Ion spectrometer composed of time-of-flight and Thomson parabola spectrometers for simultaneous characterization of laser-driven ions.

An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS. The two spectrometers show very good agreement of maximum proton energy even for a single laser shot. The composite ion spectrometer can provide two complementary spectra measured by TOFS with a large solid angle and TPS with a small one for the same ion source, which are useful to estimate precise total ion number and to investigate fine structure of energy spectrum at high energy depending on the detection position and solid angle. Advantage and comparison to other online measurement system, such as the TPS equipped with microchannel plate, are discussed in terms of overlay of ion species, high-repetition rate operation, detection solid angle, and detector characteristics of imaging plate.

2-[18F]-Fluoro-2-deoxy-D-glucose positron emission tomography as guidance for primary treatment in patients with advanced-stage resectable squamous cell carcinoma of the larynx and hypopharynx.

BACKGROUND: High uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) is associated with unfavorable results. Pretreatment FDG uptake was evaluated as a predictor of survival and guidance for primary surgery or radiotherapy (RT) in patients with squamous cell carcinoma (SCC) of the larynx and hypopharynx. MATERIALS AND METHODS: Seventy-nine consecutive patients with newly diagnosed advanced resectable SCC of the larynx and hypopharynx underwent FDG positron emission tomography (PET) before surgical resection plus RT and chemotherapy (surgery group, n=40) or RT with chemotherapy and surgical salvage (RT group, n=39). Age, tumor stage, histological grade, treatment strategy, and standardized uptake value (SUV) were analyzed for association with local control and survival. RESULTS: Overall local control and survival in the two groups did not differ (P>0.1). In univariate analysis, nodal positivity (P=0.014) and SUV>8.0 (P=0.007) were associated with poorer disease-free survival (DFS). In multivariate analysis, SUV remained an independent determinant of DFS (P=0.014). When patients with SUV>8.0 in the two treatment groups were analyzed separately, those in the surgery group tended to have a higher 3-year DFS than those in the RT group, despite no statistical significance (48% vs. 27%, P=0.085). CONCLUSIONS: High FDG uptake is associated with poor survival in patients with advanced laryngopharyngeal SCC. Patients with high FDG uptake may be better treated by surgical resection followed by RT and chemotherapy.