Tc-99m-N-MPO: Novel cationic Tc-99m radiotracer for myocardial perfusion imaging

Abstract

The combination of favorable organ biodistribution and myocardial uptake with rapid liver clearance makes Tc-99m-N-MPO a very promising myocardial perfusion radiotracer worthy of further evaluation in various preclinical animal models.

Rapid hepatic clearance of 99mTc‐TMEOP: a new candidate for myocardial perfusion imaging

“…the heart-liver ratio of 99m Tc-TMEOP, derived from the SPECT data, is twice that of 99m Tc-sestamibi and 99m Tc-tetrofosmin. These results are comparable to the 30 min values published for 99m Tc-N-DBODC5 (6.01 AE 1.45) (21), but inferior to the data reported for 99m Tc-N-MPO (12.75 AE 3.34) (22). The heart uptake of cationic radiotracers and the factors governing their liver clearance kinetics are not fully understood.…”

Evaluation of new positively charged 11‐ and 12‐carbon 99mTc‐labeled fatty acid derivatives for myocardial imaging

“…[5][6][7][8][9][10][11][12][13][14][15] Among the different cores of 21 core has shown excellent in vivo characteristics suitable for myocardial imaging. 16,17 This is a pseudo octahedral complex, with two positions in a square basal plane being occupied by phosphorus atoms of the long chain PNP ligand (cis-arrangement) and the other two cis-positions are labile, which can be easily replaced by a suitable p-donor bidentate ligand having donor groups, such as SS/SO/SN. Thus, the amino acid cysteine is a useful bi-functional chelator, where a bio-molecule, like fatty acid, can be attached either at -COOH or at -NH 2 group, and the other two groups, SH and NH 2 /COOH, can be used for labeling with [ 99m TcN(PNP)] 21 core.…”

Novel SPECT perfusion imaging agents with improved myocardial or liver kinetics: Experimental studies and the need for clinical evaluation

“…25 Additional studies in guinea pigs led to somewhat disappointing results with similar Tc-N-MPO and Tc-MIBI myocardial and liver activities resulting in a modest and transiently significant advantage of Tc-N-MPO over Tc-MIBI with respect to heart-to-liver ratio. 26 Finally, a recent study indicated a heart-to-liver ratio of 1.2 ± 0.1 in a canine model. 27 Again, no clinical data are yet available regarding the myocardial and liver kinetics of Tc-N-MPO in patients.…”

“…25 Biodistribution experiments performed in the same experimental model indicated that Tc-99 m-N-MPO heart-to-liver ratio was much higher than that of Tc-MIBI at all time points, and slightly and transiently higher than that of the novel perfusion imaging agent Tc-DBODC5 (see below). 26 The likely mechanism for fast liver clearance of Tc-N-MPO in rats is an efficient recognition of the tracer by the MDR transport function of hepatocytes. 25 Additional studies in guinea pigs led to somewhat disappointing results with similar Tc-N-MPO and Tc-MIBI myocardial and liver activities resulting in a modest and transiently significant advantage of Tc-N-MPO over Tc-MIBI with respect to heart-to-liver ratio.…”