TABLE 2

Parameter Estimation Results

Model	Parameter*	True value	Initial guess	Bounds		Estimate^†		Error^‡ (%)
Model	Parameter*	True value	Initial guess	Lower	Upper	Mean	SD	Mean	SD
Blood flow	K₁	0.5	0.4	0.1	5.0	0.491	0.013	−1.83	2.68
	k₂	0.5	0.6	0.1	5.0	0.467	0.056	−6.70	11.87
FDG	K₁	0.102	0.05	0.01	2.0	0.102	0.0013	−0.08	1.30
	k₂	0.13	0.2	0.001	1.0	0.130	0.0050	0.01	3.86
	k₃	0.062	0.1	0.01	0.2	0.0618	0.0022	−0.29	3.64
	k₄	0.0068	0.005	0.001	0.01	0.00667	0.00023	−1.93	3.43
Receptor	K₁	0.29	0.2	0.1	2.0	0.292	0.0026	0.62	0.91
	k₂	1.8	1.0	0.05	5.0	1.81	0.016	0.57	0.89
	k_on	2.3	1.0	0.5	10.	2.26	0.19	−1.78	8.43
	k_off	0.294	0.1	0.05	10.	0.293	0.002	−0.28	0.69
	B_max	37.1	25	10.	100.	36.98	0.35	−0.31	0.93

↵* Values for parameter k_on are expressed in units of mL/(pmol min), for parameter B_max in units of pmol/mL, and for all other parameters in units of min⁻¹.
↵† Estimates are obtained from fitting model to 10 noise realizations as described in text and using input functions described in Table 1.
↵‡ Errors are calculated as mean (estimate − true)/true and SD(estimate − true)/true.