A Controlled Machine Authorization (CMA) is required for any electronic device that emits ionizing radiation. In the health care setting, radiographic and fluoroscopic units are the most common examples. X‐ray diffraction units, cabinet x‐ray machines, and accelerators may be found in the university research setting.
The following instructions were developed for the projects that do not involve administration of ionizing radiation to humans. If you have a human use project, consult with Health Physics to determine the appropriate information to submit.
Application to obtain or fabricate a device
Before you acquire, fabricate, or modify a radiation producing device, submit the following information in a memorandum to Health Physics.
- Description of the device. Specify the type and manufacturer, energy load, and levels of radiation anticipated. Indicate typical energies, beam currents, work load in hours per week and a description of how the device will be used. Submit the manufacturer’s brochure and a copy of your purchase request. Provide information about interlock systems, warning devices, and installed monitoring systems.
- Procedures. Include a copy of operating and safety procedures. These procedures should be posted. Describe how the device is secured against unauthorized use.
- Sketch of the facility. Include shielding calculations and specifications, and beam directions. Specify occupants of adjacent areas, including areas above and below. If portable shielding is to be used, describe it. Health Physics will provide assistance with shielding calculations.
- Monitors. Indicate portable monitoring instruments that are available. Each project must provide necessary survey instruments. Indicate the type of personal monitoring devices, such as film badges or finger dosimeters that will be used. For XRDs, only finger rings are required.
- Training and experience. Provide a brief but explicit resume of the project director’s pertinent training and experience. For the PI and radiation safety contact, provide desk phone, fax, and e‐mail information. Note if minors will be in the lab. Each individual user must complete appropriate x‐ray device radiation protection training before using the device. Each individual user must also complete hands‐on training from a person experienced in the use of the x‐ray device. Anyone who performs or supervises x‐ray procedures on humans must hold a California Department of Public Health certification.
Conditional Approval
The review and approval process is as described earlier for CRAs. However, initiation of work is contingent on a pre‐use survey. Research involving human subjects must be approved by the CRSCo.
Pre‐use survey
Depending on the type of device, there will be radiation surveys and checks of warning lights and interlocks. The details of this inspection are specific to the device. After shielding, warning devices, and interlocks are shown to be in order, the final operating approval is issued. Proper posting and labeling are also confirmed during the pre‐use survey. A console warning statement, list of authorized users, standard operating procedures, and emergency procedures are required to be posted.
Cabinet x‐ray machines
Cabinet x‐ray machines are enclosed, self‐shielded, interlocked cabinets. The machine can only operate when the opening is securely closed. The exposure levels at every location on the exterior must meet the level specified for uncontrolled areas. Do not operate a machine if the interlocks appear to be malfunctioning. All operators must be trained in the proper operation of the device and be certified by Health Physics in radiation safety associated with the device. Personal dosimetry may be recommended for some operators.
Electron microscopes excepted
Due to their design and operating voltage, electron microscopes do not normally present a radiation hazard. Operators do not need personal dosimeters. Health Physics performs a radiation survey every two years, after alteration, repair or movement of the microscope, or when requested by the project director. Electron microscopes should not be modified in any way to increase the radiation output or reduce the shielding.
These devices are labeled “Caution—this equipment produces ionizing radiation when energized.”
Staff who prepare uranyl acetate (UA) solutions from the bulk vial must receive radiological training and be listed on a CRA before ordering or using radioactive materials. Staff who work from the dilute solution only are exempt from this requirement.
Medical and veterinary x‐ray machines
Medical radiographic units are used for internal imaging of patients and research subjects. Depending on the design, they are capable of making still radiographic or real time fluoroscopic images. In either case localized doses of more than 1 rem to a nearby operator and several rem in the beam are readily attainable. Therefore, training and experience and device safety criteria are stringent.
Registration required
All radiation‐producing machines at Stanford whether for research or clinical use must be registered with the State of California within thirty days after acquisition. Health Physics registers machines on behalf of the owner; the user’s department pays the associated registration fee. Contact Health Physics prior to ordering. The registration fee is billed after initial registration, and thereafter every two years. This fee is due as long as the machine is in the user’s possession, even if it is inactive or broken. Please notify Health Physics (3‐3201) if the machine is being sold, transferred or scrapped. We need to notify the state of the new user, or of its dismantling, otherwise the user’s department will continue to be billed for the registration fee.
