PET studies with 18F-deoxyglucose and 15O labelled water in patients with liver metastases

Perfusion of the target areas is a major parameter for the chemotherapy of liver metastases. Positron emission tomography (PET) and 15O labelled water were used for perfusion studies in patients with liver metastases from colorectal carcinoma and melanoma. All patients were scheduled for chemotherapy using surgically implanted catheters and subcutaneous port systems. Repeated flow studies with 15O labelled water were carried out after intravenous, intra-arterial (hepatic artery), intraportal and intralienal tracer injection (30-100 mCi). Different chemotherapeutic protocols are in use for the treatment of patients with metastatic melanomas. PET studies with 18F-deoxyglucose (18FDG) were carried out in order to obtain basic data on metabolism in 128 metastases obtained from 27 patients with metastatic malignant melanoma prior to therapy. Furthermore, 35 metastatic lesions in 12 melanoma patients were examined prior to and after one chemotherapeutic cycle. All patients were studied immediately prior to and after one chemotherapeutic cycle. PET was performed prior to therapy, after one day of DTIC therapy and after completion of the chemotherapeutic cycle. Four of the patients showed a decrease in 18FDG uptake after the one day DTIC chemotherapy, followed by an increase after the end of the cycle. A steady increase in tumour metabolism in two patients was noted. The results show that PET with 18FDG can be used to quantify early effects on tumour metabolism and select those patients who will not respond to chemotherapy. 5 figs