AAPM TG-43 formalism for brachytherapy dose calculation of a 137Cs tube source

We present a development of the use of the AAPM TG-43 dose formalism applied to Cs-137 gynecological implant sources. The geometry factor, radial dose function, and anisotropy function of a Cs-137 source modeled after the Nuclear Associates 67-809 series stainless steel jacketed tube source were derived following the AAPM TG-43 formalism. The dose rate distribution through the center of the source using the AAPM TG-43 dose formalism is calculated and compared with the calculations obtained using the Sievert summation and Monte Carlo simulation. The three methods resulted in an agreement within less than 5%, or an isodose rate line agreement within 2 mm. We demonstrate that the AAPM TG-43 formalism can be applied to Cs-137 linear sources and is capable of serving as a Cs-137 dose calculation algorithm that can be used for treatment planning purpose. (C) 2004 American Association of Physicists in Medicine.