TRiP98 optimize command
 GSI Biophysics
 TRiP98 long writeup

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 chisquare
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 H2Oequivalent 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 peaktodose 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:

classic
or cl
(default)

allpoints
or ap

multiplescatter
or ms
 bioalgorithm(balg)

Selects
algorithm
for biological effect calculation.

classic
or cl
(default)

lowdose
or ld
 optalgorithm(oalg)

Selects
algorithm
for dose optimization.
Only effective for
CTbased
optimizations. Choices are

classic
or cl
(classic)

cjggrad
or cg
(conjugate gradients, default)

gradient
or gr
(plain gradients)

bortfeld
or bf
(Bortfeld's algorithm)

fletcherreeves
or fr
(FletcherReeves algorithm)
As it turns out, "FletcherReeves" is usually the fastest converging one.
 events(nevt)

Not yet implemented.
 eps(eps)

Minimum relative change of chisquare.
If the actual change is below, the iteration is aborted.
Startup default is 1E3.
 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 1E3, 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 chisquare
evaluation.
Startup default is 2.5E2.
 field(idlist)

List of field id's to be optimized.
 debug

Debug switch. Lots of output !
Remarks
later
Examples

opt / field(*) bio
Optimize all defined fields using the biologically effective dose.
Fields are optimized separately with "classic" algorithms

opt / field(*) ctbased bio dosealg(ap) optalg(cg) bioalg(ld) geps(1E4) eps(1e3) iter(500)
Optimize all defined fields simultaneously (IMRTstyle),
with "fast" biological calculations and a conjugate gradient algorithm.
 GSI Biophysics
 TRiP98 long writeup

Last updated:
$Id: trip98cmdopt.html,v 1.6 2009/08/18 12:57:17 kraemer Exp $
M.Kraemer@gsi.de