Stress and Rest Myocardial Tomoscintigraphies Using Mono- or Double-isotope Protocol With a Semiconductor Camera

Overview

The purpose is to demonstrate the concordance of diagnostic information obtained with: 1. a conventional examination with 2 distinct recordings on D.SPECT camera after 99mTc-sestamibi injections, the first post-stress and the second at rest, 2 to 3 hours later, and 2. a double isotope examination with a supplementary recording after injection of a little activity of thallium-201 at rest after the first recording and before the second injection of 99mTc-sestamibi for conventional recording at rest, in patients showing abnormalities of myocardial perfusion in stress myocardial tomoscintigraphy.

Myocardial perfusion tomoscintigraphy is very used for diagnosis and characterization of abnormalities of stress and rest myocardial perfusion. This examination can be performed with semiconductor gamma cameras that are more performant than conventional cameras regarding spatial resolution, detection sensitivity and energy resolution. The amelioration of energy resolution could allow the realization of simultaneous recordings of a dye injected at rest and another injected during stress (double isotope recording), while conventional examination needs 2 different recordings, stress and rest, separated from several hours. In this study patients undergo a conventional examination with D.SPECT camera with 2 recordings, the first after injection of a little activity of 99mTc-sestamibi at stress (≤ 100 MBq) and the second, 2 hours later, after injection at rest of a 3 time bigger activity of 99mTc-sestamibi (≤ 300 MBq). An activity of thallium-201(≤ 50 MBq) is injected at rest after the first recording of stress. 5 minutes later, a supplementary double isotope recording is realized with D.SPECT camera (99mTc-Sestamibi-stress / thallium201-rest). The demonstration of the hypothesis of this study could considerably diminish the duration of the examination (from 3 to 4 hours to less than 1 hour).