Geometric stability of intracavitary pulsed dose rate brachytherapy monitored by in vivo rectal dosimetry

A new mathematical method has been developed, enabling us to quantitate and monitor relative positions of applicator and rectal diodes during a PDR treatment. The spatial relation between rectal dosimeter and applicator was very stable during extended PDR treatments suggesting that the geometric stability of PDR treatment is at the same level as the stability reported for HDR brachytherapy.