Molecular Imaging and Therapy

Preclinical Imaging and Therapy

Preclinical imaging plays a central role in translational biomedical research. It enables non-invasive, longitudinal visualization of biological processes in small animal models, typically mice and rats, under controlled experimental conditions. By combining molecular targeting with advanced imaging physics, researchers can quantify target expression, assess pharmacokinetics, evaluate therapeutic response, and perform dosimetry before a compound enters clinical development.

Nuclear Imaging and Radionuclide Therapy in Preclinical Research

Preclinical nuclear imaging relies primarily on PET (Positron Emission Tomography) and SPECT (Single Photon Emission Computed Tomography). These techniques detect gamma photons emitted by radiolabeled tracers and provide highly sensitive, quantitative, whole-body imaging.

PET offers high sensitivity and quantitative accuracy, typically using radionuclides such as ¹⁸F or ⁶⁸Ga. SPECT provides flexibility in radionuclide selection (e.g., ^99mTc, ¹¹¹In) and enables multi-isotope imaging in a single experiment.

The strength of nuclear imaging lies in its ability to visualize molecular targets at picomolar concentrations. In oncology, this allows researchers to study receptor expression, tumor heterogeneity, drug-target engagement, and systemic biodistribution. Importantly, the same molecular constructs can often be labeled with therapeutic radionuclides (e.g., ¹⁷⁷Lu or ²²⁵Ac), creating a theranostic pair that links imaging to targeted radionuclide therapy (TRNT). 
TRNT in small animal models allows rigorous evaluation of dose–response relationships, therapeutic windows, and toxicity profiles. Imaging-based dosimetry enables organ-specific absorbed dose calculations, which are essential for regulatory translation. Longitudinal imaging further permits non-invasive monitoring of treatment response, reducing animal numbers and improving statistical robustness.

Optical Imaging and Image-Guided Surgery

Optical imaging complements nuclear techniques by providing high spatial resolution and real-time visualization. Fluorescent probes, particularly those emitting in the near-infrared (NIR) range, are widely used in preclinical research to study tumor margins, vascularization, and tissue distribution.

In image-guided surgery research, targeted fluorescent tracers enable intraoperative tumor delineation, improving resection accuracy in experimental models. Although optical imaging has limited tissue penetration compared to nuclear imaging, it offers superior spatial detail and does not require ionizing radiation. Multimodal tracers—combining radioactive and fluorescent labels—bridge preoperative whole-body imaging with intraoperative precision.

Under the Molecular Imaging and Therapy research group, these nuclear and optical imaging strategies are implemented and optimized within the ICMI Core Facility, where dedicated radiochemistry infrastructure and preclinical PET/SPECT/CT systems support full tracer development from labeling to in vitro and in vivo validation. The ICMI Core Facility provides quantitative analysis expertise required to perform these studies according to high methodological standards, facilitating direct translation to clinical protocols. Translation from preclinical validation to patient application is achieved through close collaboration with the Department of Nuclear Medicine at UZ Brussel.Tr