Agreement Between Institutional Measurements and Treatment Planning System Calculations for Basic Dosimetric Parameters as Measured by the Imaging and Radiation Oncology Core-Houston

Differences in basic dosimetric parameters between machine measurements and TPS values vary widely depending on the parameter, although agreement does not seem to vary by TPS and has not changed over time. Intensity modulated radiation therapy-style output factors, stereotactic body radiation therapy-style output factors, and upper physical wedge output factors had the largest disagreement and should be carefully modeled to ensure accuracy.