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@ARTICLE{Wahl:157338,
author = {N. Wahl$^*$ and P. Hennig and H.-P. Wieser$^*$ and M.
Bangert$^*$},
title = {{A}nalytical probabilistic modeling of dose-volume
histograms.},
journal = {Medical physics},
volume = {47},
number = {10},
issn = {2473-4209},
address = {College Park, Md.},
publisher = {AAPM},
reportid = {DKFZ-2020-01567},
pages = {5260-5273},
year = {2020},
note = {#EA:E040#LA:E040#2020 Oct;47(10):5260-5273},
abstract = {Radiotherapy, especially with charged particles, is
sensitive to executional and preparational uncertainties
that propagate to uncertainty in dose and plan quality
indicators, e. g., dose-volume histograms (DVHs). Current
approaches to quantify and mitigate such uncertainties rely
on explicitly computed error scenarios and are thus subject
to statistical uncertainty and limitations regarding the
underlying uncertainty model. Here we present an
alternative, analytical method to approximate moments, in
particular expectation value and (co)variance, of the
probability distribution of DVH-points, and evaluate its
accuracy on patient data.We use Analytical Probabilistic
Modeling (APM) to derive moments of the probability
distribution over individual DVH-points based on the
probability distribution over dose. By using the computed
moments to parameterize distinct probability distributions
over DVH-points (here normal or beta distributions), not
only the moments but also percentiles, i. e., α-DVHs, are
computed. The model is subsequently evaluated on three
patient cases (intracranial, paraspinal, prostate) in 30-
and singlefraction scenarios by assuming the dose to follow
a multivariate normal distribution, whose moments are
computed in closed-form with APM. The results are compared
to a benchmark based on discrete random sampling.The
evaluation of the new probabilistic model on the three
patient cases against a sampling benchmark proves its
correctness under perfect assumptions as well as good
agreement in realistic conditions. More precisely, ca.
$90\%$ of all computed expected DVH-points and their
standard deviations agree within $1\%$ volume with their
empirical counterpart from sampling computations, for both
fractionated and single fraction treatments. When computing
α-DVHs, the assumption of a beta distribution achieved
better agreement with empirical percentiles than the
assumption of a normal distribution: While in both cases
probabilities locally showed large deviations (up to ±0.2),
the respective α -DVHs for α = {0:05; 0:5; 0:95} only
showed small deviations in respective volume (up to $±5\%$
volume for a normal distribution, and up to $2\%$ for a beta
distribution). A previously published model from literature,
which was included for comparison, exhibited substantially
larger deviations.With APM we could derive a mathematically
exact description of moments of probability distributions
over DVH-points given a probability distribution over dose.
The model generalizes previous attempts and performs well
for both choices of probability distributions, i. e., normal
or beta distributions, over DVH-points.},
cin = {E040},
ddc = {610},
cid = {I:(DE-He78)E040-20160331},
pnm = {315 - Imaging and radiooncology (POF3-315)},
pid = {G:(DE-HGF)POF3-315},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:32740930},
doi = {10.1002/mp.14414},
url = {https://inrepo02.dkfz.de/record/157338},
}