RESUMO
Upgrades and optimisation achieved 160 µA total target current operation of a GE PETtrace cyclotron in dual target mode for the routine production of [(18)F]FDG for >2 years. Approximately 900 GBq of (18)F(-) and >500 GBq of [(18)F]FDG can be produced routinely in a single production run, meeting the routine [(18)F]FDG requirements with our customer base and achieving economies of scale. Production of >1 TBq of (18)F(-) in a single run was achieved. Reliability, saturation and synthesis yields were not adversely affected.
Assuntos
Ciclotrons , Fluordesoxiglucose F18/síntese química , Marcação por Isótopo/instrumentação , Tomografia por Emissão de Pósitrons/instrumentação , Compostos Radiofarmacêuticos/síntese química , Desenho de Equipamento , Análise de Falha de Equipamento , Fluordesoxiglucose F18/efeitos da radiação , Teste de Materiais , Doses de RadiaçãoRESUMO
BACKGROUND: The purpose of this study was to develop the Perceived Restorativeness for Activities Scale (PRAS) based on the conceptual framework of attention-restoration theory (ART). ART suggests that 4 latent constructs (being away, fascination, extent, and compatibility) must be present to enable a switch from voluntary (effortful, directed) attention to involuntary (effortless) attention and facilitate restored attention. METHOD: Data were collected from 238 participants in a variety of university exercise classes. Exploratory factor analysis reduced items to a parsimonious 12-item scale. Confirmatory factor analysis tested the best fit between a 1-dimensional versus a 4-factor solution. RESULTS: The Cronbach alpha was .925. The significant analysis (P < .001) suggested that the model with 4 distinct subscales has the best data fit (goodness-of-fit index = .94, standardized root-mean-square residual = .041, incremental-fit index = .98, expected-cross-validation index = .66, comparative-fit index = .98). Composite reliability and variance extracted were calculated for each construct represented by ART: being away, .81, .59; fascination, .79, .63; extent, .89, .78; and compatibility, .68, .42. CONCLUSION: The 12-item, 4-factor solution of the PRAS can help researchers understand the within-individual preconceptions toward the activity experience that can influence cognitive restoration.