Molecular Imaging - The Future of Medicine
Modern Medical Imaging
A radical change for radiology is the development of functional or physiologic imaging instead of just anatomic imaging. Basically, this revolutionary change is aimed at uncovering the "process of disease" rather than the location or shape of disease. It helps to get at basic questions: Is a disease a result of a genetic predisposition or an environmental situation? And how is it affecting the body?
The CT and the MRI scanners ushered in a revolution in radiology a few decades ago, producing superb anatomic images that are rapidly improving. Now we will witness a new revolution-a transformational technology-changing how we understand disease through molecular imaging. In the past the radiographer saw a shape and offered a diagnosis such as "broken bone" or "pneumonia." With molecular imaging, we will "see" what is happening at a molecular level in our cells. Imaging the actual disease process is a radical change, and it will radically alter medicine.
PET Scan of Heart
Elements of molecular imaging have been around for some years (we have already discussed MRI spectroscopy and functional MRI), but the acceleration and the new technologies are rather dramatic. The acceleration will only pick up speed in the coming years with increasing numbers of new technologies. Molecular imaging will be able to look at the cellular level of function and the molecular level as well. The key technologies available or in development today are nuclear imaging using PET or SPECT imaging, optical imaging, magnetic imaging with MRI, and ultrasound imaging.
PET has emerged as a powerful imaging tool for cancer and heart care and is increasingly being recognized as valuable in neuro care as well. It is excellent for detecting occult tumors and for staging cancer. Sometimes when cancer is treated with radiation or chemotherapy, the X-ray, CAT, or MRI scan still shows something left behind. But is this tumor, or is it scar tissue, fibrous tissue, or just necrotic dead tumor cells? Here again the PET scan can be helpful. The PET scanner can also see changes in a tumor much sooner than can a CAT scan or MRI.
With molecular imaging your doctor will be better able to make an early diagnosis of cancer, see what is happening inside atherosclerotic plaques in your coronary arteries, study your arthritic joints, and know if you are in the earliest stages of Alzheimer's disease.
PET Scan used to monitor cancer therapy
Personalized medicine will come closer to reality as molecular imaging develops during the next five to fifteen years. For example, a person's cancer can be biopsied, cells placed in a mouse, and the tumor allowed to grow. Now use an agent that will bind to the tumor cells and inject it into the mouse. It will bind to the tumor and show it on an imaging device, such as PET, MRI, or optical. Next, treat the mouse with a drug or biologic expected to be effective for this type of tumor. Or use a new experimental drug that has not been tested much in humans yet. Immediately scan the mouse to see if the drug has been taken up by the tumor cells. Then scan again in hours or days to see if the drug has had the desired effect of killing the tumor cells.
All this can be done in the mouse today, and the results can be observed with various imaging devices. Soon these techniques can become commonplace for human use, and as a result the physician can feel reasonably confident that the drug or biologic agent will indeed work in the patient. Personalized medicine, again.
Last Modified: June 11, 2010