Table II.
Parameter Estimates of the 4C Model for the [11C]Erlotinib + Erlotinib Data Set
| Subject | Arterial input functiona | Dual input functionb | |||||||
|---|---|---|---|---|---|---|---|---|---|
| k1 (min−1) | k2 (min−1) | k3 (min−1) | k5 (min−1) | k1 (min−1) | k2 (min−1) | k3 (min−1) | k5 (min−1) | β (min) | |
| Baseline scan | |||||||||
| p12 | 3.000 (7) | 0.052 (16) | 0.088 (7) | 0.006 (1) | 4.748 (6) | 0.015 (45) | 0.103 (8) | 0.010 (1) | 0.827 (139) |
| p13 | 2.300 (8) | 0.050 (10) | 0.013 (10) | 0.007 (7) | 4.899 (13) | 0.050 (20) | 0.021 (13) | 0.008 (8) | 0.799 (172) |
| p14 | 2.102 (5) | 0.028 (8) | 0.010 (4) | 0.039 (9) | 4.038 (11) | 0.134 (36) | 0.339 (15) | 0.009 (1) | 2.152 (58) |
| p15 | 2.092 (13) | 0.089 (41) | 0.285 (21) | 0.008 (2) | 4.587 (21) | 0.113 (148) | 0.777 (43) | 0.007 (1) | 1.899 (36) |
| p24 | 2.686 (8) | 0.069 (13) | 0.028 (9) | 0.005 (4) | 5.000 (23) | 0.055 (44) | 0.050 (11) | 0.007 (3) | 1.807 (158) |
| p30 | 2.164 (5) | 0.070 (7) | 0.037 (8) | 0.011 (3) | 4.301 (17) | 0.139 (32) | 0.189 (16) | 0.012 (2) | 1.482 (164) |
| Mean ± SD | 2.391 ± 0.372 | 0.060 ± 0.021 | 0.077 ± 0.106 | 0.013 ± 0.013 | 4.596 ± 0.368 | 0.084 ± 0.051 | 0.247 ± 0.284 | 0.009 ± 0.002 | 1.494 ± 0.570 |
| Second scan (after oral erlotinib) | |||||||||
| p12 | 2.801 (9) | 0.160 (12) | 0.015 (9) | 0.015 (7) | 4.250 (12) | 0.133 (15) | 0.026 (7) | 0.018 (4) | 2.169 (55) |
| p13 | 1.907 (16) | 0.168 (19) | 0.009 (16) | 0.006 (12) | 3.439 (16) | 0.131 (21) | 0.012 (18) | 0.007 (13) | 0.787 (173) |
| p14 | 2.547 (9) | 0.249 (10) | 0.012 (5) | 0.021 (5) | 3.457 (12) | 0.164 (12) | 0.027 (5) | 0.022 (3) | 1.899 (45) |
| p15 | 2.205 (11) | 0.190 (14) | 0.012 (8) | 0.018 (7) | 3.956 (17) | 0.158 (14) | 0.022 (10) | 0.022 (8) | 1.889 (75) |
| p24 | 2.560 (13) | 0.189 (13) | 0.002 (17) | 0.016 (21) | 4.330 (18) | 0.150 (16) | 0.005 (12) | 0.011 (12) | 0.800 (85) |
| p30 | 2.606 (12) | 0.189 (12) | 0.002 (19) | 0.003 (18) | 4.000 (19) | 0.140 (17) | 0.006 (10) | 0.002 (8) | 1.050 (88) |
| Mean ± SD | 2.438 ± 0.323 | 0.191 ± 0.031 | 0.009 ± 0.006 | 0.013 ± 0.007 | 3.905 ± 0.382 | 0.146 ± 0.014 | 0.016 ± 0.010 | 0.014 ± 0.008 | 1.432 ± 0.621 |
Values in parentheses represent the precision of the parameter estimates (%CV). k1 and k2 are the exchange rate constants between blood and liver tissue, k3 is the transfer rate constant from liver tissue to the intrahepatic bile duct, and k5 is the transfer rate constant from the intrahepatic bile duct to the extrahepatic bile duct and gall bladder. β is the mean transit time for the passage of radiotracer from intestinal arteries to the portal vein
a4C model using the blood sampled from the radial artery as the model input function. β estimation is not necessary since portal vein concentration is not calculated
b4C model using the dual input (combination of hepatic artery and portal vein) as the model input function