X-ray safety program

The x-ray safety program is monitored by the Laboratory Safety Committee.

The following sections outline the structure of the x-ray safety program including duties and responsibilities.

All x-ray instruments need to be registered with the Ministry of Labor and an internal permit issued by the Safety Office (X-Ray Safety Officer). Please contact Greg Friday (gfriday@uwaterloo.ca or ext. 35755) prior to purchasing an x-ray instrument.


University of Waterloo's x-ray safety program encompasses all work with x-ray emitting devices under University of Waterloo (UW) control.

This program reflects the requirements in Ontario Regulation 861/1990 X-ray Safety and the Federal Radiation Emitting Devices Act.


This program outlines procedures and controls to ensure safe working conditions when working with or near x-ray emitting devices at the University of Waterloo. 

X-ray physics

Understanding how x-rays are produced and their interaction with materials and people requires a rudimentary knowledge of matter and radiation.

X-ray procedures

The University of Waterloo has many varied types of x-ray equipment used for various teaching or research programs.

Regardless of the type of equipment, production of x-rays is based on the same principles.


Since the effects of ionizing radiation are directly proportional to the amount received, a system had to be set up to measure the quantity of ionizing radiation. The following section will cover units of measure for ionizing radiation, conversion from SI units and the dosimetry requirements for persons using x-rays at UW.

Biological effects

This next section will discuss the relationship between exposure (dose) and response as well as describe various effects of ionizing radiation.

For example, a large quantity of X-rays has the potential of producing an undesired effect on a person.  However, used properly with appropriate shielding the x-rays will have no biological effect.  

Paracelsus (16 th Century): "It's the dose that makes the poison".


To insure that x-ray radiation dose rates are not exceeded, various ionizing radiation detectors have been developed and sold commercially. 

This section deals with the most common types of radiation detectors used at the University of Waterloo.

Controlling exposures


As described in the program section under legislation, operation of non medical x-ray emitting devices is under the Ontario Ministry of Labour and the construction is controlled by Health Canada.


Over exposure

If a worker/student has received a dose equivalent in excess of the annual limits in a period of three months, the x-ray Safety Officer shall investigate the cause of the exposure. 

The x-ray Safety Officer shall provide a report in writing of the findings of the investigation and of the corrective action taken to:

  • The Director of the Health and Safety Support Services Branch of the Ministry of Labour
  • The Joint Health and Safety Committee
  • Permit holder
  • The worker/student

Equipment failure

Any accident, failure of any equipment or other incident occurs that may have resulted in a worker/student receiving a dose equivalent in excess of the annual limits, the x-ray Safety Officer shall notify the Director of the Health and Safety Support Services Branch of the Ministry of Labour and the Joint Health and Safety Committee.

A written report of the accident or failure shall be sent to the Director of the Health and Safety Support Services Branch of the Ministry of Labour within forty-eight hours.

Quiz introduction

  • This quiz is limited to persons working x-ray emitting device and members of the UW community.  
  • The current quiz no longer maintains records.  For this reason, the Safety Office is developing a Learn based X-ray Safety Course which will be available by the end of March 2020.  When complete, this course will meet the theoretical portion of our training program.
  • If you cannot wait for the Learn course, you can access the current training program hereNote, if you take the quiz in this format, you will need to take the Learn course as well to ensure your training record is updated.

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