The TriTom platform is based on Photoacoustic Fluorescence Tomography (PAFT) technology that provides unparalleled capabilities for whole body imaging and in vivo characterization of small animal models. Complimentary 3D imaging modalities are integrated into a single powerful instrument by enabling co-registered Photoacoustic Tomography and Fluorescence Molecular Tomography. Combining high-resolution photoacoustic imaging with high contrast fluorescence optical tomography allows deep tissue imaging, superior molecular sensitivity, and 3D localization of anatomical, functional, and molecular data. Utilizing an innovative and compact design, simultaneous co-registration of orthogonal photoacoustic and fluorescent optical data can be acquired. The platform provides high-resolution robust anatomical registration of optical biomarkers while maintaining high molecular sensitivity. TriTom has a broad spectrum of preclinical research applications ranging from cancer, toxicology, developmental biology to tissue engineering and regeneration.

PhotoSound Technologies, Inc. has been developing and commercializing devices and electronic components for biomedical imaging utilizing optics and photoacoustics. They develop 3D imaging platforms for in vivo preclinical research and drug discovery based on the co-registration of photoacoustic and fluorescent images.

TriTom is a dual-modality system in which 3D photoacoustic and fluorescence data are acquired simultaneously from the same volume within the subject. It combines high-resolution photoacoustic imaging with the high contrast fluorescence optical tomography allowing anatomical, functional, and molecular imaging in one system. This combination allows for high molecular sensitivity, deep tissue imaging, 3D imaging, and anatomical references. Several scans may be performed with the subject repositioned along the rotation axis, allowing for a larger volume to be investigated. The photoacoustic tomography unit’s rotational configuration allows the reconstruction of the volumetric images with isotropic spatial resolution on the order of 100-200 um. The TriTom has a camera to observe the animal during the imaging procedure to maintain animal safety. Animals are submerged under water with the mouse head kept inside a “diving bell” to facilitate breathing and anesthesia. The de-ionised, temperature-controlled water bath functions as an acoustic coupling medium and an electrical isolator while supporting the animal structurally and preventing hypothermia during the rotational scan.

PhotoAcoustic-Fluorescence Tomography (PAFT) is a 3D multi-modality imaging concept designed for non-invasive in vivo investigation of small laboratory animals. Combining high-resolution photoacoustic imaging with high contrast fluorescence optical tomography allows deep tissue imaging, superior molecular sensitivity, and 3D localization of anatomical, functional, and molecular imaging. The multi-modality of TriTom brings in vivo molecular imaging to the highest fidelity level, enabling quantitative volumetric measurements and up to 10 times improvement in spatial resolution compared to state-of-the-art optical methods. Also, multi-wavelength optical excitation enables spectroscopic analysis within the spatially resolved regions of interest, such as injection sites, blood vessels, internal organs, and contrast agents. In addition to molecular imaging, TriTom enables functional imaging of volumetric blood content and oxygenation without a need for any contrast agent and imaging of various NIR absorbing probes.

Optical excitation’s unique configuration induces simultaneous co-registration of fluorescence and photoacoustic data by utilizing the same optical excitation spectrum and irradiation pattern. The optical excitation is oriented orthogonally to the photoacoustic and optical detectors, which results in minimal noise clutter from optical energy absorbed within the bulk of the subject. This allows smaller isotropic signals generated by internal tissues and organs to be visualized more readily, which then can be reconstructed into high-fidelity volumes showing internal anatomy and regions with induced optical contrast. An additional epi-illumination photoacoustic arrangement provides high-fidelity imaging of skin and superficial structures in a separate co-registered dataset.

Applications of TriTom include but are not limited to cancer biology, toxicology, developmental biology, neuroscience, the morphology of internal organs, non-contrasted angiography, stem cell research, and the development of contrast agents. TriTom technology provides many advantages: in vivo tracking, mapping, and longitudinal studies of externally labeled or internally expressed light-emitting or absorbing molecular constructs.

The key features of the TriTom system include:

  • An imaging chamber with strategically arranged optical excitation ports and safety interlocks on dual access doors
  • A 96-channel data acquisition unit optimized for detection of photoacoustic waves
  • An electromagnetic interference protected 96-channel curved transducer array
  • 360 degrees of angular coverage allowing 3D data
  • Tunable optical parametric oscillator laser
  • A camera covering a broad range of fluorescent emission wavelengths
  • A temperature control unit that maintains the sample environment within ± 0.1°C
  • A water control unit that maintains a clean, heated sound coupling medium with fill/drain/degassing capabilities
  • Durable key slot extrusion housing with safety interlocks
  • A precision rotary stage enabling tomographic scan of the sample
  • Gas table-top anesthesia for small animal imaging

TriTom is a dual-modality system allowing anatomical, functional, and molecular imaging to all be performed within one system. Therefore, TriTom can provide and co-register multi-modal data within the same subject, critical to understanding the biological mechanisms that underlie many diseases and potential therapies. As a result, TriTom is a valuable tool for numerous preclinical fields of research. Common applications include:

  • Cancer research

  • Developmental biology

  • Neuroscience

  • Morphology of internal organs

  • Non-contrasted angiography

  • Stem cell research

  • Development of contrast agents