@Article{Toossi2016,
journal="Contemporary Oncology/Współczesna Onkologia",
issn="1428-2526",
volume="20",
number="4",
year="2016",
title="Comparison of the hypothetical 57Co brachytherapy source with the 192Ir source",
abstract=" Aim of the study : The  57 Co radioisotope has recently been proposed as a hypothetical brachytherapy source due to its high specific activity, appropriate half-life (272 days) and medium energy photons (114.17 keV on average). In this study, Task Group No. 43 dosimetric parameters were calculated and reported for a hypothetical  57 Co source.    Material and methods : A hypothetical  57 Co source was simulated in MCNPX, consisting of an active cylinder with 3.5 mm length and 0.6 mm radius encapsulated in a stainless steel capsule. Three photon energies were utilized (136 keV [10.68%], 122 keV [85.60%], 14 keV [9.16%]) for the  57 Co source. Air kerma strength, dose rate constant, radial dose function, anisotropy function, and isodose curves for the source were calculated and compared to the corresponding data for a  192 Ir source.   Results : The results are presented as tables and figures. Air kerma strength per 1 mCi activity for the  57 Co source was 0.46 cGyh–1 cm 2 mCi–1. The dose rate constant for the  57 Co source was determined to be 1.215 cGyh–1U–1. The radial dose function for the  57 Co source has an increasing trend due to multiple scattering of low energy photons. The anisotropy function for the  57 Co source at various distances from the source is more isotropic than the  192 Ir source.   Conclusions : The  57 Co source has advantages over  192 Ir due to its lower energy photons, longer half-life, higher dose rate constant and more isotropic anisotropic function. However, the  192 Ir source has a higher initial air kerma strength and more uniform radial dose function. These properties make  57 Co a suitable source for use in brachytherapy applications.",
author="Toossi, Mohammad Taghi Bahreyni
and Ghorbani, Mahdi
and Rostami, Atefeh
and Khosroabadi, Mohsen
and Khademi, Sara
and Knaup, Courtney",
pages="327--334",
doi="10.5114/wo.2016.61854",
url="http://dx.doi.org/10.5114/wo.2016.61854"
}