ESTRO 2024 - Abstract Book

S352

Beachytherapy - Physics

ESTRO 2024

Table 1: Dose values measured with radiochromic films compared with those of the TPS for both 192 Ir and 60 Co HDR BT sources.

192 Ir

60 Co

Film (Gy)

3.04 ± 0.14

3.06 ± 0.10

TPS (Gy)

3.083 ± 0.013

3.093 ± 0.004

Local γ(2%,2mm) 10% threshold (%)

94.4

97.9

Conclusion:

The phantom and method here described can be used to validate the dose distribution of HDR BT systems using either 192 Ir or 60 Co sources. The results obtained with this method can be compared directly with the TPS dose calculations. This system may be valuable in external dosimetry audits.

Keywords: Raciohcromic film, audit, dose measurement

References:

1. Rivard, M.J.; Coursey, B.M.; DeWerd, L.A.; Hanson, W.F.; Saiful Huq, M.; Ibbott, G.S.; Mitch, M.G.; Nath, R.; Williamson, J.F. Update of AAPM Task Group No. 43 Report: A revised AAPM protocol for brachytherapy dose calculations. Med. Phys 2004, 31 : 633-674, doi: 10.1118/1.1646040 2. Niroomand-Rad, A.; Chiu-Tsao, S.-T.; Grams, M. P.; Lewis, D. F.; Soares, C. G.; Van Battum, L. J.; Das, I. J.; Trichter, S.; Kissick, M. W.; Massillon-JL, G.; Alvarez, P. E.; Chan, M. F. Report of AAPM Task Group 235 Radiochromic Film Dosimetry: An Update to TG-55. Medical Physics 2020, 47 (12), 5986–6025. https://doi.org/10.1002/mp.14497 3. Butson, M. J.; Cheung, T.; Yu, P. K. N. Weak Energy Dependence of EBT Gafchromic Film Dose Response in the 50kVp–10MVp X-Ray Range. Applied Radiation and Isotopes 2006, 64 (1), 60–62. https://doi.org/10.1016/j.apradiso.2005.07.002.

4. Low, D. A.; Harms, W. B.; Mutic, S.; Purdy, J. A. A Technique for the Quantitative Evaluation of Dose Distributions. Med Phys 1998, 25 (5), 656–661. https://doi.org/10.1118/1.598248.

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