Protocol for the measurement of the absorbed dose rate to water for a planar P beta emitting brachytherapy source: A multi-institutional validation.

Purpose: This is a multi-institutional report on inter-observer and inter-instrument variation in the calibration of the absorbed dose rate for a planar P beta emitting brachytherapy source. Measurement accuracy is essential since the dose profile is steep and the source is used for the treatment of tumors that are located in close proximity to healthy nervous system structures.

Methods And Materials: An RIC-100 P source was calibrated by three institutions using their own equipment and following their standard procedures.