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The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy.
Phys Med Biol 2013; 58(4):1027-40PM

Abstract

This work aims to investigate the dosimetric impact of dental implants on volumetric modulated arc therapy (VMAT) for head-and-neck patients and to evaluate the effectiveness of using the material's electron-density ratio for the correction. An in-house Monte Carlo (MC) code was utilized for the dose calculation to account for the scattering and attenuation caused by the high-Z implant material. Three different dental implant materials were studied in this work: titanium, Degubond®4 and gold. The dose perturbations caused by the dental implant materials were first investigated in a water phantom with a 1 cm(3) insert. The per cent depth dose distributions of a 3 × 3 cm(2) photon field were compared with the insert material as water and the three selected dental implant materials. To evaluate the impact of the dental implant on VMAT patient dose calculation, four head-and-neck cases were selected. For each case, the VMAT plan was designed based on the artifact-corrected patient geometry using a treatment planning system (TPS) that was typically utilized for routine patient treatment. The plans were re-calculated using the MC code for five situations: uncorrected geometry, artifact-corrected geometry and artifact-corrected geometry with one of the three different implant materials. The isodose distributions and the dose-volume histograms were cross-compared with each other. To evaluate the effectiveness of using the material's electron-density ratio for dental implant correction, the implant region was set as water with the material's electron-density ratio and the calculated dose was compared with the MC simulation with the real material. The main effect of the dental implant was the severe attenuation in the downstream. The 1 cm(3) dental implant can lower the downstream dose by 10% (Ti) to 51% (Au) for a 3 × 3 cm(2) field. The TPS failed to account for the dose perturbation if the dental implant material was not precisely defined. For the VMAT patient dose calculation, the presence of dental implants degrades the PTV coverage significantly. With the material's electron-density ratio applied, the dose calculation accuracy in the water phantom and the VMAT patient was improved to a clinically acceptable level. The effects of the dental implant material can be clinically significant and its impact varies with the density of the dental implant material. We demonstrated that it was effective to use the material's electron-density ratio to account for the dosimetric impact of the dental implant.

Authors+Show Affiliations

Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA. mu-han.lin@fccc.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

23363570

Citation

Lin, Mu-Han, et al. "The Dosimetric Impact of Dental Implants On Head-and-neck Volumetric Modulated Arc Therapy." Physics in Medicine and Biology, vol. 58, no. 4, 2013, pp. 1027-40.
Lin MH, Li J, Price RA, et al. The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy. Phys Med Biol. 2013;58(4):1027-40.
Lin, M. H., Li, J., Price, R. A., Wang, L., Lee, C. C., & Ma, C. M. (2013). The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy. Physics in Medicine and Biology, 58(4), pp. 1027-40. doi:10.1088/0031-9155/58/4/1027.
Lin MH, et al. The Dosimetric Impact of Dental Implants On Head-and-neck Volumetric Modulated Arc Therapy. Phys Med Biol. 2013 Feb 21;58(4):1027-40. PubMed PMID: 23363570.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy. AU - Lin,Mu-Han, AU - Li,Jinsheng, AU - Price,Robert A,Jr AU - Wang,Lu, AU - Lee,Chung-Chi, AU - Ma,C-M, Y1 - 2013/01/31/ PY - 2013/2/1/entrez PY - 2013/2/1/pubmed PY - 2013/8/7/medline SP - 1027 EP - 40 JF - Physics in medicine and biology JO - Phys Med Biol VL - 58 IS - 4 N2 - This work aims to investigate the dosimetric impact of dental implants on volumetric modulated arc therapy (VMAT) for head-and-neck patients and to evaluate the effectiveness of using the material's electron-density ratio for the correction. An in-house Monte Carlo (MC) code was utilized for the dose calculation to account for the scattering and attenuation caused by the high-Z implant material. Three different dental implant materials were studied in this work: titanium, Degubond®4 and gold. The dose perturbations caused by the dental implant materials were first investigated in a water phantom with a 1 cm(3) insert. The per cent depth dose distributions of a 3 × 3 cm(2) photon field were compared with the insert material as water and the three selected dental implant materials. To evaluate the impact of the dental implant on VMAT patient dose calculation, four head-and-neck cases were selected. For each case, the VMAT plan was designed based on the artifact-corrected patient geometry using a treatment planning system (TPS) that was typically utilized for routine patient treatment. The plans were re-calculated using the MC code for five situations: uncorrected geometry, artifact-corrected geometry and artifact-corrected geometry with one of the three different implant materials. The isodose distributions and the dose-volume histograms were cross-compared with each other. To evaluate the effectiveness of using the material's electron-density ratio for dental implant correction, the implant region was set as water with the material's electron-density ratio and the calculated dose was compared with the MC simulation with the real material. The main effect of the dental implant was the severe attenuation in the downstream. The 1 cm(3) dental implant can lower the downstream dose by 10% (Ti) to 51% (Au) for a 3 × 3 cm(2) field. The TPS failed to account for the dose perturbation if the dental implant material was not precisely defined. For the VMAT patient dose calculation, the presence of dental implants degrades the PTV coverage significantly. With the material's electron-density ratio applied, the dose calculation accuracy in the water phantom and the VMAT patient was improved to a clinically acceptable level. The effects of the dental implant material can be clinically significant and its impact varies with the density of the dental implant material. We demonstrated that it was effective to use the material's electron-density ratio to account for the dosimetric impact of the dental implant. SN - 1361-6560 UR - https://www.unboundmedicine.com/medline/citation/23363570/The_dosimetric_impact_of_dental_implants_on_head_and_neck_volumetric_modulated_arc_therapy_ L2 - https://doi.org/10.1088/0031-9155/58/4/1027 DB - PRIME DP - Unbound Medicine ER -