The stf struct - e0404/matRad GitHub Wiki

The stf struct holds all geometric information about the irradiation. The individual fields contain the following information.

Screenshot of the stf structure:

Field Description
gantry angle specification of the gantry angle for each beam in °. Range: 0° - 359°
couch angle specification of the couch angle for each beam in °. Range: 0°- 359°
bixel width Photons: lateral width of each bixel. Particles: lateral spot spacing.
radiation mode specification of the radiation mode. Options are: 'photons', 'protons' or 'carbon'.
number of Rays number of rays for each beam
ray the ray substructure contains the information about the position and orientation of each ray / bixel for a single beam.
source point position of the virtual radiation source in LPS coordinates.
number of bixels per ray Photons: each ray is a single bixel. Particles: number of bixels / dose spots along each ray
total number of bixels total number of bixels for each beam.

stf.ray substructure

The stf.ray substructure contains the information about the position and orientation of each ray/bixel for a single beam.

Screenshot of the stf.ray substructure:

Field code Description
ray position (beam's eye view) rayPos_bev Point where the ray crosses the isocenter plane in the beam's eye view.
target point (beam's eye view) targetPoint_bev target point of the ray from the beam's eye view. The target point extends the ray from source to rayPos_bev to behind the patient for use in rayTracing.
ray position (LPS-coordinates) rayPos rayPos_bev in the LPS coordinate system.
target point (LPS-coordinates) targetPoint targetPoint_bev in the LPS coordinate system.
energy energy Photons: Single value (max. LINAC energy). Particles: Energy values of the dose spots along the ray. The number of energies corresponds to the number of bixels per ray.

stf.ray.energy field

The stf.ray.energy field contains all energy values for the spots along the specified ray. If the radiation mode 'Photons' was selected, it will be set to NaN.

Screenshot of the stf.ray.energy field:

stf.numOfBixelsPerRay field

The stf.numOfBixelsPerRay field contains the number of bixels / dose spots for every ray of the specified beam. This corresponds to the number of energy values per ray in the stf.ray substructure.

Screenshot of the stf.numOfBixelsPerRay field:

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