OptoSonics (United States)

Purpose: The purpose of this study is to calibrate the PCT small animal scanner system with a blood phantom and to measure the blood hemoglobin concentration and oxygen saturation level in mouse tail vein and tumors. Methods and Materials: A blood phantom with variable blood flow and oxygen content was integrated into the PCT scanner with a circulation system. The circulation system consisted of a pump, an oxygen electrode detector and a tonometer. The SaO2 values were determined based on a linear combination model of oxy-hemoglobin and deoxy-hemoglobin absorption spectrum curves. Hemoglobin concentration (CHb) was determined by measuring the linear relationship for different blood dilutions. SaO2 and CHb as measured in vivo for the artery and vein in a mouse tail were also measured. Results: The PCT spectra of blood phantom samples were measured and compared with hemoglobin optical absorption spectra. The linear relationship between hemoglobin concentration and PCT intensities were observed by phantom study. The hemoglobin concentration of mouse is ~9.7g/dL. The saturation difference between arteries and veins in mouse tail is also measured by PCT scan. Conclusions: Both the phantom and living mouse tail vessel scans have shown that NIR PCT-spectroscopy can be used to measure the hemoglobin saturation level and hemoglobin concentration in small animal for future tumor hypoxia study.

Purpose: The purpose of this study is to evaluate PCT Imaging technique to classify tissue and extract kidney cysts in pcy mice model of human adolescent nephronophthisis. Method: Four mice with late stages of nephronophthisis with polycystic kidney disease-PKD and one normal mouse were scanned in the PCT Small Animal Scanner. Both vivo and ex-vivo images of mice kidney were taken at wavelength from 680 nm to 940 nm. The ex-vivo PCT images were compared with histology photographs to check the sensitivity of detecting cysts. Histograms of kidney images were generated over slices and fitted to Gaussian-curve model for volumetric analysis. The portions of cysts in kidneys were estimated and kidney images were segmented by three different colors to present the distribution of different tissues. Result: A good correspondence between PCT imaging findings and PKD histology result was observed. Histogram curves from images of pcy kidneys and normal kidneys were fitted to Gaussian-curve model. Portions of cysts, parenchyma and area of high level hemoglobin were estimated according to the curve fit result. A growth of cysts associated with relatively volume decrease of parenchyma and tissues with high perfusion of hemoglobin was observed. Conclusion: The PCT enabled visualization of renal cysts for mouse model and had the potential for volumetric measurements of kidney.

We have developed instrumentation for measuring the tissue- absorption properties of radio waves in the human body using thermoacoustic interactions. The imaging principles upon which this instrumentation is based are applicable to other irradiation sources, such as visible and IR. We present the imaging reconstruction methodology that we have developed for mapping radiation absorption pattern sin 3D. Both simulated and experimental data are used to illustrate imaging principles.