When Michael E. Phelps, PhD, the subject of our cover story, was working on the development of positron emission tomography (PET) with colleagues at Washington University School of Medicine in St Louis, he confesses to having had no interest whatsoever in medicine. With a doctorate in chemistry, Phelps was a scientist who did not question the invisible wall that stood between the art of medicine and the science of biology.
That was in 1972, and today the world is a changed place. The smart money on Wall Street says biology and biochemistry will help to transform medicine from an art into a science, which is happening routinely as we count down the remaining days in this century. A radio news announcement this past week reported on a mouthwash developed by a British researcher and containing peptides that deceive bacteria into the assumption that the tooth is already so bacteria-laden, it can host no more. As someone who has spent many hours in a dentist’s chair, I nearly stopped the car on the freeway during rush hour to get out and genuflect. Though I have high regard for the abilities of certain dentists who are skillful in the art of restorative dentistry, getting a cavity filled or a tooth pulled is a downright barbarity that has not changed enough over time. The significance for all of us, patients, dentists, and scientists alike, is great. The implications for medicine are profound. We are on the verge of entering a new land in medicine in which imaging will play a key role in understanding the biological basis of disease. Scientists are already at work unlocking the secrets of the human genome, and there is nothing that sets a scientist-or a business person for that matter-aquiver like the idea of possessing the secrets of the human genome.
The journey into any new land requires scouts and pioneers to develop maps of the uncharted territory. Efforts are under way by the National Human Genome Research Institute and the Medical Research Council’s Human Genome Mapping Project. A new $45 million project was announced in April by a consortium of 10 pharmaceutical companies, the medical research charity Wellcome Trust, Whitehead Institute for Biomedical Research, Washington University School of Medicine, Sanger Center, Stanford Human Genome Center, and Cold Spring Harbor Laboratory. They will collaborate on an initiative to identify and analyze genetic markers known as single nucleotide polymorphisms (SNPs), and ensure that this information remains in the public domain. With roughly 3 billion nucleotide pairs in the human genome, 99.99% are estimated to be the same for everyone and the remaining .01% account for the idiosyncrasies that provide our uniqueness as well as our genetic predisposition to disease. A variation in a single base-an SNP-is estimated to occur every 1,000 bases. The consortium hopes to identify up to 300,000 SNPs and map another 150,000 that can then be used in association studies comparing SNP patterns in a target population to SNP patterns found in a control population to uncover genetic variations shared only by the target group. The map is anticipated to be useful not only in facilitating the discovery of new interventions in the disease process but also in developing new diagnostic tests.
How will these new maps be used in radiology? What role in developing and delivering new therapies will imaging play? How will disease be diagnosed, recognized, and even predicted? What are the modalities of the future? For radiology the mandate is clear: Reach out to the biologists and chemists, in addition to the physicists and mathematicians, to stake a strong claim in this New Land.