The sensitivity of detecting small delivery errors was checked by inducing seven types of errors in the IMRT clinical plans for head & neck, prostate and the IQM test plan by modifying the number of delivered MU (between 1 and 3 per beam) and by introducing deviations in linac leaf positions mimicking an MLC bank error as closing and opening one or both banks. The influence of those errors on the IQM signal, the change in Gamma Index as well as the influence on the dose volume histogram (PTV V95%) was analyzed.
IQM signal variation is plotted vs 2D Gamma per beam (1%/1mm, th10, local approach) and the PTV V95% for the H&N example. The correlation function R shows a good correlation especially with DVH parameters.
Monitoring treatment accuracy has never been easier. User-definable tolerance levels create verification corridors. Two corridors - three levels.
The tolerance level represents the daily output fluctuation of your Linear Accelerator. The watch level shows acceptable deviations outside the normal fluctuation. The action level indicates a potentially harmful treatment delivery deviation. Segment-by-segment, beam-by-beam, fraction-by-fraction for every patient.
Treating your cancer patients has never been safer.