Intensity-modulated radiosurgery/radiotherapy using a micromultileaf collimator

Intensity modulation with inverse treatment planning for 3 clinical stereotactic radiotherapy cases were directly compared against forward planning techniques using beam modification by enhanced dynamic wedge. Dose-volume histogram (DVH) analysis demonstrated that a significant reduction in dose to neighboring critical structures can-be achieved through intensity modulation patterns determined from inverse planning, while a marginal change is achieved in the target volume dose uniformity. This study also demonstrates that the intensity modulated dose patterns generated from inverse planning may differ significantly from the intuitive beam modified patterns developed in the forward planning model. These results suggest that one advantage of intensity modulated radiosurgery/radiotherapy with inverse planning is the significant reduction in dose to normal tissue and critical structures, with its coincident implications for dose escalation studies.