An ion is an atom or group of atoms that has an electric charge. Ions with a positive charge are called cations. Ions with a negative charge are called anions.

Many normal substances exist in the body as ions. Common examples include sodium, potassium, calcium, chloride, and bicarbonate. (See: Electrolytes)

Ions can be created using radiation such as x-rays. Ionizing radiation is often used for diagnostic or therapeutic procedures, since the ions that are produced can be used to scan for or treat some diseases.

Related topics:

• Adrenal medullary imaging
• Bone scan
• Gall bladder radionuclide scan
• Gallium (GA) scan
• Isotope study
• Liver scan
• Lung gallium (GA) scan
• Nuclear ventriculography (MUGA or RNV)
• Pulmonary ventilation/perfusion scan
• Radiation therapy
• Radioactive iodine uptake
• Radionuclide cystogram
• Renal venogram
• RHISA scan
• Thyroid scan
• WBC (nuclear) scan

Alternative Names

Cations; Anions