Forward planning using multileaf collimation as a replacement for patient tissue compensation.

In treatment planning, a dosimetrist may encounter a technique that would best be treated by including some type of compensation to correct for tissue or depth variations throughout the field, allowing for a more homogeneous dose distribution. Recent innovations, such as intensity-modulated radiotherapy (IMRT), have been introduced in an effort to address these issues. In many institutions, however, the treatment planning capabilities available may not accommodate consideration of such new technologies. The treatment planner is therefore left to determine how to incorporate these concepts with the current technologies available. While compensation may be an option, this may not always be possible due to the position of the beam or to actual mechanical restraints. Some institutions may also lack the ability and equipment to consider compensation at all. The answer is forward planning IMRT. This concept combines current forward planning techniques with multiple asymmetrically blocked treatment fields, varying the intensity of the beam from a given orientation to produce the desired treatment plan.