Diagnostic X-Ray Exposure

Radiographers should always apply the As Low As Reasonably Achievable or ALARA principle when undertaking a medical X-ray exposure. There are evidences that demonstrate that diagnostic X-ray procedures have the ability to induce cancer and genetic effects, although the risk is known to be very low. Hence, it is the responsibility of radiographers to always ensure to minimise this risk by minimising the radiation dose to the patient, ultimately producing the best diagnostic image and delivering the highest quality of care.

Stochastic effects are those that occur by chance and are mainly related to cancer or genetic effects as a result of DNA disruption. For stochastic effects, there is no threshold dose, therefore for any amount of radiation

Thus, when you double the dose, the risk of inducing cancer is doubled. There is a linear relationship as risk of stochastic effects is proportional to the dose, which is expressed in the Linear No Threshold Model. However, the severity of the effects does not increase with dose as the patient will either develop cancer or not.

Additionally, in stochastic effects there is also some risk from background radiation. In some instances, even without exposure to radiation above the background levels, stochastic effects can still occur in individuals. Hence, it can never be determined for certain that an occurrence of cancer or genetic damage was due to a specific exposure.

The Linear No Threshold Model is a model used in establishing radiation protection regulations as it hypothesizes the response of cancer to ionising radiation such as X-rays. The model suggests that cancer risk is directly proportional to absorbed dose (energy absorbed per unit mass of material subject to ionising radiation) and the risk will only be nothing at zero dose. The Linear No Treshold Model concludes that there is no level of radiation that is completely safe and consequently radiation exposure must be reduced until it is as low as reasonably

The study of Pearce et. al in 2012 looked into the risk of developing leukemia and brain tumours in pediatric CT by studying 280,000 CT scans between 1985-2002 of individuals under 22 in the United Kingdom. The results showed that there were significant linear associations between the risks of developing cancer after radiation dose to the brain with the probability of less than .001 and between the risk of developing leukemia after radiation dose to the bone marrow with the probability of .01. Hence, the results suggest the risks were small but they were undoubtly present in 1 case per 10,000 individuals. Pearce et al. have demonstrated that CT scans produce a small cancer risk and the diagnostic procedure should be clinically justified. We have to make sure that the benefits of CT scan such as better surgery, better diagnosis and treatment of cancer outweighs the risk of inducing