X-ray image intensifier

An X-ray image intensifier (XRII), sometimes referred to as a "C-Arm" or "Fluoroscope" in medical settings, is a highly complex piece of equipment which uses x-rays and produces a 'live' image feed which is displayed on a TV screen.

The term image intensifier refers to a special component of the machine, which allows low intensity x-rays to be amplified, resulting in a smaller dose to the patient. The overall system consists of an x-ray source, input window, input phosphor, photocathode, vacuum and electron optics, output phosphor and output window. It allows for lower x-ray doses to be used on patients by magnifying the intensity produced in the output image, enabling the viewer to easily see the structure of the object being imaged. They were introduced by Philips in 1955.

Clinical Applications of An Image Intensifier

An image intensifier or "II" is used in two ways:

*As a fixed piece of equipment in a dedicated screening room
*Mobile Equipment for use in theatre

Components of an Image Intensifier System

*C-Arm (encompasses the actual X-ray source and Image intensifier)
*Table
*Radiographic exposure and program controls
*Post processing software
*Viewing monitors

Fixed Image Intensifiers

These are used in most x-ray departments as 'screening rooms'. The types of investigations for which this machine can be used for is vast. Examples include:

*Barium Studies (Swallows, Meals, Enemas)
*Endoscopy Studies (ERCP)
*Fertility Studies (HSG)
*Angiography Studies (Peripheral, Central and Cerebral)
*Therapeutic Studies (Line placements i.e. "Permacath" / "Hickman", Transjugular Biopsies, TIPS Stent, Embolisations)
*Cardiac Studies (PTCA)

Mobile Image Intensifiers (MII)

Smaller in design than a fixed image intensifier, mobile screening units are becoming more and more powerful. This has enabled more advanced and technical procedures to be carried out in confined locations. MII's are routinely used in most hospitals for:

*Orthopaedic Imaging in theatre (DHS, ORIF's and MUA's)
*Neurolgical Imaging in theatre
*Endovascular Imaging in theatre (EVAR)
*Therapeutic Procedures in theatre (pain clinic)

Technical Capabilites

Image intensifiers are usually set up for two purposes. For either plain fluoroscopy or digital subtraction angiography (DSA). All image intensifiers are set up with software capable of adjusting settings to suit different user requirements, depending on the procedure and body area being imaged. In simple flouroscopy for example, imaging of the throat would not require the same amount of exposure as that of the abdomen. And on DSA capable models, preset programs are available which enables the user to decide a rate of how many images or frames per second are acquired.

Future Developments

*Flat Panel
*Dual Head
*Low Dose Imaging

External links

* [http://www.toshiba-europe.com/medical Toshiba Medical Systems Europe]
* [http://www.medical.philips.com/uk/ Philips Medical]
* [http://www.medical.siemens.com/ Siemens Medical]
* [http://www.gehealthcare.com/uken/index.html GE Healthcare]
* [http://www.goingfora.com/radiology/index.html An interactive experience of Imaging Departments]
* [http://www.medical.philips.com/us/company/rsna_2005/showcase/c_arms.asp Philips C-Arm 50th Anniversary]
* [http://www.medicalimagingmag.com/issues/articles/2004-01_04.asp C-Arms: Strong Arm]
* [http://www.amberusa.com/c-arms/index.asp Pain Management C-Arm information and services] Amber Diagnostics
* [http://www.nyssrs.org] NY State Society of Radiologic Sciences
* [http://www.ziehmimaging.net C-Arms Manufacturer Ziehm Imaging] Ziehm Imaging