TABLE 1.

Characteristics of the patients with Parkinson's disease

	Patient No.
Characteristics	1	2	3	4	5
Dose of caffeine, mg	259	259	129.5	129.5	129.5
Age, y	74	61	71	69	61
Sex	Male	Male	Male	Female	Female
Weight, kg	60.1	47.5	61.5	52.3	48.2
Coffee consumption	1 cup/day	1 cup/day	Occasionally	Occasionally	Rarely
Duration, y	6	13	3	5	3
Hoehn & Yahr stage	3	3	3	3	2
Medication	l‐Dopa pramipexole	l‐Dopa pramipexole	l‐Dopa	l‐Dopa pramipexole	Ropinirole
Serum caffeine level, μg/mL
Baseline	0.56	0.29	0.06	0.96	0.00
Caffeine loading	8.94	8.90	4.51	4.58	4.36
BPND in the striatum a
Baseline	4.34	3.89	3.16	3.06	4.16
Caffeine loading	1.68	1.21	1.50	1.42	1.79
Occupancy, %	61.3	68.9	52.4	53.4	57.0

Patients 1–5 correspond to Fig. 1A–E, respectively.

l‐Dopa, levodopa.

^a Binding potential (BP_ND) was calculated using the volume‐of‐interest‐based method. ¹¹