Figure 1.

Positron emission tomography (PET) methods that provide information on the underlying biochemical processes. PET imaging not only can improve clinical diagnostics but also potentially predict treatment effects. ¹⁸F-FDG, 2-deoxy-2-(fluorine-18)fluoro-D-glucose, provides information on glycolysis and glucose uptake; ¹¹C-DASA23, a class of N, N-diarylsulfonamides, is able to measure PKM2 uptake; ¹⁸F-Gln, ¹⁸F-(2S,4R)4-fluoroglutamine, allows for the monitoring of glutamine metabolism. ¹¹C-Met, ¹¹C-methionine; ¹⁸F-FET, O-(2-[¹⁸F]fluoroethyl)-L-tyrosine; ¹⁸F-FAMT, L-3-(18F)-Fluoro-α-methyl tyrosine; radiolabeled methionine and tyrosine can provide data on amino acid uptake and protein synthesis. Finally, ¹¹C-acetate is converted to acetyl-CoA and used in mitochondria in TCA cycle or incorporated into cell membranes. MCT4, monocarboxylate transporter 4; GLUT1, glucose transporter 1; MCT1, monocarboxylate transporter 1; R-5-P, ribose-5-phosphate; PGD, phosphogluconate dehydrogenase; 6-PG, 6-phosphogluconate; G6PD, glucose-6-phosphate-dehydrogenase; HK, hexokinase; PFK1, phosphofructokinase 1; F2,6BP, fructose-2,6-bisphosphate; PFKFB3, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3; dTMP, deoxythymidine monophosphate; dUMP, deoxyuridine monophosphate; TS, thymidylate synthase; THF, tetrahydrofolate; DHF, dihydrofolate; DHFR, dihydrofolate reductase; CK, choline kinase; PKM2, pyruvate kinase muscle isozyme M2; LDHα, lactate dehydrogenase A; CA, carbonic anhydrase; ACC, acetyl-CoA carboxylase; FAS, fatty acid synthase; PDK1, pyruvate dehydrogenase kinase 1; IDH, isocitrate dehydrogenase; α-KGDH, alpha-ketoglutarate dehydrogenase; GLS, glutaminase.