A Monte Carlo Interstitial Brachytherapy Study for AAPM TG-43 Dose Calculation Formalism in Heterogeneous Media

The precision of AAPM TG-43 dose calculation formalism in heterogeneous media has been studied based on the survey and evaluation of the status of interstitial brachytherapy. After a brief introduction of radioactive seeds (¹²⁵I, ¹⁹²Ir and ¹⁰³Pd) and AAPM TG-43 formalism, the radial dose rates calculated by Monte Carlo code MCNP-4C and TG-43 formalism were compared with homogeneous and heterogeneous phantoms. The reason of errors between the results of the above two methods was analyzed, and modified dose rates constant were proposed and testified. With the updated dose rates constant, AAPM TG-43 formalism can predict the dose rate distribution accurately and rapidly in clinical.