Abstract:
:This paper presents a new algorithm for constrained intensity-modulated radiotherapy (IMRT) planning, made tractable by a dimensionality reduction using a set of plans obtained by fast, unconstrained optimizations. The main result is to reduce planning time by an order of magnitude, producing viable five field prostate IMRT plans in about 5 min. Broadly, the algorithm has three steps. First, we solve a series of independent unconstrained minimization problems based on standard penalty-based objective functions, 'probing' the space of reasonable beamlet intensities. Next, we apply principal component analysis (PCA) to this set of plans, revealing that the high-dimensional intensity space can be spanned by only a few basis vectors. Finally, we parameterize an IMRT plan as a linear combination of these few basis vectors, enabling the fast solution of a constrained optimization problem for the desired intensities. We describe a simple iterative process for handling the dose-volume constraints that are typically required for clinical evaluation, and demonstrate that the resulting plans meet all clinical constraints based on an approximate dose calculation algorithm.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Lu R,Radke RJ,Yang J,Happersett L,Yorke E,Jackson Adoi
10.1088/0031-9155/53/23/007subject
Has Abstractpub_date
2008-12-07 00:00:00pages
6749-66issue
23eissn
0031-9155issn
1361-6560pii
S0031-9155(08)86596-7journal_volume
53pub_type
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