What should I know?
More than 95 per cent of the radiation dose the global population is exposed to from man-made sources, stems from medical exposures. In medicine, ionizing radiation is used to diagnose and treat diseases.
It has been estimated that the annual number of medical procedures using ionizing radiation world-wide grew from about 1.7 billion in 1980 to 4 billion in 2007.
There is no doubt that the application of ionizing radiation in diagnostic, interventional and therapeutic applications in medicine is beneficial to hundreds of millions of people each year. However, using radiation in medicine must carefully balance the benefits of enhancing human health and welfare against the inherent risks of exposing people to radiation.
The goal in medical exposure is not to give the lowest dose, but to deliver a dose to the patient that is commensurate with the intended medical purpose. While doses that are higher than necessary are a problem, doses that are reduced too far will either cause images to be too poor to make a diagnosis, or too low to cure a tumour.
It is important to reduce unnecessary and unintended exposures in practice through a dedicated radiation protection programme and activities. Unnecessary exposures can be a result of procedures that are not justified for a specified objective; from the application of medical radiation procedures to individuals whose condition does not warrant such interventions; and from medical exposures that are not appropriately optimized for the situation in which they are being used. As for unintended exposures, these can be a consequence of an unsafe design or inappropriate use of medical radiation technology.
Examples of medical procedures using ionizing radiation:
Radiology is using medical imagining techniques such as X-rays to detect and diagnose diseases and injuries, manage patient care, and guide many forms of treatment. In radiology, radiation penetrates the body from outside and usually operates with small doses.
Nuclear medicine is the use of unsealed radioactive sources in diagnosis, therapy and biomedical research. Patients with clinical problems are diagnosed or treated by the use of radiopharmaceuticals, which are released into the patient’s body.
Interventional procedures are used for image guidance of diagnosis or treatment that often involves minimally invasive surgeries. The procedures are associated with higher radiation doses.
Radiotherapy uses very high doses of ionizing radiation to destroy cancer cells and limit cell growth. It is applied by a team of qualified experts to a targeted body part externally or internally.
Radiation is also used in other medical specialties such as in
dentistry, urology or in orthopedic surgery.
Questions and answers
In this section, you will find some questions related to nuclear safety. To help you better prepare your answers for the media, you can find relevant answers under each question.
Q: How safe are X rays in medicine?
A: For most diagnostic X-ray investigations, there will be no adverse effects from irradiation. Although there are many different types of radiation effect, those that can occur in diagnostic practice are only a few and their likelihood is very small. For example, the amount of radiation received in a simple X ray examination such as a chest X-ray is quite low and is equivalent to less than one year of radiation exposure from natural background sources. At these levels of radiation exposure, cancer and genetic effects cannot be ruled out but remain only a theoretical possibility, as there is no practical evidence of such effects from any human studies to date.
Q: How much radiation is acceptable for a patient?
A: There are no prescribed limits on radiation doses to patients. This means that no amount of radiation is considered too much for a patient when the procedure is justified by the doctor. The doctor will consider the benefits versus the risk. There are well established guidelines and recommendations from a number of international organizations on this issue, which are based on scientific data. Every effort should be made to optimize the exposure to ionizing radiation. An examination that does not help medical management is inappropriate, no matter how small the dose.
Q: What are the principle of justification and optimization?
A: Each medical procedure using radiation should be justified. This requires weighing the benefits and risks of the intended procedure, with due consideration of alternative procedure that do not use ionizing radiation (Justification). Once justified, the examination should be performed with appropriate radiation dose for diagnosis or treatment (Optimization).
Q: Are children more sensitive to radiation than adults?
A: Children have higher radiation sensitivity than adults and have a longer life expectancy. Therefore, imaging techniques that do not use ionizing radiation should always be considered as an alternative, keeping in mind that sometimes the imaging technique that do use ionizing radiation may be the best choice for the patient.
Q: Can pregnant women undergo medical procedures with ionizing radiation?
A: Yes, but with certain precautions. The aim is to minimize exposure of the unborn child. The unborn child is considered to be more sensitive than adults or children to potential adverse radiation effects. For many investigations such as X-ray examinations of the head (including dental X-rays), chest and limbs, where the unborn child is not in the direct X ray beam, the dose to the unborn child will be very low. These investigations can be conducted without concern provided there is medical justification. With these procedures the radiographer or technologist might provide some radiation shielding to cover the woman’s pelvic region as an added precaution. If a procedure is being considered in which the pelvic region and the unborn child will be in the direct path of the X-ray beam, especially e.g. fluoroscopy or Computed Tomography (CT), which can produce a higher dose than plain X-ray examinations, the doctor might consider delaying the procedure, using an alternative investigation such as ultrasound (where ionizing radiation is not used), or taking special actions to keep the dose to the unborn child as low as possible when the procedure is essential to the mother’s health.
Q: Are the medical professionals working in the medical facilities affected by the use of ionizing radiation? What measures can they take to protect themselves?
A: Yes. The number of occupationally radiation -exposed persons is much greater in medicine than is due to any other source or practice, because of the widespread nature and volume of medical procedures. Individual occupational exposure can vary widely among those involved in medical care. Most receive annual doses that are well below dose limits; however, there are some procedures that may give significant doses to medical staff. High doses can, for example, be incurred by those doing fluoroscopically guided interventional medical procedures. The doses of an individual can vary widely depending upon the number of procedures performed and the skill and technique of the operator. Protective equipment, such as lead aprons and lead glass eyewear, and shielding, such as ceiling suspended screens, must be used to limit occupational exposure.
Further reading
IAEA website on radiation protection of patients (RPOP) >>
IAEA website on human health >>
Website of the World Health Organization (WHO) on medical radiation exposure >>
IAEA Diagnostic Radiology Physics: A Handbook for Teachers and Students >>
Factsheets for decision makers in radiation protection in medicine >>
The Image Gently Alliance >>
Frequently asked questions of patients related to:
