Mobile Multiwire Gamma Camera for First-Pass Radionuclide Angiography

Abstract

In this paper, we describe a compact mobile multiwire gamma camera (MWGC) dedicated to first-pass radionuclide angiography (FPRNA). Studies with this camera are performed utilizing the short-lived (T½ = 9.3 min) isotope tantalum-178 (¹⁷⁸Ta), eluted (up to 100 mCi doses) at the patient’s bedside from a portable tungsten-tantalum generator. Processing is completed on-site within ~8 min, including calculation of right and left ventricular (LV) ejection fraction (EF), ejection rate, peak filling rate (PFR), and time to peak ejection and filling. Regional ventricular volume curves allow assessment of segmental ejection and filling indices. In a recent study, high count-rate FPRNA was performed before and during coronary angioplasty in the cardiac catheterization laboratory. During coronary angioplasty, a significant transient depression in LV function was seen: the LV EF fell from 52% ± 12% to 40% ± 14% (p = 0.0001) and the PFR from 2.4 ± 0.8 to 2.0 ± 0.8 EDV/sec (p = 0.0007). Thus, the mobile MWGC, combined with ¹⁷⁸Ta, expands the range of first-pass cardiac imaging. Imaging can now be conveniently used at bedside, during cardiac catheterization, and during coronary interventional procedures, allowing study of transient changes in ventricular function and possibly assisting in therapeutic decisions during emergency situations.