Radiation Producing Devices

Radiation-producing devices are regulated by Federal and State agencies. The Food and Drug Administration (FDA) regulates manufacturers of electronic systems capable of producing X-rays. The state of Wisconsin Department of Health Services regulates and licenses X-ray producing devices within the state. Wisconsin Administrative Code, Radiation Protection Chapter 157 describes regulations for radiation producing devices. The Office of Radiation Safety is the official liaison on behalf of the University of Wisconsin–Madison for all matters involving applications, approvals, registrations, and operation of radiation producing devices on campus.

Important:  Radiation producing devices that are used for healing arts (human-use) outside of standard of care (i.e., research purposes) must be reviewed and approved by one of the UW Institutional Review Boards and the Wisconsin Department of Health Services/X-ray Program Manager. More details can be reviewed in Appendix M of Chapter 157.

This X-ray safety manual describes the responsibilities and safe work practices for all individuals involved with the use of X-ray producing devices. At UW-Madison, X-ray producing devices are used for teaching and research purposes. Specific responsibilities for the equipment owner, user, and maintenance personnel are described throughout the manual.

This manual is not intended to be a fully comprehensive reference. Further advice concerning hazards associated with specific X-ray producing devices and/or the development of new and unfamiliar procedures should be obtained through consultation with the Office of Radiation Safety. Please review the tabs below for specific information pertaining to radiation producing devices.

Contact

Matt Labron
Health Physicist, UW-Madison
Matt.Labron@wisc.edu
Phone: 608-219-2657

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New Device Process and Registry Information

Notify the Office of Radiation Safety
If you plan to purchase or have recently received a new X-ray producing device, please contact the Office of Radiation Safety. The Office of Radiation Safety is required to inventory all X-ray producing devices at the UW. An X-ray producing device Certificate of Registration will be generated by the Office or Radiation Safety to the lab. Once generated, you will become an “X-ray Certificate Holder” for the devices you have been registered to.

Register with the Wisconsin Department of Health Services
All radiation-producing devices must also be registered with the Wisconsin Department of Health Services within 30 days of installation. The Office of Radiation Safety will assist with registering all devices used at the UW–Madison. When purchasing, replacing or repairing a radiation producing device, notify the Office of Radiation Safety so the necessary changes in registration can be accomplished.

Radiation Shielding Plans (if applicable)
Preliminary shielding calculations should be done before new X-ray specific room designs are approved. The Wisconsin Department of Health Services may require UW–Madison to submit a facility radiation shielding plan, drawn to scale, for approval prior to registering a radiation producing device. The devices that most commonly required these shieling calculations include CT and Micro CT scanners, Cyclotrons, Dual-Energy X-ray (DEXA) Scanners, Fluorescence Spectrometers (XRF), Fluoroscopy Devices (C-arm & mini C-arm), Linear Accelerators (Linac) and TomoTherapy® Devices.

Post Installation Inspection and Survey
The Office of Radiation Safety is required to inspect the X-ray producing device setup, in addition to the manufacturer’s installation records, before operation begins to assure radiation safety prior to using the device. A post installation survey must also be conducted following relocation, device modification, and other changes made to the device.

All necessary signage and regulatory postings will be supplied by the Office of Radiation Safety during or after the post installation survey. All safety devices must be installed and verified to be operational.

It is the responsibility of the X-ray user to promptly notify the Office of Radiation Safety of any changes that warrant an inspection such as repairs or modification to a device.

For registration purposes, covered device categories include but are not limited to:

  • Cabinet and Analytical X-ray Devices
  • CT and Micro CT scanners
  • Cyclotrons
  • Dental devices
  • Dual-Energy X-ray (DEXA) Scanners
  • Electron Microscopes
  • Fluorescence Spectrometers (XRF)
  • Fluoroscopy Devices (C-arm & mini C-arm)
  • Linear Accelerator (Linac)
  • TomoTherapy® Devices
  • X-ray Diffraction Devices or X-Ray Crystallography
  • X-ray Irradiators

More information on these devices can be found in the Description of Common Devices section below.

Modifications, Alteration, Repairs

In most instances, routine repairs by a qualified factory or vendor service representative does not require Office of Radiation Safety approval, however, you must obtain approval from the Office of Radiation Safety prior to modifying or altering radiation-generating devices in any manner that can affect:

  • Output
  • Inherent shielding
  • Interlock operation
  • Warning lights
  • Any factor that may implicate safety of:
    • Users
    • Patients
    • Research subjects

In some instances, such changes may require a re-survey of the radiation-generating device or new shielding plan approvals

Removal (Disposal) Information

Disposal of radiation producing devices needs to be completed through the Office of Radiation Safety. Devices must be permanently disabled (e.g., typically sever the power cord) and any X-ray tubes with toxic beryllium windows or lead components removed. Non-operational devices should be identified, repaired, transferred or disposed within a reasonable amount of time. Additionally, the X-ray Certificate Holder will be required to contact Campus Capital Equipment to obtain the proper clearance prior to disposing the devices.

Newer X-ray devices don’t contain hazardous materials except beryllium and lead. Generally, beryllium is contained within the X-ray tube and must be removed from the system and disposed of as chemical waste. This important information can be found within the X-ray tube’s manufacture’s manual. It is also commonly indicated on the tube itself. Before the disposal process, the X-ray user must remove the head, being careful not to break the X-ray tube. The tube is under vacuum and, if broken, could splinter and cause injuries and exposure to beryllium. Some X-ray systems have beryllium windows and a “poison” sign on the window unit that warns users that the window unit contains a toxic chemical and must be disposed of properly. If you need assistance, please contact the Office of Radiation Safety.

Older X-ray devices may contain hazardous materials including hazardous metals and toxic chemical called polychlorinated biphenyls or PCBs in the transformer oil if the X-ray devices were manufactured before July 1979. Before taking a device out of service you need to be aware of what’s in the device and what needs to be done to dispose of it properly. Contact the Office of Radiation Safety and for assistance. The Office or Radiation Safety and EH&S can help you to determine if your old device contains a hazardous waste regulated by the U.S. Environmental Protection Agency and assist you to properly dispose of it.

Basic Safety Guidelines

X-rays are a type of ionizing electromagnetic radiation similar to gamma radiation. They are distinguished based on their source: X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus.

With properly functioning instrumentation and by following the correct safety precautions, the risk of radiation exposure when working with X-ray producing devices is minimal. However, it is good to know the signs of an acute exposure to a localized area of the human body.

Be aware that these effects can be caused by contact with the beam for only a fraction of a second depending on what device you are using. Typical primary beam exposures are 100,000 to 400,000 rad per minute. The most common effect of large radiation exposure from an X-ray producing device is reddening of the skin (erythema). With a dose of a few hundred rem, the superficial layers of the skin are damaged, and the skin will redden in a fashion similar but more complex than a sunburn. The erythema effect will most often reverse itself within a few weeks.

It is also possible that doses at this level could damage cell division which could temporarily stop hair growth and possibly causes hair loss. Hair growth should return with lower doses.

There could also be damage to the sebaceous glands that produces the oil of the skin, which could cause a temporary decrease in the amount of oil produced.

There are other less common and less transitory responses. If a large area is exposure to a large amount of radiation, there could be changes in the skin pigmentation. This effect may not be reversible and could result in permanent skin changes.

If the exposure is large, the transitory damage to the skin, skin hair, or sebaceous glands could cause skin scarring or lead to radiation dermatitis, chronic radiation dermatitis, or radiation induced skin cancer.

Unintended X-ray radiation exposure

If you think you have experienced an unintended or inappropriate X-ray exposure, contact the Office of Radiation Safety immediately.

An incident interview will need to be conducted and an incident report will need to be generated with the Office of Radiation Safety to determine the estimated unintended exposure. Besides the description of incident, your name, date and location, type of device, and estimated exposure will all be requested during the interview. The Office of Radiation Safety will then complete a dose estimate and let you know if there are any further actions needed.

Good Safety Practices

  • Each laboratory should designate a primary responsible user for the X-ray producing device. This person will be responsible for the interlock bypass keys, performing the alignments, and manufacturer required maintenance on the X-ray producing device(s). This person will also coordinate calibrations, repairs, and modifications of the equipment with the company or manufacturer representative, when appropriate.

Radiation Protection Practices

  • Time – The shorter the time spent around an X-ray producing device, the lower the radiation dose. X-ray users should minimize their exposures to keep their occupational radiation dose As Low As Reasonably Achievable (ALARA).
  • Distance – Radiation levels decrease significantly with increase in distance from the source of radiation. The use of distance is one of the easiest and most effective methods for radiation protection. X-ray users should try to maintain the greatest distance from the X-ray source as possible when working with devices.
  • Shielding – Lead or concrete shielding can be used to reduce radiation levels when appropriate. Most devices have built-in shielding. Some will require additional shielding placed around the device or within the room.

To protect yourself from the radiation, consider the following potential sources of radiation exposure:

  • The primary beam.
  • Primary beam leakage
  • Beam penetration through stops and shutters
  • Secondary radiations from beam interaction of the primary beam with the sample or shielding

Radiation released from the diffraction of the beam

Emergency Procedures

Written emergency procedures pertaining to radiation safety shall be established for each X-ray producing device and be posted in a conspicuous location.

These procedures shall list the contact information of the X-Ray Certificate Holder for that device, and at a minimum, include the following actions to be taken in case of a known, or suspected accident involving radiation exposure:

  • How to notify the Office of Radiation Safety
  • How to arrange for medical a medical examination and when it is required.

Signage, Labels, & Postings

Entry to Laboratory
The following signage must be placed at the entrance of each X-ray device and easily visible to users as they enter the area:

  • Wisconsin Department of Health Services “Notice to Employees”
  • Wisconsin Department of Health Services X-ray Facility Registration Permit

Control Panel (if applicable)
The following signage must be placed near the control panel of each X-ray device and readily visible to the operator:

  • At least one sign conspicuously posted bearing the radiation symbol and the words “CAUTION RADIATION – THIS EQUIPMENT PRODUCES RADIATION WHEN ENERGIZED,” or words having a similar intent, near any switch that energizes an x-ray tube if the radiation source is an x-ray tube.

Radiation Producing Device (X-ray Equipment)

  • Label bearing the words “Caution Radiation This Equipment Produces Radiation When Energized” near the tube activation switch.
  • For Analytical or Cabinet X-ray producing devices a label bearing the words “Caution High-Intensity X-ray Beam,” next to each tube-head. The sign must be clearly visible to any person operating, aligning, or adjusting the device or handling or changing a sample.

Record Keeping and Audits

Records
Certain records are required to be maintained by all X-ray Certificate Holder’s and readily available for internal and/or external inspections. All records should be maintained in one central location in the lab. Applicable records needing to be maintained include:

  • Equipment manuals
  • Purchasing/Receipt/Installation records (Includes transfers or donations)
  • Standard Operating Procedures for each X-ray producing device.
  • Calibration, maintenance, and modification records.
  • Use logbook – to be filled out each time the device is used. The log shall include, at a minimum, the user’s name, date of use, and settings or description of use. This can be in a digital form, if desired.

Audits
Compliance with internal and external regulations is confirmed through inspections and audits carried out by the Office of Radiation Safety. You will be contacted by the Office of Radiation Safety when your areas audit is due. If items of non-compliance are observed, confirmation should be obtained that the deficient items are corrected immediately at the time of inspection, or for more complicated items through re-inspection.

Training

All X-ray users are required to complete the initial X-ray safety training. The initial training can be found here Radiation 106: X-ray Devices.

In addition to the online training, all X-ray users must be provided specific written instructions by the X-ray Certificate Holder before using the devices. These instructions include notice of radiation hazards; device specific safe work practices; proper operating procedure; symptoms of acute exposure; procedure for reporting an emergency situation.

Dosimetry (Individual Radiation Monitoring Requirements)

Dosimetry is issued if it is believed that greater than 10% of annual dose limits will be received. The Office of Radiation Safety will do an assessment to determine if X-ray users will need to be issued dosimetry or not. This is completed by considering the type of device, completing an exposure survey, and reviewing the experimental protocols.

Changes made to the room configuration, such as relocation of x-ray devices or replacement of one type of device with another (e.g., panorex vs. intra-oral), may require a new radiation survey or the use of dosimeters to ensure that adequate operating procedures are in place.

More information can be found on our Dosimetry page.

Pregnancy Surveillance Program

For questions on the form or additional information, contact the Pregnancy Surveillance Program Coordinator.

Descriptions of Common X-Ray Devices at UW-Madison

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Cabinet and Analytical X-ray Devices

A cabinet X-ray system is an x-ray producing system installed within an enclosure. These devices are used in research to determine heterogeneities in the structure of a sample. The box-like design includes a shielded interior cabinet, which houses the X-ray tube, the beam collimator, and the detector. The doors provide shielded access. The shielded control panels include a key switch that enables the X-ray tube and an ON/OFF switch for X-ray generation. In addition, the devices are equipped with ‘power on/off’ warning lights and safety interlocks on the door and exterior panels. In order to penetrate dense samples, intense high energy X-rays are required, therefore, thicker lead shielding is often required to avoid radiation leakage. Exposure to the direct beam can cause severe injury. To prevent exposures, newer instruments are designed with hood enclosures, interlocks, and beam shielding to minimize the risk of inadvertent exposures.

Analytical X-ray producing devices usually have a low energy that can be readily shielded with about one millimeter (1 mm) of lead. Depending on the intensity of the primary beam, leakage and scatter may create a significant source of unwanted radiation. Use shutters and collimators, secure unused ports, reduce the beam cross-section by collimation, and whenever appropriate enclose the entire beam path or use a sufficient beam stop.

X-ray Irradiators

X-ray irradiators are similar to cabinet x-ray devices in that the device is designed as an enclosed unit. The difference is that X-ray irradiation devices often require higher energy X-rays and therefore require more shielding, typically in the form of a thick lead enclosure.

Electron Microscopes

These are a common device used on campus. With these devices, X-rays are produced in the electron microscope whenever the primary electron beam or back scattered electrons strike metal parts with sufficient energy to excite continuous and/or characteristic X-ray radiation. In terms of X-ray hazards, two aspects are important: the composition of the parts which are struck and their efficiency as X-ray sources and the effectiveness/integrity of the shielding provided by the metal casing of the microscope around these.

The shielding provided for these devices are usually adequate to ensure that radiation exposure to personnel is kept to a minimum. These devices are typically categorized as minimal threat devices, however, are still required to be registered with the Wisconsin Department of Health Services. They must have an exposure rate below the 2.5 mrem per hour from 5 centimeter on surfaces. X-ray users must notify the Office of Radiation Safety of each newly acquired devices that can generate X-rays. If a user has or receives an older device, they need to contact the Office of Radiation Safety who will schedule a radiation survey of the machine. Some older devices have been reported to leak above below the 2.5 mrem per hour from 5 centimeter on surfaces limits.

X-ray Diffraction Devices or X-Ray Crystallography

X-ray Diffraction devices or X-ray crystallography is a technique used for determining the crystal and molecular structure of material. The crystalline structure causes an X-ray beam to diffract at specific angles. The analysis of the intensities and the angles of the diffracted beams allow the prediction of a three-dimensional image of the electron density within the crystal. Upon analysis, the structure and identity of the material will be passing X-rays through a gasket manufactured of a specific material (e.g., beryllium), which is transparent to X-rays, and allows it to make specific diffraction patterns.

Please note that Beryllium is a well-suited gasket material as it is the lightest air stable metal.  Beryllium helps to generate a strong vacuum seal but is extremely toxic and is required to be disposed of properly.

In most cases, the device design protects the operator from receiving a dose from radiation scattered off the sample and other components in the beam line. Shielding is incorporated specifically to maintain leakage and keep secondary/primary radiation exposure below 2.5 mrem in one hour at 5 centimeters from the surface.

Other design features that protect the operator from radiation exposure are transparent, acrylic enclosures around the diffraction equipment. Sliding doors are part of the enclosure and are interlocked with the X-ray tube power supply to prevent accidental access to high radiation areas. If the sliding doors are opened while the X-ray tube is energized or the shutter is open, a magnetic switch on the door is activated which automatically turns off the X-ray tube.

Dual-Energy X-ray (DEXA) Scanners

These devices are a widely used for assessing bone mineral density. With these devices, two energies of X-rays are created by continuous switching of high & low voltage or by use of filters. The low energy X-ray beam is absorbed by soft tissue while the high energy X-ray beam is absorbed by the bone tissue. Bone absorption depends on the thickness of the bone and mineral content. Computer software allows for subtraction of and calculates the calcium content. DEXA scanners make use of rather small doses of ionizing radiation to produce images of, for example, a patient’s lower lumbar spine or hips to diagnose osteoporosis or osteoporotic fractures. No radiation remains in the patient’s body after an X-ray examination. Special care is taken during the X-ray examination to use the lowest radiation dose possible while producing the best images for evaluation. The X-ray system has very controlled X-ray beam and dose control measures in place in order to minimize stray (scatter) radiation.

Fluorescence Spectrometers (XRF)

These devices are used to determine the elemental analysis of material. X-ray fluorescence emits characteristic ‘secondary’ (or fluorescent) X-rays from a material that have been excited by being bombarded with high energy X-rays or gamma rays. When materials are exposed to short wavelength X-rays, elements are able to produce a characteristic fluorescence spectrum.

While XRD equipment requires low and specific energy X-rays, XRF spectrometers utilize poly-energetic X-rays and allow a simple design to eliminate X-rays of certain energies, which are not needed. The disadvantage is that any scatter or leakage radiation consists of higher and more penetrating energy X-rays. XRF spectrometers use an open port with a collimated primary beam, filter and internal detector to register generated X-rays. They are equipped with lead shielding and a closed design to reduce the hazard from the high energy X-rays. The closed design eliminates the need to gain access to the X-ray beam, which makes the instrumentation safer than XRD equipment, where the access to the beam is possible.

Hand-held XRF

A special hazard exists for the hand-held XRF devices as they house an open port from the collimated, high intensity primary beam.

Linac

Linac is short for linear accelerator. It uses electricity to generate high energy beams of X-rays or electrons. These beams have a variety of uses, both in research and for treating cancer. X-ray users must only work in the room at the control panel near the accelerator, where only background levels of radiation exposure are measured. Follow up radiation protection surveys will be performed and documented when changes are made in shielding, operation, equipment, or occupancy of adjacent areas.

No one shall be permitted to operate the accelerator unless such person has received instruction in and demonstrated competence with:

  • The operating and safety procedures for the accelerator.
  • Radiation warning and safety devices incorporated into the equipment and the room.
  • Identification of radiation safety hazards associated with the use of the equipment.
  • Procedures for reporting an actual or suspected exposure in excess of the limits.

In addition, the X-ray Certificate Holder must provide all X-ray users with specific training in the use of the accelerator and associated radiation hazards.

Cyclotron

A cyclotron is a particle accelerator similar to a Linac. As the name suggests, a cyclotron accelerates charged particles in a spiral path, which allows for a much longer acceleration path than a linear accelerator. In addition to the radioactive material the cyclotron creates, it can also produce X-rays in the form of synchrotron radiation. To protect against these hazards, safety precautions such as concrete room or vault for shielding and operating the device from only the control room are required.

 

Fluoroscopy Devices (C-arm & mini C-arm)

Fluoroscopy is a type of medical imaging that shows a continuous X-ray image on a monitor, much like an X-ray movie. During a fluoroscopy procedure, an X-ray beam is passed through the body. The image is transmitted to a monitor so the movement of a body part or of an instrument or contrast agent (“X-ray dye”) through the body can be seen in detail. Fluoroscopy can result in relatively high radiation doses, especially for complex interventional procedures (such as placing stents or other devices inside the body) which can sometimes require long exposure times. Radiation-related risks associated with fluoroscopy include radiation-induced injuries to the skin and underlying tissues (“burns”), which occur shortly after the exposure, and radiation-induced cancers, which may occur sometime later in life. To minimize the radiation risk, fluoroscopy should always be performed with the lowest acceptable exposure for the shortest time necessary.

Mini C-arms emit about 1/10th the dose rate as compared to a regular C-arm, however, good radiation safety practices must still be followed to keep staff and patient exposure As Low as Reasonably Achievable (ALARA).

  • Leaded aprons should be worn by all personnel located within 6 feet of the Mini C-arm during operation.

Mini C-arms should be limited to extremity use only. They are not designed to examine thick structures.

TomoTherapy®

TomoTherapy® is an advanced treatment for cancer that uses radiation to destroy or shrink tumors. It combines the precision of intensity-modulated radiation therapy (IMRT) with the real-time accuracy of CT scanning (also known as image-guided radiation therapy, or IGRT). It is often used to treat cancers of the prostate, breast, lung, brain and other structures in the head or neck. In addition, it can treat multiple tumors at one time. Similar to other high energy producing devices, to protect against these hazards’ safety precautions such as large concrete vaults for shielding and operating the device only from the control room are required.

Dental devices

X-rays are an indispensable diagnostic aid in dentistry as they allow the detection of disease and other abnormalities, as well as disease progression to be monitored. However, exposure to ionizing radiation also carries the risk of harm. Dental personnel during patient exposure may not do any of the following:

  • Hold the patient
  • Hold the image receptor (i.e., film, phosphor plate (PSP), CCD, or CMOS) inside the patient’s mouth
  • Hold X-ray tube housing, unless a valid exemption is in place and on file at the dental facility
  • Hold the aiming cylinder (also known as PID or pointer cone)
  • Stand in the path of the useful X-ray beam
  • Stand closer than six feet from the patient being radiographed

Dental personnel must not expose any individual to the useful beam for training or demonstration purposes without a valid X-ray prescription from a licensed dentist or a medical doctor stating a diagnostic need for the exposure.

CT and Micro PET/CT scanners

Like other X-ray imaging exams, CT scans expose a sample to a small, targeted amount of ionizing radiation. The radiation helps create an image of structures inside the sample. CT scans provide more-detailed images of more types of tissue than traditional X-rays do, which allows you to detect and locate many medical conditions.

MicroCT uses X-ray imaging and computed tomography to produce 3D images of very high resolution, with voxel sizes down to 1µm or smaller. MicroCT, which utilizes differences in X-ray attenuation properties of materials to reconstruct 3D structure, differs from conventional CT by combining a much smaller field-of-view with a high-resolution detector. MicroCT is used to study diverse materials including bone, teeth, medical implants, snow, textiles, concrete and precious stones. MicroCT reveals in great detail the internal structure of these materials, such as the trabecular architecture within bone or grain within wood, allowing quantitative analysis of properties such as density and strength.

X-ray Producing Device Use in Veterinary Medicine

No radiation may be deliberately applied to animals in a research setting except when used under an approved Institutional Animal Care and Use Committee (IACUC) protocol.  More details on IACUC review process, requirements and approval can be found here.

Protective devices including aprons, gloves, and shields shall be inspected annually for defects, such as holes, cracks, and tears. If a defect is found, protective devices must be replaced or removed from service until repaired. The X-ray Certificate Holder must inspect protective devices periodically for their safety.

No individual other than the animal and operator shall be in the X-ray room or area while being X-rayed unless the operator needs assistance. When an animal or image receptor must be held in position during exposure, a mechanical supporting or restraining devices should be used, when possible. If an animal or image receptor must be held by an individual during an exposure, The Office of Radiation Safety can be consulted for advice, if needed. If it is appropriate, the individual’s dose may be monitored, and a dose record will be maintained. No one is allowed to hold the X-ray tube or tube housing assembly supports during any exposure.