Wis. Stat. § 462.04: Prescription or order required.

A person who holds a license or limited X-ray machine operator permit under this chapter may not use diagnostic X-ray equipment on humans for diagnostic purposes unless authorized to do so by prescription or order of a physician licensed under s. 448.04 (1) (a), a naturopathic doctor licensed under s. 466.04 (1), a dentist who is licensed under s. 447.04 (1) or who holds a compact privilege under subch. II of ch. 447, a dental therapist licensed under s. 447.04 (1m), a podiatrist licensed under s. 448.63, a chiropractor licensed under s. 446.02, an advanced practice registered nurse licensed under s. 441.09, a physician assistant who is licensed under s. 448.974 or who holds a compact privilege under subch. XIII of ch. 448, or, subject to s. 448.56 (7) (a), a physical therapist who is licensed under s. 448.53 or who holds a compact privilege under subch. XI of ch. 448.