On August 24, 2010, the NRC issued a Notice of Violation to the Christiana Care Health Services (CCHS), for a Severity Level III violation involving the failure to develop and maintain written procedures to provide high confidence that each administration requiring a written directive was performed in accordance with the written directive as required by 10 CFR 35.41. Specifically, CCHS's written procedures for high dose rate remote afterloader (HDR) treatments did not: (i) include a quality assurance process to test and evaluate proper functioning of all measurement tools used to determine treatment parameters; and, (ii) specify how personnel should respond when unknown and questionable treatment distances were encountered during HDR simulation measurements. As a result of these procedural inadequacies, a medical event occurred, in which the patient received a dose to unintended tissue and did not receive the prescribed dose to the intended tissue during an HDR treatment conducted between January 18 and January 22, 2010.