This term usually refers to the storage of patient data and images. Images are best archived in digital form (e.g., on optical disks, DVDs, PACS systems) and not only on films (hard copies, prints). Data compression via a reduction in matrix size, pixel depth or CT numbers, will result in a loss of spatial and contrast resolution. Digital images should be converted into a universal format such as DICOM. Raw data saving is necessary when additional image reconstructions are required.

See also Picture Archiving and Communication System, and Digital Imaging and Communications in Medicine.

An arthrography is a radiographic examination of a joint (such as the knee, shoulder, hip, elbow or wrist) that requires an injection of a contrast medium into the joint space.
For an opaque x-ray arthrography a water-soluble iodinated contrast agent is injected and a series of fluoroscopic controlled images is produced. Magnetic resonance arthrography combines the arthrogram with MRI. A small quantity of gadolinium contrast agent is added to the injection into the joint space. The traditional radiographic images are followed by an MRI of the extremities. A non-invasive possibility is an indirect MR arthrography, which doesn't require the injection into the joint. The dye is given prior to the imaging procedure.
The contrast fluid produces a bright signal and allows evaluation of small defects of the joint capsule, assessment of articular surface and labral cartilage, and in case of an indirect arthrogram also of the surrounding soft tissue. If a gaseous medium is used, this exam is called pneumoarthrography and a combination with liquid contrast is used in double-contrast arthrography.
MR arthrography is often used to evaluate hip and acetabular labrum, shoulder rotator cuff and glenoid labrum (see Shoulder MRI), and less often in wrist and knee MRI studies. Also combinations of CT and nuclear medical techniques with arthrography are available.

A lower orbited electron leaves the atom - the reoccupation of this vacancy by a higher orbited electron leads to the emission of energy which in turn leads to the emission of a second electron, the Auger electron.

See also Auger Electron, Electron Excitation, Megaelectron Volt and Auger Pierre Victor.

Natural background radiation originates from radioactive elements in the environment, including food, water, soil and rock (also building materials), the atmosphere and cosmic rays. The level of natural exposure to radiation can vary greatly between different locations. In the US, the average annual exposure from natural sources to humans is about 3 mSv (millisievert) corresponding to 0.3 rem. Radon gas accounts for two-thirds of this exposure.
Background radiation may also interfere with measurements. Background radiation includes radioactive contamination of samples or incomplete absorption of radiation in a detector.

In June 2006 Bayer AG has bought the majority of shares of Schering AG. As a result of this take-over Schering AG has been renamed in December 2006 in Bayer Schering Pharma AG. The Bayer Schering Pharma AG is part of the Bayer HealthCare AG, which represents the pharmaceutical part of the Bayer Group.
Berlex Laboratories (USA) and Berlex Canada Inc., former affiliates of Schering AG, have been integrated into Bayer HealthCare and operate as a specialty pharmaceuticals business that also sells MRI contrast agents, under the name Bayer HealthCare Pharmaceuticals, which is a subsidiary of Bayer Schering Pharma AG.