in the diagnosis and screening of cardiovascular diseases and gastrointestinal tumors.Interventional photoacoustic imaging systems reported at home and abroad have relatively few combinations with photoacoustic spectroscopy.On the one hand,micro-interventional imaging catheters meeting the clinical size requirements(intravascular interventional dimensions need to be less than 1 mm)make it difficult to achieve high signal-to-noise imaging.However,in photoacoustic spectroscopy,the signal-to-noise ratio directly affects the accuracy of the spectrogram and quantitative analysis.On the other hand,the spectral data cannot be guaranteed from the same spatial point due to the uneven motion of the imaging catheter in vivo,which greatly affects the accuracy of spectral analysis.In view of this,a quantitative photoacoustic spectroscopic imaging method for interventional application has been studied.1.An interventional photoacoustic spectroscopy imaging system has been designed.Using dual light source illumination mode,the photoacoustic spectrum analysis of oxygen saturation and blood vessels' vulnerable plaque are realized in a flexible conversion way.The longitudinal resolution of the system up to 40.2?m,and the maximum signal-to-noise ratio is 58.6dB.2.The certainty of correspondence between photoacoustic spectroscopy and its spatial sources is ensured by scanning wavelength before moving sample.And the combination of upper / lower computer is used to achieve precise control of the system and the spectrum scanning method.3.A series of experimental studies on quantitative photoacoustic spectroscopic imaging method for interventional application were performed.Analysis result of oxygen saturation phantom and the default value of only about 1% error.And the correlation between photoacoustic spectroscopy of lipid phanton and absorption spectrum of lipid is 85.87%,which shows good consistency.Based on the above,photoacoustic imaging and spectral signal of rabbit abdominal aorta isolated ex vivo blood vessel,which with plaque,are acquired.Subsequently,the separation of the tissue components and the spatial distribution of the concentration are achieved.Finally,rat's rectal in vivo photoacoustic imaging and the quantitative analysis of oxygen saturation are acquired.The above results show that the designed photoacoustic spectroscopy quantitative imaging method possesses the ability of photoacoustic structural imaging and functional imaging of animals,in vivo and ex vivo.