Alanine EPR dosimetry in brachytherapy

The paper reports the experimental procedure adopted to determine the absor bed dose rate in water per reference air kerma rate, D-Kr(d, theta), along the transverse bisector axis of a Cs-137 brachytherapy source. The dose rat e measurements have been carried out at difference distances, d, from the s ource using alanine dosemeters in a water phantom. The reference air kerma rate, K-r, was determined adopting a 'direct procedure' that uses a spheric al ionization chamber in air. The dose rate constant of the source examined was D-Kr (1, pi/2) = 0.99 +/- 0.03 cGy h(-1) (mu Gy h(-1))(-1). The values of the radial dose function along the transverse axis, g(d), determined wi th an uncertainty of 3.4% (1 sigma), were found to be in good agreement wit h the results reported in the literature. The uncertainty in dose rate value has been estimated as 2.8% (1 sigma) for distances from the source up to 7 cm. K-r has been determined with 1.2% (1 sigma) uncertainty. So D-Kr (d, pi/2) values were determined with 3% (1 si gma) uncertainty.