A method to relate StarTrack (R) measurements to R-50 variations in clinical linacs

作者：de la Vega J M^*; Ruiz Arrebola S; Tornero Lopez A M; Vilches M; Guerrero R; Guirado D; Lallena A M

来源：Physica Medica, 2014, 30(7): 827-832.

DOI：10.1016/j.ejmp.2014.03.007

• Radiotherapy
• Electron beams
• Quality control

The relation between the data recorded with any device for the daily checking of the behavior of a clinical linac and the reference magnitudes to be monitored may be unknown. An experimental method relating the energy stability of the electron beam measured with StarTrack (R) to the R-50 beam quality index is proposed. The bending magnet current is varied producing a change in the exit energy window and, therefore, a modification of the R-50 value. For different values of this current, the output data of StarTrack (R) and the R-50, obtained from depth doses measured in a water phantom are determined. A linear fit between both sets of data allows the identification of the StarTrack (R) output that provides the best way to obtain the quality index R-50, for each beam nominal energy. Using these fits, an historical datum series is used to analyze the method proposed in the daily quality control. %26lt;br%26gt;The ouput data of the StarTrack (R) and the R-50 values show a good linear correlation. It is possible to establish a methodology that allows the monitoring of R-50 by direct use of the daily quality control data measured with StarTrack (R). %26lt;br%26gt;A method to monitor R-50 in the daily quality control using the StarTrack (R) device has been developed. The method may be applied to similar devices in which the statistical control variable does not show a linear behavior with R-50.

• 出版日期2014-11
• 单位河北医科大学