The pln struct

The pln struct holds the meta information about the radiation treatment plan in the following fields.

pln.SAD

Specifies the source-to-axis distance of the virtual radiation source to the iso center in [mm]. Note that beam divergence is currently only modeled for photons; protons and carbon ions specify a parallel beam geometry.

pln.isocenter

Specifies the iso center of the treatment plan in voxel coordinates within the ct.cube. By default, the iso center is calculated as the center of gravity of all voxels belonging to structures that have been modeled as target volume in the cst struct.

pln.bixelWidth

Specifies the width (and height) of quadratic photon bixels (i.e. discrete fluence elements). For particles, this parameter specifies the lateral spot distance.

pln.gantryAngles

Specifies the gantry angles as matlab vector according to the matRad coordinate system.

pln.couchAngles

Specifies the couch angles as matlab vector according to the matRad coordinate system.

pln.numOfBeams

Specifies the number of beam directions. During the matRad script, this parameter is automatically determined.

pln.numOfVoxels

The number of voxels in the ct cube.

pln.voxelDimensions

Number of voxels in the ct cube along the x-, y-, and z-axis.

pln.radiationMode

Specifies the radiation modality. Can either be photons, protons, or carbon.

pln.bioOptimization

Specifies the type of biological optimization. none corresponds to a conventional optimization based on the physical dose. effect corresponds to an effect based optimization according to Wilkens & Oelfke. RBExD corresponds to an optimization of the RBE weighted dose according to Krämer & Scholz.

pln.numOfFractions

Specifies the number of fractions. Note that this parameter only needs to be set for biological treatment planning for carbon ions, where the optimization process is based on the fraction dose and not based on the overall dose.

Screenshot of the pln-struct: