Molecular Imaging Gains Ground, But Roadblocks Remain

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imageWhile molecular imaging is slowly becoming a reality, several obstacles will need to be removed from the path to full realization of its potential in personalized medicine, reports Fabian Kiessling, MD, chair of experimental molecular imaging at the University of Aachen, Aachen, Germany.

In a presentation delivered yesterday at the European Congress of Radiology (ECR) in Vienna, Kiessling said many physicians continue to perceive molecular imaging as “something that is performed by some strange scientists working in the basement of their hospital, playing with mice” and think “ there is some sort of non-applicable radiology that is only good for chemists and biologists." By contrast, he says, almost all non-traumatic diseases originate at the cell and tissue level, with the earliest signs being alterations that occur at the DNA or molecular receptor level in the cells.

"There will be some tissue [remodeling] and these, in the end, will cause the symptoms that the patient feels," Kiessling states. "If you want to be early, fast, and sensitive, we need to image that. That's what molecular imaging is for."

Kiessling points to several misconceptions about molecular imaging; notably, he says, many no longer consider the modality molecular imaging per se immediately after it leaves the research setting, He offers the example of MR spectroscopy, which can assess different metabolic activity in tissue and how tissue changes under disease conditions (e.g., in prostate cancer), to refute that claim. "If you combine this molecular imaging tool with a morphological MRI, you can get higher sensitivity (95%) and higher specificity (91%) in prostate cancer detection," he observes.

The physician also cites the value of molecular ultrasound imaging for prostate and breast cancer, as well as for soft-tissue and vascular diseases. He explains that as molecular imaging migrates toward more individualized, increasingly specific patient therapies, new therapeutics designed to target receptors that ideally have fewer side effects and more directly detect the reason for a patient's disease are being developed. A multitude of “promising” radiotracers that enable the visualization of different metabolic, physiological, and molecular characteristics have evolved for PET and SPECT.

Despite perception and other issues, Kiessling asserts, molecular imaging is "not just a dream; it is already a clinical reality. It is an important tool for the clinical translation of personalized medicine concepts. He anticipates that more clinical and diagnostic molecular imaging tools will become available over the next few years, but believes the use of molecular imaging to target small precancerous lesions, or even single diseased cells in the human body, remains farther away from becoming a reality.