Frequently Asked Questions
Below are some frequently asked questions. If you require more information, do not hesitate to contact us with your query.
Medical procedures for the benefits of patients are generally the greatest source of exposure to man-made radiation. Request for exposures should be justified and the protection of patients should be optimized. Justification is needed at two levels.
Medical profession or other relevant authorities decide on justification for general procedures such as breast cancer screening, pre-employment examinations.
The referring clinician justifies the request for the individual patient. The decision is based on risk vs. benefit factor.
Optimization is achieved by using good (usually modern) equipment and techniques that obtain quality information with lowest reasonable dose. This is a matter for the radiologist, radiographer and medical physicists. Dose reference levels (DRL) are set up to act as a benchmark against which the performance of diagnostic techniques could be judged. DRL are not limits and can be over-ridden by clinical judgement. Doses from the same type of x-ray equipment can vary from patient to patient. Values above the established DRL should prompt an investigation of the circumstance.
Radiation is a frightening word to most people, but its important to remember that radiation is natural. Sources of naturally occurring background radiation are the atmosphere, the earths crust and cosmic rays. Annually, the average American is exposed to about 3 millisieverts (mSv) of background radiation from his or her environment. In England the background radiation is around 2 mSv. Those who live at high altitudes, where the atmosphere is thinner, are exposed to more. By comparison, a typical dental x-ray exposes a patient to approximately 0.06 mSv; a chest x-ray delivers 0.08 mSv; a mammogram delivers about 1.0 mSv; and an x-ray of the thoracic spine delivers 1.5 mSv. Thus x-ray for diagnostic purposes based on justification is considered as safe.
Certain organs are radiosensitive, which means they are more sensitive to radiation exposure than other parts of the body. Those organs, including the thyroid gland and the male and female reproductive organs, are shielded when they are in the path of the x-ray beam. Because a developing fetus also is radiosensitive, pregnant women should seek a physicians advice before undergoing an x-ray examination.
Qualified registered radiographers are educated in radiation safety and protection and use techniques to minimize dose and exposure (optimization).