Escalation of dose to tumor while sparing adjacent critical structures is a hypothesis being tested by major radiotherapy centers, most notably for prostate cancer through an NCI funded cooperative trial and several program projects. Conformal therapy may also be effective in oral cancers, if technical hurdles can be overcome. The goal of this pilot study is to develop and evaluate technologies which may improve oral cancer treatment with external beam conformal radiation therapy. Specifically, we that three technologies are critical to the effective implementation of conformal therapy for oral cancers: a) the radiation oncologist must have tools to clearly visualize anatomy, including nodes, vessels and other structures not normally segmented during the treatment planning process b) once the complete three dimensional target and normal tissues are defined, a desired dose distribution is specified. A method is needed to calculate the intensity profiles of beams to be used. Summation of these intensity profiles from the multiple beams results in a composite dose distribution which should closely approximate the desired dose distribution. This process is referred to as inverse planning. Commercial software and delivery systems are now available to deliver such intensity modulated fields, although FDA approval in some cases is still pending. Finally, the patient must be accurately repositioned from day to day for fractionated radiotherapy. It appears that in addition to electronic portal imaging devices, which provide signals on internal anatomy relative to isocenter, that video may also be very helpful in interactively repositioning patients. The goal of this pilot project is to provide feasible clinical solutions to these technical challenges, such that oral cancer treatment with external beam radiation can be improved.
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