fabrication and characterization of beam quality phantom for external beam radiotherapy

Introduction: radiation dose measurement plays a major role in radiation dosimetry. effective dose delivery to the patient is ensured with the recommendation of some protocol called quality assurance (qa). it is necessary to confirm that the beam that is used for treatment is a good quality beam and it is given by beam quality factor tpr 20/10 which is one of the qa protocols. material and methods: in the present tpr20,10 phantom both depth (20 and 10 cm) doses can be measured at the same procedure without changing any setup. as the reference condition is maintained, the gelatin-based phantom is kept for irradiation in the siemens linear accelerator (linac) machine. initially source axis distance (sad) of 100 cm from the surface and 10×10 cm2 of field size. the measurement is taken by ion chamber at 10 and 20 cm depth in gantry angles 90° and 270° and the ratio of these values is taken and compared with the measurements of the water-based tpr phantom. results: the values for the tpr20,10 ratio for the gelatin and water phantom are measured using the above method and the values are tabulated and compared. likewise, the output measurements are done and tabulated for comparison. these measurements are carried out for several days to check the repeatability, and reproducibility of the phantom. also, the measured set of values was analyzed using mean, median, standard deviation, etc. conclusion: the fabricated phantom had good outcomes in its response. and the result projects that the phantom can be a better alternative for the other phantom materials and gelatin has more advantages over water, we conclude that gel can be used for better dosimetric procedures.