Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures.

Improving the reliability of single-subject fMRI by weighting intra-run variability.

At present, functional magnetic resonance imaging (fMRI) is one of the most useful methods of studying cognitive processes in the human brain in vivo, both for basic science and clinical goals. Although neuroscience studies often rely on group analysis, clinical applications must investigate single subjects (patients) only. Particularly for the latter, issues regarding the reliability of fMRI readings remain to be resolved. To determine the ability of intra-run variability (IRV) weighting to consistently detect active voxels, we first acquired fMRI data from a sample of healthy subjects, each of whom performed 4 runs (4 blocks each) of self-paced finger-tapping. Each subject's data was analyzed using single-run general linear model (GLM), and each block was then analyzed separately to calculate the IRV weighting. Results show that integrating IRV information into standard single-subject GLM activation maps significantly improved the reliability (p=0.007) of the single-subject fMRI data. This suggests that taking IRV into account can help identify the most constant and relevant neuronal activity at the single-subject level.

Children's perceptions of peers with AIDS: assessing the impact of contagion information, perceived similarity, and illness conceptualization.

Assessed factors that affected acceptance of a hypothetical peer with AIDS. Children in Grades 4-6 read vignettes containing one of four levels of contagion information and one of two levels of perceived similarity. Illness conceptualization was measured as a continuous variable. Results indicated that the type of AIDS information given to children affected their perception of the peer. Specifically, informing children about the modes of HIV transmission was not sufficient to increase acceptance, but clearing misconceptions by describing ways HIV is not transmitted positively affected children's reactions to the peer. No other significant results were found. Results of the current study have clear and practical implications for AIDS education programs in schools.

Psychosocial policies in hospitals serving children: comparative characteristics.

This investigation identified and assessed the extent to which hospitals are implementing psychosocial services to meet the needs of children and their families. Following up a similar survey in 1981, a comprehensive questionnaire was sent to the directors of pediatric nursing at pediatric hospitals and general hospitals with pediatric residency programs in the U.S. and Canada. Data were analyzed in a variety of ways to determine the relation between characteristics of pediatric hospitals and general hospitals; Canadian and U.S. hospitals; and hospitals with short, medium, and long lengths of pediatric patient stay. Overall, pediatric hospitals provided more psychosocial services than did general hospitals, and more of these services were implemented in 1988 as compared to 1981. No consistent trends were evident among hospitals when countries or lengths of pediatric patient stay were compared.