Positron emission tomography in urologic oncology : on the application of 11C-labeled radiopharmaceuticals in prostate and bladder cancer

Prostate cancer is an important disease as it has become the most common diagnosed malignancy in men in an increasing number of countries. Moreover, it is the second cause of cancer death, exceeded by lung cancer only. For the diagnosis of prostate cancer, the serum prostate specific antigen (PSA) is the strongest predictor and with the general availability of PSA, the detection of prostate cancer has improved. This has led to an increased incidence as well as to an increase in the detection of early stage tumors. Currently, PSA is under study as a tool for screening of prostate cancer but it is expected that the answers to the scientific questions on screening of prostate cancer are not to be anticipated for many years. For clinical staging several conventional imaging modalities as transrectal ultrasound (TRUS), computerized tomography (CT) scans and magnetic resonance imaging (MRI) scans are used, but they all share a limited sensitivity in the detection of tumor extension beyond the capsule of the prostate, in preoperative staging of the lymph nodes and in the detection of recurrent tumor. Although improvement has been obtained with contrast enhanced MRI, further improvement of pre-operative staging and of imaging methods to detect the site of recurrent prostate cancer is needed. This improvement may be reached by employing an imaging technique which is not dependent on the size of anatomical distortions. For this, positron emission tomography (PET) could be of use as sensitive imaging technique, provided radiopharmaceuticals would be available which combine a high uptake in the tumor with minimal excretion of radioactivity in the urine. In the present thesis the visualization of prostate and bladder cancer with PET is investigated using three different carbon-11 labeled radiopharmaceuticals, 11C-choline, 11C-acetate and 11C-tyrosine. Next, clinical application of 11C-choline, as the tracer with the finest imaging qualities, was studied in preoperative lymph node staging and in the evaluation of treatment of patients with prostate cancer.