Procedure for working with X-ray equipment

Procedure for working with X-ray equipment

Purpose

The purpose of this procedure is to ensure the correct use of X-ray equipment, and to ensure that radiation protection work at NTNU complies with regulatory requirements and safeguards the safety of employees, students, and others at NTNU.

Scope and anchoring

The procedure applies to all units, employees, and students at units that use radiation sources belonging to NTNU. The procedure is a measure to reduce the risk associated with working with X-ray equipment.

Guideline for radiation protection and use of radiation sources is governing for this procedure.

Definitions

X-rays

X-rays are electromagnetic waves (radiation) with high energy that can penetrate various materials. The radiation ceases immediately when the power to the X-ray device is turned off.

X-ray equipment with open beam path

X-ray equipment with a beam path exposed to air. In case of an accident, one may be exposed to X-ray radiation.

X-ray equipment with enclosed beam path

The beam path is built into the instrument. The maximum permitted radiation outside the instrument is 5 µSv/h. The shielding must have a safety switch so that the source is automatically turned off if parts of the instrument are opened.

Controlled area

The unit must classify the workplace as a controlled area if employees may be exposed to radiation doses greater than 6 mSv/year,  if the dose to the hands may exceed 150 mSv/year or if the dose to the eye lens may exceed 15mSv/year. Controlled areas must be physically separated or clearly marked in another way if physical separation is not possible.

Supervised area

The unit must classify the workplace as a supervised area if employees may be exposed to radiation doses exceeding 1 mSv/year, or if the dose to the hands may exceed 50 mSv/year.

Responsibilities

Line Manager

The line manager has overall responsibility for ensuring proper radiation protection within the unit and shall carry out the tasks described in the Guideline for radiation protection and use of radiation sources.

The line manager shall ensure that there are designated persons with scientific responsibility and, if applicable, instrument custodians for the unit’s X-ray equipment—or assume this role personally if necessary.

Procedure for Working with X-ray Equipment

Local radiation protection coordinator

The local radiation protection coordinator shall, at a minimum, carry out the tasks described in the Guideline for radiation protection and use of radiation sources.

The local radiation protection coordinator shall also ensure that a backup copy of the form/list of authorized users and documentation of the past year’s activity with the X-ray equipment is stored at the end of the year. The backup copy must be stored at the unit for 10 years.

Academic Supervisor

The academic supervisor for X-ray equipment shall, at a minimum, carry out the tasks described in the Guideline for radiation protection and use of radiation sources.

In addition, the academic supervisor shall ensure the following when using X-ray equipment:

Before the unit procures X-ray equipment:

  • Assess whether it is appropriate to appoint a dedicated person as instrument custodian. If the academic supervisor does not appoint such a person when planning to acquire new X-ray equipment, they are themselves responsible for the tasks listed under the Instrument custodian section.
  • Inform the local radiation protection coordinator. The coordinator must be notified of all acquisitions, relocations, and disposals of X-ray equipment.

Before installation and use of X-ray equipment:

  • Conduct a risk assessment as described in the Guideline for Radiation Protection and Use of Radiation Sources.
  • Ensure that all X-ray devices are adequately labeled and signposted, and equipped with key/code locks, warning lights, and similar safety measures.
  • Inform external personnel in the workplace (e.g., cleaning staff, maintenance workers, others) about the key properties and hazards of the X-ray device, cleaning routines, the significance of warning signs and lights, contact information, etc.
  • Implement and document technical measures that prevent exposure to ionizing radiation beyond the dose limits. For example, open beam paths should be shielded as much as possible using plexiglass, lead screens, lead curtains, or equivalent protection.
  • Secure X-ray equipment and sources against theft, sabotage, fire, and water damage.

During use of X-ray equipment, ensure that:

  • Regular control measurements are carried out.
  • The need for personal dosimeters is assessed in cooperation with the local radiation protection coordinator.
  • Time spent near the radiation source is minimized.
  • The competence of users is evaluated to determine whether they are qualified to act as authorized users of the relevant radiation sources. This shall be documented in a dedicated form/list stored in the X-ray device’s logbook. At year-end: send a copy of the form/list and documentation of the past year’s activity involving X-ray equipment with open beam path to the local radiation protection coordinator.
  • Ensure that all persons present during experiments/demonstrations understand the hazards associated with the X-ray equipment and act accordingly. For demonstrations involving special groups, such as children, the enforcement of safety measures is particularly important. If possible, demonstrations for such groups should be carried out with the X-ray equipment turned off.

 

Instrument custodian

The instrument custodian for X-ray equipment shall, at a minimum, carry out the tasks described in the Guideline for radiation protection and use of radiation sources.

The instrument custodian is responsible for the equipment, radiation protection, and user training related to the relevant X-ray sources. By agreement with the instrument custodian, an operator/technical personnel may provide user training, operate the X-ray equipment, and organize maintenance. In collaboration with the instrument custodian, individuals who are not authorized users may carry out measurements using the X-ray equipment.

Authorized User


Authorized users must have sufficient competence to independently assess and operate the X-ray equipment safely. Sufficient competence includes: instrument-specific knowledge of start-up procedures, instrument settings, safety mechanisms, shutdown procedures, any emergency procedures, contents of the information binder, relevant radiation measurements, and more.

Documentation

Information Binder

Each X-ray device shall have an information binder containing at least the following information:

Data about the equipment, such as:

  • Manufacturer, model, age, owner, serial number
  • Current [mA], maximum peak voltage [kV]
  • Regulatory labeling
  • Adjustment range (maximum, minimum) for output power/energy

General information

Instructions for Users

  • Operating instructions for practical use, safety precautions, logging, locking, use of radiation monitors, etc.

Emergency Procedures

  • Procedures for emergency situations (fire, water leaks, radiation injuries, others)
  • Procedures should describe how to properly shut down the device, ensure no radiation when the equipment is turned off, actions to take in case of radiation injury, contact information, reporting
  • Use pictures/figures in the emergency procedures if possible
  • Refer to emergency procedures as needed: locally, and/or distributed to others (e.g., janitorial staff and cleaning personnel)
  • See also central and local emergency plans, DFU10 Accident and incident with radiation sources.
  • Procedure for preparedness and action in case of accidents or incidents involving radiation sources
  • Consider whether emergency procedures should  be provided in both English and Norwegian

Logbook

Each X-ray device shall have a logbook containing:

  • Names of all users, dates, type of work, and duration of work. This includes a list of authorized users and the periods during which they have been authorized.
  • Service work and significant changes to instrument setup.
  • Performed radiation measurements.

 

Safety and Technical Requirements

Labeling and Signage

Install standard warning signs with the ionizing radiation symbol on all doors leading to rooms containing X-ray equipment or areas with X-ray devices. Also display room cards. If the workplace is classified as a controlled area or supervised area, this must be indicated on the door or at the entrance to the area with the X-ray equipment. An explanation of what these terms mean should also be provided.

The radiation-emitting source on all types of X-ray equipment must be labeled with the standard warning sign bearing the ionizing radiation symbol. The labeling shall be in Norwegian. The same information should be provided in other languages if necessary.

Key or Electronic Lock on X-ray Equipment

It can not be possible to start the X-ray equipment without a key or code. For equipment with a key function: remove the key and keep it inaccessible to unauthorized persons when the equipment is not in use. Electronic locks requiring a username and password for startup may also be used.

Access to Laboratories

Access to rooms with X-ray sources should be restricted as much as possible. These rooms shall only be accessible to those with a legitimate need for entry. Keep doors locked when no one is present.

Instrument Security

Some X-ray devices have the radiation source continuously on. This is due to the long startup time of the equipment and to extend the lifetime of the radiation source. At NTNU, this applies to certain X-ray diffractometers. Access restriction — as mentioned in the previous paragraph — will be sufficient security. X-ray equipment with continuously active radiation sources shall be equipped with a system that shuts off the equipment if the user accidentally touches the instrument and/or turns off the cooling system.

Control Measurements

Measure the radiation dose to the surrounding environment (excluding the direct beam) routinely at least once a year, after service, and after significant changes to the instrument setup. Record the results in the instrument’s logbook.

Use radiation monitors adapted to the characteristics of the radiation. Contact the local or central radiation protection coordinator to perform such measurements.

Dosimetry

According to the Radiation protection regulations section 33, it is required that all occupationally exposed persons in category A and occupationally exposed persons in category B who may receive an effective dose exceeding 1 mSv/year must have their individual radiation exposure determined. The determination of radiation exposure can be done through individual measurements using personal dosimeters or based on individual dose calculations.

Workers who use X-ray equipment may be required to wear personal dosimeters. Students performing practical work in their studies (for example, in laboratories or internships in a workplace) are considered workers (more about this here) and must therefore also wear personal dosimeters in situations where it is necessary. NTNU provides personal dosimeters to students going out on internships.

Dosimeters are not necessary if:

  • The effective radiation dose for a person is estimated to be less than 1 mSv/year, based on dose rate measurements, actual usage patterns, and with no significant risk of exposure near the direct beam.
  • There are annual control measurements for leakage radiation, after various types of service work, and after any significant changes to instrument setup.

Each individual user of X-ray equipment shall perform a risk assessment of their work with the X-ray equipment. This includes evaluating the need for wearing a radiation dosimeter. The local radiation protection coordinator typically manages the dosimeter service.

Results from dosimeter measurements are collected in the National cccupational dose register maintained by the Norwegian Radiation and Nuclear Safety Authority. NTNU’s dosimetry service providers enter the data into the register. Employees/students who have worked with dosimeters and NTNU’s radiation protection coordinators can log into the register via ID-porten. The purpose of the register is to provide a comprehensive overview of doses from ionizing radiation to workers in Norway, regardless of whether a worker has had multiple employers.

If doses are estimated, the results must be provided in writing to the user and to the central radiation protection coordinator. The information must be provided at least annually (in connection with the annual reporting) and may be sent electronically. Note: This is personal information and must be handled in accordance with section 13 of the Freedom of Information Act. The central radiation protection coordinator ensures that the results are also registered in the users’ medical records with the occupational health service. Because of this, the names and social security numbers of users must be reported together with the dose estimates.

Exposure index

Work involving ionizing radiation may require an exposure register. Visit the dedicated page Exposure index to see what actions are required. The register itself can be found via the chemical database: Log in to the chemical database, click "Eksponeringer" in the left menu.