Objective:An automatic method for the optimization of importance factors was proposed to improve the efficiency of inverse planning.Methods:The automatic method consists of 3 steps: (1) First, the importance factors are automatically and iteratively adjusted based on our proposed penalty strategies. (2) Then, plan evaluation is performed to determine whether the obtained plan is acceptable. (3) If not, a higher penalty is assigned to the unsatisfied objective by multiplying it by a compensation coefficient. The optimization processes are performed alternately until an acceptable plan is obtained or the maximum iteration N max of step (3) is reached.Results:Tested on 2 kinds of clinical cases and compared with manual method, the results showed that the quality of the proposed automatic plan was comparable to, or even better than, the manual plan in terms of the dose–volume histogram and dose distributions.Conclusions:The proposed algorithm has potential to significantly improve the efficiency of the existing manual adjustment methods for importance factors and contributes to the development of fully automated planning. Especially, the more the subobjective functions, the more obvious the advantage of our algorithm.

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Near-infrared diffuse correlation imaging (DCT) is an important method of tissue blood flow imaging for the prognosis and diagnosis of various diseases. A new solution of DCT that is based on the Nth-order linear (NL) algorithm, termed as NL-DCT, was proposed in our previous study to overcome the limitation of tissue geometry and heterogeneity. The NL-DCT converts the image reconstruction into linear equations, and this solution is an ill-posed problem in mathematics. To improve the accuracy and robustness of the DCT image reconstruction, a combination of algebra reconstruction technique (ART) and total variation (TV), namely ART-TV, is proposed in this study. After each ART iteration, the TV model is used as an a priori constraint to reduce noise. The validations from computer simulation and phantom experiments with different anomalies demonstrate that the proposed ART-TV algorithm is efficient in DCT blood flow image reconstruction.INDEX TERMS diffuse correlation tomography, blood flow index, image reconstruction, Nth-order linear approach, algebra reconstruction technique, total variation

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