Remote afterloading brachytherapy: human factors in a partially automated treatment system

Remote afterloading brachytherapy (RAB) introduces a radioactive source close to a target (or tumor) in the body with the object of delivering a prescribed dose of radiation to that target. Partial automation of the treatment delivery system using a computer to control the position of the source produces precise and repeatable control of source placement and has eliminated staff exposure to radiation during most RAB procedures. Some treatment planning and delivery problems affecting the radiation dose to the patient have been reported with these devices. A few of these problems have been traced to faulty equipment, but most have been attributed to human error. As part of a research study sponsored by The United States Nuclear Regulatory Commission, a human factors team has visited 23 RAB treatment delivery sites in the United States. The team performed a function and task analysis of RAB and used the results of that analysis to provide a framework for a systems analysis of the potential causes of human error in RAB. The authors present some of the error protection and detection methods used in these partially automated treatment systems and discuss ways in which they can be expected to succeed or fail from a human factors standpoint