Author + information
- Received September 24, 1985
- Revision received January 7, 1986
- Accepted January 10, 1986
- Published online June 1, 1986.
- Gary V. Heller, MD, PHD*,a,
- S. Ted Treves, MD†,
- J. Anthony Parker, MD, PHD‡,
- Lori A. Duke, BS†,
- Gail M. O'Brien, BS†,
- Royal T. Davis, NMT†,
- Christine Fitzgibbon, NMT† and
- Alan B. Packard, PHD†
- ↵aAddress for reprints: Gary V. Heller, MD, PhD, Division of Cardiology, The Memorial Hospital, Pawtucket, Rhode Island 02860.
Ultrashort-lived iridium-191m (Ir-191m, physical halflife = 5.0 seconds) has been used in angiocardiography, primarily in pediatric patients. A theoretical obstacle to more widespread use of Ir-191m is the belief that its physical half-life is too short to permit evaluation of left ventricular function in adult patients. To evaluate its usefulness in adults, first pass ejection fractions of the left and right ventricles determined with use of Ir-191m and technetium-99m (Tc-99m) were compared in 33 adult patients. An osmium-191m 薔 iridium-191m (Os-191 薔 Ir-191m) generator was employed to deliver doses of 150 to 250 mCi (5.5 to 9.2 GBq) of Ir-191m for intravenous injection. The whole body radiation absorbed dose with Ir-191m was 15 to 25 mrad.
High quality angiocardiograms were obtained with both Tc-99m and Ir-191m. Total counts per image for the right ventricle were 51,000 ± 8,000 (mean ± SD) for Jr-191m and 30,000 ± 8,000 for Tc-99m. The left ventricular counts were comparable for both radiotracers (25,000 ± 7,000 for Ir-191m and 25,000 ± 8,000 for Tc-99m). Right ventricular ejection fractions were similar: 44 ± 8% for Ir-191m and 47 ± 9% for Tc99m. The correlation coefficient was 0.93 with a standard deviation of the regression of 3.1 % ejection fraction units. The left ventricular ejection fractions were also similar: 45 ± 14% for Ir-191m and 46 ± 13% for Tc99m. The left ventricular ejection fraction correlation coefficient was 0.96 with a standard deviation of the regression of 3.7%.
It is concluded that adequate Ir-191m first pass angiocardiograms are possible in adult patients, and that measurements of right and left ventricular ejection fractions obtained by first pass studies with Tc-99m and Ir191m are similar.
This study was supported in part by grants from the Department of Energy (Contract DEAC02-82ER60084), Washington, D.C., from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health (RR-01034), Bethesda, Maryland, Research Training Grant HL073474 from the National Heart, Lung, and Blood Institute, National Institutes of Health and from the Fannie Ripple Foundation, Morristown, New Jersey. Dr. Parker is the recipient of Research Career Development Award 5 K04HL00465 from the National Heart, Lung and Blood Institute. This study was presented in part at the 57th Annual Scientific Sessions of the American Heart Association, Miami, Florida, November, 1984.
- Received September 24, 1985.
- Revision received January 7, 1986.
- Accepted January 10, 1986.
- American College of Cardiology Foundation