### 1-Tissue Compartment Model

The 1-Tissue Compartment Model only separates tissue uptake and washout. All tracer in tissue is included in a single compartment C_{1}.

Differential Equation of the Mass Balance

with input curve C_{p}(t), tissue concentration C_{1}(t), uptake rate constant K_{1} [ml/ccm/min] and clearance rate constant k_{2} [1/min].

Operational Model Curve

with the concentration C_{B}(t) of tracer in whole blood, and the blood volume fraction v_{B}.

Parameter Fitting

The model includes the three fitable parameters **vB**, **K1**, **k2**. Often, **vB** is fixed at a physiologic value of 3-5%.