Treatment planning dose accuracy improvement in the presence of dental implants

Parenica, H.; Ford, John; Mavroidis, Panayiotis; Li, Ying; Papanikolaou, Nikos; Stathakis, Sotirios

doi:10.1016/j.meddos.2018.04.005

Cited by 6 publications

(10 citation statements)

References 13 publications

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“…The reduced D 95% on CT cor resulted from a reduced PTV. The same authors in another study 71 found similar results for density correction method on data of a phantom with Al, Zn, and SS inserts, and clinical H&N CT scans with dental implants.…”

Section: Resultssupporting

confidence: 58%

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The application of metal artifact reduction methods on computed tomography scans for radiotherapy applications: A literature review

Puvanasunthararajah

Fontanarosa

Wille

et al. 2021

J Applied Clin Med Phys

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Metal artifact reduction (MAR) methods are used to reduce artifacts from metals or metal components in computed tomography (CT). In radiotherapy (RT), CT is the most used imaging modality for planning, whose quality is often affected by metal artifacts. The aim of this study is to systematically review the impact of MAR methods on CT Hounsfield Unit values, contouring of regions of interest, and dose calculation for RT applications. This systematic review is performed in accordance with the PRISMA guidelines; the PubMed and Web of Science databases were searched using the main keywords "metal artifact reduction", "computed tomography" and "radiotherapy". A total of 382 publications were identified, of which 40 (including one review article) met the inclusion criteria and were included in this review. The selected publications (except for the review article) were grouped into two main categories: commercial MAR methods and research-based MAR methods. Conclusion: The application of MAR methods on CT scans can improve treatment planning quality in RT. However, none of the investigated or proposed MAR methods was completely satisfactory for RT applications because of limitations such as the introduction of other errors (e.g., other artifacts) or image quality degradation (e.g., blurring), and further research is still necessary to overcome these challenges.

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Section: Resultssupporting

confidence: 58%

“…Density correction methods 38,67,68,71 for artifact correction. Among the deep learning-based MAR algorithms, DL-MAR does not require paired data for artifact correction, and it provided similar results for dose calculation when compared with the water density override.…”

Section: Mar Methods Strength Weaknessmentioning

confidence: 99%

The application of metal artifact reduction methods on computed tomography scans for radiotherapy applications: A literature review

Puvanasunthararajah

Fontanarosa

Wille

et al. 2021

J Applied Clin Med Phys

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“…Kim et al 7 reported that denture artifacts could lead to hot spots in the OAR and cold spots in each target volume. Furthermore, Parenica et al 15 reported an increased dose in OARs affected by streak artifacts from dentures. Although they mention the physical dose distribution effect of dental metal artifacts, they do not report the effect of artificial variation of dental metal artifact contouring on the dose distribution during head‐and‐neck VMAT planning.…”

Section: Discussionmentioning

confidence: 99%

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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“…The difference between dose to water calculations and more accurate calculations that apply dose to medium with radiation transport in the medium (i. e. Monto Carlo simulation) can be largely depending on the mean ionization number of the consisting materials [ 13 ]. Default density scaling of CCCS water kernels may be inadequate, and a worse approximation encounters when the difference between its effective atomic number and water is larger [ 25 ]. Zirconium containing implants can induce more pronounced streaking artifacts when compared to pure titanium in CT images [ 3 ].…”

Section: Discussionmentioning

confidence: 99%

“…When the material composition was used to modify the dose kernels, calculations improved. The authors suggested that density corrections should be considered for cases in which their PTV includes many slices affected by streaking artifacts [ 25 ]. Moreover, beam orientation, device location, and technique of radiotherapy affect the intensity of errors, as a study showed that calculation errors were less intense when an implant in a cylindrical phantom was exposed by VMAT rather than another IMRT plan for both uncorrected and corrected planning CT for metal artifacts [ 20 ].…”

Section: Discussionmentioning

confidence: 99%

Investigating dose homogeneity in radiotherapy of oral cancers in the presence of a dental implant system: an in vitro phantom study

Khaleghi

Mahdavi

et al. 2021

Int J Implant Dent

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Background Materials with high atomic numbers are part of the composition of dental implant systems. In radiotherapy of oral cavity cancers, an implant can cause dose perturbations that affect target definition, dose calculation, and dose distribution. In consequence, this may result in poor tumor control and higher complications. In this study, we evaluated dose homogeneity when a dental implant replaced a normal tooth. We also aimed to evaluate the concordance of dose calculations with dose measurements. Materials and methods In this study, 2 sets of planning CT scans of a phantom with a normal tooth and the same phantom with the tooth replaced by a Z1 TBR dental implant system were used. The implant system was composed of a porcelain-fused-to-metal crown and titanium with a zirconium collar. Three radiotherapy plans were designed when the density of the implant material was corrected to match their elements, or when all were set to the density of water, or when using the default density conversion. Gafchromic EBT-3 films at the level of isocenter and crowns were used for measurements. Results At the level of crowns, upstream and downstream dose calculations were reduced when metal kernels were applied (M-plan). Moreover, relatively measured dose distribution patterns were most similar to M-plan. At this level, relative to the non-implanted phantom, mean doses values were higher with the implant (215.93 vs. 192.25), also, new high-dose areas appeared around a low-dose streak forward to the implant (119% vs. 95%). Conclusions Implants can cause a high dose to the oral cavity in radiotherapy because of extra scattered radiation. Knowledge of the implant dimensions and defining their material enhances the accuracy of calculations.

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Treatment planning dose accuracy improvement in the presence of dental implants

Cited by 6 publications

References 13 publications

The application of metal artifact reduction methods on computed tomography scans for radiotherapy applications: A literature review

The application of metal artifact reduction methods on computed tomography scans for radiotherapy applications: A literature review

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

Investigating dose homogeneity in radiotherapy of oral cancers in the presence of a dental implant system: an in vitro phantom study

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