Representative PET time–activity curves of L-3-11C-lactate obtained from intralipid (IL), insulin clamp (CLAMP), lactate infusion (LACTATE), or lactate and phenylepherine (LAC/PHEN) studies and corresponding myocardial images obtained 5–10 min after tracer injection and depicting primarily early tracer uptake. Images are displayed on horizontal long axis. Blood 11C = 11C time–activity curves obtained from region of interest (ROI) placed on left atrium; blood 11C-lactate = blood 11C time–activity curves after removing 11CO2, 11C-neutral, and 11C-basic metabolites; myocardial 11C = 11C time–activity curves obtained from ROI placed on lateral wall. A = apical wall; S = septal wall; L = lateral wall; LV = left ventricle. Reproduced with permission from Herrero P, Dence CS, Coggan AR, Kisrieva-Ware Z, Eisenbeis P, Gropler RJ. L-3-11C-lactate as a PET tracer of myocardial lactate metabolism: a feasibility study. J Nucl Med. Dec 2007;48(12):2046–2055.