Use of Tc heart agents needs analytical support

Food and Drug Administration approval earlier this year of technetium-labeledsingle-photon emission computed tomography cardiac perfusion agentsshould boost clinical demand for SPECT cameras. Market activitywill not pick up dramatically, however, until the new radiopharmaceuticalsbecome clinically routine.

The technetium agents--CardioTec from Bristol-Myers Squibband Cardiolite from Du Pont Merk--offer the potential for bothimproved diagnostic accuracy and faster examination times relativeto thallium perfusion studies.

Clinical use of the technetium heart agents should increaseonce there is a way to compare and quantify normal and abnormalimage data, said Dr. Naomi P. Alazraki, president of the Societyof Nuclear Medicine and co-director of the division of nuclearmedicine at Emory University Hospital in Atlanta.

Alazraki is helping to test a software package for the quantitativeanalysis of cardiac perfusion imaging using Tc-99m-labeled agents.The program, called CEqual, is under joint development by Cedars-SinaiMedical Center and Emory.

"People who have attended our (nuclear medicine) coursesat Emory say they are not going to switch from thallium to technetium--nomatter how good technetium is--if they don't have quantitativenormal files to work with and valid quantitative ways of analyzingthe data," she said.

The Cedars-Emory consortium is preparing a 510(k) marketingapplication for submission to the FDA, Alazraki said. Severalnuclear equipment vendors, including GE and Siemens, are workingwith the group in developing the CEqual program. Participationis open to all nuclear vendors, she said.

GE and Du Pont have been working together along with the Cedars-Emorygroup, according to Karen S. Sargent, nuclear product managerfor GE.

Sargent, a former Squibb manager involved with CardioTec, isresponsible for coordinating GE's interaction with research institutionsand the drug companies relative to radiopharmaceutical development.

The imaging equipment vendor showed CEqual as a works-in-progressproduct for use with Cardiolite at the June SNM meeting in Cincinnati.GE plans to distribute the software program to its customers onceFDA approval is obtained, Sargent said.

Availability of this analysis package is only one step in theclinical acceptance of the SPECT agents, she noted.

"It takes the medical community a period of time to evaluatethese agents and make a decision on how they wish to practice.Every physician will run little mini-trials," she said.