Initial clinical experience with a new kit formulation of Tc-99m-β galactosylated albumin for functional hepatic imaging

We studied the biodistribution, imaging characteristics and pharmacokinetics of a new kit formulation of Tc-99m-β galactosylated albumin (NGA). In all subjects, even in those patients with severe hepatocellular dysfunction, Tc99m-NGA provided excellent hepatic images and the liver was the only site of uptake of the tracer. Between 2 and 15 min post injection, the blood disappearance curve was found to be adequately described by a mono-exponential function. The fractional desappearance rate (ki) ranged from 0.089 min in normals to 0.039 in cirrhotic patients. The initial volume of distribution (VDi) of the tracer was always higher than the expected blood volume, the difference ranging from 5% in patients with the most impaired liver function to 54% in those with normal liver function. Both parameters discriminated completely the cirrhotic patients from the normal control group. A significant dose dependency of VDi was observed indicating that at least during the minutes after injection liver uptake is determined by both available receptor concentration and hepatic blood flow.