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Dosimetric validation of the Theragenics AgX-100® I-125 seed for ROPES eye plaque brachytherapy

  • Claire PagulayanEmail author
  • Soo Min Heng
  • Stephanie Corde
Scientific Paper
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Abstract

With the discontinued distribution of the I-125 Oncura Onco seed (model 6711), the Theragenics AgX100® I-125 seeds were considered as a suitable alternative for eye plaque brachytherapy as their physical properties matched the requirements for use with the ROPES eye plaques. The purpose of this study aims at validating the dosimetry of the AgX-100 loaded ROPES plaques (11 mm diameter, 15 mm diameter with flange, 15 mm diameter with notch, 18 mm diameter) and assess the differences with the discontinued I-125 6711 model. To independently verify the plaque dosimetry, the brachytherapy module of RADCALC® version 6.2.3.6 was commissioned for the new AgX-100 I-125 seed using the published AAPM TG43 data from the literature. Experimental dosimetry verification was performed using EBT3 Gafchromic™ film and TLD-100 micro-cubes in a specially designed Solid Water® phantom. Both RADCALC® and film confirmed the dosimetry calculated by Plaque Simulator (PS) version 6.4.6 The dose calculated by PS agrees with RADCALC® to within 2% for depths of 1–15 mm for the 4 available ROPES plaques. The dosimetric measurements agreed with the calculations of PS for clinically relevant depths (4 mm to 6 mm) within the evaluated uncertainties of 4.7% and 7.2% for EBT3 film and TLDs respectively. The AgX-100 I-125 seed was a suitable replacement for the 6711 I-125 seed. Due to the introduction of the stainless-steel backscatter factor in PS v6.4.6, the department has decided to report both the homogenous dose and heterogeneity corrected dose for each eye plaque patient.

Keywords

ROPES Eye plaques I-125 seeds Brachytherapy Ocular melanoma 

Notes

Acknowledgements

The authors would like to acknowledge Matthew Newall for his contributions to the figures of this paper.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This research did not involve any human participants or animal experiments.

References

  1. 1.
    Chiu-Tsao ST et al (2012) Dosimetry of 125I and 103Pd COMS eye plaques for intraocular tumors: report of task group 129 by the AAPM and ABS. Med Phys 39(10):6161–6184CrossRefGoogle Scholar
  2. 2.
    Saidi P, Sadeghi M, Shirazi A, Tenreiro C (2011) ROPES eye plaque brachytherapy dosimetry for two models of 103Pd seeds. Australas Phys Eng Sci Med 34(2):223–231CrossRefGoogle Scholar
  3. 3.
    Dolan J, Williamson JF (2006) Monte Carlo and experimental dosimetry of an I brachytherapy seed. Med Phys 33(12):4675–4684CrossRefGoogle Scholar
  4. 4.
    Mourtada F, Mikell J, Ibbott G (2012) Monte Carlo calculations of AAPM Task group report no. 43 dosimetry parameters for the 125I I-seed AgX100 source model. Brachytherapy 11(3):237–244CrossRefGoogle Scholar
  5. 5.
    Chen Z, Bongiorni P, Nath R (2011) MO-F-BRB-06: experimental characterization of the dosimetric properties of a newly designed I-seed model AgX100 125I Interstitial brachytherapy source. Med Phys 38(6):3723CrossRefGoogle Scholar
  6. 6.
    Rivard MJ et al (2017) Supplement 2 for the 2004 update of the AAPM task group no. 43 report: joint recommendations by the AAPM and GEC-ESTRO: joint. Med Phys 44(9):e297–e338CrossRefGoogle Scholar
  7. 7.
    Poder J, Corde S (2013) I-125 ROPES eye plaque dosimetry: validation of a commercial 3D ophthalmic brachytherapy treatment planning system and independent dose calculation software with GafChromic® EBT3 films. Med Phys 40:12CrossRefGoogle Scholar
  8. 8.
    A. Niroomand-Rad et al (1998) Radiochromic film dosimetry: recommendation of AAPM radiation therapy. Med Phys 25(11):2093–2115CrossRefGoogle Scholar
  9. 9.
    Luxton G (1994) Comparison of radiation dosimetry in water and in solid phantom materials for I-125 and Pd-103 brachytherapy sources: EGS4 Monte Carlo study. Med Phys 21(5):631–641CrossRefGoogle Scholar
  10. 10.
    Williamson JF (1991) Comparison of measured and calculated dose rates in water near I-125 and Ir-192 seeds. Med Phys 18(4):776CrossRefGoogle Scholar
  11. 11.
    Tailor R, Tolani N, Ibbott GS (2008) Thermoluminescence dosimetry measurements of brachytherapy sources in liquid water. Med Phys 35(9):4063–4069CrossRefGoogle Scholar
  12. 12.
    Nunn AA, Davis SD, Micka JA, DeWerd LA (2008) LiF:Mg, Ti TLD response as a function of photon energy for moderately filtered X-ray spectra in the range of 20–250 kVp relative to60Co. Med Phys 35(5):1859–1869CrossRefGoogle Scholar
  13. 13.
    Davis SD, Ross CK, Mobit PN, Van der Zwan L, Chase WJ, Shortt KR (2003) The response of lif thermoluminescence dosemeters to photon beams in the energy range from 30 kV X rays to 60Co gamma rays. Radiat Prot Dosimetry 106(1):33–43CrossRefGoogle Scholar
  14. 14.
    Tedgren A, Hedman A, Grindborg JE, Carlsson GA (2011) Response of LiF:Mg, Ti thermoluminescent dosimeters at photon energies relevant to the dosimetry of brachytherapy (%3c1 MeV). Med Phys 38(10):5539–5550CrossRefGoogle Scholar
  15. 15.
    León Marroquin EY, Herrera González JA, Camacho López MA, Villarreal Barajas JE, García-Garduño OA (2016) Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density. J Appl Clin Med Phys 17(5):466–481CrossRefGoogle Scholar
  16. 16.
    Brown TAD, Hogstrom KR, Alvarez D, Ii KLM, Ham K, Dugas JP (2012) Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic X-ray beams. Med Phys 39(12):7412–7417CrossRefGoogle Scholar
  17. 17.
    Moura ES et al (2015) Development of a phantom to validate high-dose-rate brachytherapy treatment planning systems with heterogeneous algorithms. Med Phys 42(4):1566–1574CrossRefGoogle Scholar
  18. 18.
    DeWerd LA et al (2011) A dosimetric uncertainty analysis for photon-emitting brachytherapy sources: Report of AAPM task group no. 138 and GEC-ESTRO. Med Phys 38(2):782–801CrossRefGoogle Scholar

Copyright information

© Australasian College of Physical Scientists and Engineers in Medicine 2019

Authors and Affiliations

  1. 1.Nelune Comprehensive Cancer CentrePrince of Wales HospitalSydneyAustralia

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