Telemedicine experiment showsvalue of NASA satellite connection

Field tests may lead to instant global telemedicine

Field trials at the University of Washington in Seattle are layingthe groundwork for routine telemedicine links connecting remoteclinical sites anywhere on earth with major medical centers viasatellite hookups.

The project is demonstrating the proof of principle involvingNASA's Advanced Communications Technology Satellite (ACTS) andthe ACTS Mobile Terminal van developed by the Jet Propulsion Laboratoryin Pasadena, CA.

The satellite promises low-cost, high-frequency bandwidth communicationsfor medical, business and other applications.

The ground-based transmitter is small enough to work in conjunctionwith an ATL Ultramark 4 scanner in a Ford Econoline van. Dataare transmitted through an antenna that can track the satellitewhile the vehicle is moving.

Among those with a stake in the success of the recent experimentare Microsoft founder Bill Gates and cellular communications magnateCraig McCaw. The pair are collaborating in Teledesic, a Kirkland,WA, joint venture that plans to invest $9 billion in an 840-satellitenetwork. The global communications system could be operationalby 2001.

Telemedicine experiments conducted in recent weeks examinedreal-time consultations between radiologists at the Universityof Washington and technologists conducting ultrasound examinationsat two remote sites.

On June 30, a two-way video transmission link was establishedbetween radiologists at the university and a technologist operatingan ATL HDI 3000 at the company's headquarters in Bothell, WA.Fixed images and dynamic video of abdominal and carotid arteryexams were transmitted via satellite.

On July 6, an attempt was made to establish a link betweenthe university and Miles Cramer Sonography, a diagnostic ultrasoundeducation facility in Whidbey Island, WA, using real-time dynamicvideo and still images from vascular and obstetrical exams acquiredby an Acuson 128XP.

The effort failed, however, because of problems with the physicalorientation of the satellite, according to Dr. Brent Stewart,director of diagnostic physics at the University of Washington.A videotape of a dynamic vascular study performed on July 6 wastransmitted and a consultation between the clinic and universitypersonnel was conducted a day later after a link with the satellitewas established, Stewart said.

The ultrasound systems in both demonstrations were connectedby cable to the ACTS mobile van, according to Stewart. The videostream underwent 100:1 compression before transmission to thesatellite, where it was rebroadcast to the Jet Propulsion Laboratoryin Pasadena.

At JPL, the data were transmitted using a 128-kilobit-per secondbandwidth over ISDN telephone lines to the UW digital imagingsciences center in Seattle. Images traversed the 60,000-mile circuitin 1.25 seconds, Stewart said.

"The significant thing we've demonstrated is that we cando remote real-time imaging over a wide-area network with satelliteand terrestrial systems," Stewart said.

Problems were also identified. An earlier field test with TriplerArmy Medical Center in Oahu, Hawaii, showed that static filescould be transmitted, but not enough bandwidth was available toreliably move dynamic video over the Internet, according to Stewart.

Experiments planned for October will examine higher bandwidths(384 kilobits per second) to transmit real-time ultrasound anddigital fluoro images compressed at 30:1.

This configuration promises significant image quality improvements,according to Stewart.

"We feel that all of our real-time ultrasound will bediagnostic quality and some of our fluoro will be up to that level,"he said.

Further tests will also involve the transmission of CT, MRI,computed radiography and digital mammography. Any digital imageacquired by scanners equipped with NTSC video outputs can be transmittedusing the ACT mobile terminal, Stewart said.

In addition to a collaborative arrangement with ATL, the projectreceived a $40,000 grant from GE Medical Systems.