TRiP98 optimize command
| GSI Biophysics | TRiP98 long write-up |

Optimize


optimize / iterations() graceiterations(5) H2Obased CTbased  events() debug
           bio        singly         eps() geps() myfac(0.5) 
           phys       matchonly      doseweightfactor()  
           field(*)      
                      optalgorithm(cg)
                      bioalgorithm(classic)
                      dosealgorithm(allpoints)

Purpose

Handles optimization of dose with respect to particle numbers.

Parameters

iter()
Maximum number of iterations. Remembered. Startup default is 5.
graceiter()
Number of initial "grace" iterations for which tests on relative change of chi-square are suspended. Startup default is 5.
bio
Optimize using biological dose. Remembered.
phys
Optimize using physical dose. Remembered.
H2Obased
CTbased
Optimization principle.
H2Obased selects separate optimization of single fields, with fast, but less accurate algorithms, based on a H2O-equivalent grid. Default.
CTbased selects optimization based on the CT grid. Mandatory for simultaneous optimization of multiple fields.
singly
Separate optimization of multiple fields.
matchonly
Optimize using only a simple peak-to-dose matching algorithm. Otherwise a conjugate gradient method is used to equilibrate peaks and valleys.
dosealgorithm(dalg)
Selects algorithm for dose calculation. Same choices as for dose cube calculation:
bioalgorithm(balg)
Selects algorithm for biological effect calculation.
optalgorithm(oalg)
Selects algorithm for dose optimization. Only effective for CTbased optimizations. Choices are As it turns out, "Fletcher-Reeves" is usually the fastest converging one.
events(nevt)
Not yet implemented.
eps(eps)
Minimum relative change of chi-square. If the actual change is below, the iteration is aborted. Startup default is 1E-3.
geps(geps)
Controls relative contribution of raster points to dose voxels. Contributions less than geps are omitted, thereby reducing memory and time consumption. Should not be raised above some 1E-3, otherwise optimized and real dose distributions will differ.
myfac(myfac)
Controls search stepsize for gradient based optimization algorithms. The default value is 0.5, designed for total biological doses about 3GyE. For lower doses (0.5..1GyE) lower values should be chosen, down to 0.1 to 0.25.
doseweightfactor(dwf)
The prescribed dose is multiplied with this factor to yield sort of an experimental error, which enters as a weight in the chi-square evaluation. Startup default is 2.5E-2.
field(idlist)
List of field id's to be optimized.
debug
Debug switch. Lots of output !

Remarks

later

Examples

  1. opt / field(*) bio
    
    Optimize all defined fields using the biologically effective dose. Fields are optimized separately with "classic" algorithms
  2. opt / field(*) ctbased bio dosealg(ap) optalg(cg) bioalg(ld) geps(1E-4) eps(1e-3) iter(500)
    
    Optimize all defined fields simultaneously (IMRT-style), with "fast" biological calculations and a conjugate gradient algorithm.

| GSI Biophysics | TRiP98 long write-up |
Last updated:
$Id: trip98cmdopt.html,v 1.6 2009/08/18 12:57:17 kraemer Exp $
M.Kraemer@gsi.de