AbstractID: 9722 Title: Dose verification for image-guided radiotherapy
The use of imaging during treatment allows not only for guidance during patient setup and on-line visualization of anatomy changes,
is also permits post processing techniques that are geared toward treatment adaptation. Dose verification is such a process.
Specifically, a treatment-time image is used to verify the dose distribution delivered to a patient. This dose distribution can be
compared with the planned to address treatment quality and perform off-line corrections. Because the treatment time image is used,
patient setup errors and anatomy changes are accounted for in the verified dose. However, due to the fact that the verified fluence is
not used for the dose calculation (as it is with dose reconstruction), dose verification assumes ideal linac and MLC behavior. Dose
verification was performed for a canine nasopharyngeal treatment conducted on the University of Wisconsin helical tomotherapy
prototype. The sensitivity of the techniques was tested by including and not including the treatment couch for treatment planning.
Dose verification showed that the target dose was 4% lower as may be expected when the planning is not accounting for couch
attenuation. Dose verification allows one to verify (to within tolerances specified for the accelerator and MLC) the distribution of dose
actually delivered to a patient and in doing so is a very useful tool in the practice of radiotherapy.
Research supported by TomoTherapy, Inc.