Correlación entre el metabolismo de la glucosa cerebral (18F-FDG) y el flujo sanguíneo cerebral con marcadores de amiloide (18F-florbetapir) en práctica clínica: evidencias preliminares / Correlation between brain glucose metabolism (18F-FDG) and cerebral blood flow with amyloid tracers (18F-florbetapir) in clinical routine: Preliminary evidences

Este estudio comparó el rendimiento de las adquisiciones tempranas de 18F-florbetapir PET/TC con el de 18F-FDG PET/TC. Métodos: Se incluyó a 12 pacientes que se sometieron a PET/TC con 18F-FDG y una PET/TC con 18F-florbetapir en dos tiempos (exploración temprana de 1 a 6 min y exploración tardía de 50 min). La PET/TC fue analizada visualmente por 3médicos de medicina nuclear con diferente experiencia utilizando una escala de 4puntos (0=sin reducción, 1=leve, 2=moderada, 3=reducción severa) para 18F-florbetapir en fase temprana y 18F-FDG imágenes en 10 regiones corticales (frontal bilateral, temporal, parietal, occipital, cingulado/precúneo posterior) y fase tardía de 18F-florbetapir en las mismas regiones corticales utilizando una escala de 3puntos (0=normal, 1=anormal con placas menores, 2=anormal con placas importantes). Usamos SPM12 para el análisis semicuantitativo aplicando un análisis de correlación basado en ROI (considerando precúneo como región objetivo y normalizado para la unión global media), un análisis de covarianza tomando precúneo como objetivo y una comparación de DMN global (red de modo predeterminado). resultados: La concordancia entre lectores fue alta (kappa de Cohen 0,762 para 18F-FDG, 0,775 para 18F-florbetapir en la fase temprana y 0,794 para la fase tardía). Las puntuaciones visuales regionales de la fase temprana y la 18F-FDG se correlacionaron significativamente (ρ=0,867). También el análisis basado en el ROI, el análisis visual cerebral global y la comparación de DMN revelaron resultados concordantes, especialmente en parietal y precúneo (p <0,001). Conclusiones: Las exploraciones de fase temprana de 18F-florbetapir se correlacionan significativamente en imágenes cuantitativas y visuales con las exploraciones de 18F-FDG-PET/TC, lo que sugiere que se podría usar un marcadore de amiloide en lugar de 18F-FDG (AU)

This study compared the performance of 18F-florbetapir PET/CT early acquisitions to 18F-FDG PET/CT. Methods: We included 12 patients who underwent 18F-FDG PET/CT and a dual-time 18F-florbetapir PET/CT (1-6minutes early-scan and 50minutes late-scan). PET/CT were analyzed visually by 3nuclear medicine physicians with different experience using a four-point scale (0=no reduction, 1=slight, 2=moderate, 3=severe reduction) for 18F-florbetapir early-phase and 18F-FDG images in 10 cortical regions (bilateral frontal, temporal, parietal, occipital, posterior cingulate/precuneus), and 18F-florbetapir late-phase in the same cortical regions using a three-point scale (0=normal, 1=abnormal with minor plaques, 2=abnormal with major plaques). We used SPM12 for semiquantitative analysis applying a ROI-based correlation analysis (considering precuneus as target region and normalized for the mean global binding), a covariance-analysis taking precuneus as target and a comparison of global DMN (default mode network). esults: Inter-reader agreement was high (Cohen's kappa 0.762 for 18F-FDG, 0.775 for 18F-florbetapir early-phase and 0.794 for late-phase). Regional visual scores of early-phase and 18F-FDG were significantly correlated (ρ=0.867). Also ROI-based analysis, global brain visual analysis and DMN comparison revealed concordant results, especially at parietal and precuneus(p<0.001). Conclusions: 18F-florbetapir early-phase scans significantly correlate on quantitative and visual images with 18F-FDG-PET/CT scans, suggesting that amyloid tracer could be used instead of 18F-FDG (AU)

Behavioural and electrophysiological modulations induced by transcranial direct current stimulation in healthy elderly and Alzheimer's disease patients: A pilot study.

OBJECTIVE: To investigate whether anodal and cathodal transcranial direct current stimulation (tDCS) can modify cognitive performance and neural activity in healthy elderly and Alzheimer's disease (AD) patients. METHODS: Fourteen healthy elderly and twelve AD patients performed a working memory task during an electroencephalogram recording before and after receiving anodal, cathodal, and sham tDCS over the left dorsolateral prefrontal cortex. Behavioural performance, event-related potentials (P200, P300) and evoked cortical oscillations were studied as correlates of working memory. RESULTS: Anodal tDCS increased P200 and P300 amplitudes in healthy elderly. Cathodal tDCS increased P200 amplitude and frontal theta activity between 150 and 300 ms in AD patients. Improved working memory after anodal tDCS correlated with increased P300 in healthy elderly. In AD patients, slight tendencies between enhanced working memory and increased P200 after cathodal tDCS were observed. CONCLUSIONS: Functional neural modulations were promoted by anodal tDCS in healthy elderly and by cathodal tDCS in AD patients. SIGNIFICANCE: Interaction between tDCS polarity and the neural state (e.g., hyper-excitability exhibited by AD patients) suggests that appropriate tDCS parameters (in terms of tDCS polarity) to induce behavioural improvements should be chosen based on the participant's characteristics. Future studies using higher sample sizes should confirm and extend the present findings.

X-ray powder diffraction at the XRD1 beamline at LNLS.

Various upgrades have been completed at the XRD1 beamline at the Brazilian synchrotron light source (LNLS). The upgrades are comprehensive, with changes to both hardware and software, now allowing users of the beamline to conduct X-ray powder diffraction experiments with faster data acquisition times and improved quality. The main beamline parameters and the results obtained for different standards are presented, showing the beamline ability of performing high-quality experiments in transmission geometry. XRD1 operates in the 5.5-14 keV range and has a photon flux of 7.8 × 109 photons s-1 (with 100 mA) at 12 keV, which is one of the typical working energies. At 8 keV (the other typical working energy) the photon flux at the sample position is 3.4 × 1010 photons s-1 and the energy resolution ΔE/E = 3 × 10-4.

Reduced Current Spread by Concentric Electrodes in Transcranial Electrical Stimulation (tES).

OBJECTIVE: We propose the use of a new montage for transcranial direct current stimulation (tDCS), called concentric electrodes tDCS (CE-tDCS), involving two concentric round electrodes that may improve stimulation focality. METHODS: To test efficacy and focality of CE-tDCS, we modelled the current distribution and tested physiological effects on cortical excitability. Motor evoked potentials (MEPs) from first dorsal interosseous (FDI) and abductor digiti minimi (ADM) were recorded before and after the delivery of anodal, cathodal and sham stimulation on the FDI hotspot for 10 minutes. RESULTS: MEP amplitude of FDI increased after anodal-tDCS and decreased after cathodal-tDCS, supporting the efficacy of CE-tDCS in modulating cortical excitability. Moreover, modelled current distribution and no significant effects of stimulation on MEP amplitude of ADM suggest high focality of CE-tDCS. CONCLUSIONS: CE-tDCS may allow a better control of current distribution and may represent a novel tool for applying tDCS and other transcranial current stimulation approaches.

[A survey on dental offices: risk assessment and practicable preventive and protective measures]. / Indagine su un campione di studi odontoiatrici: valutazione dei rischi e misure preventive e protettive attuabili.

The survey was aimed at developing a method and providing valuable tools to be used for risk assessment in dental practices and for the implementation of preventive and protective measures. For these purposes general (inspection card for the definition of risk level for health and safety) and specific tools (check-lists) were used. In each dental office chemical and physical hazards (noise and hand-arm vibration) were assessed. Adequate levels of security were achieved, even if workers' training was evidenced as a critical element. In the 90% of cases, rooms for specific use were available and suitable according the law. The risk of work-related stress was acceptable in almost all the analyzed dental offices. Chemical and specific physical hazards appeared to be below the action level. Biological risk doesn't seem to be a critical element, even though its control could be further improved.

Staff dosimetry in interventional cardiology.

In interventional cardiology (IC) staff can be exposed to high dose levels due to the long fluoroscopy procedures performed. Staff dosimetry can yield information on the optimisation level of radiation protection, which is influenced by the equipment performance, auxiliary protection devices, training in radiation protection and procedure complexity. Staff exposure data assessed in haemodynamic laboratories of four hospitals in Spain, Greece and Italy participating in the DIMOND concerted action are analysed and compared with data in the literature.