Holy cow! Cardiac PET/CT!

By Greg Freiherr, Editor, gfreiherr@cmp.com

I'm from the dairy state, so you can imagine my surprise when I heard that sheep's milk is the best. This conclusion supposedly came from a comparative study of milk from sheep, goats, and cows and their effect on coronary artery disease. Sheep were found to be smaller than goats and much smaller than cows. Therefore, it was concluded, sheep milk molecules are the smallest milk molecules, and because they are so small they are less likely to cause the furry stuff that hangs from vessel walls and clogs arteries.

I was not completely persuaded. I liked the idea of doing comparisons, but I got hung up on the conclusions. It's a little like the argument for applying PET/CT in cardiology.

PET/CT has done really well in oncology. Perfusion imaging was one of the first applications of PET. CT is coming into its own as a credible source of coronary angiography. PET and CT, therefore, can do a better job together in cardiology than they can separately, just like they did in oncology. There are, unfortunately, some problems with that line of thinking.

SPECT does a pretty good job of perfusion imaging, ergo its widespread use in place of PET. It's also a lot less expensive. CT is on the verge of a quantum leap to 32 slices and beyond, which may have major advantages in CV applications. Those scanners, however, are only beginning to get into the hands of practitioners, and it will take 12 to 18 months to see how effective they really are in assessing CV anatomy. If the history of 16-slice CT integration with PET scanners is an indicator, it will take about that long for this generation of CT to hook up with PET.

But there's a bigger problem, one more basic even than the scanners themselves. Cardiac PET needs a better radiotracer. One with a half-life longer than a Pepcid AC commercial. One that can be made in a cyclotron.

The coming fusion between GE Healthcare and Amersham may be the key to just such a development. Both companies are talking about how their merger will offer an unprecedented opportunity to evolve imaging pharmaceuticals and scanners. Alliances, if not unions, between other radiology vendors and other makers

of imaging agents will likely follow with obvious resultant development possibilities. And herein lies the true opportunity.

That this hybridized technology should be explored and nurtured for cardiac applications is a no-brainer. Its future, however, is more likely to be found not in the near-term software or hardware but in the corporate collaborations that have yet to come.