Wednesday, January 06, 2010

Jim Koger explains the origin of IVUS transducers


Here's Jim Koger test probing early IVUS transducers that worked at the then unbelievable fequency of 30 MHz with fractional bandwidths of 50% or greater.  Not only that, but these particular transducers, which Jim developed, iterated and built over and over many times, had nearly zero ringdown. That meant that close-up imaging, where the transducer is very close to the wall of a heart artery, for instance, could become a reality.

It did.  Today, so-called Direct View IVUS (intravascular ultrasound) is the gold standard for measuring coronary lesions and directing the implantation of arterial stents.  IVUS is about a 600 million dollar business today.  The stent business is many times that, but probably would never had developed were it not for the images provided by IVUS, which were key to the clinical trials and device approvals.  Stent trials drove much of the sales of IVUS in the beginning, but eventually clinicians realized they could do a better job putting stents in if they used IVUS in their daily practice, so many hospitals use IVUS in most coronary interventions involving stents.

All this costs money though, and ultimately lengthens lives, so somebody has to pay for it. Same with new drugs, the cost of development is very high.  But IVUS was done more cheaply, using Ham Radio flea market equipment in this example!

Image: TMAX  6X4.5cm negative processed in pyro.  Shot around 1989 or 1990 and scanned in today using a neato epson 750 pro scanner.


The equipment is interesting and very similar to the way Crowley and Tripp ribbon microphones were developed.  Once exception is the Panametrics 5052UA Ultrasonic Analyzer that I bought at Hosstrader's Hamfest and used at Boston Scientific for many years.  That same analyzer still does the job at Soundwave Research today and is a very valuable, rare piece of gear, combining a short pulse transmitter, stepless gate, and a high gain broadband receiver.



1 comment:

Anonymous said...

Wow look at that guy. Nerd glasses! What a trip! The picture has to be almost 20 years old. N1IPP