{Reference Type}: Journal Article
{Title}: A phantom based evaluation of the clinical imaging performance of electronic portal imaging devices.
{Author}: Tzomakas MK;Peppa V;Alexiou A;Karakatsanis G;Episkopakis A;Michail C;Valais I;Fountos G;Kalyvas N;Kandarakis IS;
{Journal}: Heliyon
{Volume}: 9
{Issue}: 10
{Year}: 2023 Oct
{Factor}: 3.776
{DOI}: 10.1016/j.heliyon.2023.e21116
{Abstract}: UNASSIGNED: In this study an evaluation of the imaging performance of an electronic portal imaging device (EPID) is presented. The evaluation performed employing the QC-3V image quality phantom.
UNASSIGNED: An EPID system of a 6 MV LINAC, was used to obtain images of a QC-3V EPID phantom. The X-ray source to phantom distance was 100 cm and the field size was 15x15 cm2. The irradiation conditions comprised Dose Rates (DR) of 200, 400 and 600 for a 2 MU-100 MU range. The Contrast Transfer Function (CTF), the Noise Power Spectrum (NPS), the Normalized Noise Power Spectrum (NNPS) and the Contrast-to-Noise Ratio (CNR) were studied. In addition, an alternative factor showing a frequency related output signal-to-noise ratio (SNR), the Signal-to-Noise-Frequency Response (SNFR), has been introduced. SNFR is a comprehensive quality index, easily determined in clinical environment.
UNASSIGNED: The CTF curves were found comparable to each other. The lowest values were measured at 2 MU and 200 MU/min. Concerning the NPS and NNPS graphs it was found that the values decrease up to approximately 0.3 lp/mm and demonstrate a white noise shape afterwards. SNFR values were found reducing with spatial frequency. Highest CNR were found between the region 7 and 11 of the phantom.
UNASSIGNED: The influence of MU and DR on EPID performance were investigated. Image quality was assessed using the QC-3V phantom. The presented results can lead to image quality amelioration and act supportively to current image quality control routine protocols.