PET STUDIES OF PERFUSION AND GLUCOSE-METABOLISM IN PATIENTS WITH UNTREATED HEAD AND NECK TUMORS

Background: In spite of technical advances in conventional morphologic al imaging, these techniques cannot assess biological characteristics of a tumour. By contrast, positron emission tomography (PET) provides quantitative metabolic information of tumour and normal tissues. Altho ugh PET has demonstrated its value for diagnosis and follow-up of diff erent tumours, reliable quantitative data on tumour metabolism and per fusion are still limited. Patients and Methods: 25 patients with untre ated and histologically proven head and neck cancer were investigated with dynamic PET. Standardised uptake values of 18F-fluorodeoxyglucose (FDG) and O-15-labelled water were calculated for tumour, lymph node metastases, soft tissue and blood vessels. Results: Lymph node metasta ses and tumour tissue revealed markedly FDG metabolism and perfusion. By contrast, there was only moderate uptake of FDG and O-15-labelled w ater in soft tissue. Standardised uptake values measured in tumours us ually proved higher than the values calculated for any other tissue. C onclusion: These findings underline that PET can be used to compare an d distinguish different tissues in cancer patients quantitatively. A r eliable distinction between tumour tissue, lymph nodes and soft tissue can be based on the characteristic changes in the uptake values of th ese tissues within the measurement sequence.