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Optimization of Intensity-modulated Radiation Therapy Treatment Planning under Uncertainty

Arzanipour, Atousa | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54198 (01)
  4. University: Sharif University of Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Rafiee, Majid; Mahnam, Mehdi
  7. Abstract:
  8. Today, cancer is one of the leading causes of death globally, killing millions of people around the world every year. This indicates the need for more attention to the treatment of this disease. Cancer can be prevented from growing by being diagnosed at an early stage and choosing the proper treatment. Among cancer treatment methods, radiation therapy is one of the most widely used methods, and Intensity-Modulated Radiation Therapy (IMRT) is one of the most efficient and resilient methods of radiation therapy. In the IMRT treatment plan, the optimal choice of radiation intensity is of particular importance abd the mathematical modeling problems related to determining the intensity of beams are known as fluence map optimization problems. The principal goal in this category of optimization problems is to choose a beam intensity that delivers the prescribed dose to the tumor while sparing the healthy tissues and organs at risk.As therapy sessions continue, the re-population of some cancer cells may come to an end; therefore, there may be a need for a new treatment plan. In this study, a robust mathematical modeling using a polyhedral uncertainty set is proposed regarding the tumor's lower bound uncertainty. The proposed mathematical programming consists of linear constraints and a quadratic objective function based on physical dose calculations. In the following, the proposed model is solved with real-world data from a prostate cancer patient. To solve the proposed mathematical model, interior-point and reduced gradient algorithms are used and compared. The solutions obtained in both methods are a global optimum, and both equal. Still, in the reduced-gradient method, the solution time is less than the interior-point method, and this is why this method outperforms the interior point method in this problem. Experimental results show that the proposed model can reduce the dose delivered to normal tissues while maintaining an appropriate amount for the tumor. Also, the proposed model caused a nine percent decrease in the summation of the mean penalties from the prescribed dose for healthy organs
  9. Keywords:
  10. Fluence Map Optimization ; Convex Optimization ; Robust Optimization ; Intensity Modulated Radiation Therapy (IMRT) ; Treatment Planning

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