ABSTRACT
@#The Monte Carlo (MC) method was utilized widely to various problems like an absorbed dose calculation as the method able to apply in a complex geometry such as mammography. Since 1980, the approach was utilized in mammographic dosimetry to calculate the backscatter factor and absorbed dose in breast phantoms because it was considered as the most accurate dose calculation algorithm in several experimental setup. This paper provides a review of the applications of Monte Carlo simulation (MC) for the process dosimetry in mammography. In comparison to experimental measurements, this approach poses a minimum calculation uncertainty (less than 2%), realistic measurement positions, and appropriate for low-energy radiation simulation. The applications of the MC codes in mammography, such as radiation modelling, organ dose calculation, tumor growth analysis, etc., were discussed in this review.
Subject(s)
MammographyABSTRACT
Introduction: Recent compensators are commonly applied in IMRT. The precise properties of applied compensators such as thickness, attenuation coefficient and build up factor are intensively important for IMRT calculations. Method: The brass compensator used for 6 MV photon beam was studied to estimate the relative effect of thickness and field size on IMRT calculations. Various field size together with several compensator thicknesses were examined. Result: The average reduction of effective attenuation coefficient (EAC), for the fields of 10×10 cm2 to 20×20 cm2, was 9.94%. By increasing the field size, EAC was decreased. The major reduction of EAC due to increasing field size was found to be 9.62%. The build up factor was increased by 2% to 21.8% respect to field size and compensator thickness. Also, the build up factor was increased by adding up the thickness. The rate of changes ranged from 24% to 48 %.Conclusion: The compensator thickness and field size are significantly important to calculate the effective attenuation coefficient and build up facto