Measurement of Short-Term ¹¹C-Thymidine Activity in Human Head and Neck Tumours Using Positron Emission Tomography (PET)

Abstract

Tumour uptake of ¹¹C-thymidine labeled in the methyl position was assessed after intravenous injection in 13 patients with head and neck tumours. This activity was compared to other tracers such as C¹⁵O, ¹³NH₃ and C¹⁵O₂. In every single case a ‘positive’ tumour image after injection of ¹¹ C-thymidine was obtained. Time-activity curves showed the initial activity to be followed by a rapid decrease over the first 10–15 min with an apparent plateau thereafter. A similar level of uptake was found in normal salivary gland regions and myocardium, while higher activities were noted in liver and kidney parenchyma. It is suggested that both blood flow and cellular metabolism can influence ¹¹C-thymidine imaging in this class of human tumours.