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Main steps in the OOPS (Object Oriented Pixel
Shadowing) back projection algorithm for head
scatter geometry integrations:
I. Cover scattering surface by a pixel matrix.
II. Set all pixels as scattering.
III. Illuminate the matrix by a light source place
in the calculation point.
IV. Construct the shadow cast on the matrix
from each collimating element (collimator,
MLC, block,…).
V. Combine all shadows (reset shadowed
pixels).
Only visible pixels remains set !
Head scatter fluence calculation
- integration over extended sources
Can not be seen through
the collimators
Can be seen through
the collimators
Calculation point
Collimator
Scatter source