vitamin-u and Brain-Neoplasms

Positron emission tomography (PET) is an imaging technology that can detect and characterize tumors based on their molecular and biochemical properties, such as altered glucose, nucleoside, or amino acid metabolism. PET plays a significant role in the diagnosis, prognostication, and treatment of various cancers, including brain tumors. In this article, we compare uptake mechanisms and the clinical performance of the amino acid PET radiotracers (l-[methyl-11C]methionine [MET], 18F-fluoroethyl-tyrosine [FET], 18F-fluoro-l-dihydroxy-phenylalanine [FDOPA], and 11C-alpha-methyl-l-tryptophan [AMT]) most commonly used for brain tumor imaging. First, we discuss and compare the mechanisms of tumoral transport and accumulation, the basis of differential performance of these radioligands in clinical studies. Then we summarize studies that provided direct comparisons among these amino acid tracers and to clinically used 2-deoxy-2[18F]fluoro-d-glucose [FDG] PET imaging. We also discuss how tracer kinetic analysis can enhance the clinical information obtained from amino acid PET images. We discuss both similarities and differences in potential clinical value for each radioligand. This comparative review can guide which radiotracer to favor in future clinical trials aimed at defining the role of these molecular imaging modalities in the clinical management of brain tumor patients.

Topics: Amino Acids; Brain Neoplasms; Carbon Radioisotopes; Fluorine Radioisotopes; Glucose; Humans; Neoplasm Metastasis; Positron-Emission Tomography; Radiopharmaceuticals; Vitamin U

To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection.. Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas.. (11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.

Topics: Adult; Aged; Animals; Brain; Brain Neoplasms; Carbon Radioisotopes; Female; Glioma; Humans; Injections, Intravenous; Male; Middle Aged; Positron-Emission Tomography; Radiopharmaceuticals; Rats; Rats, Wistar; Sensitivity and Specificity; Tissue Distribution; Vitamin U

We studied 15 patients clinically suspected to have recurrent brain tumor or radiation injury, using positron emission tomography (PET) with 18F-fluorodeoxyglucose (18FDG) and L-methyl-11C-methionine (11C-Met). PET with 11C-Met (Met-PET) clearly delineated the extent of recurrent brain tumor as focal areas of increased accumulation of 11C-Met, and was useful for early detection of recurrent brain tumor. PET with 18FDG (FDG-PET) showed focal 18FDG-hypermetabolism in one patient with malignant transformation of low grade glioma, and demonstrated its usefulness for evaluation of malignant transformation. 18FDG-hypometabolism was observed in all patients with radiation injury, but was also found in one patient with recurrent malignant brain tumor. 11C-Met uptake in 3 patients with radiation injury was similar to that of the normal cortical tissue. FDG-PET can be used to initially exclude recurrent brain tumor which is seen as 18FDG-hypermetabolism. The combined use of Met-PET in addition to FDG-PET can improve the accuracy of differentiation of recurrent brain tumor with 18FDG-hypometabolism from radiation injury.

Topics: Adolescent; Adult; Brain; Brain Neoplasms; Child; Child, Preschool; Deoxyglucose; Female; Fluorodeoxyglucose F18; Humans; Male; Methionine; Middle Aged; Neoplasm Recurrence, Local; Radiation Injuries; Radiography; Radiotherapy; Tomography, Emission-Computed; Vitamin U