Premium
SU‐E‐T‐425: Feasibility of Establishing a National Postal Dosimetry System Using EBT3 Gafchromic Film
Author(s) -
AbdelRahman W,
Mohammed I,
Bamajboor S
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4924786
Subject(s) - dosimeter , imaging phantom , dosimetry , irradiation , photon , optics , materials science , photon energy , physics , nuclear medicine , radiation , nuclear physics , medicine
Purpose: To evaluate the performance of a postal dosimeter consisting of EBT3 films and a miniature Lucite phantom to be used for photon beams output audits for mega‐voltage photon beams across the Saudi Arabia. Methods: Two batches of EBT3 films were calibrated in 5 mega‐voltage photon beams with energies ranging between 6 MV and 18 MV in the dose range between 0 to 4 Gy. A 4×4×20 cm 3 lucite phantom was constructed to be used as an irradiation phantom. The lucite irradiation phantom consists of two parts and allows for embedding a 2.5×2.0 cm 2 EBT3 film at 8.9 cm depth. Factors that convert the dose measured in the lucite irradiation phantom at 8.9 cm depth to the dose at 10 cm depth in water for 10×10 cm 2 field for different photon energies were calculated using the dosxyznrc/EGSnrcMP user code. The performance of the proposed postal dosimeter was tested in 17 different photon beams across 4 radiotherapy centres in Saudi Arabia. The outputs of the 17 beams are monitored by either the International Atomic Energy Agency or by the Radiological Physics Centre. Results: For the 17 photon beams, the average of the ratios of measured to stated outputs was 1.01 ± 0.02 and with a maximum ratio of 1.05. Conclusion: The results of our work indicate that the proposed postal dosimetry system can be used for national auditing of outputs for mega‐voltage photon beams. The service can be offered to other national radiotherapy centres or to a be used for credentialing of centres participating in national trials.