SORGENTINA-RF FUSION NEUTRON PLANT: PRELIMINARY DESIGN OF THE BIOSHIELDING IN COMPLIANCE WITH DOSE CONSTRAINTS FOR WORKERS EXPOSURE.

An accelerator-driven 14 MeV neutron source of new concept, denominated SORGENTINA-RF, will be installed in ENEA Brasimone Research Centre, to test the feasibility of producing radionuclides of medical relevance using fusion neutrons. The main goal of the facility is generating 99Mo as precursor of 99mTc, a radionuclide widely used in nuclear medicine diagnostic procedures, using the 14 MeV fusion neutrons produced by the plant. This work describes the study performed for the design of a proper shielding structure that aims at fulfilling the requirement of 0.01 mSv/h dose rate limit on the external surface of the shielding during beam-on operations. The proposed shielding consists of a layered structure composed of 2 m standard concrete and 1 m baritic concrete. The design is still in the preliminary phase to assess the feasibility and the economic issues as well as structural impact of the shielding structure.

Large-scale individual thyroid monitoring following nuclear accidents by means of non-spectrometric devices.

In order to properly respond to an emergency caused by an accident in a nuclear power plant with a spread of radionuclides in the atmosphere, we propose a field procedure to perform a large-scale individual thyroid monitoring of internal contamination due to inhalation of 131I, by means of non-spectrometric equipment, in particular dose rate meters. Specific attention is paid to the individual monitoring of children, because of the very high radiosensitivity of the child's thyroid to the carcinogenic effects of ionising radiation. The device performance was evaluated by measuring mock iodine sources provided in the Child and Adult Thyroid Monitoring After Reactor Accident (CAThyMARA) intercomparison and, just for a scintillator dose rate meter, by means of 60 s acquisitions of healthy volunteers' thyroids. All the devices showed a remarkable accuracy in quantification of equivalent 131I activity in the thyroids of persons of all ages. The selected scintillator dose rate meter showed detection limit values resulting in a maximum committed equivalent dose to thyroid HT, assuming an acute 131I inhalation occurred five days before the measurement, equal to 10 mSv (related to five-year-old children). Considering the level of HT values associated with the calculated detection limit activities, the proposed procedure has a significant sensitivity to be used for fast internally thyroid monitoring in nuclear or radiological emergencies, allowing daily monitoring a large amount of individuals.

Relationship between Prolactin Plasma Levels and White Matter Volume in Women with Multiple Sclerosis.

BACKGROUND: The role of prolactin (PRL) on tissue injury and repair mechanisms in multiple sclerosis (MS) remains unclear. The aim of this work was to investigate the relationship between PRL plasma levels and brain damage as measured by magnetic resonance imaging (MRI). METHODS: We employed a chemiluminescence immunoassay for measuring plasma levels of PRL. We used a 1.5 T scanner to acquire images and Jim 4.0 and SIENAX software to analyse them. RESULTS: We included 106 women with relapsing remitting (RR) MS and stable disease in the last two months. There was no difference in PRL plasma levels between patients with and without gadolinium enhancement on MRI. PRL plasma levels correlated with white matter volume (WMV) (rho = 0.284, p = 0.014) but not with grey matter volume (GMV). Moreover, PRL levels predicted changes in WMV (Beta: 984, p = 0.034). CONCLUSIONS: Our data of a positive association between PRL serum levels and WMV support the role of PRL in promoting myelin repair as documented in animal models of demyelination. The lack of an increase of PRL in the presence of gadolinium enhancement, contrasts with the view considering this hormone as an immune-stimulating and detrimental factor in the inflammatory process associated with MS.

Weighted-peak assessment of occupational exposure due to MRI gradient fields and movements in a nonhomogeneous static magnetic field.

PURPOSE: A procedure for assessing occupational exposure due to magnetic resonance imaging (MRI) gradient magnetic fields and movement-induced effects in the static magnetic field is proposed and tested. METHODS: The procedure was based on the application of the weighted-peak method in time domain. It was tested in two 1.5 T total-body and one 3 T head-only scanner MRI facilities in Rome (Italy). Exposure due to switched gradient fields was evaluated in locations inside the magnet room where operators usually stay during particular medical procedures (e.g., cardiac examinations of anesthetized patients); MRI sequences were selected to approach as far as possible a representative worst case exposure scenario. Movement-induced effects were evaluated considering the actual movements of volunteer operators during work activity, by measuring the perceived time-varying magnetic field by a head-worn probe. The analysis of results was based on ICNIRP 1998 and 2010 guidelines, following a weighted-peak approach and including an ad hoc extension to the latter ones, needed to verify compliance in the frequency range 0-1 Hz. RESULTS: Exposures due to switched gradient fields in 1.5 T MRI scanners mostly resulted noncompliant with ICNIRP 1998 occupational reference levels, being, at the same time, always compliant with ICNIRP 2010 ones. Gradient field levels and ICNIRP indexes were significantly lower for the 3 T unit, due to its small dimensions, as that unit was a head-only scanner. Movement-induced effects resulted potentially noncompliant only in the case the operator moved the head inside the bore of a 1.5 T scanner. CONCLUSIONS: The procedure had proven to be a sound approach to exposure assessment in MRI. Its testing allowed to draw some general considerations about exposures to gradient magnetic fields and movement-induced effects.

Structural brain MR imaging changes associated with obsessive-compulsive disorder in patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Psychiatric symptoms occur in approximately 30% of patients with MS. Such symptoms include OCD, which may interfere heavily with the patient's daily life. We hypothesized that the widespread involvement of both GM and WM, which characterizes MS, may be responsible for the occurrence of OCD when specific brain structures are affected. The aim of this study was to evaluate the relationship between GM and WM tissue damage and OCD in patients with MS. MATERIALS AND METHODS: We evaluated 16 patients with relapsing-remitting MS who had been diagnosed with OCD on the basis of the Diagnostic and Statistical Manual of Mental Disorders (4th edition) and 15 age- and sex-matched patients with relapsing-remitting MS with no psychiatric disorders as a CG. The MR study (1.5T) included 3D T1-weighted fast-field echo sequences, DTI (32 directions), and conventional MRI. Images were processed using SPM5, FSL, and Jim 5.0 software to evaluate VBM, TBSS, and global and regional LV, respectively. RESULTS: The VBM analysis revealed a set of clusters of reduced GM volume in the OCD group, compared with the CG, located in the right inferior and middle temporal gyri and in the inferior frontal gyrus. TBSS did not detect any differences in the FA values between the 2 groups; global and regional LV values also did not differ significantly between the 2 groups. CONCLUSIONS: Our study suggests that OCD in MS may be caused by damage in the right frontotemporal cortex.

A transverse and longitudinal MR imaging voxel-based morphometry study in patients with primary cervical dystonia.

BACKGROUND AND PURPOSE: Findings of standard MR imaging examinations are usually normal in primary CD. These findings are now increasingly challenged by studies using advanced neuroimaging techniques detecting abnormalities in brain areas that may be functionally involved in the pathophysiology of CD. Our purpose was to evaluate GM volumes in patients with CD at baseline and 5 years later. MATERIALS AND METHODS: We enrolled 19 patients (F/M = 15:4, mean age = 53.2 + 11.2 years), 12 of whom were studied at baseline and again approximately 5 years later. Twenty-eight healthy volunteers acted as controls (F/M = 17:11, mean age = 47.5 + 15.6 years). The subjects were imaged with a 1.5T scanner by using a 3D T1-weighted sequence on 150 contiguous axial 1-mm-thick sections to apply VBM. RESULTS: At entry, VBM analysis disclosed significantly lower GM volumes in the left caudate head and putamen and in the premotor and primary sensorimotor cortices bilaterally in patients than in controls. No correlation was found between decreased GM volumes and patient age, severity of dystonia, or disease duration. At the 5-year follow-up, GM volumes in the left primary sensorimotor cortex in patients had decreased significantly from baseline. CONCLUSIONS: The findings obtained at entry and after a 5-year follow-up consistently showed decreased caudate, putamen, and sensorimotor cortex GM volumes in patients with CD, and they probably play a pathophysiologic role in CD.

Exposure to magnetic fields of railway engine drivers: a case study in Italy.

A case study of exposure assessment of railway workers to static and extremely low frequency (ELF) magnetic fields is presented. A measurement campaign was conducted in aboard Italian main line trains. All measurements were performed on board during regular service (two engine drivers were simultaneously present), in all places potentially accessible to personnel, considering routes ranging from a few tens of kilometres to hundreds of kilometres. The measurement protocol was mostly based on broadband metres and personal metres were employed to assess individual exposure. Surveys on static and ELF magnetic fields were performed for seven different models of engine or electrified train. Traction motors were fed by alternating current (AC) current, except for two engines, where AC current fed only auxiliary services. The final result is that the average exposure to static magnetic field was a little higher than the background geomagnetic field; occasionally in few areas it could reach levels of the order of millitesla. The average exposure to ELF magnetic fields was in the order of 1-2 µT, with higher levels (few microtesla) only for one engine; occasionally in hot spots, close to wiring or specific equipment, the field values could reach several tens of microtesla.