Mathematical descriptions of human bodies-anthropomorphic phantoms-are widely used in computer calculations of doses delivered to the entire body and to specific organs, and are valuable tools in the design and assessment of shielding against occupational exposure. Human phantoms are also useful in determining doses to other parts of the body when a diagnostic or therapeutic dose is delivered to a specific site. They are useful in radiation transport calculations that synthesize a nuclear medicine gamma camera image in order to infer site-specific doses due to an internal radioactive agent.
Specific organs need to be considered at times, such as when the dose to a fetus is required. The inclusion of soft organs not of interest is undesirable because the unnecessary complexity increases the Monte Carlo simulation time.
Even when the size of an extant phantom is adequate, the enabling or omission of organs can be tedious and prone to error. In a combinatorial geometry description, for example, one must consider both the organ itself and the surrounding tissue and ensure all volumes of space are defined and belong to one and only one cell. Simply treating the entire body as a single cell and excluding all defined organs yields an extremely complex cell description that will result in greatly increased Monte Carlo execution time (if the code accepts it at all).
The selection of an organ as a source of photons or other radiation or as a tally region, for which a dose is to be calculated, also requires knowledge of the input syntax for the target transport code.
With BodyBuilder, a user can easily build a phantom with a desired size and organ selections without writing a complicated input file for the MCNP radiation transport code.