Routine 18F-2-Deoxy-2-Fluoro-D-Glucose (18F-FDG) Myocardial Tomography Using a Normal Large Field of View Gamma-Camera

Abstract

There is a recent need to study glucose metabolism of the heart in is chemic, as well as in "hibernating or stunned" myocardium, and compare it with that in perfusion studies. In non-positron emission tomography centers, positron imaging is possible with a standard Anger-type camera if proper collimation and adequate shielding of the camera crystal can be achieved. For the study with fast-de caying isotopes, seven-pinhole tomo graphy (7PHT), a limited-angle method designed for transaxial tomo graphy of the left ventricle using a nonrotating camera, is well suited, because projections are acquired si multaneously. Individual adjustment (patient supine) of the camera's view axis (CAx) with the left ventricular axis (LVAx) gives excellent results: sensitivity for CHD 82%, specificity 72% in a prospective ²⁰¹TI study (48 patients, x-ray coronarography as reference). Good alignment of CAx with LVAx is also achieved with the patient prone in LAO in a hammock above the camera surface. In this set ting additional lead shielding of the camera is possible using a table rein forced with 5 cm of lead with a cen tral hole for the 7PH-collimator, which has a special lead inlay. This allows utilization of the 511 KeV emitter ¹⁸F-FDG, which with a half- life of 109 minutes, can be trans ported a reasonable distance from the production site. System sensitiv ity and resolution for ¹⁸F was found comparable to ²⁰¹Tl, ^99mTc, and ¹²³ I us ing a phantom. First clinical exami nations after ²⁰¹Tl stress/redistribu tion studies showed increased ¹⁸F- FDG uptake in ischemic heart segments, as well as in "hibernating" nonperfused or "stunned" myocar dium.