Skin Dosimetry in Radiotherapy of Breast Cancer: a Comparison between EBT and EBT3 Radiochromic Films.
OBJECTIVE
Radiochromic EBT3 film is a later generation of radiochromic films. The aim of this study is to compare EBT and EBT3 radiochromic films in radiotherapy fields of breast cancer.


METHODS
A RANDO phantom was irradiated by a 6 MV Siemens Primus linac with medial and lateral fields of radiotherapy of breast cancer. Dosimetry was performed in various points in the fields using EBT and EBT3 films. Films were scanned by a Microtek color scanner. Dose values from two films in corresponding points were compared.


RESULTS
In the investigation of calibration, net optical density (NOD) of EBT radiochromic is more than the EBT3 radiochromic film. The highest percentage difference between NODs of two films is related to 0.75 Gy and equals to 14.19%. The lowest value is related to 0.2 Gy dose and is equal to 3.31%. The highest percentage difference between two films on the RANDO phantom in breast cancer fields is 13.51% and the minimum value is equal to 0.33%.


CONCLUSIONS
From the comparison between the two films, most of the points show differences in dose in the measurements in fields of breast cancer radiotherapy. These differences are attributed to the thickness of the active layers, the overall thickness of the films, and the difference in the calibration fitted functions. The advantage of EBT film over EBT3 is a higher sensitivity; on the other hand EBT3 film allows to use its both sides in the scanning process and it is a new version of this film type.
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
M T
MT
Bahreyni Toosi
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
N
N
Mohamadian
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
M
M
Ghorbani
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
F
F
Khorshidi
Medical Physics Department, Reza Radiation Oncology Center, Mashhad, Iran.
F
F
Akbari
Comprehensive Cancer Centers of Nevada, Las Vegas, NV, USA.
C
C
Knaup
Breast cancer; EBT radiochromic film; EBT3 radiochromic film; Film dosimetry; radiotherapy
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