Radiation safety

In case of questions regarding radiation safety, guidance, or planning, or working in laboratories during pregnancy, do not refrain from contacting either of the Radiation Safety Officers (RSOs):

• Heine Dølrath Thomsen (Radiation Generators)
• Hans Fynbo (Radioactive Sources)

Sources of ionizing radiation are a common and essential tool in research and teaching at IFA. Radiation sources include both 

• Radiation generators: e.g. compact X-ray machines, particle accelerators.
• Radioactive materials (sources): sealed or unsealed sources used in laboratories. 

NB: radiation generators are typically also associated with other hazards, e.g. electrical and mechanical hazards, which are not within the scope of the following description

Radiation Workers (researchers, technicians, students) must 

• Follow approved procedures and wear protective equipment accordingly
• Report any incidents, unsafe conditions or need for additional instructions to the lab manager and/or RSO.

Not interfere with safety systems, e.g. bypass or modify radiation safety measures (including radiation shielding) or procedures.

While the sources of ionizing radiation provide significant benefits, they must be handled with strict attention to safety. 

• IFA is committed to ensuring that ionizing radiation dose rates and exposures are kept as low as reasonably achievable (ALARA), in compliance with national regulations and international best practices.
• The department’s Radiation Safety Committee refers directly to Sundhedsstyrelsen, Strålebeskyttelse (SIS) which constitutes the Danish authority that oversees radiation generators and exposure. SIS conducts an annual inspection at the department, including surveys of a selection of labs.

Radiation protection is built on three core principles:

• Justification: Any use of radiation must provide an essential and net benefit that outweighs the downsides and risks.
• Optimization: Exposures must be kept ALARA, balancing risk (product of frequency of event and impact of hazardous outcome) with benefits.
• Dose limitation: No individual shall exceed legal dose limits.

For university personnel, students, and visitors, these principles are applied through training, monitoring, engineered controls, procedures, and personal protective measures. The principles can be adhered to through the following approaches to mitigate the risk:

• Whenever possible, DISTANCE yourself appropriately from the sources of radiation. Doubling the distance, quarters the exposure rate.
• Plan procedures ahead to minimize the TIME of exposure. Perform a training / trial run with the actual intended procedures to minimize the exposure time. Prepare all necessary tools and equipment.

Use appropriate amount and type of SHIELDING to adhere to the ALARA principle. Apart from containing the source of radiation (breaking line of sight), the shielding can be used to establish a safe position, where the operator can prepare the following steps. The operator can also utilize shielding to protect more vital organs, e.g. the torso, while only exposing the limbs during the procedure. 

Types of Generators

The department possesses a wide suite of radiation generators for research, analysis and teaching. Almost all are classified as self-contained, i.e. only insignificant exposure should be possible during nominal generator application by a trained operator.

• X-ray (Bremsstrahlung) generators: used in laboratories and teaching labs for diagnostic and analytical material studies. Generates Bremsstrahlung photons up to the equivalent of the accelerating voltage.
• Particle accelerators: electron and ion accelerators for various applications.

NB: machines with >5 kV accelerating voltage are classified as a device that legally requires registration and annual inspection from SIS.

Hazards

Radiation generators produce ionizing radiation (X-rays, gamma rays, or particle beams). The related hazards include:

• External exposure to skin and whole body.
• Secondary radiation (neutrons, scattered particles).

Safety Measures

Safety measures, ideally multiple combined in series, must be taken to reduce the frequency or impact of exposure:

• Shielding: Concrete, lead, or more specialized barriers enclosing the source, breaking line of sight, or at least introducing a minimum distance to it.
• Interlocks: Access doors / hatches that are linked to – ideally multiple – active elements that are essential to beam operation. Such designs should be designed to fail gracefully and passively hinder radiation generator operation, unless said interlock system is operating nominally and all inputs are valid.
• Status and warning indication: Lights and sirens with signage unambiguously indicating in which state the radiation generation is on.
• Training of operators: Only authorized, trained users may operate radiation generators. Only expert users (the lab manager or a delegate) with an intricate knowledge of the machine are to train new users.
• Monitoring: Area radiation monitors and personal dosimeters (typically passive) can be applied, depending on the radiation generator type and intensity.
• Administrative controls: Written procedures, logbooks, access restrictions.

Immediately notify the system responsible and / or RSO, if a radiation generator appears faulty with respect to safety measures.

Types of Sources

• Sealed sources: Encapsulated materials (e.g. calibration sources, check sources).
• Unsealed sources: Liquids, powders, or gases used in tracer studies, biological labeling, and radiochemistry.

The latter group is not common at the department and should be treated with great care, due to the higher risk of containment failures.

Hazards

• External exposure from gamma or high-energy beta emitters.
• Internal contamination via inhalation, ingestion, skin absorption, or wounds.
• Environmental contamination from spills or leaks.

Safety Measures

• Storage: Locked, shielded containers; secured inventory control. Clear labelling on containers and sources.
• Handling: Use of tongs, fume hoods, gloveboxes, shielding.
• Contamination Control: Bench protection, absorbent pads, regular wipe tests.
• Personal Protection: Lab coats, gloves, eye protection, dosimeters. Never handle sources while having unprotected cuts or breaks in the skin, particularly on the hands or forearms. Never use any mouth-operated equipment in an area, where unsealed radioactive material is used.
• Waste Management: Decay-in-storage, segregation by isotope and half-life, labeling, and disposal in compliance with regulations.
• Emergency Procedures: Spill response, contamination surveys, reporting protocols.

• Initial Training: All workers must receive instructions on radiation safety basics, hazards, safe work practices, and emergency procedures.
• Dosimetry: Personal badges (TLD, OSL, or electronic dosimeters) provided to workers at risk of exposure.
• Surveys: Routine area monitoring with Geiger-Müller counters, ion chambers, or liquid scintillation counters.
• Audits: Regular inspections of labs and records by the RSO.

Radiation Generators

• Shut down equipment immediately; through emergency stop, putting containment shielding in place, or exploiting an interlock.
• Evacuate the area if shielding or interlocks should fail to cease operation.
• Immediately notify the RSO and system responsible.

Radioactive Sources

• For spills: Stop work, alert others, contain spread, and call RSO.
• For personal contamination: Remove clothing, wash skin, and monitor. Call RSO.
• For lost or stolen sources: Secure the area and immediately notify the RSO, who will inform the authorities.

Proper use of a personal dosimeter

• Place the dosimeter in chest height, or where the highest exposure is expected.
• Leave the dosimeter at IFA outside of working hours, but not near radiation sources. A good place, for example, is in an office. The dosimeter must not be removed from IFA without agreement with an RSO.
• Return and exchange the dosimeter film when instructed to do so. The red carrier is not to be exchanged.
• Please inform an RSO if there has been an incident that is likely to have caused an elevated dose to the dosimeter or / and the bearer.

What to avoid

• Do not tear the wrapping of the dosimeter film. If torn upon receipt, contact the radiation safety officer as soon as possible.
• Do not share dosimeters: a dosimeter is considered personal and additional units and bearers can be registered instead.
• Do not leave the dosimeter near a radiation source, e.g. overnight.
• Do not take a dosimeter to other (external) radiation sources: medical/dental examinations, air travel baggage scans, other research institutions, etc.
• Do not use a dosimeter to estimate dose rates from e.g. radioactive sources. The radiation safety officer can provide equipment for doing so.

The personal dosimeter is intended to monitor the accumulated dose received while working at IFA. Generally, a dosimeter is issued, if the bearer is to work near a specific radiation source, and the dosimeter should thus (only) be worn while being in the vicinity of this.

The dosimetry monitoring program at IFA aids to confirm a safe working environment in terms of radiation. Elevated doses, also those caused by improper use, may thus launch an investigation and require a statement to SIS.

Additional information (in Danish only): Spørgsmål og svar om persondosimetri