Wavelength optimization in the multispectral photoacoustic tomography of the lymphatic drainage in mice

Abstract

Multispectral photoacoustic tomography provides mapping of the tissue chromophore distributions using sets of tunable laser wavelengths. With the overall goal of studying the dynamics of cerebrospinal fluid in mice in vivo, our work aims to minimize the number of wavelengths to reduce scanning time, improve the temporal resolution, reduce the energy deposition and avoid the tracer photobleaching while maintaining high image quality. To select small sets of wavelengths we directly searched for the combinations of wavelengths providing the best and worst image quality in comparison with a reference image obtained using 131 closely spaced wavelengths between 680 and 940 nm in terms of the peak signal-to-noise ratio (PSNR). We have shown that using the PSNR optimization method, additional improvements could be achieved over the wavelength set selected using the method of the minimization of the extinction matrix condition number.

Structure‐Activity Studies of Nitroreductase‐Responsive Near‐Infrared Heptamethine Cyanine Fluorescent Probes

“…Reasons for this include the usual advantages using NIR light, such as deeper tissue penetration, lower autofluorescence, and enhanced image resolution due to reduced scattering; along with the specific advantage of attenuated signal interference caused by variation in the blood oxygen level (a common circumstance in hypoxia imaging) because oxyhemoglobin and deoxyhemoglobin have isosbestic points near 808 nm. [32][33][34] With these desired probe wavelength properties in mind, we decided to synthesize and evaluate homologous next-generation versions of probes 1 and 3 with redshifted absorption/emission wavelengths. A specific goal was to determine if a red-shifted derivative exhibited hyperchromism and produced enhanced photon output when excited at 808 nm.…”

Optimizing Photoacoustic Measurement of Lymphatic Drainage of Cerebrospinal Fluid in Pigmented Mice for Microgravity Experiments

“…were chosen based on the minimum condition number of the molar extinction coefficients of QBB, Hb, HbO2 and melanin [78]. The following table shows the wavelengths chosen in detail for each wavelength set.…”

Optimizing Photoacoustic Measurement of Lymphatic Drainage of Cerebrospinal Fluid in Pigmented Mice for Microgravity Experiments

“…were chosen based on the minimum condition number of the molar extinction coefficients of QBB, Hb, HbO2 and melanin [78]. The following table shows the wavelengths chosen in detail for each wavelength set.…”