The AAPM TG-43 Protocol for Brachytherapy Reference Dosimetry Has Proven Success and Is

The AAPM TG-43 protocol for brachytherapy reference dosimetry has proven success and is the standard dosimetry protocol used worldwide for clinical dose calculations. While there have been a number of updates refining the approach, the basic formalism based on superposition of single-source dose distributions in a fixed water sphere has remained. The joint AAPM/ESTRO report on high-energy (> 50 keV) photon-emitting brachytherapy source dosimetry further refines the basic TG-43 formalism. Specific to high-energy radionuclide sources such as 192Ir, the report includes the following: a) consensus datasets of brachytherapy dosimetry parameters and recommended methods for evaluating these consensus datasets, b) recommendations on dosimetry methods to characterize the source dose distribution (based on experimental procedures and Monte Carlo methods of radiation transport simulations), and c) interpolation/extrapolation techniques for the 2D anisotropy function and radial dose function, specific to high-energy sources, which differ from the low-energy techniques in the 2004 and 2007 AAPM updates.

In addition to explaining this joint AAPM/ESTRO HEBD report, other advances are discussed such as dose calculation methods using model-based dose calculation algorithms as examined in the joint AAPM/ESTRO/ABG TG-186 report, and clinical implementation of primary HDR 192Ir doserate-to-water calibrations.