Nickel-63
Dose Rate and Shielding
Dose rate to the skin at 10 cm: negligible (for an unshielded point source)
Dose rate to epidermal basal cells from skin contamination of 1 µCi/cm2: negligible
Shielding: None needed.
Annual Limit on Intake (ALI): 9000 microcuries via ingestion and 2000 microcuries via inhalation. The ingestion of one ALI will produce a dose of 5 rem.
https://ehs.princeton.edu/laboratory-research/radiation-safety/radioactive-materials/radioisotope-fact-sheets/nickel-63