10 CFR § 35.2433 - Records of decay of strontium-90 sources for ophthalmic treatments.
(a) A licensee shall maintain a record of the activity of a strontium-90 source required by § 35.433 for the life of the source.
(b) The record must include -
(1) The date and initial activity of the source as determined under § 35.432; and
(2) For each decay calculation, the date and the source activity as determined under § 35.433.