Resampling: {A}n optimization method for inverse planning in robotic radiosurgery

Type of publication:  Artikel
Zeitschrift: Medical Physics
Band: 33
Nummer: 11
Jahr: 2006
Monat: November
Seiten: 4005--4011
DOI: 10.1118/1.2357020
Abriss: By design, the range of beam directions in conventional radiosurgery are constrained to an isocentric array. However, the recent introduction of robotic radiosurgery dramatically increases the flexibility of targeting, and as a consequence, beams need be neither coplanar nor isocentric. Such a nonisocentric design permits a large number of distinct beam directions to be used in one single treatment. These major technical differences provide an opportunity to improve upon the wellestablished principles for treatment planning used with GammaKnife or LINAC radiosurgery. With this objective in mind, our group has developed over the past decade an inverse planning tool for robotic radiosurgery. This system first computes a set of beam directions, and then during an optimization step, weights each individual beam. Optimization begins with a feasibility query, the answer to which is derived through linear programming. This approach offers the advantage of completeness and avoids local optima. Final beam selection is based on heuristics. In this report we present and evaluate a new strategy for utilizing the advantages of linear programming to improve beam selection. Starting from an initial solution, a heuristically determined set of beams is added to the optimization problem, while beams with zero weight are removed. This process is repeated to sample a set of beams much larger compared with typical optimization. Experimental results indicate that the planning approach efficiently finds acceptable plans and that resampling can further improve its efficiency.
Nutzerfelder: file={ssa_06.pdf:ssa_06.pdf:PDF}
Schlagworte: inverse planning, optimization, Radiosurgery
Autoren: Schweikard, Achim
Schlaefer, Alexander
Adler, Jr., John R.