Requirements for controlling potential hazards associated with analytical x‑ray systems are specified in most states by law. In Iowa, these requirements are found in 641‑45.5(136C) of the Iowa Administrative Code. Portions of these hazard control and safety measures are summarized here.
- Beam Entry Shut‑off Device - All open-beam configurations shall be equipped with a device that prevents the entry of any portion of an individual’s body into the primary beam path or that causes the beam to be shut off upon entry into its path.
- Housing Interlock - Each x-ray tube housing shall be equipped with an interlock that shuts off power to the tube if the tube is removed from the housing or if the housing is disassembled.
- Labeling - All analytical x-ray equipment shall be labeled with a readily discernible sign bearing the radiation symbol and the words: “CAUTION - HIGH INTENSITY X-RAY BEAM” or words having a similar intent, on the x-ray source housing, and “CAUTION - RADIATION - THIS EQUIPMENT PRODUCES RADIATION WHEN ENERGIZED” or words having a similar intent, near any switch that energized an x-ray tube.
- Shielding Provided by Housing - Each x‑ray tube housing shall be constructed so that, with all shutters closed, the radiation, measured at a distance of five centimeters from its surface, is not capable of producing a dose in excess of 2.5 millirems in one hour.
- Shutters - For open‑beam configurations, each port on the source housing shall be equipped with a shutter that cannot be opened unless a collimator or coupling has been connected to the port.
- Warning Lights - An easily visible warning light with the words “X‑RAY ON” shall be located near any switch that energizes an x‑ray tube and shall be illuminated only when the tube is energized.
Standard Operating Procedures - Standard operating procedures shall be written and available to all analytical x-ray equipment workers. Note that these procedures also need to address possible emergencies.
Bypassing Safety Devices - No individual shall bypass a safety device or interlock unless the individual has obtained the written approval of the Radiation Safety Officer (RSO).
Altering System Components - No operation involving the removal or alteration of shielding materials, tube housing, shutter, collimators, or beam stops shall be performed until it has been determined that the beam is off and will remain off until safe conditions have been restored.
Area Requirements- Postings
- Each area containing analytical x-ray equipment shall be conspicuously posted with a sign bearing the radiation symbol and the words “CAUTION ‑ X‑RAY EQUIPMENT.”
- Each area containing analytical x-ray equipment shall be conspicuously posted with the Iowa Department of Public Health (IDPH) “NOTICE TO EMPLOYEES” (PDF) sign.