Decontamination is a process to reduce or remove unwanted material, such as radioactive, toxic chemical or biological substances. Decontamination from the surface of an object or from an area applies to removal by washing, biological agents, chemical action, mechanical cleaning, or other techniques.

(DICOM) DICOM is the industry standard for transferral of radiologic images and other medical information between computers. Patterned after the Open System Interconnection of the International Standards Organization, DICOM enables digital communication between diagnostic and therapeutic equipment and systems from various manufacturers.
The DICOM 3.0 standard evolved from versions 1.0 (1985) and 2.0 (1988) of a standard developed by the American College of Radiology (ACR) and National Electrical Manufacturers Association (NEMA). To support the implementation and demonstration of DICOM 3.0, the RSNA Electronic Communications Committee began to work with the ACR-NEMA MedPacs ad hoc section in 1992.
Also Picture Archiving and Communication Systems (PACS), which are connected with the Radiology Information System (RIS), use commonly the DICOM standard for the transfer and storage of medical images.

See also Barcode, Annotation, Printer and Diagnostic Imaging.

(K-capture) An unstable atom with too many protons in the nucleus, and not enough energy to emit a positron, reaches a stable state in the way, that one proton captured an electron from the atom's inner shell (K-shell) and change to a neutron. A neutrino is emitted from the atoms nucleus by this process. The atomic mass of the atom is unchanged, but the decreased number of protons transformed the atom to a different element.

Electron excitation is the discrete energy storage in an orbital electron. The excitation energy results from the absorption of a photon (photoexcitation) or from the absorption of another electron (electrical excitation). The absorbed energy lifts the electron to a higher energy level. This process ends with electron relaxation.

See also Electron Relaxation.

X-rays contain a range of energies (polychromatic photons), the higher energies pass through the patient, the lower energies are absorbed or scattered by the body. Ideally, the x-ray beam should be monochromatic or composed of photons having the same energy. Strong filtration of the beam results in more uniformity. The more uniform the beam, the more accurate the attenuation values or CT numbers are for the scanned anatomical region.
There are two types of filtration utilized in CT:
Inherent tube filtration and filters made of aluminum or Teflon are utilized to shape the beam intensity by filtering out the undesirable x-rays with low energy. Filtration of the x-ray beam is usually done by the manufacturer prior to installation. The half value layer provides information about the energy characteristics of the x-ray beam. Too much filtration produces a loss of contrast in the x-ray image.
A mathematical filter such as a bone or soft tissue algorithm is included into the CT reconstruction process to enhance resolution of a particular anatomical region of interest.