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SU‐F‐T‐573: Evaluation of EBT‐XD Radiochromic Films for Verification of SBRT and SRS Treatment Delivery
Author(s) -
Aubry J,
Zerouali K
Publication year - 2016
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 - 10.1118/1.4956758
Subject(s) - imaging phantom , nuclear medicine , ionization chamber , radiosurgery , dosimetry , materials science , dose profile , calibration , scanner , irradiation , radiation therapy , medicine , physics , optics , radiology , ion , quantum mechanics , nuclear physics , ionization
Purpose: To evaluate the accuracy and precision of radiochromic films EBT‐XD for quality control of stereotaxic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) plan delivery. Methods: A film cut in 3×10 cm2 strips was irradiated from 0 to 20 Gy in increments of 1 to 1.5 Gy using a 15 MeV electron beam. Triple‐channel film calibration was completed 24 hours later by scanning the film strips on an Epson 10000XL scanner using a well‐defined protocol. Several dose measurements of increasing complexity were subsequently performed with Varian iX accelerators. Pieces of films were first irradiated in a solid water phantom with 6 MV photon beams and a static gantry to doses spanning the calibration range, either in a single field or multiple fields setup. High dose (>15 Gy per fraction) IMRT plans were then measured. Finally films were irradiated with volumetric modulated arc therapy (VMAT) plans of lung and spinal lesions with prescribed doses per fraction between 8 and 20 Gy. The dose measured with the films was compared to the calculated dose from the Eclipse planning system using the Anisotropic Analytical Algorithm (AAA). Results: 77 dose measurements were compared to either ion chamber measurements or dose calculations (reference). The average dose difference between film measurements and reference was 0.7 % and the standard deviation was 1.3%. The maximum and minimum dose differences were +3.5% and −2% in the 4 Gy to 20 Gy range. Measured dose profiles of lung and vertebra treatment plans agreed very well with the calculations. Conclusion: EBT‐XD films are a useful dosimeter for quality control of SBRT and SRS plan delivery. The measurement of a full 2D dose plane with high spatial resolution and acceptable dose accuracy make it an advantageous choice compared to other detectors such as ion chambers or diodes.