Monte Carlo calculations of absolute dose rate in liquid water are presented in the form of away-along tables for 1 and 5 cm 192Ir wires of 0.3 mm diameter. Simulated absolute dose rate values can be used as benchmark data to verify the calculation results of treatment planning systems or directly as input data for treatment planning. Best fit value of attenuation coefficient suitable for use in Sievert-integrals-type calculations has been derived based on Monte Carlo calculation results. For the treatment planning systems that are based on TG43 formalism we have also calculated the required dosimetry parameters.

The purpose of this study is to calculate basic dosimetry data for a CSM11 low dose rate 137Cs source in water. This source is widely used in afterloadable dome cylinders designed to homogeneously irradiate the vaginal cuff alone or additional areas of the vagina in hysterectomized patients. In this study, the Monte Carlo simulation code GEANT, incorporating in detail source geometry, is used to investigate the dosimetric characteristics of the source. The calculated data were analyzed using a fitting procedure that is described in detail. Absolute dose rate distributions in water were calculated around this source and are presented as conventional 2D Cartesian lookup tables (classically along-away tables). Also, the dose calculation formalism endorsed by the Interstitial Collaborative Working Group and the AAPM Task Group 43 have been calculated. The calculated dose rate constant for this source is lambda = 1.096 +/- 0.002 cGy h(-1) U(-1). The anisotropy function results in about 50% deviations from isotropy at positions near the long axis of the source. The radial dose function is given as a polynomial that reproduces the calculated data up to 20 cm. Best-fit values of attenuation coefficients suitable for use in Sievert integral calculations have been derived.

The Amersham CDCS-M-type 137Cs stainless-steel encapsulated source is widely used in low dose rate brachytherapy with manual afterloading. However there is a need for more accurate dosimetry data. In this study we present Monte Carlo calculations of absolute dose rate in water around this source using the Monte Carlo code GEANT, discuss dosimetric features of these data, and compare them with Krishnaswamy's results for 137Cs intracavitary sources. Dose rate distributions are presented in the form of along-away tables and in the TG43 formalism. Simulated absolute dose rate values can be used as benchmark data to verify the treatment planning system calculation results or directly as input data for treatment planning. Best-fit values of attenuation coefficients suitable for use in Sievert integral type calculations have been derived comparing dose rate distributions calculated using this algorithm with those obtained from Monte Carlo calculations.

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PurposeIn this work a spreadsheet based program is presented that to a large extent independently verifies the calculations of individual plans of brachytherapy treatment planning systems for low dose rate, high dose rate and pulsed dose rate techniques.Material and methodsThe verification program has been developed based on workbooks/spreadsheets. The treatment planning system output text files are automatically loaded into the new program, allowing the use of the source coordinates, the desired calculation point coordinates, and the dwell times of a patient plan. The source strength and the reference dates are entered by the user and then dose points calculations are independently performed. The program shows its results in a comparison of its calculated point dose data with the corresponding TPS outcome.ResultsResults of 250 clinical cases show agreement with the TPS outcome within a 2% level.ConclusionsThe program allows the implementation of the recommendations to verify the clinical brachytherapy dosimetry in a simple and accurate way, in only few minutes and with a minimum of user interactions.