In healthcare, it seems, there is no shortage of flavor-of-the-month inventions. It would take a scorecard the size of Ohio to tally all the breathless marketing exclamations in the vein of Scan-a-rama is the biggest breakthrough since X-ray!

Such overworked pronouncements usually succeed best at inducing naps. But the latest offerings of hybrid imaging, however, are a sure bet not to. The Journal of Nuclear Medicine may have said it best in May 2001: “Some believe [hybrid technology] to be the ‘Eureka!’ factor that will propel nuclear medicine to the forefront of imaging in the 21st century.”

Without question, technologies such as PET-CT, PET-SPECT and SPECT-CT are coming into their own. First they transformed case outcomes in unprecedented ways by supplying a long-needed edge to oncology. Now they’re promising to do the same for cardiology, neurology and gene therapy. And the reasons behind this very real breakthrough owe much, interestingly enough, to racy quartzes and the fickle whims of Feds.

Wild ride
There was a great flurry of experimentation with nuclear hybrids in the 1980s and 1990s, primarily with PET-SPECT, SPECT-CT and PET-CT. The first commercial system to combine functional and anatomic imagers became available in 1998. It was a SPECT-CT system, the Hawkeye Millennium VG, from GE Medical Solutions (GEMS of Waukesha, Wis.).

PET scanners, like CT, have been in clinical use for more than two decades, and coincidence imaging with high-energy tracers such as FDG has been around since the mid-’90s. Early combinations of them, however, were short of ideal. The difference in sensitivity between PET and SPECT, for instance, limits the size of tumors a combined system can effectively scan. With PET-CT, the images are far more detailed than those of FDG-PET alone, but registration is problematical when scans are done separately. Physicians had to rely on mentally blending images or using fusion software that didn’t always work well. Even when it did, the results were often compromised by the biological discrepancies that occur in images taken in different rooms on different days.

Please refer to the June 2002 issue for the complete story. For information on article reprints, contact Martin St. Denis