Beam shaping for SRT/SRS.

Field shaping for stereotactic radiosurgery and stereotactic radiotherapy has evolved from static field shaping techniques applied to static or arc fields and now includes dynamic field shaping definition which can be dynamically modified during the arc. This allows greater conformation of dose to the target volume while minimizing dose to surrounding normal tissue. This results in treatment to a single isocenter, which simplifies the treatment planning and dose delivery, thereby minimizing treatment time and improving patient comfort and satisfaction during the treatment. A number of optimization techniques remain to be investigated.