Model Preferences

In this preference pane you can adjust the default startup properties of the eye and plaque models and how plaques are exported for 3D rapid prototyping.


The Beta kernel group parameters (crossover,slope,halo,bias,shift,threshold and silver/water) are semi-empirically derived parameters which modify the patch source dose calculation near the surface of beta-ray applicators such as the BEBIG Ru plaques in order to match measured values. The farfield and ffThreshold parameters modify the dose calculation far from the plaque surface. The default values listed here are approximate starting values used in the auto-optimization process. There is no reason for end users to change these values. All BEBIG Ru plaques MUST be individually calibrated.

The point kernel nearfield crossover and slope parameters influence the dose calculation close to the plaque surface. These two parameters define the transition from an approximately inverse square model in the farfield to a linear model in the nearfield. The halo parameter represents the minimum distance from a source at which dose can be calculated, typically 0.2 mm. This limits dose on and within the plaque surface. The anisotropy threshold parameter is the distance at which the anisotropy kernel (which accounts for anisotropic attenuation and spectral hardening in the silver plaque) becomes fully effective. The shift parameter is an angular offset of the basic anisotropy kernel to account for differences between plaques. The bias parameter affects the rate at which the anisotropy correction is applied within the threshold range, typically it is around 0.15. The farfield parameter (n≈2) is the maximum power of the approximately inverse square behavior in the farfield. The ffThreshold is the distance from each source at which the inverse square model begins the transition from 1/r2 to 1/rn over a 5 mm range. The silver/water parameter is the pseudo specific gravity of water which would have the same effect on beta radiation as silver.