A Review on Main Defects of TG-43

Abstract

In 1995, the American Association of Physicists in Medicine (AAPM)) published a report on the dosimetry of sources used in interstitial brachytherapy, Task Group No. 43 (TG-43) (Nath et al., 1995). This report introduces dose calculation formalism utilizing new quantities like air kerma strength (SK), dose rate constant (Λ), geometry function (G (r,θ)), radial dose function (g (r)), and anisotropy function (F (r,θ)). These dosimetry parameters consider geometry, encapsulation and self-filtration of the source, the spatial distribution of radioactivity within the source, and scattering in water surrounding the source. According to this protocol, the absorbed dose rate distribution around a sealed brachytherapy source at point P with polar coordinates (r, 肯) can be determined using the following formalism: 経.岫堅, 肯岻 噺 Λ 鯨賃 G 岫r, θ岻 G 岫r待, θ待岻 訣岫堅岻繋 岫堅, 肯岻 (1) where r is the distance to the point P and 肯 is the angle with respect to the long axis of the source, and (r0, 肯0) is reference point that r0= 1 cm and 肯0= 講/2 (Fig. 1).