The Nuclear Energy Act - Radiography

The Nuclear Energy Act - Radiography
Working with ionizing radiation is legally bound in the Netherlands by rules laid down in the Nuclear Energy Act (KEW). A KEW file must be present in every dental practice, in which the equipment and use are documented.

The Nuclear Energy Act


Working with ionizing radiation is legally bound in the Netherlands by rules laid down in the Nuclear Energy Act (NEA). A NEA file must be present in every dental practice, in which the equipment and use are documented. It is also recorded who uses the equipment and whether regular training is followed. The following is an overview of the points with which the operator or user of an X-ray machine must be familiar.


According to the Nuclear Energy Act, an X-ray device in a dental practice is a device that can emit ionizing radiation. The use of the device is subject to certain rules. For example, there is a reporting or licensing obligation for each type of X-ray device, which means that the Netherlands Enterprise Agency must be notified of the placement of each new X-ray device. The law distinguishes between the user and the operator of the X-ray machine. The user is the person who actually uses the X-ray device or has it used (eg a school dental care service). In a general practice, the dentist (owner) is the user, but he is not always the only person who works with the X-ray machine. Dental personnel also operate the device and operate by law.


Requirements for the user (dentist)

The law requires the user to be an expert in the field of:

  • The nature of the radiation that is generated in the device in question;
  • The dangers of that radiation;
  • The way in which the environment can be protected against these hazards.


Obligations of the user

  • Working with the X-ray machine must be done under his guidance and supervision. This means that the assistant may take X-rays, but only on the instructions of the dentist and if the dentist is physically present in the practice.
  • The device must be properly maintained.
  • The X-ray device with all auxiliary and safety equipment and the design of the room in which it is installed must be designed in such a way that physical damage caused by X-rays is prevented as much as possible.
  • Persons other than the person under investigation must be protected against radiation as much as possible. For example, the arrangement must be chosen such that no one except the patient is exposed to the primary bundle.


Requirements for the operator (assistant)

  • The operator must have the same expertise as the user, unless work is carried out under the direct supervision of the user or his deputy. The operator must have sufficient insight into the dangers of working with X-rays.
  • The operator is obliged to follow the written instructions of the user.


Both the user (dentist) and the operator (assistant) are required to follow in-service training every three years. The X-ray equipment must be checked annually.



Requirements for X-ray equipment in dental practice

  • The device must be equipped with a sufficient radiation-absorbing jacket.
  • The device must be well maintained.
  • The emerging beam must be sufficiently filtered. For devices with a tube voltage of no more than 70 kV, a filter must be installed corresponding to at least 1.5 mm aluminum; with a higher kilovoltage, the filter must be at least 2 or 2.5 mm aluminum.
  • A device with a round aperture has a rectangular radiation field at the end of the cone.


Maximum permitted doses

In law, the amount of radiation that may come on a body or part of it per year is expressed in Sievert or brake (100 Sv = 1 brake). The maximum permitted legal dose is specified for each group:

  • Persons outside the parcel where the X-ray machine is used (eg neighbors or passers-by): <0.1 mSv per year;
  • Persons present in practice who do not perform work on or with the device: <? 1 mSv per year
  • Employees who perform work with or at the X-ray machine: 20 mSv per year;
  • Pregnant women: as low as possible, maximum 1 mSv during the entire pregnancy.


No limit is specified for patients, but the dose should be as low as possible, that is, no unnecessary X-ray photography.


Fortunately, the radiation dose in dental practice when making an X-ray is not large. A bitewing gives a radiation load of 4 µSv (0.004 mSv). For comparison: during a flight to Ibiza for example you incur 10 µSv. A panorama shot (OPT) gives a radiation risk of 16-20 µSv. With a cone beam CT scan, the radiation load of the patient is much higher, namely 100-250 µSv. The operator of the X-ray equipment is never in the radiation beam. The radiation limit is therefore not reached if the instructions are followed correctly.