Abstract

Aim: Dosimetric properties of a CCD camera-based Electronic Portal Imaging Device (EPID) for clinical dosimetric application have been evaluated. Characteristics obtained by EPID also compared with commercial 2D array of ion chambers. Materials and Methods: Portal images acquired in dosimetry mode then exported raw fluence or uncorrected images were investigated. Integration time of image acquisition mode has adjusted on 1 s per frame. Results: As saturation of camera of the EPID, dose response does not have linear behavior. The slight nonlinearity of the camera response can be corrected by a logarithmic expression. A fourth order polynomial regression model with coefficient of determination of 0.998 predicts a response to absolute dose values at less than 50 cGy. A field size dependent response of up to 7% (0.99-1.06) relative OCTAVIUS detector measurement was found. The EPID response can be fitted by a cubic regression for field size changes, yielded coefficient of determination of 0.999. Conclusions: These results indicate that the EPID is well suited for accurate dosimetric purposes, the major limitation currently being due to integration time and dead-time in frame acquisition.

Details

Title
Dose response characteristics of a novel CCD camera-based electronic portal imaging device comparison with OCTAVIUS detector
Author
Anvari, Akbar; Aghamiri, Seyed Mahmoud; Mahdavi, Seyed; Alaei, Parham
Publication year
2015
Publication date
Oct-Dec 2015
Publisher
Medknow Publications & Media Pvt. Ltd.
ISSN
09731482
e-ISSN
19984138
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1785766852
Copyright
Copyright Medknow Publications & Media Pvt Ltd Oct-Dec 2015