Reproducibility of Repeated Measures of Cholinergic Terminal Density Using [18F](+)-4-Fluorobenzyltrozamicol and PET in the Rhesus Monkey Brain

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FIGURE 1.
Example of radiotracer distribution in specific binding region, basal ganglia (A), and nonspecific binding region, cerebellum (B), in frame 26 (160–180 min after tracer injection) for test and retest study. Regions of interest (ROIs) defined using isocontour method are also shown.
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FIGURE 2.
Percentage injected dose per milliliter in plasma (study 1, ♦; study 2, ⋄) as corrected for metabolites over logarithm (log) of scan period in minutes.
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FIGURE 3.
Percentage injected dose per cubic centimeter in basal ganglia (study 1, ♦; study 2, ⋄) and cerebellum (study 1, •; study 2, ○) over scan period in minutes.

TABLE 1.

Summary of Demographic and [¹⁸F]FBT Injection Data

Subject no.	Study	Age (y)	Weight (kg)	Interscan interval (d)	Injection amount
Subject no.	Study	Age (y)	Weight (kg)	Interscan interval (d)	MBq	MBq/nmol	μg
916	1	13.1	11.3	189	91	18	2.2
	2	13.6	10.3		85	25	1.5
919	1	14.8	13.4	301	211	14	6.9
	2	15.6	15.5		159	16	4.3
942	1	14.0	13.7	42	181	47	1.7
	2	14.2	12.4		175	48	1.6
1000	1	11.2	12.2	63	130	26	2.2
	2	11.4	11.9		148	12	5.4
1011	1	10.6	11.3	124	102	21	2.1
	2	10.9	11.7		189	13	6.6
1199	1	11.0	11.8	32	211	221	0.4
	2	11.1	12.2		230	74	1.4

TABLE 2.

Percentage of Unmetabolized [¹⁸F]FBT in Arterial Plasma (± Percentage SD)

Study	1 min	10 min	20 min	60 min	90 min
1	93% ± 7%	82% ± 17%	72% ± 20%	45% ± 35%	33% ± 56%
	(n = 6)	(n = 6)	(n = 6)	(n = 6)	(n = 4)
2	92% ± 4%	77% ± 11%	64% ± 13%	41% ± 35%	27% ± 28%
	(n = 6)	(n = 6)	(n = 4)	(n = 6)	(n = 5)

TABLE 3.

Analysis of Time–Activity Curves of [¹⁸F]FBT in Basal Ganglia (BG) and Cerebellum (CB)

Subject no.	Study	Peak uptake (%ID/cm³)		Absolute % change		Time to peak uptake (min)		% Decrease from peak at 170 min
Subject no.	Study	BG	CB	BG	CB	BG	CB	BG	CB
916	1	0.061	0.054			10.0	14.0	39.0	66.0
	2	0.042	0.033	37	48	37.5	17.5	17.0	49.0
919	1	0.046	0.055			37.5	10.0	27.0	65.0
	2	0.039	0.048	16	14	37.5	17.5	32.0	64.0
942	1	0.057	0.053			37.5	10.0	27.0	62.0
	2	0.047	0.049	19	8	32.5	12.0	27.0	62.0
1000	1	0.037	0.032			37.5	22.5	21.0	49.0
	2	0.042	0.039	13	19	32.5	12.0	22.0	55.0
1011	1	0.073	0.059			14.0	14.0	42.0	64.0
	2	0.066	0.056	10	5	22.5	14.0	39.0	68.0
1199	1	0.042	0.039			37.5	22.5	26.0	55.0
	2	0.045	0.044	7	12	22.5	14.0	26.0	58.0

TABLE 4.

Basal Ganglia (BG) to Cerebellar (CB) Ratios for [¹⁸F]FBT Radioactivity and Distribution Volumes

Subject no.	Study	RAC	Absolute % change	Distribution volume
Subject no.	Study	RAC	Absolute % change	BG	CB	BG/CB	Absolute % change (ratio)
916	1	1.72		92.74	48.37	1.92
	2	1.82	6	94.44	42.95	2.20	14
919	1	1.49		47.14	30.76	1.53
	2	1.36	9	88.64	57.41	1.54	1
942	1	1.69		102.18	51.75	1.97
	2	1.58	7	127.89	63.31	2.02	3
1000	1	1.54		90.59	50.76	1.78
	2	1.59	3	70.24	39.56	1.78	0
1011	1	1.76		101.99	55.03	1.85
	2	1.96	11	82.43	39.11	2.11	13
1199	1	1.54		94.93	47.65	1.99
	2	1.58	3	83.71	48.02	1.74	13
Mean	1	1.62 ± 0.10	6 ± 3			1.84 ± 0.20	7 ± 7
	2	1.65 ± 0.20				1.90 ± 0.30

TABLE 5.

Comparison of DVRs Obtained Using Graphic Analysis and Modeling and K₁ Summary

Subject no.	Study	Logan DVR	Modeling DVR	Absolute % difference	K₁ BG	K₁ CB	Ratio	Absolute % change (ratio)
916	1	1.92	1.96	2	1.53	1.45	1.05
	2	2.20	2.09	5	1.04	1.00	1.04	1
919	1	1.53	1.36	12	1.37	2.37	0.58
	2	1.54	1.47	5	1.23	1.74	0.71	20
942	1	1.97	1.89	4	1.68	2.14	0.78
	2	2.02	2.10	11	1.25	1.52	0.82	5
1000	1	1.78	1.82	2	1.29	1.38	0.94
	2	1.78	1.62	9	1.33	1.56	0.85	10
1011	1	1.85	1.89	2	1.98	1.68	1.18
	2	2.11	2.17	3	1.71	1.57	1.09	8
1199	1	1.99	2.10	5	1.01	1.06	0.95
	2	1.74	1.77	2	1.52	1.69	0.90	5