BEAM ANGLE OPTIMIZATION IN IMRT (INTENSITY MODULATED RADIATION THERAPY) FOR NASOPHARYNGEAL CANCER

• Main Author: Oktafiani, Lia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/65602
• Institution: Institut Teknologi Bandung

IMRT (Intensity Modulated Radiotherapy) is a modern technique in radiotherapy that uses multiple radiation fields in its irradiation with non-uniform intensity in each direction of the radiation field to obtain an optimum dose distribution. Prior to irradiation, an optimal plan is needed so that radiotherapy goals can be achieved. When irradiating a patient, there is a possibility that the Organ at Risk (OAR) around the target volume will receive a high dose and optimal HI (Homogeneity Index) and CI (Conormity Index) values. Therefore, it is necessary to optimize the irradiation angle at the appropriate IMRT so that the goals is achieved. In this study, the process of optimizing the beam angle in IMRT technique for nasopharyngeal cancer cases using the Simulated Annealing method for 7 and 9 fields will be compared with the results of manual planning. Based on the optimization process carried out using the initial temperature parameter value of 1000 K and the cold temperature of 1 K, a new angle configuration was obtained with smaller objective function values than manual planning. After obtaining the configuration of the beam angle of the optimization results, then an analysis was carried out through the display of dose distribution with the Dose Volume Histogram (DVH) curve, OAR value, HI and CI values between manual planning and SA optimization planning. In this study, it was found that planning using SA optimization was more optimal than manual planning because it could reduce the dose of OAR and obtain better HI & CI values. Futhermore, the irradiation angle with the number of 9 fields resulted in a more optimal planning compared to the use of 7 fields.