Figure 4.
VT/fP was calculated for caudate using an unconstrained two-tissue compartment model. Scans were analyzed using brain data from time 0 to the specified time on x-axis. VT/fP was expressed as a percentage of terminal value – i.e., VT/fP calculated from the entire 120-min data set. Error bars are identifiability (standard errors %) of VT/fP. Imaging for the initial 80 min provided VT/fP within 10% (dashed lines) of that obtained with the full length data and also provided good identifiability of < 12%. Note that VT and VT/fP have the identical dependency on the length of data.