Introduction: Dwell times are defined manually in the intracavitary brachytherapy, while it can be determined with inverse planning methods. Recently at several brachytherapy centers in Iran, the Multisource brachytherapy system and HDRplus treatment planning software are installed, that its input parameters are based on maximum and minimum dose. Whereas the physician decision is based on DVH parameters. Determination of appropriate values of dwell times are typically done by physicist in a trial-and-error manner in practice. This process will take about 15 minutes. Sometimes, dwell times are set manually by physicist. In this way, some of dwell times may be zero, due to disregard of the dwell time’s proportions by physicist. In this paper, we attempted to develop the treatment planning software based on DVH parameters and reduce the execution time. Methods: In this study, the simulated annealing algorithm was applied to determine the optimized values of dwell times. Input parameters were defined based on DVH. For example, parameters such as D90% and D2cc were assumed for CTV and OARs, respectively. Results: The program was examined for simple case of cylindrical applicator and OARs such as bladder, rectum, and sigmoid were considered. Using this method, for 90% of patients under investigation, at less than 1 minute, obtained DVH parameters were consistent with prescribed dose. Discussion and conclusion: In Interstitial brachytherapy, which is developing, using inverse planning is necessary. For this purpose, the treatment planning software should be based on desired parameters of physician to minimize the time of treatment planning for each patient.

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