Journal of nuclear medicine : official publication, Society of Nuclear Medicine
-
Because of the high glucose metabolism in normal brain tissue 18F-FDG is not the ideal tracer for the detection of gliomas. Methyl-11C-l-methionine (11C-MET) is better suited for imaging the extent of gliomas, because it is transported specifically into tumors but only insignificantly into normal brain. 3'-Deoxy-3'-18F-fluorothymidine (18F-FLT) has been introduced as a proliferation marker in a variety of neoplasias and has promising potential for the detection of brain tumors, because its uptake in normal brain is low. Additionally, the longer half-life might permit differentiation between transport and intracellular phosphorylation. ⋯ 18F-FLT is a promising tracer for the detection and characterization of primary central nervous system tumors and might help to differentiate between low- and high-grade gliomas. 18F-FLT uptake is mainly due to increased transport, but irreversible incorporation by phosphorylation might also contribute. In some tumors and tumor areas, 18F-FLT uptake is not related to 11C-MET uptake. In view of the high sensitivity and specificity of 11C-MET PET for imaging of gliomas, it cannot be excluded that 18F-FLT PET was false positive in these areas. However, the discrepancies observed for the various imaging modalities (18F-FLT and 11C-MET PET as well as gadolinium-enhanced MRI) yield complementary information on the activity and the extent of gliomas and might improve early evaluation of treatment effects, especially in patients with high-grade gliomas. Further studies are needed, including coregistered histology and kinetic analysis in patients undergoing chemotherapy.
-
This article reports the results of performance measurements obtained for the lutetium oxyorthosilicate (LSO)-based whole-body PET/CT scanner Biograph 16 HI-REZ with the National Electrical Manufacturers Association (NEMA) NU 2-2001 standard. The Biograph 16 HI-REZ combines a multislice (16-slice) spiral CT scanner with a PET scanner composed of 24.336 LSO crystals arranged in 39 rings. The crystal dimensions are 4.0x4.0x20 mm3, and the crystals are organized in 13x13 blocks coupled to 4 photomultiplier tubes each. The 39 rings allow the acquisition of 81 images 2.0 mm thick, covering an axial field of view of 162 mm. The low- and high-energy thresholds are set to 425 and 650 keV, respectively, acquiring data within a 4.5-ns-wide coincidence window. ⋯ The new integrated PET/CT system Biograph 16 HI-REZ has good overall performance, with, in particular, a high resolution, a low scatter fraction, and a very good NEC response.
-
This review focuses on the clinical potential of PET/CT for the characterization of coronary artery disease. We describe the technical challenges of combining instrumentation with very different imaging performances and speculate on future clinical applications in the field of cardiology.
-
Controlled Clinical Trial
Lymph node staging of gastric cancer using (18)F-FDG PET: a comparison study with CT.
This study was performed to compare (18)F-FDG PET with CT for the evaluation of primary tumors and lymph node metastases in gastric cancer. ⋯ (18)F-FDG PET is as accurate as CT for the detection of primary tumors of either EGC or AGC. The low sensitivities of PET and CT were insufficient to allow decision making on the extent of lymphadenectomy. In contrast, the high specificity of PET for N disease appeared valuable, and the presence of N disease on PET may have a clinically significant impact on the choice of initial therapy.
-
In recent years, monoamine oxidase B (MAO-B) inhibitors have become widely used in the treatment of early-stage Parkinson's disease. (11)C-l-deprenyl PET has been used by others to characterize MAO-B ligands in terms of their in vivo potency toward MAO-B and duration of action. In this study, we used (11)C-l-deprenyl PET to demonstrate the specific binding characteristics of the new irreversible selective MAO-B inhibitor rasagiline in 3 healthy volunteers. ⋯ (11)C-l-deprenyl PET showed binding of rasagiline to MAO-B, confirming blocking of MAO-B sites after 10 d of treatment with 1 mg of rasagiline per day, with immediate post-rasagiline treatment tracer uptake and metabolism in the basal ganglia compatible only with nonspecific binding. Subsequent gradual recovery was also seen, with return to near-baseline uptake. This finding is compatible with the known rate of de novo synthesis of MAO-B, confirming the irreversible binding of rasagiline.