Computer-assisted rotation and multiple stationary irradiation technique. Newly designed overrunning multi-leaf collimators for conformation radiotherapy.

A computer-assisted rotation and stationary conformation radiotherapy system with overrunning multileaf collimators has been developed. This system can produce any shape of target volume, including a number of target areas outside the axis of the rotation, regardless of the location of the axis at 360 degrees rotation irradiation. In addition, by changing the dose rate and deleting a partial region within a field, multiple stationary irradiation can produce more homogeneous target volumes--thus avoiding excessive irradiation to critical organs--than the rotation technique.