28 C.F.R. § 552.13
(b) The institution physician may authorize use of a medical x-ray device for medical reasons and only with the consent of the inmate. When there exists no reasonable alternative, and an examination using a medical x-ray device is determined necessary for the security, good order, or discipline of the institution, the Warden, upon approval of the Regional Director, may authorize the institution physician to order a non-repetitive examination using a medical x-ray device for the purpose of determining if contraband is concealed in or on the inmate (for example: In a cast or body cavity). The examination using a medical x-ray device may not be performed if it is determined by the institution physician that it is likely to result in serious or lasting medical injury or harm to the inmate. Staff shall place documentation of the examination and the reasons for the examination in the inmate's central file and medical file.
[80 FR 32002, June 5, 2015]