AbstractID: 7103 Title: Computer-assisted beam orientation selection for IMRT
Computer-assisted beam orientation selection for IMRT
To facilitate the selection of beam orientations in IMRT treatment planning, the pseudo
beam’s-eye-view (pBEV) method has been developed. In this method, each beam orientation is evaluated
using the score function based on the maximum target dose deliverable by the beam. For the score
function calculation, the beam portal at a given gantry and couch angles was divided into a grid of
beamlets. Each beamlet crossing the target was assigned the maximum intensity that could be used
without exceeding the dose tolerances of the organs at risk (OARs) and normal tissue. Thereafter, a score
was assigned to the beam according to the target dose deliverable by the beam. The beams for the
treatment were selected among those with the highest scores.
In this report we present application of the pBEV technique to the selection of beam
orientations for a paraspinal treatment. The pBEV-selected coplanar beam configuration improved the
target coverage and OAR sparing, compared to the equiangular spaced beam configuration. For noncoplanar beams, the improvement was even more pronounced: the target coverage was better and, at the
same time, dramatic reduction of kidney dose was achieved. Both coplanar and non-coplanar beam
configurations resulted in significant improvement of the liver sparing.
The technique developed in this work allows one to effectively select beam orientations for
complicated IMRT treatments, where the target is surrounded by several sensitive structures. In our
opinion, the pBEV technique has strong potential for simplification of IMRT treatment planning process.