In radiotherapy, the geometrical uncertainty of the target due to setup variations or patient/organ motions causes the 3D dose distribution actually received by a patient to deviate from the static dose distribution produced by treatment-planning systems. Instead of adding a CTV-PTV margin, the robust fluence approach is to manage the intensity modulation of the fluence to counter the geometrical uncertainty which results in less dose to the surrounding normal tissues and more robust dose distribution, especially for intensity modulated radiotherapy (IMRT). In this paper a new algorithm is developed to obtain robust fluence through the deconvolution of the nominal static one given by any treatment planning system. It incorporates the geometrical uncertainty outside the dose optimization procedure, therefore avoiding the error of dose-convolution, and is more flexible and easier to integrate into different existing treatment planning systems to obtain robust fluence.

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