American brachytherapy society recommendations for clinical implementation of NIST-1999 standards for (103)palladium brachytherapy. The clinical research committee of the American Brachytherapy Society.

PURPOSE

Recent important developments in palladium-103 ((103)Pd) dosimetry mandate a reevaluation of (103)Pd brachytherapy prescribing practices.

METHODS AND MATERIALS

The clinical research committee of the American Brachytherapy Society (ABS) convened a consensus session of brachytherapists and physicists to develop recommendations regarding future dose prescribing guidelines for National Institute of Standards and Technology (NIST-1999) calibrated (103)Pd sources.

RESULTS

The ABS recommends that clinicians attempt to reproduce the implant doses delivered and reported in the literature through the past decade.

CONCLUSIONS

The following should be immediately implemented for (103)Pd dosimetry: 1) All practicing physicians, physicists, dosimetrists, and suppliers implement NIST-1999 air-kerma strength standard for (103)Pd brachytherapy. 2) All treatment planning systems and dose calculation algorithms must be updated to reflect new dose rate constants. The AAPM-recommended validated value for Theraseed model 200 is 0.665 cGy h(-1) U(-1). The dose rate constant for the Mentor MED3633 seed is currently reported as 0.68 cGy h(-1) U(-1). This latter value and the values for seeds from other manufacturers are awaiting independent confirmation. 3) Physicians who previously prescribed 115 Gy for (103)Pd monotherapy prostate implants should now prescribe 125 Gy. When using (103)Pd as a boost following 45 Gy of external beam irradiation, 100 Gy should be prescribed instead of the previous 90 Gy. It is critical that all three changes be implemented concurrently, because they are interdependent.