Characterization of an irradiating system used in radiotherapy to calibrate clinical dosemeters

This work presents the steps of adequacy and characterization of a ⁶⁰Co irradiator, which was used for treatment to be used in calibration procedures of clinical dosimeters used in radiotherapy. The adaptation of a donor irradiator system to the IPEN Calibration Laboratory and the characterization of the beam and the radiation field were carried out in accordance with the recommendations of the IAEA guide (TRS 469, 2009). For the installation of the new radiator, an adjustment was made in the current calibration room to accommodate the head in the calibration position. A holder has been made for your positioning. Correction was necessary in the collimation system, which presented flaws in its use. For the characterization of the radiation beam, the initial tests of uniformity of the radiation field were carried out, determining the size and the center of the radiation beam. Using a small volume ionization chamber, uniformity greater than 90% was found both vertically and horizontally for a 8 x 8 cm radiation beam. Measurements for the determination of the air kerma rates performed demonstrate that the system is ready for use in the calibration. (author)