An investigation in the effects of MRI receive bandwidth on PAGATUG polymer gel dosimeter response

The aim of this research is to investigate the effects of the band width of magnetic resonance imaging (MRI) on the response of the PAGATUG polymer gel dosimeter. Sampling time decreases by increase in receive band width. Therefore, the scan time can decrease by increase in receive band width. Hence, the cost of gel dosimetry reduces by proper choose of MRI receive band width. To this aim the PAGATUG polymer gel dosimeter was prepared. The polymer gel cuvettes were irradiated using a clinical 60Co one day after preparation. Afterward, the gels responses were readout using a 1.5 T MRI system. Receive band widths of 60, 80, 90, 100 and 120 Hz/pixel were selected for imaging protocols. It was found that the R2 responses and the R2 sensitivities were not changed significantly by varying the receive band width. However, for receive band widths more than 90 Hz/pixel the dose resolution was decreased significantly. It is suggested to select the receive band width of 90 Hz/pixel for PAGATUG polymer gel dosimeters scanning. Theoretical calculations show that a receive band width of 90 Hz/Pixel causes a chemical shift of 0.82 mm which is of order of one pixel dimension. By using this receive band width the scanning time were reduced by 22% from receive band width of 60 Hz/pixel.