Pd103

Pd-103 is a radioactive isotope of palladium with mass number 103. It is not found naturally and is produced artificially for specialized medical uses. As a radioisotope, its properties are dominated by its decay scheme and short-lived radioactivity.

Pd-103 decays by electron capture to Rh-103, with a physical half-life of about 17.3 days. The decay releases low-energy photons and characteristic X-rays in the region of a few tens of keV, which makes Pd-103 suitable for localized radiation delivery. The low energy also means rapid attenuation in tissue, allowing targeted dose deposition with limited penetration.

Production of Pd-103 typically involves neutron irradiation of stable palladium targets in a nuclear reactor, often starting from Pd-102 or other palladium isotopes. After irradiation, chemical separation and radiochemical processing yield Pd-103 suitable for incorporation into sealed sources or seeds used in brachytherapy. Because the isotope decays relatively quickly, its activity declines noticeably over weeks, influencing source design and clinical planning.

In medical use, Pd-103 is employed as a sealed brachytherapy source for localized treatment. It has been used in prostate brachytherapy and in ocular plaque therapy, where its low-energy emissions enable precise, short-range dose delivery. Handling and use require stringent radiation protection, source encapsulation, and adherence to regulatory standards for medical isotopes and radioactive sources.

See also: brachytherapy isotopes, palladium isotopes, electron capture decay.