Serpil Wilson, MS, DABR
At RockHill Radiation Therapy Center every month I check the calibration to make sure isocenter is not deviated from the previous month or last Monthly QA
We set our morning QA tolerance to 0.5 cm .. As we all know , if they fail daily QA test 3 times, the monthly QA wipes out. At our site, RTT is well trained to do a monthly qa with a raised plate calibration so that in case physicist is not arrived they can treat patients without any interruption. However, they notify physics right away to redo the monthly QA and check Isocal during lunch or at the end of that day. We have been utilizing ART (Align RT) since summer of 2015 and we have never failed daily QA and RTT never had to do monthly QA in the absence of physicist.
I check Isocal once a month to verify there is no shift. If we have an SRS patient, I will check the entire system (Mechanical Iso, Imaging Iso and Align RT) during W-L test. In the morning of the SRS treatment, I will do a quick check on ODI, and laser and set ART Iso Cube. I have a QA patient collimators/ MLC’s are set for center ball of the IsoCube. I will acquire W-L images and using the entire cube I will re acquire portal images to check ART Isocal and verify this set up with Kv pair and CBCT. There is usually no shifts in images and W-L values are less than 0.5 mm. Real delta values for ART Iso is very close to zero.