Multispectral optoacoustic tomography (MSOT) scanner for whole-body small animal imaging

Abstract

A major difficulty arising from whole-body optoacoustic imaging is the long acquisition times associated with recording signals from multiple spatial projections. The acquired signals are also generally weak and the signal-to-noise-ratio is low, problems often solved by signal averaging, which complicates acquisition and increases acquisition times to an extent that makes many in vivo applications challenging or even impossible. Herein we present a fast acquisition multispectral optoacoustic tomography (MSOT) scanner for whole-body visualization of molecular markers in small animals. Multi-wavelength illumination offers the possibility to resolve exogenously administered fluorescent probes, biomarkers, and other intrinsic and exogenous chromophores. The system performance is determined in phantom experiments involving molecular probes and validated by imaging of small animals of various scales.

Quantitative spectroscopic photoacoustic imaging: a review

“…[81][82][83] A similarly restrictive assumption of nonchanging fluence underlies the suggestion that over a small wavelength range the fluence may be invariant to changes in the wavelength, so "measurements (images) at one wavelength can be explicitly used to normalize for photon intensity heterogeneity in tissues at the other wavelengths." 84 Earlier, Kiser et al 85 obtained PAT images of tumors implanted in murine mammary fat pads at 758 nm (peak Hb absorption) and 798 nm (isosbestic point), and by making the assumption that the fluence distribution does not change between the two wavelengths, they obtain images estimating the "oxygenated component" and "deoxygenated component," although no scale (relative or absolute) is given.…”

Unleashing Optics and Optoacoustics for Developmental Biology

“…In addition, multispectral illumination at several wavelengths combined with spectral unmixing can reveal specific chromophores and fluorescent proteins, distinguishing between oxy-and deoxyhemoglobin, a technique termed multispectral optoacoustic tomography (MSOT) [29,30]. The large penetration depths and the relatively high resolution of $100 mm (note that this resolution is one tenth of the transport mean free path, $1 mm) make this approach ideal for macroscopic imaging of small animals [31][32][33]. Higher resolution might be achieved with optoacoustic tomography, as seen in Figure 1B-D where Razansky et al [34] show how MSOT can be used to resolve fluorophores in the brain of an adult transgenic zebrafish in vivo with a scalable spatial resolution of a few tenths of microns.…”

Passive element enriched photoacoustic computed tomography (PER PACT) for simultaneous imaging of acoustic propagation properties and light absorption

“…Some important applications of this technique include breast cancer detection [2][3][4][5], skin cancer visualization [6] and small animal imaging [7][8][9][10]. The technique relies on irradiating tissue with nanosecond pulses of visible or near infrared (NIR) light.…”