Which mechanism can alert fluoroscopic x-ray production after a preset period?

The cumulative timer is specifically designed to monitor and control the duration of fluoroscopy exposure. It provides a visual alert to the operator after a predetermined amount of time has elapsed, helping to prevent excessive radiation exposure to patients and operators. By ensuring that the fluoroscopic procedure does not exceed safe time limits, the cumulative timer plays a critical role in radiation safety protocols.

In contrast, other options serve different functions. An image receptor timer is typically used in conjunction with certain imaging modalities to measure exposure times related to the image capture process, rather than specifically managing fluoroscopic exposure time limits. An exposure detector is responsible for sensing the presence of radiation and may be utilized in various imaging contexts, but it does not manage or alert operators after a set period of exposure. An electric timer, on the other hand, generally functions to provide precise timing for the x-ray exposure but may not provide an alert based on cumulative time in the same way a cumulative timer does. Thus, the cumulative timer is the correct choice as it is purpose-built to alert operators after a specified exposure duration during fluoroscopy.