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A comparison of surface doses for very small field size x-ray beams: Monte Carlo calculations and radiochromic film measurements

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Abstract

Stereotactic radiosurgery treatments involve the delivery of very high doses for a small number of fractions. To date, there is limited data in terms of the skin dose for the very small field sizes used in these treatments. In this work, we determine relative surface doses for small size circular collimators as used in stereotactic radiosurgery treatments. Monte Carlo calculations were performed using the BEAMnrc code with a model of the Novalis Trilogy linear accelerator and the BrainLab circular collimators. The surface doses were calculated at the ICRP skin dose depth of 70 μm all using the 6 MV SRS x-ray beam. The calculated surface doses varied between 15 and 12 % with decreasing values as the field size increased from 4 to 30 mm. In comparison, surface doses were measured using Gafchromic EBT3 film positioned at the surface of a Virtual Water phantom. The absolute agreement between calculated and measured surface doses was better than 2.0 % which is well within the uncertainties of the Monte Carlo calculations and the film measurements. Based on these results, we have shown that the Gafchromic EBT3 film is suitable for surface dose estimates in very small size fields as used in SRS.

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References

  1. Warrington J (2007) Stereotactic Techniques. In: Mayles P, Nahum AE, Rosenwald J (eds) Handbook of Radiotherapy Physics, CRC Press, Boca Raton, pp 987–1003

  2. Devic S et al (2006) Accurate skin dose measurements using radiochromic film in clinical applications. Med Phys 33(4):1116–1124

    Article  PubMed  CAS  Google Scholar 

  3. Hsu SH et al (2008) Assessment of skin dose for breast chest wall radiotherapy as a function of bolus material. Phys Med Biol 53(10):2593–2606

    Article  PubMed  Google Scholar 

  4. Kry SF et al (2012) Skin dose during radiotherapy: a summary and general estimation technique. J Appl Clin Med Phys 13(3):20–34

    Google Scholar 

  5. ICRP The biological basis for dose limitation in the skin (1992). ICRP

  6. Kim KA et al (2013) Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams. Radiat Prot Dosim 153(3):294–299

    Article  CAS  Google Scholar 

  7. Dogan N, Glasgow GP (2003) Surface and build-up region dosimetry for obliquely incident intensity modulated radiotherapy 6 MV x-rays. Med Phys 30(12):3091–3096

    Article  PubMed  Google Scholar 

  8. Moylan R, Aland T, Kairn T (2013) Dosimetric accuracy of Gafchromic EBT2 and EBT3 film for in vivo dosimetry. Australasian Phys Eng Sci Med 36(3):331–337

    Article  Google Scholar 

  9. Chung H et al (2005) Evaluation of surface and build-up region dose for intensity-modulated radiation therapy in head and neck cancer. Med Phys 32:2682

    Article  PubMed  Google Scholar 

  10. Court LE et al (2008) Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system. J Appl Clin Med Phys 9(1):29–35

    Article  Google Scholar 

  11. Deng J et al (2003) Commissioning 6 MV photon beams of a stereotactic radiosurgery system for Monte Carlo treatment planning. Med Phys 30(12):3124–3134

    Article  PubMed  Google Scholar 

  12. Gerbi BJ, Khan FM (1990) Measurement of dose in the buildup region using fixed-separation plane-parallel ionization chambers. Med Phys 17(1):17–26

    Article  PubMed  CAS  Google Scholar 

  13. Kim S et al (1998) Photon beam skin dose analyses for different clinical setups. Med Phys 25(6):860–866

    Article  PubMed  CAS  Google Scholar 

  14. Kron T et al (1993) X-ray surface dose measurements using TLD extrapolation. Med Phys 20:703

    Article  PubMed  CAS  Google Scholar 

  15. Kwan IS et al (2008) Skin dosimetry with new MOSFET detectors. Radiat Meas 43(2–6):929–932

    Article  CAS  Google Scholar 

  16. Nelson VK, Hill RF (2011) Backscatter factor measurements for kilovoltage X-ray beams using thermoluminescent dosimeters (TLDs). Radiat Meas 46(12):2097–2099

    Article  CAS  Google Scholar 

  17. Roberson PL, Moran JM, Kulasekere R (2008) Radiographic film dosimetry for IMRT fields in the near-surface buildup region. J Appl Clin Med Phys 9(4):87–97

    Article  Google Scholar 

  18. Xiang HF et al (2007) Build-up and surface dose measurements on phantoms using micro-MOSFET in 6 and 10 MV x-ray beams and comparisons with Monte Carlo calculations. Med Phys 34(4):1266–1273

    Article  PubMed  Google Scholar 

  19. Sors A et al (2013) An optimized calibration method for surface measurements with MOSFETs in shaped-beam radiosurgery. Physica Medica

  20. Nakano M et al (2012) A study of surface dosimetry for breast cancer radiotherapy treatments using Gafchromic EBT2 film. J Appl Clin Med Phys 13(3):83–97

    Google Scholar 

  21. Rogers DWO (2006) Fifty years of Monte Carlo simulations for medical physics. Phys Med Biol 51(13)

  22. Rogers DWO et al (1995) BEAM: a Monte Carlo code to simulate radiotherapy treatment units. Med Phys 22(5):503–524

    Article  PubMed  CAS  Google Scholar 

  23. Verhaegen F, Seuntjens J (2003) Monte Carlo modelling of external radiotherapy photon beams. Phys Med Biol 48(21)

  24. Abdel-Rahman W et al (2005) Validation of Monte Carlo calculated surface doses for megavoltage photon beams. Med Phys 32(1):286–298

    Article  PubMed  Google Scholar 

  25. Kim JH, Hill R, Kuncic Z (2012) Practical considerations for reporting surface dose in external beam radiotherapy: a 6 MV X-ray beam study. Australasian Phys Eng Sci Med 35(3):271–282

    Article  Google Scholar 

  26. Kim JH, Hill R, Kuncic Z (2012) An evaluation of calculation parameters in the EGSnrc/BEAMnrc Monte Carlo codes and their effect on surface dose calculation. Phys Med Biol 57(14):N267–N278

    Article  PubMed  Google Scholar 

  27. Apipunyasopon L, Srisatit S, Phaisangittisakul N (2013) An investigation of the depth dose in the build-up region, and surface dose for a 6 MV therapeutic photon beam: Monte Carlo simulation and measurements. J Radiat Res 54(2):374–382

    Article  PubMed  PubMed Central  Google Scholar 

  28. Ding GX, Duggan DM, Coffey CW (2006) Commissioning stereotactic radiosurgery beams using both experimental and theoretical methods. Phys Med Biol 51(10):2549–2566

    Article  PubMed  Google Scholar 

  29. Paskalev KA et al (2003) Physical aspects of dynamic stereotactic radiosurgery with very small photon beams (1.5 and 3 mm in diameter). Med Phys 30(2):111–118

    Article  PubMed  Google Scholar 

  30. Chang Z et al (2008) Dosimetric characteristics of novalis Tx system with high definition multileaf collimator. Med Phys 35(10):4460–4463

    Article  PubMed  Google Scholar 

  31. Dhabaan A et al (2010) Dosimetric performance of the new high-definition multileaf collimator for intracranial stereotactic radiosurgery. J Appl Clin Med Phys 11(3):197–211

    Google Scholar 

  32. Yin F–F et al (2002) Dosimetric characteristics of Novalis shaped beam surgery unit. Med Phys 29(8):1729–1738

    Article  PubMed  Google Scholar 

  33. Kawrakow I (2000) Accurate condensed history Monte Carlo simulation of electron transport I EGSnrc, the new EGS4 version. Med Phys 27(3):485–498

    Article  PubMed  CAS  Google Scholar 

  34. Rogers DWO, Walters BRB, Kawrakow I (2005) BEAMnrc users manual ionizing radiation standards. National Research Council of Canada, Ottawa

    Google Scholar 

  35. Kawrakow I, Rogers DWO, Walters BRB (2004) Large efficiency improvements in BEAMnrc using directional bremsstrahlung splitting. Med Phys 31:2883–2898

    Article  PubMed  CAS  Google Scholar 

  36. Kawrakow I, Walters BRB (2006) Efficient photon beam dose calculations using DOSXYZnrc with BEAMnrc. Med Phys 33(8):3046–3056

    Article  PubMed  CAS  Google Scholar 

  37. Walters BRB, Kawrakow I (2007) Technical note: overprediction of dose with default PRESTA-I boundary crossing in DOSXYZnrc and BEAMnrc. Med Phys 34(2):647–650

    Article  PubMed  CAS  Google Scholar 

  38. ICRP59 (1991) The biological basis for dose limitation in the skin. Ann 22(2)

  39. Casanova BV et al (2013) Dosimetric characterization and use of GAFCHROMIC EBT3 film for IMRT dose verification. J Appl Clin Med phys/American Coll Med Phys 14(2):4111

    Google Scholar 

  40. Reinhardt S et al (2012) Comparison of Gafchromic EBT2 and EBT3 films for clinical photon and proton beams. Med Phys 39:5257

    Article  PubMed  CAS  Google Scholar 

  41. Hill R, Kuncic Z, Baldock C (2010) The water equivalence of solid phantoms for low energy photon beams. Med Phys 37(8):4355–4363

    Article  PubMed  CAS  Google Scholar 

  42. ISO Guide to the expression of uncertainties in measurement (1995). International Organisation for Standardization, Geneva

  43. McEwen MR, Kawrakow I, Ross CK (2008) The effective point of measurement of ionization chambers and the build-up anomaly in MV X-ray beams. Med Phys 35(3):950–958

    Article  PubMed  CAS  Google Scholar 

  44. Hill R et al (2009) An evaluation of ionization chambers for the relative dosimetry of kilovoltage X-ray beams. Med Phys 36(9):3971–3981

    Article  PubMed  CAS  Google Scholar 

  45. Low DA et al (1998) A techinique for the quantitative evaluation of dose distributions. Med Phys 25(5):656–661

    Article  PubMed  CAS  Google Scholar 

  46. Ding GX (2002) Energy spectra, angular spread, fluence profiles and dose distributions of 6 and 18 MV photon beams: results of Monte Carlo simulations for a Varian 2100EX accelerator. Phys Med Biol 47:1025–1046

    Article  PubMed  Google Scholar 

  47. Hoppe BS et al (2008) Acute skin toxicity following stereotactic body radiation therapy for stage I non-small-cell lung cancer: Who is at risk?. Int J Rad Oncol Bio Phys 72:1283–1286

    Google Scholar 

  48. Kelly A et al (2011) Surface dosimetry for breast radiotherapy in the presence of immobilization cast material. Phys Med Biol 56(4):1001–1013

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

Computational resources and services used in this work were provided by the High Performance Computing and Research Support Unit, Queensland University of Technology, Brisbane, Australia. Also, we’d like to acknowledge that Dr S. B. Crowe’s contribution to this work was supported by the Australian Research Council through Linkage Grant No. LP110100401.

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Authors and Affiliations

  1. School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, Australia

    J. E. Morales, S. B. Crowe, T. Kairn & J. V. Trapp

  2. Department of Radiation Oncology, Chris O’Brien Lifehouse, Sydney, NSW, 2006, Australia

    J. E. Morales & R. Hill

  3. Genesis Cancer Care (Queensland), The Wesley Medical Centre, Brisbane, QLD, Australia

    T. Kairn

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  1. J. E. Morales
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  2. R. Hill
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Correspondence to J. E. Morales.

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Morales, J.E., Hill, R., Crowe, S.B. et al. A comparison of surface doses for very small field size x-ray beams: Monte Carlo calculations and radiochromic film measurements. Australas Phys Eng Sci Med 37, 303–309 (2014). https://doi.org/10.1007/s13246-014-0260-2

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  • DOI: https://doi.org/10.1007/s13246-014-0260-2

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