Molecular imaging arouses optimism amid huge wave of interest

If you were to type the phrase "molecular imaging" into the Google search engine, you would be faced with the unenviable task of wading through more than 40 million items. Such results not only illustrate how much has been written and spoken on the topic, they also suggest that some confusion surrounds its definition, future shape, and implications for clinical practice.

A large volume of research and collaboration is under way around the globe, and the amount of electronic and paper-based material on molecular imaging (MI) looks certain to increase. During the month of May, for instance, the Japanese Society for MI was established at its inaugural meeting, as was the European Society for MI. The Korean Society for MI held its annual conference the same month.

Against this background, it is easy to see why the organizers of the 11th Asian and Oceanian Congress of Radiology (AOCR), to be held in Hong Kong from 6 to 9 August, chose to make MI the central theme of the scientific program. Organizers say that the event's title, "From nano to cosmos," reflects the fact that MI has emerged as a focal point for medical research in the 21st century. AOCR 2006 will address the impact of recent MI developments on the role of radiologists in the future.

MI is aimed at testing novel tools and methods to image specific molecular pathways in vivo, targeting key areas in the disease process. MI presents exciting prospects for radiologists because it promises earlier disease detection and visualization of cancers at the molecular and genetic levels. It can enable quantification of images in a rapid, reproducible, repetitive, and noninvasive way. However, most experts agree MI requires a different approach and mindset because instead of focusing on changes in pathology, it involves exploiting specific molecules as a source of image contrast.

During the past five years, most activity has been focused on molecular genetic imaging, also known as indirect MI. This interest originates from the sequencing of the human genome and the subsequent development of molecular biological and biotechnological assays. Radiology has had to evolve to meet the changing needs of medicine in the molecular era. Direct MI, on the other hand, covers most nuclear medicine applications and has existed since the 1970s, when radiolabeled iodine was first administered for imaging the thyroid gland.

Regular readers of our Molecular Imaging Outlook supplement will already be familiar with these issues. If you have not received copies of MIO, they can be viewed online at www.diagnosticimaging.com. Editions dating back to April 2003 are available on our Web site, and they will help you to understand the evolution of MI and the reasons for its growing clinical importance.