RESUMO
A Bonner sphere spectrometer was used to measure the neutron spectra produced at the collision of protons with an H2(18)O target at different angles. A unique H2(18)O target to produce (18)F was designed and placed in a Tandem linear particle accelerator which produces 8.5MeV protons. The neutron count rates measured with the Bonner spheres were unfolded with the MAXED code. With the GEANT4 Monte Carlo code the neutron spectrum induced in the (p, n) reaction was estimated, this spectrum was used as initial guess during unfolding. Although the cross section of the reaction (18)O(p,n)(18)F is well known, the neutron energy spectra is not correctly defined and it is necessary to verify the simulation with measurements. For this reason, the sensitivity of the unfolding method to the initial spectrum was analyzed applying small variation to the fast neutron peak.
RESUMO
This is a case report of a 63-year-old man with myotonic dystrophy in whom an ECG showed atrial flutter, complete A-V block, idioventricular rhythm with image of left bundle branch block and giant, wide and negative "T-U" waves. The microscopic study of the conduction system showed slight fibrosis of the SAN, fatty infiltration and cellular atrophy of the AVN and bundle of HIS, as wells ad basophilic degeneration of a cell at the begining of the left branch and diffuse sclerosis of the left subendocardial ramifications. Advanced coronary atherosclerosis was also found. Since only two complete pathologic descriptions of the heart in myotonic dystrophy have been reported, no definitive specificity could be atributed to this findings. It is suggested that in the present case both coronary atherosclerosis and an intrinsic myocellular dystrophy could have contributed to the final lesions of the conducting system.
