A clinical distance measure for evaluating treatment plan quality difference with Pareto fronts in radiotherapy

Petersson, Kristoffer; Kyroudi, Archonteia; Bourhis, Jean; Ceberg, Crister; Knöös, Tommy; Bochud, François; Moeckli, R.

doi:10.1016/j.phro.2017.09.003

Cited by 4 publications

(8 citation statements)

References 11 publications

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“…We generated Pareto fronts for both VMAT and HT treatment techniques using an in-house python script that controlled the TPS RayStation (RaySearch, Sweden) and compared those fronts using the clinical distance measure. 17 After which, two radiation oncologists performed a blind comparison of treatment plans on these fronts. This study was conducted according to the radiotherapy treatment planning study guidelines (RATING) and attained a score of 96% (RATING score sheet in supplementary material).…”

Section: Methodsmentioning

confidence: 99%

“…We generated Pareto fronts for both VMAT and HT treatment techniques using an in‐house python script that controlled the TPS RayStation (RaySearch, Sweden) and compared those fronts using the clinical distance measure 17 . After which, two radiation oncologists performed a blind comparison of treatment plans on these fronts.…”

Section: Methodsmentioning

confidence: 99%

“…We compared the Pareto fronts of the VMAT and HT treatment technique using the clinical distance measure, which has been described in detail elsewhere 17 . The clinical distance of a treatment plan α and a Pareto front B was defined as follows:

$$\begin{eqnarray} c{d_B}\left( \alpha \right) &=& \min \left( \sqrt {\mathop \sum \limits_{i = 1}^n {{\left( {\left( {{a_i} - {b_{i,1}}} \right){k_i}} \right)}^2}} ,\sqrt {\mathop \sum \limits_{i = 1}^n {{\left( {\left( {{a_i} - {b_{i,2}}} \right){k_i}} \right)}^2}} ,\right.\nonumber\\ &&\left.

…”

Section: Methodsmentioning

confidence: 99%

“…We compared the Pareto fronts of the VMAT and HT treatment technique using the clinical distance measure, which has been described in detail elsewhere. 17 The clinical distance of a treatment plan α and a Pareto front B was defined as follows:…”

Section: Treatment Technique Comparisonmentioning

confidence: 99%

“…considered the clinical importance of the corresponding evaluation parameter, whose unit was reciprocal to the unit of k i . 14,17,40,41 A previous study 17 suggested using a clinical scaling factor of 0.5 for the PTV undercoverage and 0.05 Gy −1 for the rectum mean dose.…”

Section: Treatment Technique Comparisonmentioning

confidence: 99%

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Comparison of volumetric modulated arc therapy and helical tomotherapy for prostate cancer using Pareto fronts

Wüthrich,

Wang,

Zeverino

et al. 2023

Medical Physics

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BackgroundStudies comparing different radiotherapy treatment techniques—such as volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT)—typically compare one treatment plan per technique. Often, some dose metrics favor one plan and others favor the other, so the final plan decision involves subjective preferences. Pareto front comparisons provide a more objective framework for comparing different treatment techniques. A Pareto front is the set of all treatment plans where improvement in one criterion is possible only by worsening another criterion. However, different Pareto fronts can be obtained depending on the chosen machine settings.PurposeTo compare VMAT and HT using Pareto fronts and blind expert evaluation, to explain the observed differences, and to illustrate limitations of using Pareto fronts.MethodsWe generated Pareto fronts for twenty‐four prostate cancer patients treated at our clinic for VMAT and HT techniques using an in‐house script that controlled a commercial treatment planning system. We varied the PTV under‐coverage (100% ‐ V95%) and the rectum mean dose, and fixed the mean doses to the bladder and femoral heads. In order to ensure a fair comparison, those fixed mean doses were the same for the two treatment techniques and the sets of objective functions were chosen so that the conformity indexes of the two treatment techniques were also the same. We used the same machine settings as are used in our clinic. Then, we compared the VMAT and HT Pareto fronts using a specific metric (clinical distance measure) and validated the comparison using a blinded expert evaluation of treatment plans on these fronts for all patients in the cohort. Furthermore, we investigated the observed differences between VMAT and HT and pointed out limitations of using Pareto fronts.ResultsBoth clinical distance and blind treatment plan comparison showed that VMAT Pareto fronts were better than HT fronts. VMAT fronts for 10 and 6 MV beam energy were almost identical. HT fronts improved with different machine settings, but were still inferior to VMAT fronts.ConclusionsThat VMAT Pareto fronts are better than HT fronts may be explained by the fact that the linear accelerator can rapidly vary the dose rate. This is an advantage in simple geometries that might vanish in more complex geometries. Furthermore, one should be cautious when speaking about Pareto optimal plans as the best possible plans, as their calculation depends on many parameters.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%