Contouring and dose calculation in head and neck cancer radiotherapy after reduction of metal artifacts in CT images

Hansen, Christian Rønn; Christiansen, Rasmus Lübeck; Lorenzen, Ebbe Laugaard; Bertelsen, Anders; Asmussen, Jon Thor; Gyldenkerne, Niels; Eriksen, Jesper Grau; Johansen, Jørgen; Brink, Carsten

doi:10.1080/0284186x.2017.1287427

Cited by 31 publications

(39 citation statements)

References 20 publications

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“…The visual grading evaluation showed that the MAR algorithms improve image quality, which agrees with previous studies . Only one iMAR image series was scored by one oncologist for one criterion to be of worse image quality compared to the uncorrected series.…”

Section: Discussionmentioning

confidence: 95%

“…Previous studies have shown that the O‐MAR algorithm improves CT‐number accuracy and visualization of target and OARs, but that the algorithm does not have a significant impact on photon dose distributions . Kwon et al concluded that O‐MAR improved CT‐number accuracy for H&N imaging, but that the dosimetric differences for closed‐mouth patients treated with photon volumetric arc therapy were insignificant.…”

Section: Discussionmentioning

confidence: 99%

“…Kwon et al concluded that O‐MAR improved CT‐number accuracy for H&N imaging, but that the dosimetric differences for closed‐mouth patients treated with photon volumetric arc therapy were insignificant. Hansen et al also concluded insignificant photon dose differences with O‐MAR for the majority of the H&N patients studied, with exception for a few cases where considerable differences were seen.…”

Section: Discussionmentioning

confidence: 99%

“…MAR through the creation of virtual monoenergetic reconstructions is another proposed method, but this is only possible with dual‐energy CT imaging . Some of the commercial MAR algorithms have previously been evaluated for use in RT planning . However, studies comparing different MAR methods in RT treatment planning are lacking and very few studies include treatment planning with protons.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of two commercial CT metal artifact reduction algorithms for use in proton radiotherapy treatment planning in the head and neck area

Andersson

Dahlgren²,

Reizenstein

et al. 2018

Medical Physics

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O-MAR and iMAR significantly improved image quality in terms of anatomical visualization for target and OAR delineation in dental implant patient images. WET calculations along several directions, all outside the metallic regions, showed that both uncorrected and MAR images contained metal artifacts which could potentially lead to unacceptable errors in proton treatment planning. ΔWET was reduced by MAR in some areas, while increased or unchanged deviations were seen for other path directions. The proton treatment plans created for the phantom images showed overall acceptable dose distributions differences when compared to the reference cases, both for the uncorrected and MAR images. However, substantial dose distribution differences in the areas of most severe artifacts were seen for some plans, which were reduced by MAR in some cases but not all. In conclusion, MAR could be beneficial to use for proton treatment planning; however, case-by-case evaluations of the metal artifact-degraded images are always recommended.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of two commercial CT metal artifact reduction algorithms for use in proton radiotherapy treatment planning in the head and neck area

Andersson

Dahlgren²,

Reizenstein

et al. 2018

Medical Physics

View full text Add to dashboard Cite

show abstract

“…Different methods have been presented on detecting volume changes13 and landmark movements,14 but most rely solely on visual inspection by clinicians. These visual inspections may not be consistent as shown by inter‐observer studies 15. Several groups have presented adaptation strategies and schedules throughout treatment 16, 17.…”

Section: Introductionmentioning

confidence: 97%

Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Vickress

Battista

Barnett

et al. 2018

J Applied Clin Med Phys

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BackgroundHead and neck cancers are commonly treated with radiation therapy, but due to possible volume changes, plan adaptation may be required during the course of treatment. Currently, plan adaptations consume significant clinical resources. Existing methods to evaluate the need for plan adaptation requires deformable image registration (DIR) to a new CT simulation or daily cone beam CT (CBCT) images and the recalculation of the dose distribution. In this study, we explore a tool to assist the decision for plan adaptation using a CBCT without re‐computation of dose, allowing for rapid online assessment.MethodsThis study involved 18 head and neck cancer patients treated with CBCT image guidance who had their treatment plan modified based on a new CT simulation (ReCT). Dose changes were estimated using different methods and compared to the current gold standard of using DIR between the planning CT scan (PCT) and ReCT with recomputed dose. The first and second methods used DIR between the PCT and daily CBCT with the planned dose or recalculated dose from the ReCT respectively, with the dose transferred to the CBCT using rigid registration. The necessity of plan adaptation was assessed by the change in dose to 95% of the planning target volume (D95) and mean dose to the parotids.ResultsThe treatment plans were adapted clinically for all 18 patients but only 7 actually needed an adaptation yielding 11 unnecessary adaptations. Applying a method using the daily CBCT with the planned dose distribution would have yielded only four unnecessary adaptations and no missed adaptations: a significant improvement from that done clinically.ConclusionUsing the DIR between the planning CT and daily CBCT can flag cases for plan adaptation before every fraction while not requiring a new re‐planning CT scan and dose recalculation.

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Effect of dental metal artifact conversion volume on dose distribution in head‐and‐neck volumetric‐modulated arc therapy

Kitagawa

Ikushima²,

Sasaki³

et al. 2020

J Applied Clin Med Phys

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Purpose: During treatment planning for head-and-neck volumetric-modulated arc therapy (VMAT), manual contouring of the metal artifact area of artificial teeth is done, and the area is replaced with water computed tomography (CT) values for dose calculation. This contouring of the metal artifact areas, which is performed manually, is subject to human variability. The purpose of this study is to evaluate and analyze the effect of inter-observer variation on dose distribution. Methods: The subjects were 25 cases of cancer of the oropharynx for which VMAT was performed. Six radiation oncologists (ROs) performed metal artifact contouring for all of the cases. Gross tumor volume, clinical target volume, planning target volume (PTV), and oral cavity were evaluated. The contouring of the six ROs was divided into two groups, small and large groups. A reference RO was determined for each group and the dose distribution was compared with those of the other radiation oncologists by gamma analysis (GA). As an additional experiment, we changed the contouring of each dental metal artifact area, creating enlarged contours (L), reduced contours (S), and undrawn contours (N) based on the contouring by the six ROs and compared these structure sets. Results: The evaluation of inter-observer variation showed no significant difference between the large and small groups, and the GA pass rate was 100%. Similar results were obtained comparing structure sets L and S, but in the comparison of structure sets L and N, there were cases with pass rates below 70%. Conclusions: The results show that the artificial variability of manual artificial tooth metal artifact contouring has little effect on the dose distribution of VMAT. However, it should be noted that the dose distribution may change depending on the contouring method in cases where the overlap between PTV and metal artifact areas is large.

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Contouring and dose calculation in head and neck cancer radiotherapy after reduction of metal artifacts in CT images

Abstract: Delineation of structures in the head and neck were affected by metal artifacts and volumes were generally larger and more consistent after reduction of metal artifacts, however, only small changes were observed in the dose calculations.

Cited by 31 publications

References 20 publications

Evaluation of two commercial CT metal artifact reduction algorithms for use in proton radiotherapy treatment planning in the head and neck area

Evaluation of two commercial CT metal artifact reduction algorithms for use in proton radiotherapy treatment planning in the head and neck area

Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Effect of dental metal artifact conversion volume on dose distribution in head‐and‐neck volumetric‐modulated arc therapy

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