These are the CT and MRI licenses, which are now collectively known as the Large Medical Equipment Use License.
According to the relevant laws and regulations, those engaged in radiation-related occupations should apply for a radiation personnel work permit, and should participate in radiation-related training, occupational physical examination, and dosage testing. Therefore, to engage in general radiography, CT, DSA, radiotherapy, lithotripsy and other occupations need to apply for a radiation worker's license. One of the documents related to CT/MR/DSA and other such large equipment is the large equipment induction license, but the State Council eliminated these licenses in 2016 (I think) when streamlining the policy. So this license is not a state necessity now, but some units still need to see it.