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Improved critical structure sparing with biologically based IMRT optimization
Author(s) -
Qi X. Sharon,
Semenenko Vladimir A.,
Li X. Allen
Publication year - 2009
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 - 10.1118/1.3116775
Subject(s) - tomotherapy , radiation treatment planning , nuclear medicine , dosimetry , head and neck , medicine , computer science , medical physics , radiation therapy , radiology , surgery
The impact of using biological models in treatment planning on plan quality is studied by comparing IMRT plans generated using selected commercially available treatment planning systems (TPSs) employing biological models/quantities in IMRT optimization (bIMRT) and the conventional physically (dose‐volume) based optimization (pIMRT). A total of 25 IMRT plans, generated for five cases of different anatomic sites (brain, head and neck, lung, pancreas, and prostate) using five TPSs, two bIMRT (CMS Monaco and PhillipsPinnacle 3P 3 IMRT ) and three pIMRT (CMS Xio, PhillipsPinnacle 3 , and Tomotherapy) systems, were compared. Dose‐volume histograms, maximum, minimum, and mean doses, target heterogeneity and conformity indices, equivalent uniform dose (EUD), and an overall plan‐ranking index (fEUD) were used in the comparison. It is clear from the comparison that the use of biological models in treatment planning optimization can generate IMRT plans with significantly improved normal tissue sparing with similar or slightly increased dose heterogeneity in the target, as compared to the conventional dose‐volume based optimization for the same beam arrangement. For example, the bIMRT plans lead to smaller EUDs in 32 out of 37 normal structures in all five cases combined, as compared to the pIMRT plans. Caution should be exercised in choosing appropriate models and/or model parameters and in evaluating the plan obtained when using the biologically based treatment planning system.