Table 1.
Symbols and units
| Symbol | Description | Typical Units |
|---|---|---|
| Cp,T | Blood plasma concentration of targeted agent | nmol.(L of plasma)−1 |
| Cf,T | Free concentration of targeted agent | nmol.(L of tissue)−1 |
| Cb,T | Bound concentration of targeted agent | nmol.(L of tissue)−1 |
| K1,T | Rate constant for targeted agent transfer from blood plasma to free tissue compartment (extravasation) |
(L of plasma).(L of tissue)−1.min−1 |
| k2,T | Rate constant for targeted agent transfer from free tissue compartment to blood plasma (efflux) |
min−1 |
| k3,T | Rate constant for targeted agent binding to targeted receptor (binding) |
min−1 |
| k4,T | Rate constant for targeted agent release from targeted receptor (dissociation) |
min−1 |
| Cp,C | Blood plasma concentration of control agent | nmol.(L of plasma)−1 |
| Cf,C | Free concentration of control agent | nmol.(L of tissue)−1 |
| Cwb,T | Whole blood concentration of targeted agent | nmol.(L of tissue)−1 |
| Cwb,C | Whole blood concentration of control agent | nmol.(L of tissue)−1 |
| Ctissue,T | Tissue concentration of targeted agent | nmol.(L of tissue)−1 |
| Ctissue,C | Tissue concentration of control agent | nmol.(L of tissue)−1 |
| K1,C | Rate constant for control agent transfer from arterial plasma to free tissue compartment (extravasation) |
(L of plasma).(L of tissue)−1.min−1 |
| k2,C | Rate constant for control agent transfer from free tissue compartment to blood plasma (efflux) |
min−1 |
| ηT | Correction factor relating detected targeted agent signal to targeted agent concentration |
Signal units.(L of tissue).nmol−1 |
| ηC | Correction factor relating detected control agent signal to control agent concentration |
Signal units.(L of tissue).nmol−1 |
| ROIT | Detected targeted agent signal measured in a region of interest |
Signal units |
| ROIC | Detected control agent signal measured in a region of interest |
Signal units |
| R1 | Ratio of K1,T/K1,C | unitless |
| kD = koff/kon | In vitro dissociation constant | nmol.(L of diffusible “free” space)−1 |
| kon | In vitro association rate constant | (L of free space).min −1.nmol−1 |
| koff |
In vitro dissociation rate constant (assumed to be equivalent to in vivo k4) (Innis et al., 2007) |
min−1 |
| KD = vfkD | In vivo dissociation constant | nmol.(L of tissue)−1 |
| Kon = vfkon | In vivo association rate constant | (L of tissue).min−1.nmol−1 |
| vf | Diffusible free space volume fraction | (L of free space).(L of tissue)−1 |
| Vwb | Whole blood volume | unitless |
| Bavail | Maximum concentration of receptors that could be bound by the targeted imaging agent prior to agent injection |
nmol.(L of tissue)−1 |
| BP*= Bavail/(KD) | Binding potential | unitless |
*
BP is displayed as BPND (Nondisplaceable binding potential) in some other references (Innis et al., 2007)