In announcing his annual Image of the Year, Henry N. Wagner Jr., M.D., SNM past president and historian and professor of environmental health sciences at Johns Hopkins University in Baltimore, Md., explained that the Stanford researchers "stretched volume imaging" and produced "an exquisite structural and biochemical image." Wagner, who for 28 years has summarized current trends in molecular/nuclear imaging and the meeting's significant findings, annually picks an Image of the Year. This one image, chosen from the thousands presented at SNM's Annual Meeting, illustrates what Wagner predicts will be the future direction of this dynamic and ever-expanding field.
The image is part of the study "Novel 3-D Rendered FDG PET-CT Virtual Bronchoscopy and Colonography for Improved Lesion Localization and Pre-Surgical Evaluation," performed by researchers from the department of radiology in the division of nuclear medicine at Stanford University. "This study is intended to be an initial step in developing a new paradigm for reviewing and interpreting positron emission tomography (PET)/computed tomography (CT) images in a fully 3-D-rendered format," said senior scientist and SNM member Sanjiv (Sam) Gambhir, director of the Molecular Imaging Program at Stanford University, Stanford, Calif. (http://mips.stanford.edu), and chief of nuclear medicine and a professor in the departments of radiology and bioengineering at the Stanford School of Medicine. "Our new strategy is to fuse PET and CT in order to travel through and around organs for improved visualization of the 3-D anatomical and functional data sets," detailed Gambhir.
Combining PET with CT provides merged or "fused" 3-D pictures (volumetric) of the body's metabolism and structure. The Stanford researchers--Andrew Quon, Sandy Napel, Christopher Beaulieu and Gambhir--took PET/CT one step further, offering the possibility of actually visualizing structure and function from the inside out throughout the patient's body, such as the airways and bowels. "As computer and scanner technology advances, imaging modalities--such as virtual CT colonography and bronchoscopy--will propagate, particularly for presurgical planning and visualization," noted Quon, clinical assistant professor of radiology/diagnostic radiology at Stanford. "This pilot study demonstrates the usefulness of fusing 3-D-rendered PET images to CT images, allowing for simultaneous 3-D viewing of multiple modalities," added the SNM member. "Our Stanford team hopes this work will be significant for our patients and for the molecular/nuclear imaging field, leading to multiple applications of our work," said Gambhir. Of course, more research needs to be done; additional studies with larger, specific patient populations and additional radiotracers need to be carried out, he said.
The use of PET to gain molecular or functional information and CT/MRI for anatomical imaging has been dramatic over the past few years. PET is a powerful medical imaging modality that noninvasively (nonsurgically) uses special imaging systems and radioactive tracers to produce pictures of the function and metabolism of the cells in the body. CT is an X-ray procedure that generates a detailed view of the anatomy or structure of organs and tissues in the body.
Although virtual bronchoscopies and virtual colonographies are already available, they do not provide the important functional and biochemical information that can be captured with this new strategy, said Gambhir. "This is a possible starting point for procedures for years to come," he said, "and as PET tracers improve, we will be able to better visualize earlier signs of diseases, such as cancer," said Gambhir.
Scientific Paper Abstract 313
About the Society of Nuclear Medicine
The Society of Nuclear Medicine held its 52nd Annual Meeting June 18–22 at the Metro Toronto Convention Centre, Toronto, Canada. Research topics for the 2005 meeting include techniques for the early diagnosis of Alzheimer's disease; advanced imaging for the diagnosis, staging and treatment of cancer; nuclear cardiology; and the collaboration between nuclear medicine and bioengineering in the fight against cancer. SNM is an international scientific and professional organization of more than 16,000 members dedicated to promoting the science, technology and practical applications of molecular imaging/nuclear medicine. SNM is based in Reston, Va.; additional information can be found online at http://www.snm.org.