Myocardial Positron Tomography with Manganese-52m

Abstract

The biodistribution of radiomanganese (54Mn) was studied in mice, rats, and dogs. Disappearance of radioactivity from the blood was extremely rapid, with a half-time of approximately 0.8 minutes. This resulted in very favorable myocardium-to-blood ratios, even at early times after administration. The myocardial uptake in dogs was greater than 3% at three and 15 minutes, with myocardium-to-blood ratios of about 40:1 at 15 minutes. Positron tomograms obtained with 52mMn clearly demonstrated regional myocardial perfusion. There was good correlation (r = 0.89) of microsphere-to-radiomanganese distribution in the infarcted dog heart.

T1 efficacy of EVP‐ABD: A potential manganese‐based MR contrast agent for hepatic vascular and tissue phase imaging

“…The blood T1 response of EVP-ABD was consistent with the previously observed multiexponential kinetics of Mn in blood (23,24). This confirmed that EVP-ABD behaved kinetically like free Mn in blood and explained its strong vascular enhancing capability resulting from the large molar relaxivity of Mn in blood (15,23).…”

“…A previous study (22) confirmed that, as seen for Mn alone (23,24), the initial distribution of EVP-ABD from the blood was rapid. To follow such a T1 response pattern, we used a single-shot turbo-FLASH sequence at a single TI to achieve sufficient temporal resolution through the first 8 minutes post contrast injection.…”

MR Contrast Agents for Cardiac Imaging

“…In nuclear scintigraphic tomography, active uptake of radioactive thallium-201 ( 201 Tl) as a potassium analog (Schoeder et al 1993), and manganese 52 m ( 52m Mn) and manganese 54 ( 54 Mn) as calcium antagonists (Chauncey et al 1977;Atkins et al 1979) by viable myocytes has been applied for assessment of myocardial viability (MV). Similar approach has been adopted in cardiac MRI using cold cation Mn 2+ preparations as intracellular contrast agents for infarct imaging, since Mn 2+ is potent for T1 shortening and is taken up only in cells capable of active calcium (Ca 2+ ) transport, and thereby provides an analog to 201 Tl imaging in cardiac scintigraphy (Bremerich et al 2000;Karlsson et al 2001;Flacke et al 2003;Storey et al 2003;Krombach et al 2004).…”

Production of the positron emitter 51Mn via the 50Cr(d, n) reaction: targetry and separation of no-carrier-added radiomanganese

“…While in the case of Gd-compounds the SPECT nuclide 147 Gd (t 1/2 = 38.1 h, E γ = 229 keV (61%)) has been shown to be suitable [11], manganese offers two PET nuclides, namely 52m Mn (t 1/2 = 21.1 min, I β + = 97%, E β + (max) = 0.6 MeV, IT = 1.75%) and 51 Mn (t 1/2 = 46.2 min, I β + = 97%, E β + (max) = 2.5 MeV). 52m Mn of high radionuclidic purity is only available from the 52 Fe/ 52m Mn generator [12][13][14][15][16][17][18][19][20], since direct nuclear reactions, such as the 52 Cr( p, 2n) process, always lead to an isomeric mixture [3,4]. The almost pure positron emitter 51 Mn in comparison has a suitable half-life and can be produced at a small cyclotron in high radionuclidic purity using the 50 Cr(d, n) reaction [3,21].…”