Is there a role for PET imaging in the early evaluation of prostate cancer relapse?

The patient population with a rising prostate specific antigen (PSA) post-therapy with no evidence of disease on standard imaging studies currently represents the second largest group of prostate cancer patients. Little information is still available regarding the specificity and sensitivity of positron emission tomography (PET) tracers in the assessment of early biochemical recurrence. Ideally, PET imaging would allow one to accurately discriminate between local vs nodal vs distant relapse, thus enabling appropriate selection of patients for salvage local therapy. The vast majority of studies show a relatively poor yield of positive scans with PSA values < 4 ng ml(-1). So far, no tracer has been shown to be able to detect local recurrence within the clinically useful 1 ng ml(-1) PSA threshold, clearly limiting the use of PET imaging in the post-surgical setting. Preliminary evidence, however, suggests that 11C-choline PET may be useful in selecting out patients with early biochemical relapse (PSA < 2 ng ml(-1)) who have pelvic nodal oligometastasis potentially amenable to local treatment. The role of PET imaging in prostate cancer is gradually evolving but still remains within the experimental realm. Well-conducted studies comparing the merits of different tracers are needed

Molecular imaging of brain tumors with radiolabeled choline PET

Several positron emission tomography (PET) radiopharmaceuticals have been emerged in the last decade as feasible in the management of brain lesions, due to the low performance in this field of the 18F-fluoro-deoxyglucose (18F-FDG), for its high physiological gradient of distribution in the brain. Beyond its usefulness in prostate cancer imaging, the radiolabeled choline is becoming a promising tool in diagnosing benign and malignant lesions of the brain, due to a very low rate of distribution in normal white and grey matters. The aim of our review was to assess the real impact of the radiolabeled choline PET/CT in the management of brain benign lesions, brain tumors, and metastases. Furthermore, emphasis was given to the comparison between the radiolabeled choline and the other radiopharmaceuticals in this field. A literature review was performed. The radiolabeled choline is useful in the management of patients with suspected brain tumor relapse, especially in association with magnetic resonance imaging (MRI), with caution regarding its intrinsic characteristic of non-tumor-specific tracer. For the same reason, it is not useful in the early evaluation of brain lesions. Similar results are reported for other radiopharmaceuticals. The inclusion of the head in the whole-body scans for somatic tumors is necessary to ensure metastases in the brain or choline-avid benign lesions