Monitoring System For Improving Radiation Safety Management

Medi SMARTS (Medical Survey Mapping Automatic Radiation Tracing System), a gamma radiation monitoring system, was installed in a nuclear medicine department. In this paper the evaluation of the system's ability to improve radiation safety management is presented. The system is based on a state of the art software that continuously collects on line radiation measurements for display, analysis and logging. Radiation is measured by GM tubes; the signal is transferred to a data processing unit and then via an RS-485 communication line to a computer. The system automatically identifies the detector type and its calibration factor, thus providing compatibility, maintainability and versatility when changing detectors. Radiation levels are displayed on the nuclear medicine department map at six locations. The system has been operating continuously for more than one year, documenting abnormal events caused by routine operation or failure incidents. In cases where abnormal working conditions were encountered, an alarm message was sent automatically to the supervisor via his tele-pager. An interesting issue observed during the system evaluation, was the inability to distinguish between high radiation levels caused by proper routine operation and those caused by safety failure incidents. The solution included examination of two parameters, radiation levels as well as their duration period. A careful analysis of the historical data, applying the appropriated combined parameters determined for each location, verified that such a system can identify abnormal events, provide alarms to warn in case of incidents and improve standard operating procedures