o-(2-fluoroethyl)tyrosine and alovudine

The purpose of this prospective study was to clarify the value of FLT PET and FET PET for the noninvasive grading and prognosis of newly diagnosed gliomas.. Twenty patients with newly diagnosed gliomas were investigated with FLT and FET PET before surgery. FLT and FET uptakes were assessed by the maximum standardized uptake (SUVmax) of tumor, and the ratio to uptake in the normal brain parenchyma (TNR). All tumors were graded by WHO system.. FLT PET detected all 17 high-grade gliomas (HGG) and did not detect all 3 low-grade gliomas (LGG). FET PET detected all 20 HGG and LGG regardless of grading. The average FLT SUVmax in HGG and LGG was 1.51 ± 0.72 and 0.30 ± 0.07, and the average FLT TNR in HGG and LGG was 5.52 ± 3.09 and 1.12 ± 0.14, respectively. The differences of FLT SUVmax and TNR between HGG and LGG were statistically significant (p=0.0069, p=0.0070). The average FET SUVmax in HGG and LGG was 2.68 ± 0.86 and 1.36 ± 0.15, and the average FET TNR in HGG and LGG was 2.31 ± 0.73 and 1.27 ± 0.12, respectively. The differences of FET SUVmax and TNR between HGG and LGG were statistically significant (p=0.0129, p=0.0095).. FET PET has higher sensitivity in detection of gliomas rather than FLT PET, but it seems that FLT PET is better than FET PET for noninvasive grading and predicting prognosis of newly diagnosed gliomas, considering high contrast of FLT and overlap of FET uptakes between HGG and LGG.

Topics: Adult; Aged; Brain Neoplasms; Dideoxynucleosides; Female; Glioma; Humans; Male; Middle Aged; Neoplasm Grading; Positron-Emission Tomography; Prognosis; Prospective Studies; Tyrosine

The goal of this study was to compare the glucose analog, 2-[18F]fluoro-2-deoxy-d-glucose ([18F]-FDG), the amino acid analog, o-(2-[18F]fluoroethyl)-l-tyrosine ([18F]-FET) and nucleoside analog, 3'-[18F]fluoro-3'-deoxythymidine ([18F]-FLT) with regard to their feasibility for differentiating tumors from inflammation.. In Fisher rat models bearing both 9L tumor and inflammation, the biodistributions and positron emission tomography (PET) images of [18F]-FDG, [18F]-FET and [18F]-FLT at 60 min post injection were compared. Pretreatment with thymidine phosphorylase before injection of [18F]-FLT was performed.. The tumor-to-blood (T/B) and tumor-to-muscle (T/M) ratios of [18F]-FDG were significantly higher than those of [18F]-FET and [18F]-FLT (P<.01); however, the accumulation of [18F]-FDG [1.23+/-0.52 percent injected dose per gram of tissue (%ID/g)] in inflammation was also elevated. T/B and T/M ratios of [18F]-FET (2.3+/-0.5 and 2.2+/-0.5) were higher than those of [18F]-FLT (1.6+/-0.6 and 1.6+/-0.5), and inflammation uptake of those tracers was very low (0.63+/-0.19 and 0.27+/-0.16 %ID/g, respectively). [18F]-FET and [18F]-FLT showed higher selectivity indices (tumor-to-inflammation ratio corrected background) than [18F]-FDG. In PET images, [18F]-FDG was found to be accumulated in both tumor and inflammation, but [18F]-FET and [18F]-FLT selectively localized in tumor.. Our data confirm the result of previous studies that [18F]-FET and [18F]-FLT are superior to [18F]-FDG in differentiating tumor from inflammation.

Topics: Animals; Diagnosis, Differential; Dideoxynucleosides; Feasibility Studies; Female; Fluorodeoxyglucose F18; Inflammation; Neoplasms; Positron-Emission Tomography; Rats; Thymidine Phosphorylase; Tissue Distribution; Tyrosine