Premium
Virtual micro‐intensity modulated radiation therapy
Author(s) -
Siochi R. Alfredo C.
Publication year - 2000
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1315314
Subject(s) - collimator , intensity (physics) , superposition principle , orientation (vector space) , dosimetry , image resolution , intensity modulation , optics , multileaf collimator , computer science , computer vision , artificial intelligence , physics , mathematics , nuclear medicine , beam (structure) , linear particle accelerator , geometry , medicine , quantum mechanics , phase modulation , phase noise
Virtual micro‐intensity modulated radiation therapy (VMIMRT) combines a 10 × 5 mm 2intensity map with a 5 × 10 mm 2intensity map, delivered at orthogonal collimator settings. The superposition of these component maps (CM) yields a 5 × 5 mm 2virtual micro‐intensity map (VMIM) that can be delivered with a 1 cm leaf width MLC. A pair of CMs with optimal delivery efficiency and quality must be chosen, since a given VMIM can be delivered using several different pairs. This is possible since, for each group of four VMIM cells that can be covered by an MLC leaf in either collimator orientation, the minimum intensity can be delivered from either collimator setting. By varying the proportions of the minimum values that go into each CM, one can simultaneously minimize the number of potential junction effects and the number of segments required to deliver the VMIM. The minimization is achieved by reducing high leaf direction gradients in the CMs. Several pseudo‐clinical and random VMIMs were studied to determine the applicability of this new technique. A nine level boost map was also studied to investigate dosimetric and spatial resolution issues. Finally, clinical issues for this technique are discussed.