Tl-201 chloride SPECT imaging of hepatocellular carcinoma

Tl-201 chloride has been used to image viable tumors in various sites of the body. There has been limited use of Tl-201 below the diaphragm because of normal uptake in the liver, spleen, kidneys, and intestines. The use of sequential Tl-201 and Tc-99m sulfur colloid in the detection and characterization of suspected hepatocellular carcinoma (HCC) was prospectively evaluated.

Four patients with indeterminate liver nodules on radiologic imaging studies were studied with sequential Tl-201 and sulfur colloid liver scans on a triple-headed gamma camera with planar and SPECT acquisition. All patients had subsequent pathologic correlation.

There were three focal nodular HCC lesions and one case of multicentric HCC, size varying between 1.9 cm and greater than 4.0 cm (multicentric HCC). In all lesions, Tl-201 SPECT images showed abnormal increased uptake at sites of HCC, which corresponded to areas of photopenia on sulfur colloid. Computed tomography detected a lesion in two of four patients, whereas US was positive in all patients. However, US was specific for tumor in only one patient and CT was not specific in any patient.

We believe that in patients with suspected HCC, Tl-201 SPECT imaging will have an important role in the detection and characterization of HCC, especially in the cirrhotic patient. Planar Tl-201 hepatic images will usually be normal, except in large lesions, and high-resolution SPECT technique is essential in successful liver tumor imaging.