Test purpose

Evaluate the error detection capability of the IQM System.

Test method

The influence of a variety of errors on the IQM signal was evaluated. The introduced errors included incorrect positioning of the beam, incorrect calibration of the MLC, wrong treatment beam energy and application of wrong treatment plan.

Test results

The IQM signal changed significantly for every introduced error. Moving the treatment beam changed the IQM signal between 0.3% and 2.8%. Moving a jaw changed the IQM signal up to 2.5%. Changing the energy on different treatment technique changed the IQM signal up to 9.5%. Delivering the incorrect plan (even when Patient Name and ID are the same) is detected before the 5th control point.


The IQM is stable, reliable & easy to use. IQM can identify:

  • Incorrect MUs & Energy
  • Shifts in the gradient direction
  • Significant MLC miscalibration
  • Incorrect plans