抄録
The focused grid has been used widely in medical radiography because of removing the scatter radiation in the large exposure field. However, it is necessary to set the focused grid on the correct position. The primary radiation is also reduced too much in the misplacement of the focused grid. In particular, it is difficult to find the inclination of the focused grid which is one kind of the misplacement. The equations of the primary radiation loss in the misplacement were associated with the grid ratio. Our computer simulation using Monte Carlo methods showed the primary radiation loss obtained by simulation was less than that of the equation, because some primary radiation passing through the lead strips. As the grid density and the tube voltage of exposure have an influence on the primary radiation passed through the lead strips, we have investigated the dependence of the primary radiation loss in the inclination of the focused grid on the grid density and the tube voltage with our simulation. Our result s showed the primary radiation loss decreased with the high grid density, and decreased with the high tube voltage.
We showed the dependence of the primary radiation loss on the grid density and the tube voltage, quantitatively.
