(1) Each licensee shall conduct a physical inventory at intervals not to exceed three months to account for all sources of radiation received and possessed. Records of such inventories shall be maintained for at least two years from the date of the inventory for inspection by the department and shall include the quantities, kinds, and serial numbers of sources of radiation, the location where such sources of radiation are assigned and/or stored, the date of the inventory, and the name of the individual conducting the inventory.

(2) Spotmarkers containing radioactive material shall be inventoried prior to arrival at a field site and prior to departure. Records of such inventories shall include the quantity and kinds of radioactive material, serial numbers where appropriate, the date and name of the person performing the inventory, and shall be maintained for inspection by the department.