Nuclear Substances and Radiation Devices

Nuclear substances and radiation devices have proven immensely valuable in many applications in medical, research and industrial fields.

The Nuclear Safety and Control Act gives the Canadian Nuclear Safety Commission (CNSC) authority to regulate such uses to protect the health and safety of Canadians and the environment, and to safeguard against the loss of nuclear materials.

CNSC oversight for each activity is based on the risks posed by the activity.

Licensed activities representing high and medium risk categories are subject to a higher degree of regulatory control, including more frequent and in-depth inspection and other activities to verify compliance with CNSC regulations and licence conditions.

Medical Uses of Nuclear Substances and Radiation Devices

Nuclear medicine uses radioactive substances (radioisotopes) incorporated into pharmaceuticals.

These “radio-pharmaceuticals” or “radio-tracers” are designed to target specific tissues and organs, allowing the delivery of the radioactive substance to specific areas of the body. Radiopharmaceuticals are widely used in the diagnosis, management and treatment of disease.

In diagnostic nuclear medicine imaging, the radiation emitted by the radiopharmaceutical (ingested, inhaled, or injected into the patient) is measured by an external detector, such as a gamma camera or a Positron Emission Tomography (PET) scanner.

The data is then processed by a computer to generate images. In therapeutic nuclear medicine, high doses of radiopharmaceuticals are administered to treat diseases such as cancer.

The radioisotopes used for PET imaging are produced in cyclotrons. Cyclotrons are also subject to CNSC regulations and are always located in a shielded facility to protect workers from radiation.

Radiation therapy is an important method for treating cancer. Dose delivery in radiation therapy is done in one of two ways: teletherapy or brachytherapy.

Teletherapy involves delivery of high doses of radiation to the tumour using intense external beams of radiation. This can be delivered by medical linear accelerators (linacs) or specially-designed teletherapy machines containing sealed radioactive sources, both of which are located in specially-designed and well shielded facilities.

Brachytherapy involves the placement of sealed radioactive sources within the body to deliver a controlled radiation dose to the tumour. Brachytherapy treatment can be delivered manually or by a machine under remote control. The latter type of treatment typically takes place in a shielded facility.

Academic and Industrial Applications

Nuclear substances and radiation devices are also widely used in research, teaching, and in industrial and commercial applications. As of March 2007, CNSC has granted over 2,100 licences in this category.

Some examples of these uses are:

• Irradiators used in research, medical and industrial institutions.
• Irradiators contain a nuclear substance for the delivery of controlled doses of radiation to non-human targets. Large, heavily shielded pool irradiator facilities are used for mass sterilization (e.g. of medical equipment).
• Irradiators are also used for the calibration of survey instruments, sterilization of blood products in blood treatment facilities, and irradiation of cells in research laboratories.
• Nuclear gauges, which incorporate sealed radioactive sources, used in measurement applications.
• Industrial radiography cameras, which incorporate radioactive sealed sources, used for the non-destructive examination of welds and castings.

Other examples include:

• Particle accelerators used principally in research facilities
• Nuclear substances used for teaching and research
• Static detectors and eliminators
• Gas chromatography devices

Other devices that may contain small (exempt) quantities of nuclear materials, such as self-luminous signs or watches, or smoke detectors, do not require a licence for possession. Their manufacture and initial distribution in Canada, however, are licensed by CNSC.

Devices containing Radium Luminous Compounds

Radium is a naturally occurring nuclear substance that can be hazardous under certain circumstances. In order to protect people and the environment, the possession, the use and transfer of radium is regulated by CNSC.

Until the 1960s, various consumer and military products were manufactured using a radium-based paint that glows in the dark, including:

• wristwatches;
• clock faces;
• marine compasses;
• a variety of military items;
• aircraft instruments.

These products are referred to as radium luminous devices, or RLDs.

A person may possess, transfer and use any number of radium luminous devices without a licence, provided that radium is the only nuclear substance in the device and the device is intact and not tampered with. 

There is a potential hazard of being exposed to low doses of radiation from these devices. If you possess RLDs, there are safety measures you take to ensure these devices are handled safely.

For more information about devices containing radium luminous compounds, radiation hazards and licensing information, please see:

• FAQs:  Devices Containing Radium Luminous Compounds