A signed consent form for a hepatobiliary study is on file when the patient is called from the waiting room. The patient says the exam was fully explained but has changed their mind and turns away from the chair. Because the paperwork is complete, a colleague starts prepping the arm anyway. Which legal claim best describes proceeding after that withdrawal of consent?

Consent to a nuclear medicine procedure is a continuing authorization that outlasts the initial signature, so once the patient withdraws it there is no longer permission to touch, inject or position them. Battery is the civil wrong that covers an intentional, unauthorized contact with another person, and it needs no proof of carelessness or harm because the wrong is the lack of permission itself. Negligence fails because that theory asks whether a reasonable technologist fell below the standard of care and thereby caused injury, and a deliberate continuation after a spoken refusal is a choice rather than a lapse. Malpractice is simply negligence committed by a licensed professional, so it carries the same missing elements of a performance below the accepted standard. Respondeat superior decides only which party pays when an employee acts within the job, so it never addresses whether the patient's authorization still exists. The exam caveat is that state law words these doctrines slightly differently, but the professional expectation is always that a withdrawn consent ends the procedure. A practical check: when a patient says stop, pause immediately, re-confirm what they want, and document the time and their exact words before anything else happens.