7,794 research outputs found
When is Better Best? A multiobjective perspective
Purpose: To identify the most informative methods for reporting results of
treatment planning comparisons.
Methods: Seven papers from the past year of International Journal of
Radiation Oncology Biology Physics reported on comparisons of treatment plans
for IMRT and IMAT. The papers were reviewed to identify methods of comparisons.
Decision theoretical concepts were used to evaluate the study methods and
highlight those that provide the most information.
Results: None of the studies examined the correlation between objectives.
Statistical comparisons provided some information but not enough to make
provide support for a robust decision analysis.
Conclusion: The increased use of treatment planning studies to evaluate
different methods in radiation therapy requires improved standards for
designing the studies and reporting the results
Beam Orientation Optimization for Intensity Modulated Radiation Therapy using Adaptive l1 Minimization
Beam orientation optimization (BOO) is a key component in the process of IMRT
treatment planning. It determines to what degree one can achieve a good
treatment plan quality in the subsequent plan optimization process. In this
paper, we have developed a BOO algorithm via adaptive l_1 minimization.
Specifically, we introduce a sparsity energy function term into our model which
contains weighting factors for each beam angle adaptively adjusted during the
optimization process. Such an energy term favors small number of beam angles.
By optimizing a total energy function containing a dosimetric term and the
sparsity term, we are able to identify the unimportant beam angles and
gradually remove them without largely sacrificing the dosimetric objective. In
one typical prostate case, the convergence property of our algorithm, as well
as the how the beam angles are selected during the optimization process, is
demonstrated. Fluence map optimization (FMO) is then performed based on the
optimized beam angles. The resulted plan quality is presented and found to be
better than that obtained from unoptimized (equiangular) beam orientations. We
have further systematically validated our algorithm in the contexts of 5-9
coplanar beams for 5 prostate cases and 1 head and neck case. For each case,
the final FMO objective function value is used to compare the optimized beam
orientations and the equiangular ones. It is found that, our BOO algorithm can
lead to beam configurations which attain lower FMO objective function values
than corresponding equiangular cases, indicating the effectiveness of our BOO
algorithm.Comment: 19 pages, 2 tables, and 5 figure
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