With the ability to image optical contrast with high resolution at depth, multispectral optoacoustic tomography (MSOT) is uniquely suited for cancer imaging in small animals. Fluorophores or antibodies conjugated to tumor-specific ligands can be used for tumor targeting. Additionally, multiple genetic reporters are available to visualize tumor growth. MSOT also offers functional endpoints, such as visualization and quantification of tissue oxygen saturation and microvascular perfusion.
Based on contrast from genetic reporters such as fluorescent proteins or tyrosinase-induced melanin expression, MSOT can clearly depict tumor boundaries. Ultrasound computed tomography (UCT) can provide distinct tumor boundaries in the absence of specific optical tumor cell contrast.
Dynamic contrast enhancement (DCE) with MSOT can quantify perfusion of injected agents and thereby reveal insights into tumor heterogeneity. DCE-MSOT provides similar information as DCE-MRI, but faster and at lower cost.
Dynamic contrast enhancement (DCE) with MSOT can also be achieved without the use of contrast agents, allowing scientists to characterize blood oxygenation heterogeneity within tumors and between tumor types following an oxygen challenge. This technique has been termed oxygen-enhanced optoacoustic tomography (OE-OAT)
MSOT can detect a wide range of tumor-targeting probes, such as functionalized fluorophores and nanoparticles. The key requirement for such agents is that their optical absorption spectrum has a characteristic shape within the laser-addressable near-infrared (NIR) wavelength range.
The high spatiotemporal resolution and depth penetration of MSOT allows unprecedented optical molecular contrast for small animal imaging.
Applications for Preclinical Research