Info
Background:
In 2018, the WMIS Innovation of the Year Award was received for the VECTor 6, a broadband multimodal imaging platform integrating PET, SPECT, CT, and optical imaging (OI, bioluminescence and fluorescence tomography) within a single system. The VECTor 6 was developed then by Freek Beekman and is team at TU Delft and then at MIlabs, and in collaboration with Gremse-IT optical tomography was incorporated. The success of VECTor 6 demonstrated the value of combining complementary imaging modalities in a unified workflow.

Hypothesis/Objective:
Here, we present U-VET (Ultra-Versatile Emission Tomography), a next-generation multimodal platform designed to dramatically reduce footprint and complexity while expanding imaging, intervention, and multimodal research capabilities.

Methods:
E-VET is based on a proprietary (pat. application NL4001645) novel open-architecture design in which the integrated PET/SPECT/CT subsystem is reduced by 70 cm by height by moving down CT, PET and SPECT modules and has direct top access to the imaging cavity by creating an opening between the PET/SPECT triangle of detectors. This reduces the need for long axial travel and therefor dramatically reduced the length of the z-stage which then is placed partly in between the nuclear detector set that is lowered in position by 70 cm. This configuration improves accessibility for animal handling (the animal is above a kind of imaging islet comparable to a cooking islet) and enables different image-guided procedures during imaging. The PET/SPECT detector geometry has an adjustable detector spacing, allowing magnification to be varied—even during acquisition—to optimize sensitivity, spatial resolution, or imaging volume. The optical imaging subsystem is mounted directly above the PET/SPECT detectors, eliminating the need for mirror-based light transport, simplifying system integration with OI and reducing the footprint of the OI-unit on the bench when used for standalone OI. The architecture additionally supports incorporation of ultrasound imaging, stereotactic injection, and image-guided biopsy simultaneous with PET, SPECT and combined PET/SPECT.

Results:
Compared with VECTor’s PET/SPECT/CT architecture, U-VET reduced system height (top plate ) by 42% and axial length by 42,7%. For the fully integrated PET/SPECT/CT/OI configuration, overall required footprint was reduced by 44%. Interchangeable collimator components were redesigned, reducing collimator weight by more than 50% while substantially improving usability and workflow. Like with VECTor-6 optical imaging subsystem can operate either as an integrated modality or as a standalone benchtop instrument while requiring 62% less bench space than its predecessor. The open architecture enables simultaneous integration of PET, SPECT, CT, optical imaging, ultrasound, and image-guided interventions within a single platform. By increasing the space between the detectors the average pinhole magnification can be increased by 20% which increases resolution of pinhole PET/SPECT system by 14%.

Conclusion:
U-VET extends the concept of broadband molecular imaging beyond image acquisition toward integrated imaging and intervention. By optimal combining PET, SPECT, CT, optical imaging, ultrasound, image guided stereotactic injection and biopsy within an extremely compact and highly accessible platform, U-VET enables entirely new experimental workflows. The architecture facilitates longitudinal multimodal studies, image-guided validation of biological findings, and theranostic research, and adaptive PET/SPECT resolution providing a versatile foundation for the next generation of preclinical molecular imaging.

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Author
Freek J. Beekman, Ph.D.
Delft University of Technology (TU Delft)