Sha Rajib Lochan, Reddy Palreddy Yadagiri, Sahoo Narayan
Department of Radiation Physics, The Indo-American Cancer Institute & Research Centre, Banjara Hills, Hyderabad, India.
Brachytherapy. 2011 May-Jun;10(3):249-52. doi: 10.1016/j.brachy.2010.08.010. Epub 2010 Oct 8.
It is a good practice for quality assurance purposes to check the high-dose rate brachytherapy source dwell times obtained from any computerized treatment planning system (TPS) by independent hand calculations. The aim of this work was to prepare a table that would help to calculate the total dwell times for cylindrical applicators used for high-dose rate brachytherapy.
The results of an earlier investigation of dose rate per unit source strength at different distances from the microSelectron-high-dose rate (192)Ir source and the relative weights for dwell times obtained from optimized plans were used to prepare a linear source table.
This table gives the product of source strength and total dwell times to deliver 1000 cGy at various distances for active lengths ranging from 1 to 8 cm and for treatment distances of 1 to 2.25 cm. One can use this table to determine the total dwell time necessary to deliver the prescribed dose at a specific distance for the source strength at the time of treatment. This can be compared with the total dwell time calculated by the computerized TPS.
The linear source table makes the determination of total dwell time very easy and would help the clinical physicist to check the accuracy of results of the TPS quickly.
