The Radiobiological Impact of Dental Root Filling Material in Intensity-Modulated Radiation Therapy (IMRT) in Patients with Nasopharyngeal Carcinoma

Document Type : Original Article (s)

Authors

1 MSc Student, Department of Medical Physics and Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

2 Assistant Professor, Department of Medical Physics and Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

3 Radiation Oncologist, Department of Radiation-Oncology, Milad Hospital, Isfahan, Iran

4 Associate Professor, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Background: Regarding the possibility of perturbation due to the presence of dental root filling material (DFM) in treatment planning of patients with nasopharyngeal cancer, we aimed to evaluate the impact of this material on tumor control probability (TCP) and normal tissue complication probability (NTCP) using dose volume histograms (DVHs) of tumor and organ at risks, measured via treatment planning system.Methods: The optimization process of two intensity modulated radiotherapy (IMRT) techniques was performed by means of Prowess treatment planning system using 7- and 9-field 6-MV photons in two groups of 15 patients with nasopharyngeal cancer, with a difference in the presence or absence of DFM. After preparing DVHs, analysis and comparing of equivalent uniform dose (EUD), TCP, and NTCP were performed using Niemierko’s equivalent.Findings: In 9-field IMRT, there was statically significant decrease in mean EUD, TCP, and conformity index (CI) of tumor in patients with DFM; but there was no significant differences in homogeneity index (HI). Moreover, due to presence of DFM, there was statically significant increase in mean EUD and NTCP of mandible in both 7- and 9-field techniques, and in NTCP of left optic nerve in 9-field IMRT. Although for right eye, there was a statically significant decrease in NTCP by 7-field IMRT technique, due to presence of DFM.Conclusion: The effect of the presence of DFM on IMRT depends on field angles, and leads to significant decrease in TCP target volume, significant increase in NTCP of and EUD mandible and NTCP of left optic nerve, and significant decrease in NTCP of right eye.

Keywords

References

  1. Zhang LL, Zhou GQ, Li YY, Tang LL, Mao YP, Lin AH, et al. Combined prognostic value of pretreatment anemia and cervical node necrosis in patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: A large-scale retrospective study. Cancer Med 2017; 6(12): 2822-31.
  2. Safavi A, Raad N, Raad N, Ghorbani J. Epidemiology of nasopharyngeal cancers in Iran: A 6-year report. Asian Pac J Cancer Prev 2015; 16(10): 4447-50.
  3. Zhang L, Chen QY, Liu H, Tang LQ, Mai HQ. Emerging treatment options for nasopharyngeal carcinoma. Drug Des Devel Ther 2013; 7: 37-52.
  4. Tham IW, Hee SW, Yeo RM, Salleh PB, Lee J, Tan TW, et al. Treatment of nasopharyngeal carcinoma using intensity-modulated radiotherapy-the national cancer centre singapore experience. Int J Radiat Oncol Biol Phys 2009; 75(5): 1481-6.
  5. Kamomae T, Itoh Y, Okudaira K, Nakaya T, Tomida M, Miyake Y, et al. Dosimetric impact of dental metallic crown on intensity-modulated radiotherapy and volumetric-modulated arc therapy for head and neck cancer. J Appl Clin Med Phys 2016; 17(1): 234-45.
  6. Lin YW, Chen CC, Lin LC, Lee SP. The impact of reduced-volume, intensity-modulated radiation therapy on disease control in nasopharyngeal carcinoma. PLoS One 2015; 10(4): e0125283.
  7. Zhang MX, Li J, Shen GP, Zou X, Xu JJ, Jiang R, et al. Intensity-modulated radiotherapy prolongs the survival of patients with nasopharyngeal carcinoma compared with conventional two-dimensional radiotherapy: A 10-year experience with a large cohort and long follow-up. Eur J Cancer 2015; 51(17): 2587-95.
  8. Bazalova M, Beaulieu L, Palefsky S, Verhaegena F. Correction of CT artifacts and its influence on Monte Carlo dose calculations. Med Phys 2007; 34(6): 2119-32.
  9. Richard P, Sandison G, Dang Q, Johnson B, Wong T, Parvathaneni U. Dental amalgam artifact: Adverse impact on tumor visualization and proton beam treatment planning in oral and oropharyngeal cancers. Pract Radiat Oncol 2015; 5(6): e583-e588.
  10. Shimamoto H, Sumida I, Kakimoto N, Marutani K, Okahata R, Usami A, et al. Evaluation of the scatter doses in the direction of the buccal mucosa from dental metals. J Appl Clin Med Phys 2015; 16(3): 5374.
  11. Asena A. Dosimetry in the vicinity of high-density materials in radiotherapy [PhD Thesis]. Brisbane, Australia: Queensland University of Technology; 2017.
  12. Webster GJ, Rowbottom CG, Mackay RI. Evaluation of the impact of dental artefacts on intensity-modulated radiotherapy planning for the head and neck. Radiother Oncol 2009; 93(3): 553-8.
  13. Wang H, Cooper BT, Schiff P, Sanfilippo NJ, Wu SP, Hu KS, et al. Dosimetric assessment of tumor control probability in intensity and volumetric modulated radiotherapy plans. Br J Radiol 2018; 20180471. [Epub ahead of print].
  14. Kim Y, Tome WA. On the radiobiological impact of metal artifacts in head-and-neck IMRT in terms of tumor control probability (TCP) and normal tissue complication probability (NTCP). Med Biol Eng Comput 2007; 45(11): 1045-51.
  15. Lee N, Kramer A, Xia P. RTOG 0225: a phase II study of intensity modulated radiation therapy (IMRT)+/-chemotherapy for nasopharyngeal cancer. Philadelphia, PA: Radiation Therapy Oncology Group; 2003.
  16. Chen BB, Huang SM, Xiao WW, Sun WZ, Liu MZ, Lu TX, et al. Prospective matched study on comparison of volumetric-modulated arc therapy and intensity-modulated radiotherapy for nasopharyngeal carcinoma: Dosimetry, delivery efficiency and outcomes. J Cancer 2018; 9(6): 978-86.
  17. Lee TF, Ting HM, Chao PJ, Fang FM. Dual arc volumetric-modulated arc radiotherapy (VMAT) of nasopharyngeal carcinomas: A simultaneous integrated boost treatment plan comparison with intensity-modulated radiotherapies and single arc VMAT. Clin Oncol (R Coll Radiol) 2012; 24(3): 196-207.
  18. Gay HA, Niemierko A. A free program for calculating EUD-based NTCP and TCP in external beam radiotherapy. Phys Med 2007; 23(3-4): 115-25.
  19. Schreiner LJ, Rogers M, Salomons G, Kerr A. Metal artifact suppression in megavoltage computed tomography. SPIE 2005; 5745: 637-45.
Journal of Isfahan Medical School
Volume 36, Issue 503 - Serial Number 503
September and October 2019
Pages 1362-1368

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History

  • Receive Date: 17 August 2018
  • Revise Date: 30 April 2024
  • Accept Date: 06 April 2022

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