<prompt> Best scan for assessing myocardial viability:ThalliumB. MIB1Tc99 pyrophosphate scanFDG PET  <response>: Ref: Harrisons Principles of Internal Medicine, 18th edition,, pg 1846Explanation: Nuclear or radionuclide imaging requires intravenous administration of radiopharmaceutical s which undergoes uptake in specific organs radiation is emitted in the form of photons gamma rays. The two most commonly used technologies in clinical nuclear cardiology are single- photon emission computed tomography SPECT and positron emission tomography PET. See the following tableThe PET FDG positron emitting tracer F-18 flurodeoxyglucose asseses myocardial viabilityUses Rubidium 82, N-13 ammoniaIt measures myocardial glucose metabolism after oral glucoseIschemichibernating myocardium show increased FDG uptake - flowmetabolism mismatchIdentifies areas of myocardium likely to improve after revascularizationCan calculate LV systolic function volumesBetter image quality compared to SPECT Single photon emission computed tomographySPECT with ThaI201 Tc99m needs viable myocardial cells for uptake, does not identify hibernating myocardium. 