Table 1.

Summary of ¹⁸F-radiolabeled TSPO ligands.

Chemical Class	TSPO Ligand	Binding Affinity/Lipophilicity	Stage of Research (Preclinical/Clinical)	Comments	Ref.
Phenoxyarylacetamides	[18F]FEPPA	Ki = 0.07 nM Log P = 2.99	LPS mouse PD patients AD patients Psychosis patients	High binding affinity Suitable lipophilicity for brain penetration Effective in clinical application	[41,42,43,44,45]
	[18F]Fluoromethyl-PBR28	Ki = 1.85 nM Log D = 2.85	LPS mouse (EAM) rats Ischemic stroke rat	Suitable lipophilicity Effective in clinical application Lack of clinical studies	[46,47]
	[18F]FEMPA	-	Atherosclerotic plaques in mice AD patients Friedreich ataxia patients	Rapid blood clearance and uptake High binding sensitivity to the human gene polymorphism rs6971 Effective in clinical application	[48,49,50]
	[18F]FEDAA1106	Ki = 0.078 nM Log D = 3.81	Rats MS patients AD patients	High binding affinity High lipophilicity Ineffective in clinical application	[51,52,53,54,55]
	[18F]DAA1106	Ki = 0.043 nM Log P = 3.65	Ischemic rats	High lipophilicity Lack of clinical studies	[56,57,58]
	[18F]PBR06	Ki = 0.997 nM Log D = 4.05	Stroke mouse HD mice MCAO mice AD mice Monkey MS patients	High lipophilicity Effective in preclinical and clinical studies	[59,60,61,62,63,64,65]
Pyrazolopyrimidines	[18F]DPA-714	Ki = 7.0 nM Log D = 2.44	Mice, Monkey, Human PACNS patients AD patients Stroke patients MS patients PD patients ALS patients	Suitable lipophilicity Rapid penetration and good retention in the brain Effective in monitoring and diagnosis for many neurological diseases	[66,67,68,69,70,71,72,73,74,75,76,77]
	[18F]VUIIS-1008	Ki = 0.27 nM Log D = 2.5	C6 Glioma-bearing rats	Suitable binding affinity and lipophilicity Effective in preclinical studies Lack of clinical studies	[78,79]
	[18F]DPA-C5yne	Ki = 0.35 nM Log P = 2.39	Rat	Suitable binding affinity and lipophilicity Effective in preclinical studies Lack of clinical studies	[80,81]
	[18F]F-DPA	Ki = 1.7 nM Log D = 2.34	Sprague Dawley Rat Neuropathic pain-induced rats Cerebral ischemia mice AD mice	Suitable lipophilicity Effective in preclinical studies Lack of clinical studies	[82,83,84,85,86]
Imidazopyridine acetamides	[18F]PBR102	Ki = 5.8 ± 0.4 Log P = 2.7 ± 0.1	Rat Excitotoxin neuroinflammation mice Non-human primates Human	Suitable lipophilicity Effective in preclinical studies Good preclinical effect for many species	[87,88,89]
	[18F]PBR111	Ki= 3.2 ± 0.4 nM Log P = 3.2 ± 0.1	Rat, Ops rat Non-human primates Human Schizophrenia patients Psychosis patients MS patients	Suitable lipophilicity Effective in preclinical studies Good preclinical effect for many species Effective in clinical application	[87,88,89,90,91,92]
	[18F]PBR316	Ki = 6.0 ± 1.4 nM Log P = 2.16 ± 0.07	Rats	Lack of preclinical and clinical studies	[93]
	[18F]CB251	Ki = 0.27 ± 0.09 nM Log D = 3.00 ± 0.03	Neuroinflammation rats Human glioblastoma	High binding affinity	[94,95,96]
	[18F]BS224	Ki = 0.51 ± 0.03 nM Log D = 2.78 ± 0.04	LPS rats Ischemic stroke rats	Suitable binding affinity and lipophilicity Effective in preclinical studies Lack of clinical studies	[97]
Oxopurine	[18F]FEDAC	Ki = 1.3 nM Log D = 3.2	Collagen arthritis mice Neuroinflammatory rat Monkey Atherosclerosis rabbit Human liver cell Acute myocardial infarction patients	Effective in preclinical studies with many species Lack of clinical studies	[98,99,100,101]
Acetamidobenzoxazolone	[18F]FEBMP	Ki = 6.6 ± 0.7 nM Log D = 3.4	Ischemic rats MCAO rats AD mice	Effective in preclinical studies Lack of clinical studies	[102,103,104,105]
	[18F]FPBMP	Ki = 16.7 ± 2.5 nM Log D = 3.5	Ischemic rats	Lack of preclinical and clinical studies	[102,103,104,105]
Pyridazinoindoles	[18F]SSR180575	Ki = 1.19 ± 0.05 nM	Rat	Lack of preclinical and clinical studies	[106,107]
Tricyclic indoles	[18F]GE180	Ki = 2.4 nM Log D = 2.95	LPS-injected mouse MCAO rats AD mice Pigs Human High-grade glioma patient	Effective in preclinical studies with many species Poor brain penetration in clinical study Clinically effective for some given diseases	[108,109,110,111,112,113,114]
	[18F]GE387	Ki = 47.3 ± 7.0 nM	LPS rats Monkeys Humans	Low binding affinity Low binding sensitivity to the human gene polymorphism rs6971	[115,116]
Quinoline carboxamide	[18F]AB5186	Ki = 2.8 ± 0.8 nM	Rats Glioma mice Baboon	Effective in preclinical studies Lack of clinical studies	[117,118,119,120]
Isoquinoline carboxamide	(R)- [18F] NEBIQUINIDE	Ki = 5.3 ± 0.6 nM Log P = 2.35 ± 0.14	Rats	Low binding sensitivity to the human gene polymorphism rs6971 Lack of preclinical and clinical studies	[121]
Quinazoline carboxamide	[18F]ER176	Ki = 3,10 ± 0,30 nM Log D = 3.55 ± 0.02	Rats	High lipophilicity Lack of preclinical and clinical studies	[122,123]