Investigation and comparison of the absorbing dose microsphere sources of Praseodymium-142 and Phosphorus-32 for liver tumor tissue and around it in brachytherapy of liver tumor

Background: One of the methods of radiotherapy is microspheres brachytherapy, in which the optimal dose rate is obtained by tumor tissue. The aim of this study is to investigation the absorbing dose rate of microsphere brachytherapy sources of phosphorus-32 and Praseodymium-142 in liver tumor tissue and around it using the MCNPX2.6 code and comparison them with each other.Methods: Absorbing dose of Phosphorus-32 and Praseodymium-142 microsphere brachytherapy sources for 200 microspheres in diameter of 50μm inside cylindrical shape vessel in diameter of 50μm and height of 1cm which lies in the spherical shape liver tumor in diameter of 1cm was calculated by use of MCNPX2.6 code. *F8 tally was used for this simulation.Results: Absorbing dose values for Phosphorus-32 and Praseodymium-142 microsphere sources obtained for 0.04 - 0.5cm radial distances from the center of tumor and compare with each other. Also absorbed dose values around the tumor were investigated. Absorbing dose values are decreased for out of the vessel by increasing the radial distance.Conclusion: A good agreement observed between the obtained data and simulated model. Radial absorbed dose values of the Phosphorus-32 microsphere source were more than Praseodymium-142 to 0.31cm radial distance. The Phosphorus-32 absorbing dose values for around the tumor were less than Praseodymim-142 which is an advantage. A higher half-life of phosphorus-32 implies a better treatment of the tumor. The Phosphorus-32 is only beta emitter, whereas Praseodymium-142 is beta and gamma emitter. The gamma yield of Praseodymium-142 and its shorter half-life is proper for imaging.

Investigation and comparison of the absorbing dose microsphere sources of Praseodymium-142 and Phosphorus-32 for liver tumor tissue and around it in brachytherapy of liver tumor Keywords:

Absorbing dose , microsphere brachytherapy , Phosphorus-32 , Praseodymium-142 , MCNPX2.6