Radiation safety in your practice: Understanding the ALARA principle

If your job entails using radiographic equipment, as a non-invasive way to assist in treating

patients, you need to familiarize yourself with ALARA. And no, this isn’t the name of someone, who had eccentric parents.


The risk associated with ionising radiation is, you guessed it, directly correlated to the amount of exposure a person has, to ionising radiation. Therefore, being exposed to radiation for long periods of time, or on a regular basis, significantly increases the risk for cell damage and harm to your body. Therefore, occupational limits are placed on the radiation dose that people may receive, on top of the omnipresent background radiation.

According to The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), the levels of radiation that occupationally exposed workers receive, for example staff at a dental practice, should not exceed 20 mSv per year.

“The current limit of radiation exposure is 20 millisieverts (mSv) per year averaged over 5 years, and not more than 50 mSv received in any one year for effective (whole body) dose.” - Radiation Protection Series C-1 (Rev. 1)

With regard to patient doses, there is no limit specified.


In the spirit of ALARA, patients may receive any justified dose of radiation requested by medical practitioners. Image: Unsplash
In the spirit of ALARA, patients may receive any justified dose of radiation requested by medical practitioners. Image: Unsplash

The ALARA principle of radiation protection

Patients may receive any justified dose of radiation requested by dental practitioners.


Enter the ALARA principle, the guiding principle of radiation safety. ALARA stands for “as low as reasonably achievable” and places the responsibility on practitioners to ensure they only use ionising radiation on a patient when required, and when the reward to the patient, outweighs the risk of the radiation. It is based on minimising radiation doses and limiting the release of radioactive materials into the environment by employing all “reasonable methods”. Dental practitioners have a professional, moral, and legal obligation to adhere to this principle.

In other words: ALARA means that even if it is a small radiation dose i.e., most dental radiography, if receiving the radiation dose has no direct benefit, it should be avoided.


How to apply ALARA in your dental practice

Before you take an x-ray, determine whether the rewards of taking the image outweigh the risk of the radiation, to the patient. Sounds easy enough, right?


In today’s modern dentistry, the radiation dose from a typical dental examination is so minimal that in most cases the ALARA principle would dictate that the reward > risk. The advancements in technology allow us to obtain dental radiographs applying such a low radiation dose, that the risk to the patient is minimal, while the information that the image provides to the dental practitioner is highly valuable for diagnosis and treatment planning.


Ask yourself, whether the rewards outweigh the risks, before sending your patient to have an x-ray taken. Image: Unsplash
Ask yourself, whether the rewards outweigh the risks, before sending your patient to have an x-ray taken. Image: Unsplash

There’s another big advantage of today’s technology, with regards to the dental Cone-beam CT (CBCT) that allows you to utilise the ALARA principle further. One example is if you are interested in a specific region of the mouth, or a particularly troubled tooth, you no longer have to radiate the entire face. Instead, you can select the field of view (FOV) that focuses on the area of interest and take an image of the specific anatomic region. In the spirit of ALARA, you have then received the image you need, without exposing your patient to a higher dose of radiation.


Another example of the ALARA principle, being utilised by the CBCT system, is that you can extract secondary modalities from a single CBCT scan. For example, the software allows you to extract a bitewing, panoramic, or ceph image from a single larger FOV scan.

ARPANSA’s safety guide Radiation Protection in Diagnostic and Interventional Radiology further touches on the changes that the digital revolution has brought with it for the production, reporting and distribution of medical images, and states:

“… when a patient is transferred to a different institution or practice, the Responsible Person should ensure that all relevant images and reports, or duplicates of the images and reports, relating to that patient are provided to the new practice. This may help to reduce the incidence of repeat examinations and therefore unnecessary patient exposures.”

Honouring the ALARA principle in your day-to-day work is key to protecting your patients, your staff, and your environment, from unnecessary exposure to ionising radiation.


If you have questions relating to radiation safety in general, or the ALARA principle in specific, contact us on 0437 230 808 or email service@gammatech.com.au.


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