To add source slots to a plaque one-at-a-time select Add/Delete Slots from the Plaque menu. The new slot(s) will be installed in the plaque at the coordinates indicated.
The origin of the plaque coordinate system in Plaque Simulator is at the center of a sphere defined by the radius of curvature (R) of the plaque's inner (concave) surface. The Z axis of this coordinate system is also the central axis of the plaque. In the Plaque window you are looking at a 2D projection of the plaque onto the XY plane. The default center of a linear source (eg I-125 seed) or a beta patch source (eg Ru-106) is tangent to a sphere of radius R' = R + Offset, with the Z axis passing through the center of the source at Z = -R'. The orientation of the linear source is parallel to the Y axis (Tilt = 0°). Plaque Simulator then uses the angle Alpha or its projection onto the XY plane, the distance r, and angles Beta and Tilt to displace the source center away from its default location and orientation on the sphere. Linear sources normally remain tangent to the sphere, beta patches follow the curvature of the sphere. You can force linear sources to remain in a plane perpendicular to the Z axis by checking the Force Z button. Sources can be grouped into patterns and entire patterns moved in a similar fashion. The default pattern ID is 0. The radio buttons in the Source location box select the data entry format: (alpha,beta,tilt) or (r,beta,tilt). The box on the lower left displays the equivalent Cartesian coordinates of the source with respect to the plaque origin. Each time you click the Add button a new source slot will be added to the plaque. If a slot already exists at the designated location an alert will be displayed. The Copy button loads the parameters of the currently selected slot into the dialog fields. The Edit button replaces the parameters of the selected slot with the dialog values. The Delete button deletes the selected slot. The indices of all slots greater than a deleted slot are decremented. The currently selected slot is indicated by the Slot # popup menu and is also hilited in the Plaque window. You can change the hilite and empty slot colors if you wish. Windows & menus are updated immediately following any action which changes their appearance.
You can always move a slot wherever you want by option clicking and dragging it in the Plaque window, or by command clicking on it and entering new coordinates.The control, option, & command keys rotate the slot interactively when dragging in the Plaque window.
Another way to "fine tune" a slot is to hold down the command (apple) key when clicking on a slot in the Plaque window. A dialog will apear which permits direct editing of slot and source parameters. This dialog also permits you to delete a pattern entirely.
You can also quickly delete an individual slot.