Journal of Isfahan Medical School

Journal of Isfahan Medical School

Evaluation of the Dose Gradient Index in Various Intensity-Modulated Radiation Therapy Techniques in Patients with Optic Nerve Sheath Meningioma

Document Type : Original Article (s)

Authors
Fahimeh Mazloomi 1
Iraj Abedi 2
Ahmad Shanei 3
Alireza Amouheidari 4
1 MSc Student, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
2 Assistant Professor, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
3 Associate Professor, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
4 Radiation Oncologist, Department of Radiation-Oncology, Milad Hospital, Isfahan, Iran
10.22122/jims.v37i543.12406
Abstract
Background: Intensity-Modulated Radiation Therapy (IMRT) is one of the best methods in the treatment of optic nerve sheath meningioma (ONSM) with tumor growth control and visual stabilization. In this study, various IMRT techniques were evaluated from the point of view of dose fall-off beyond the target boundaries to achieve the optimal technique.Methods: The optimization of 3 IMRT techniques was performed using 3, 5, and 7 fields with 6 MV photons in 15 patients with ONSM using Prowess Panther treatment planning system. To evaluate treatment plans, in addition to data extracted from dose-volume histogram (DVH) and evaluation of target coverage indices, differential and cumulative dose gradient indices (DGIs) were calculated and compared between the three techniques.Findings: The maximum and the mean dose received by the tumor increased with increasing number of IMRT fields. The uniformity (UI) and homogeneity (HI) indices were significantly different between the 3-field and 7-field techniques; and the conformity index (CI) was close to ideal value (0.99) in 7-field technique. Difference of differential dose gradient index (dDGI) was negligible between the three techniques, and only at the 45% isodose level, there was a significant difference between the 5- and 7-field techniques. Cumulative dose gradient index (cDGI) showed smaller values in 7-field technique than the other two techniques.Conclusion: The three IMRT techniques have no considerable statistical difference in dose fall-off rate beyond tumor boundaries; and their choice in the treatment of ONSM depends on the physician's discretion based on the whole patient's conditions.
Keywords
Dose gradient
Intensity modulated radiation therapy
Plan quality
Meningioma
Optic Nerve
  1. Shapey J, Sabin HI, Danesh-Meyer HV, Kaye AH. Diagnosis and management of optic nerve sheath meningiomas. J Clin Neurosci 2013; 20(8): 1045-56.
  2. Parker RT, Ovens CA, Fraser CL, Samarawickrama C. Optic nerve sheath meningiomas: Prevalence, impact, and management strategies. Eye Brain 2018; 10: 85-99.
  3. Jin J, Joo JD, Han JH, Yang HK, Hwang JM, Kim YJ, et al. Optic nerve sheath meningioma: Preliminary analysis of the role of radiation therapy. Brain Tumor Res Treat 2018; 6(1): 8-12.
  4. Sasano H, Shikishima K, Aoki M, Sakai T, Tsutsumi Y, Nakano T. Efficacy of intensity-modulated radiation therapy for optic nerve sheath meningioma. Graefes Arch Clin Exp Ophthalmol 2019; 257(10): 2297-306.
  5. Iqbal K, Isa M, Buzdar SA, Gifford KA, Afzal M. Treatment planning evaluation of sliding window and multiple static segments technique in intensity modulated radiotherapy. Rep Pract Oncol Radiother 2012; 18(2): 101-6.
  6. Paddick I, Lippitz B. A simple dose gradient measurement tool to complement the conformity index. J Neurosurg 2006; 105(Suppl): 194-201.
  7. Hinojosa J, Hernandez JO, Teh BS, Paulino AC, Butler EB. Intensity modulated radiotherapy for optic nerve sheath meningioma. In: Jeremic B, Pitz S, editors. Primary optic nerve sheath meningioma. Berlin, Heidelberg, Germany: Springer Berlin Heidelberg; 2008. p. 95-103.
  8. Scoccianti S, Detti B, Gadda D, Greto D, Furfaro I, Meacci F, et al. Organs at risk in the brain and their dose-constraints in adults and in children: A radiation oncologist's guide for delineation in everyday practice. Radiother Oncol 2015; 114(2): 230-8.
  9. Ezzell GA, Galvin JM, Low D, Palta JR, Rosen I, Sharpe MB, et al. Guidance document on delivery, treatment planning, and clinical implementation of IMRT: Report of the IMRT Subcommittee of the AAPM Radiation Therapy Committee. Med Phys 2003; 30(8): 2089-115.
  10. Sung K, Choi YE. Dose gradient curve: A new tool for evaluating dose gradient. PLoS One 2018; 13(4): e0196664.
  11. Spencer WH. Primary neoplasms of the optic nerve and its sheaths: clinical features and current concepts of pathogenetic mechanisms. Trans Am Ophthalmol Soc 1972; 70: 490-528.
  12. Smith JL, Vuksanovic MM, Yates BM, Bienfang DC. Radiation therapy for primary optic nerve meningiomas. J Clin Neuroophthalmol 1981; 1(2): 85-99.
  13. Inoue T, Mimura O, Masai N, Ohashi A, Ikenaga K, Okuno Y, et al. Early intervention using high-precision radiotherapy preserved visual function for five consecutive patients with optic nerve sheath meningioma. Int J Clin Oncol 2018; 23(5): 826-34.
  14. Maclean J, Fersht N, Bremner F, Stacey C, Sivabalasingham S, Short S. Meningioma causing visual impairment: outcomes and toxicity after intensity modulated radiation therapy. Int J Radiat Oncol Biol Phys 2013; 85(4): e179-e186.
  15. Schroeder T, Yogeswaren S, Augspurger M, Lee A, Teh B, Lu H, et al. Intensity modulated radiation therapy for optic nerve sheath meningioma. Int J Radiat Oncol Biol Phys 2004;60(1):S315.
  16. Inoue T, Mimura O, Ikenaga K, Okuno Y, Nishiguchi I. The rapid improvement in visual field defect observed with weekly perimetry during intensity-modulated radiotherapy for optic nerve sheath meningioma. Int Cancer Conf J 2019; 8(3): 136-40.
  17. Hossain S, Xia P, Huang K, Descovich M, Chuang C, Gottschalk AR, et al. Dose gradient near target-normal structure interface for nonisocentric CyberKnife and isocentric intensity-modulated body radiotherapy for prostate cancer. Int J Radiat Oncol Biol Phys 2010; 78(1): 58-63.
  18. Ohtakara K, Hayashi S, Hoshi H. Dose gradient analyses in Linac-based intracranial stereotactic radiosurgery using Paddick's gradient index: consideration of the optimal method for plan evaluation. J Radiat Res 2011; 52(5): 592-9.
  19. Gizynska MK, Kukolowicz PF, Kordowski P. Implementation of a dose gradient method into optimization of dose distribution in prostate cancer 3D-CRT plans. Rep Pract Oncol Radiother 2014; 19(6): 385-91.
Journal of Isfahan Medical School
Volume 37, Issue 543 - Serial Number 543
July and August 2019
Pages 1080-1087

  • Receive Date 24 October 2019
  • Accept Date 06 April 2022