Photo by Dean Dixon
After X-rays were first discovered in 1895, their strange and wonderful properties were almost immediately exploited for medical uses. They gave physicians for the first time the ability to “see” inside the human body non-invasively, and a whole new medical specialty, diagnostic radiology, was created. A little over a century later, a similar revolution is occurring with the development of a multitude of advanced technologies capable of providing a broad array of information to biomedical scientists and clinicians.
Imaging science is the new discipline that connects discoveries in the basic sciences and engineering to applications in biology and medicine. The new technologies build on advances in other fields such as molecular biology and proteomics, and have enormous potential to improve clinical care and to make important contributions to medical research.
Over the last few years, a compendium of powerful imaging techniques has been developed, not only for clinical medicine but also for basic research. Imaging today plays a central role in patient management and care. Radiological imaging methods such as X-rays and nuclear imaging, computed tomography (CT), magnetic resonance imaging and spectroscopy (MRI, MRS), positron emission tomography (PET) and ultrasound imaging are essential for the diagnosis of numerous disorders, for providing crucial insights into the pathophysiology of many types of disease, and for obtaining measures of the response of patients to treatments.
In vivo imaging methods also have widespread applications in research, for the elucidation of biological structure and in the study of fundamental biochemical, molecular and physiological processes. Imaging can be used in many different ways: to assess tissue structure and for quantitative morphometry, such as measuring the growth or regression of tumors; to measure intrinsic tissue characteristics and composition, such as tumor cell density or neural myelination; to map various metabolic and physiological properties, such as blood flow or oxygen use; and to detect and quantify fundamental processes at the molecular and cellular levels, such as the expression of specific genes.
Much of imaging research today is aimed at the development of biomarkers in order to be able to derive information on specific biological processes or responses to treatment. For example, in patients with cancer, imaging-based biomarkers such as measurements of tumor vascular properties may be used to predict early in the course of the disease whether a particular treatment regimen will be successful.
The development of functional brain imaging by MRI and the study of neurochemistry with MRS and PET are two other recent advances that have had a major impact on our understanding of brain architecture and function, allowing us to understand the neural basis for both normal and abnormal behaviors.
New technological developments and advances in molecular sciences, such as the development of novel agents that can target specific receptors, have expanded the applications of imaging to the molecular level, especially through the use of optical or nuclear detection methods. The result is that imaging applications permeate almost all current areas of medical research.
The greatest successes for applications of imaging science in the future will come from environments where the complementary natures of different imaging approaches is realized, and where experts in basic sciences and technical aspects of image formation and analysis work closely with biomedical scientists who ask appropriate questions. Vanderbilt University Medical Center has taken a lead in establishing a new, multidisciplinary Institute of Imaging Science (VUIIS), in recognition of the pervasive importance and intellectual vitality of imaging.
VUIIS provides Vanderbilt researchers with state-of-the-art research imaging of animals and human subjects across a broad range of modalities. It comprises an expert faculty that includes physicists, engineers, computer scientists, chemists, physiologists and clinical scientists, working together to address important problems within imaging science and applications of imaging. The Institute manages an impressive array of imaging resources, including systems dedicated to the study of preclinical models of disease such as microPET, microCT, optical, ultrasound and MR imaging of small animals. It also will shortly house a 7 Tesla human scanner for MRI and MRS, one of fewer than 10 such systems in the world, and the flagship for exciting new research directions.
These facilities will be integrated, along with chemistry labs dedicated to the development of new probes for molecular imaging and computing labs for advanced image analysis, in a new 42,000 square-foot building dedicated in 2006.
The institute will provide Vanderbilt a world-class research facility in all aspects of biomedical imaging, and provide an exemplary training environment for specialists as well as other research scientists in the use of imaging. The faculty and trainees within VUIIS are already engaged in numerous projects applying imaging methods in cancer biology, basic and clinical neurosciences, metabolic disorders and clinical trials.
This issue of Lens highlights some of the current areas of emphasis in imaging science at Vanderbilt and elsewhere.