Milad Baradaran-Ghahfarokhi - Mechanical Engineering Department, School of Engineering, Shiraz University, Shiraz, Iran
Mohammad Amin Mosleh-Shirazi - Physics Unit, Department of Radiotherapy and Oncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
Reza Faghihi - Mechanical Engineering Department, School of Engineering, Shiraz University, Shiraz, Iran
Mohammad Hadi Bagheri - Department of Radiology and Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Kamal Hadad - Mechanical Engineering Department, School of Engineering, Shiraz University, Shiraz, Iran
Ali Alavian-Ghavanini - Mechanical Engineering Department, School of Engineering, Shiraz University, Shiraz, Iran
Zahra Siavashpour - Mechanical Engineering Department, School of Engineering, Shiraz University, Shiraz, Iran
Hamed Kasayi - Medical Radiation Engineering Department, School of Engineering, Shahid Beheshti University, Tehran, Iran

Background: Limited studies are available on the calculation of radiation exposure and its associated risks for people in contact with patients who have been treated with permanent prostate brachytherapy. In this study the changes in the radiation exposure were calculated in different stages of the bladder fullness in prostate seed brachytherapy.Methods:Magnetic resonance images of three patients with full and empty bladders and different prostate sizes (۳۲-۷۱ mL; mean ۵۴.۶ mL) were used for Monte-Carlo dose calculations. Dose rate to skin for each patient was calculated using MCNP۴c, MCNPX.Results: There were no significant differences between dose distribution in the skin relative to the changes in the prostate position due to bladder filling (P=۰.۰۵).Conclusion: Our results showed a negligible change in radiation exposure around the patient due to prostate displacement after bladder filling.