Small Solution, Big Dividends - The nation's top experts weigh in on molecular imaging's future.

Advance for Imaging and Oncology Administrators, online edition
January 2003
By Christine R. McLaughlin

No doubt about it, molecular imaging will be a driving force in health care delivery. That was the consensus among participants in an Oct. 9 roundtable symposium in New York City sponsored by the Society for Molecular Imaging and Philips Healthcare, Bothell, Wash.

Although the Human Genome Project has yielded a wealth of information for mapping human biology, it doesn't explain how the human body works, said James P. Basilion, PhD, assistant professor of radiology at Harvard Medical Center, Boston. That's where molecular imaging comes in: It fills those gaps by deriving information from a patient's molecular activity rather than their physical differences. The result is earlier disease detection and diagnosis, as well as in vivo assessment of drug action.

Major goals for molecular imaging include:

· developing surrogate imaging markers of all major pathways;
· imaging pathways and interactions, and the effects of drugs on pathway flux;
· defining the most informative and clinically relevant imaging biomarkers of disease;
· advancing new discoveries more rapidly into clinical imaging tools; and
· validating new technologies to drive new research.

MI overview
Molecular imaging has two components. One is the ability to create images of specific molecules within the body while the other is the ability to apply therapy to specific targeted molecules On the therapy side, patients will receive specific and personalized treatment for cancer and cardiology disorders, which can prevent unnecessary surgeries and treatments, said David Rollo, MD, PhD, chief medical officer at ADAC/Philips Healthcare, Milpitas, Calif.

"For example, chemotherapy treats the entire body," said Dr. Rollo. "Alternatively, molecular therapy targets and treats the cancer cells only, thereby having far less toxic effects to the patient's normal body tissue."

An example of molecular imaging is the use of positron emission tomography (PET) for detecting cancer. The molecular imaging agent is a form of glucose that's labeled with a positron emitting radioactive substance. When the molecular imaging agent is injected into the patient, cancer cells concentrate more on the radiolabeled glucose than normal cells because they have a higher rate of metabolism. Imaging with PET results in images that indicate the presence, as well as extent, of cancer throughout the body. 

"It is anticipated that nuclear medicine will have a major application in molecular imaging," said Dr. Rollo, "because its imaging agents can be designed to target specific molecular sites for physiological and metabolic reasons."

Cancer and cardiology
While PET is used to treat humans, microPET-a smaller device currently used only on small animals-may also be used in the future, said David Piwnica-Worms, MD, PhD, director of the Molecular Imaging Center at Mallinckrodt Institute of Radiology, St. Louis. While he noted that a primary focus of molecular imaging is on the validation and use of image-enhancing agents that interact with the cancer cell and molecular environment, he also indicated that molecular imaging will help pinpoint drug-resistant genes and determine if therapy is effective soon after it's administered.

Molecular imaging also will help identify at-risk cardiac patients by pinpointing vulnerable plaque, which is the immediate precursor of angina and myocardial infarction, said H. William Strauss, MD, clinical director of nuclear medicine services at Memorial Sloan Kettering, New York City.

He said the PET/CT combination could have several benefits: It could aid perfusion imaging and coronary inflammation/apoptosis, help identify calcium scores and confirm coronary stenosis with CT angio.

Overall, molecular imaging provides a major paradigm shift for diagnosing and treating various diseases, added Dr. Rollo. And the methodology behind molecular imaging could bring diagnostic and therapeutic products to market much faster.

Also promising are the major grants available from the National Cancer Institute and National Institutes of Health for molecular imaging research, which encourages and supports collaborative relationships between academia and industry.

The speakers also noted that while some molecular imaging agents may be available in three to four years, most experts target 2010 as a realistic timeframe for these techniques to be readily available and actively used.

Christine R. McLaughlin is a freelance writer and editor from Oreland, Pa.