Table 1.

Sample size calculations at desired therapeutic effects for the design of disease-modifying interventions using striatal [¹¹C]CHDI-626 PET imaging as the endpoint

Therapeutic effect (%)	Sample size required per experimental arm (n)
	3 months		6 months		9 months		13 months
	(1-β) = 0.80	(1-β) = 0.90	(1-β) = 0.80	(1-β) = 0.90	(1-β) = 0.80	(1-β) = 0.90	(1-β) = 0.80	(1-β) = 0.90
100%	n = 16	n = 22	n = 3	n = 3	n = 3	n = 3	n = 3	n = 3
90%	n = 20	n = 27	n = 3	n = 3	n = 3	n = 3	n = 3	n = 3
80%	n = 25	n = 34	n = 3	n = 3	n = 3	n = 3	n = 3	n = 3
70%	n = 32	n = 44	n = 3	n = 3	n = 3	n = 3	n = 3	n = 3
60%	n = 44	n = 60	n = 3	n = 4	n = 3	n = 3	n = 3	n = 3
50%	n = 62	n = 86	n = 4	n = 5	n = 3	n = 3	n = 3	n = 3
40%	n = 97	n = 133	n = 6	n = 8	n = 3	n = 4	n = 3	n = 4
30%	n = 175	n = 242	n = 9	n = 12	n = 4	n = 5	n = 5	n = 6
20%	n = 383	n = 530	n = 20	n = 27	n = 8	n = 10	n = 9	n = 12

Values are determined based on a one-tailed test, with α = 0.05 and different (1-β) powers