1.1 This guide describes different mathematical methods that may be used to calculate absorbed dose and criteria for their selection. Absorbed dose calculations determine the effectiveness of the radiation process, estimate the absorbed-dose distribution in product, or supplement and/or complement dosimetry measurements. 1.2 Radiation processing is an evolving field and annotated examples are provided in to illustrate the applications where mathematical methods have been successfully applied. While not limited by the applications cited in these examples, applications specific to neutron transport, radiation therapy and shielding design are not addressed in this document. 1.3 This guide covers the calculation of radiation transport of electrons and photons in the energy range of 0.1 to 25 MeV. 1.4 The mathematical methods described include Monte Carlo, point kernel, discrete ordinate, semi-empirical and empirical methods. 1.5 General purpose software packages are available for the calculation of the transport of charged and/or neutral particles and photons from various types of sources of ionizing radiation. This standard is limited to the use of these software packages or other mathematical methods for the determination of spatial dose distributions for photons emitted following the decay of 137Cs or 60Co, energetic electrons from particle accelerators, or bremsstrahlung generated by electron accelerators. 1.6 This guide assists the user in determining if mathematical methods are a useful tool. This guide may assist the user in selecting an appropriate method for calculating absorbed dose. Note 1 -The user is urged to apply these predictive techniques while being aware of the need for experience and also the inherent limitations of both the method and the available software. Information pertaining to availability and updates to codes for modeling radiation transport, courses, workshops and meetings can be found in . For a basic understanding of radiation physics and a brief overview of method selection, refer to . 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.