University of Helsinki: State-of-the-art imaging techniques reveal what takes place in live tissue

Biomedical imaging can be used to obtain information on the anatomy, physiology and metabolism of the body and tissues as well as the targeting and effects of drugs.

“No other method can provide equally accurate information on the state of the body and cellular phenomena in living organisms,” says Associate Professor Pipsa Saharinen.

Saharinen chairs the Helsinki In Vivo Animal Imaging Platform (HAIP), one of the University’s research infrastructures. The over €600,000 awarded by the Academy of Finland will be used to enhance HAIP’s biomedical imaging equipment and expertise.

“The biomedical imaging carried out at HAIP takes place in real time in live tissue. This enables the investigation of dynamic pathophysiological events, such as the functioning of inflammatory cells in malignant tissues, or the examination of cardiac or pulmonary damage,” Saharinen says.

New opportunities for the development of therapies
The funding awarded to the University of Helsinki will be used to acquire a positron emission tomography (PET) scanner for preclinical use. Clinical PET imaging is used in hospitals to examine patients particularly in oncology and neurology.

“PET imaging makes it possible to describe phenomena occurring deep within the body with sub-millimetre accuracy without invasive procedures and, above all, in a quantitative manner, since the radioactivity measured in PET imaging is directly proportional to the concentration of the tracer in the tissue,” says Associate Professor Mirkka Sarparanta from the University of Helsinki’s Radiochemistry Unit.

The preclinical PET device now to be purchased for HAIP offers the opportunity to employ a similar technique in experimental models before clinical use.

In practice, preclinical PET imaging provides the best possible reference point for PET scans on humans, which are used to monitor the progression of diseases or the response to drugs.

Two techniques in one are more than the sum of their parts
With the new equipment, preclinical PET imaging can be combined with the optical imaging of tissues and cells, which is based on fluorescent or bioluminescent markers and reporter genes. This approach, unique in Finland and rare even internationally, makes it possible to obtain in real time increasingly in-depth information on, for example, disease mechanisms or the functioning of pharmaceutical agents in the body.

“By combining the two imaging techniques in what is known as multimodality imaging, researchers are able to monitor a wide range of processes simultaneously, including gene expression on the basis of a fluorescent marker gene and the binding of radiolabelled drugs with their target receptors,” Pipsa Saharinen explains.

According to Saharinen, there is a vast number of different applications and purposes for the combination of the two techniques.

“For instance, the passage of a drug under development into a malignant tumour can be investigated with PET imaging, while the effects of the drug on the activation of the immune system can be investigated through optical imaging. To boot, these things can be done at the same time,” says Saharinen, describing the new research potential.