Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University Hospital, Philadelphia, PA 19107

Conclusions:
It has been shown, for head and neck cases with invaginated targets, that the simple rule-based forward planning system described here can produce dose distributions with DVHs that are similar to those obtained with a commercially available inverse system. A major advantage for the forward technique is the reduction in the number of field segments required to model the different intensity maps. This decrease simplifies the dose delivery. A second important advantage is that a significant portion of the dose is delivered with conformal portals that can be verified using standard port filming methods.