Adaptive smoothing method of fluence map in IMRT

This paper focuses on the fluence map optimization problem in Intensity Modulated Radiation Therapy. This technology has been considered as a major breakthrough in cancer therapy. The dose distribution produced by IMRT is more desirable than other radiation therapy techniques that can guarantee killing cancer cells while protecting normal tissue from complications as much as possible. The advantages and disadvantages of the total variance smoothing method and the quadratic smoothing method have been analyst in detail in this paper. By using the local gradient information of the intensity map, the two smoothing methods are combined to form a novel adaptive smoothing strategy. This method allows not only reducing the complexity, but also to maintain good signal steepness for the intensity map in the map decomposition process, which will lead to good performance in leaf sequencing process by multileaf collimator finally in the aspects of total number of monitor units. This paper test the new method on an opening head neck clinical case, as well as the quadratic smoothing method. The results show we can get lower bound of total number of monitor units for the intensity map decomposition.