TG-43 Practice Problems
A Bebig/Theragenics I25.S06 125I source with measured air kerma strength of 29.148 U is used for a brachytherapy treatment. What is the dose rate in water, in cGy/hr, at a point located at a radial distance of 5.4 cm and a polar angle of 66o? Use the line source approximation, for a source of 0.35 cm active length. (Hint: Use Figure 1 and the geometric definition of the dot product)

**All values, unless stated within the problem, should be obtained using the TG-43 updated report.
cGy/hr