Transillumination pioneer takes aim with new laser imaging technology

IDSI's ULIT system to make debut at RSNA meeting

More than 100 years ago, British physicians experimented withthe use of light to detect cancer, holding lamps behind the testesof patients and looking for shadows cast by tumors. More recentattempts with the technique, called transillumination, have failedto ignite clinical interest in the U.S. But a new start-up, ImagingDiagnostic Systems (IDSI) of Plantation, FL, is taking anothertry with a more advanced version of the technology.

IDSI was founded by Richard Grable, a 20-year-veteran of theimaging industry, who is developing an imaging device based onultrafast laser imaging technology (ULIT). ULIT comprises a continuouswave laser and high-speed detector that Grable claims has thepotential to record tumors just 1 mm in size.

The ULIT system, currently in prototype phase, could be usedas a painless and safe method of screening for breast, testicularand other types of cancer. It holds an immediate advantage overconventional mammography in that it does not use ionizing radiation,said Grable, CEO and vice president of R&D.

Initially the company will focus on breast scanning, an areain which Grable has extensive background. A previous transilluminationinvention by Grable, dubbed Lintro-Scan, never took off in theU.S. It has, however, captured the attention of physicians inChina, he said. More than 20 companies are producing devices forbreast cancer screening in China based on the Lintro-Scan technology.

Patients scanned with the ULIT mammography system would beplaced in the prone position on a scanning table, with the breasthanging through a hole in the table. Laser pulses would be administeredfrom one side of the breast and detected on the other side. Theequipment would cost about $165,000, with the price of an examinationcomparable to that of mammography, Grable said.

Let there be light. Light attenuation is both the foundationand the undoing of transillumination. The basis for diagnosisis that tissues respond to light differently, depending on theirinherent characteristics. Early clinical work will be directedat tuning the laser to different wavelengths to determine howthe light is absorbed by the tissues.

"It may be that there are certain types of breast abnormalitiesthat image very dramatically at one wavelength and maybe not sowell at another," Grable said. "We will be able to tunethis laser to look for certain types of things, once an abnormalityis found."

Too much absorption and scattering is a problem because itreduces resolution, producing nondiagnostic images. For that reason,ULIT is limited to imaging soft tissues of the body.

High-resolution images of soft tissue are possible partly throughthe use of a powerful laser that is more at home in high-energyphysics labs than hospitals. The laser produces about 76 millionbursts of light energy per second. Light scatters most when acontinuous beam is used, Grable said. This limits the depth andsize of the lesions that can be seen.

The key to the success of ULIT, however, is the detector technology.The proprietary detector Grable designed looks only at the earlyarriving photons of each burst.

The raw data will be reconstructed in much the same way asCT data, using algorithms designed for use on the more recentgenerations of CT scanners. In fact, IDSI has contracted withPlexas Associates of Solon, OH, to develop software specific tothe ULIT system. The software will produce slices that can beexamined on a monitor or printed out, as with any other high-techimaging modality.

Because there are no pre-existing light-based imaging modalities,ULIT might have to go through the lengthy premarket approval (PMA)process at the Food and Drug Administration. Grable believes,however, that he might get the system cleared through the lessburdensome 510(k) process by demonstrating a kinship of the technologyto CT.

Grable plans to unveil early clinical images produced withULIT at the Radiological Society of North America meeting in Decemberand is in the midst of setting up the first clinical trials ofthe technology.

By showcasing the technology at the RSNA meeting, Grable hopesto recruit six or seven beta sites. Ultimately, Grable and hiscolleagues plan to gather clinical data about the technology'seffectiveness on 10,000 women.

"We are going to accumulate data and compare them to datafrom x-ray mammography and biopsies so we know what we are seeing,"said Allan L. Schwartz, executive vice president and secretary/treasurerof the company.

Comparative data will be compiled into an electronic atlasfor computer analysis of abnormalities. At the very least, thecomputer will be able to flag abnormalities for radiologists toexamine, Schwartz said.

Grable hopes to begin selling production models of the systemin Europe in early 1995 and to submit clinical efficacy data tothe FDA in the third quarter of that year.

IDSI is publicly held, with about 29 million shares outstandingand about 200,000 being traded on the over the counter (OTC) bulletinboard.