TABLE 1.

Oncologic PET Radiotracers and Their Mechanisms of Uptake in Cancer

Radiotracer	Measures or targets	Uptake mechanism	Main indications studied	Availability
¹⁸F-FDG	Glucose metabolism (indirect)	Is taken up via GLUT1 and phosphorylation by hexokinase	Various cancers	Widely, routine
SSTA	Somatostatin receptors	Binds mainly to subtype 2 and in lesser degree to subtypes 3 and 5	Well- and moderately differentiated NETs	Increasing
⁶⁸Ga-PSMA	Cellular PSMA	Binds to cellular PSMA and internalizes	Prostate cancer	Increasing
¹⁸F-NaF	Osteoblastic activity	Exchanges ¹⁸F ions with hydroxyl ions on surface of hydroxyapatite to form fluoroapatite	Bone metastases from various cancers	Increasing
¹⁸F-FLT	Cellular proliferation (indirect)	Is phosphorylated by thymidine kinase (not incorporated into DNA)	Various cancers; NSCLC, lymphomas	Limited
¹⁸F-FET	AA uptake by transporters	Enters cells by LAT1	Brain tumors, particularly gliomas	Limited
¹¹C-MET	AA uptake and protein synthesis	Enters cells by LAT1 and is involved in synthesis of proteins and phospholipids	Brain tumors, particularly gliomas	Limited
¹⁸F-FLUC	AA uptake by transporters	Enter cells by AA transporter ASCT2 and LAT1	Prostate cancer	Limited
¹⁸F-DOPA	¹⁸F-DOPA transport, storage, and metabolism	Enters neuroendocrine cells by LAT1, is converted to dopamine by AA decarboxylase, and is trapped in vesicles via VMAT	NETs, pheo, neuroblastoma, PG, gliomas	Limited
¹¹C-choline and ¹⁸F-fluorocholine	Cell membrane synthesis or cellular proliferation	Is phosphorylated by choline kinase to phosphocholine and converted to phosphatidylcholine	Prostate cancer	Limited
¹¹C-acetate	Cellular proliferation	Incorporates into cellular membrane	HCC (well-differentiated), renal cancers	Limited
⁶⁸Ga-FAPI	Cancer-associated fibroblasts	Binds to fibroblast activation protein on cancer-associated fibroblasts	Various cancers	Limited
¹⁸F-FES	Estrogen receptor	Binds to estrogen receptor	Breast cancer, ovarian cancer	Limited
⁸⁹Zr-trastuzumab	Human epidermal growth factor	Binds to human epidermal growth factor	Breast cancer	Limited
¹⁸F-FDHT	Androgen receptor	Binds to androgen receptor	Prostate cancer	Limited
¹²⁴I	Iodine metabolism	Is taken up by thyroid follicular cells via Na+/I− symporter, is oxidized by thyroid peroxidase, stays in colloid, or leaves as thyroid hormones	Well-differentiated thyroid cancer	Limited
¹²⁴I-MIBG	Norepinephrine transporter	Is taken up by sympathicomedullary tissue via norepinephrine transporter (uptake-1 system) and stored in neurosecretory granules	Pheo, neuroblastoma, PG	Limited
¹⁸F-FMISO	Hypoxia	Nitro-group undergoes reduction in hypoxia, forms highly reactive oxygen radicals, and binds to intracellular macromolecules	Various cancers, particularly brain and HN	Limited
⁶⁴Cu-ATSM	Hypoxia	Accumulates in regions with higher CD133+ expression and activates hypoxia inducible factor 1 (possible mechanisms)	Various cancers, particularly brain and HN	Limited
Folate*	Folate receptor α	Binds to folate receptor-α	Various cancers	Limited
⁶⁸Ga-pentixafor	CXC motif chemokine receptor 4	Binds to CXC motif chemokine receptor 4	Various cancers	Limited
¹¹C-lactate	Lactate metabolism	Undergoes oxidative phosphorylation	Various cancers	Limited
Immuno-PET*	Tumor-associated antigens	Monoclonal antibodies bind to tumor-associated antigens	Various cancers	Limited

* Various radiotracers.
GLUT1 = glucose transporter 1; SSTA = ⁶⁸Ga-SSTAs (somatostatin analogs); NET = neuroendocrine tumor; FLT = fluorothymidine; NSCLC = non–small cell lung carcinoma; FET = fluoroethyltyrosine; AA = amino acid; LAT1 = L-type amino acid transporter; MET = methionine; FLUC = fluciclovine; ASCT2 = alanine, serine, cysteine transporter 2; ¹⁸F-DOPA = 6-¹⁸F-fluoro-l-dopa; VMAT = volumetric modulated arc therapy; pheo = pheochromocytoma; PG = paraganglioma; HCC = hepatocellular carcinoma; FAPI = fibroblast-activation-protein inhibitor; FES = fluoroestradiol; FDHT = fluorodihydrotestosterone; MIBG = metaiodobenzylguanidine; FMISO = fluoromisonidazole; ATSM = diacetyl-bis(N⁴-methythiosemicarbazone); HN = head and neck.