Ionizing radiation is both a tool and a hazard in pediatrics.
Ionizing radiation is both a tool used in pediatrics and an environmental health issue that relates to pediatric medicine. As a tool, it is used in the diagnoses of a wide range of conditions, including bone fractures, disorders of internal organs, and cancer. However, children are sensitive to potential harmful effects of such radiation, leading physicians to carefully balance risks and benefits, and minimize use.
Ionizing Radiation
Ionizing radiation is radiation that removes electrons from atoms and molecules, thus creating positive ions. This radiation may be particles, such as protons, neutrons, or nuclei of atoms, or it may be electromagnetic waves. In the case of electromagnetic waves, it is the more energetic waves that are ionizing. This includes some ultraviolet (UV) light, as well as all x-rays and gamma rays. Ionization of atoms and molecules can lead to damage of human tissue.
Diagnostic X-rays
X-rays are a mainstay in diagnostic pediatrics.
X-rays, a type of ionizing radiation, are a mainstay of diagnosis in pediatrics. Flat film radiographs (photographs made with X-rays) are used to diagnose bone fractures, and can be used to diagnose conditions of many different internal organ systems. X-rays also are used in CT scanning, where many X-rays are taken.
Biological Effects of Diagnostic X-rays
Low doses of X-rays used in flat film radiographs are not harmful.
In the doses used in flat X-ray radiographs, X-rays are not harmful to biological tissue. Doses of X-rays to which a child may be exposed during a full-body CT scan, however, may be harmful, particularly if many CT scans are performed within a short period of time. The National Cancer Institute has recommended that physicians limit the use and dosages of CT scans in children as much as possible.
Radionuclides
Nuclear medicine makes use of radioactive compounds.
A radionuclide is a radioactive compound that may be injected into, or implanted in, a patient, usually for diagnostic purposes. In PET scanning, for example, a metabolite, such as glucose altered to make it radioactive, is injected. The type of radiation used is positron radiation--particles the same size as electrons, but with the opposite charge. Malignant tumor cells take up glucose more quickly than other cells do, so positrons then are emitted from any tumor cells. When those positrons collide with electrons, both particles are annihilated, forming two high-energy gamma rays that can be detected by a scanner. The amount of radionuclide used is so small, and the amount of radiation produced so slight, that biological tissue is not damaged.
Therapeutic Radiation
The doses of radiation used in radiation cancer therapy are highly damaging to biological tissue
By far the most damaging radiation used in pediatrics is that used as therapy to kill tumor cells. In radiation therapy, extremely high doses of X-rays, or less commonly protons, is aimed at a tumor. The doses used would be high enough to cause death by acute radiation sickness if it were not focused only at the target, and if the rest of the body were not intentionally shielded. Now that many patients cured of childhood cancer by radiation therapy have grown to adulthood, it's been found that such radiation can cause fibrosis years later in healthy tissues that were inadvertently exposed. When this happens in heart or lung tissue, the surviving pediatric cancer patient can develop severe problems as an adult.
Tags: biological tissue, radiation used, tumor cells, atoms molecules, Biological Effects, bone fractures
