Friday 23 October 2015

Digital Radiography

Radiography is an imaging technique that produces high quality anatomical images using X-ray radiography general area is currently the largest department of the hospital and includes imaging examinations abdomen, chest and extremities

The use of digital radiography has increased rapidly in recent years. Computed radiography provides an economical transition from traditional film (used since 1895) to direct digital radiography (DDR) using conventional X-ray equipment. Direct digital radiography without cassettes is a system image and is ideal for applications where high performance is of primary importance. The system of digital radiology direct allows the use of all diagnostic applications in general radiography.

The main components of a digital radiography system are:
    1. X-ray generator
    2. Rays assembly
    3. Car or other auxiliary device for patient support
    4. Support for all the X-ray tubes
    5. X-ray detector to convert an image
    6. Workstation to process and display the image
There are a variety of technologies in which the direct digital radiology is based:
1) Indirect conversion detector. X-rays are converted into flashes of light and the light is converted into electrical signals.
2) Direct conversion detector: X-rays is converted directly into electrical signals.
3) linear scanning detectors: one fan beam x-ray scans the examined area synchronously with a group of detectors



Due to the structure of the detectors, converters detectors X, direct and indirect rays, are often called flat panel detectors (flat panel detector) (FPD).
There are also portable digital cassettes available, sold as part of a system or can be adapted to a team of computed radiography (CR) or existing screen-film system.
portable detectors can be used in conjunction with a mobile X-ray unit. These detectors can be connected to a workstation for review, either by cable or by means of a radio wave.
Most digital detectors require a certain level of environmental control. This can be in terms of operating temperature, type of change in temperature and / or humidity.
To the extent that the original image of the detector is unsuitable for use, apply an image processor. Flat field correction is applied to the raw image to reflect variations in the detector sensitivity through its total area. In addition, a number of individual pixels may be defective
Most direct digital radiology units have automatic exposure control (AEC) to provide the dose selected for the detector. This may use a conventional AEC detector or the actual image detector to determine the correct dosage. It is essential that the AEC operates in a reliable and consistent manner and is properly configured for the detector exposure.


In modern systems there is a digital radiography detector incorporated dose. The detector dose indicator (DDI) gives information on the level of radiation exposure received by the detector. This is useful for monitoring the exposure is in the correct range for optimal image quality and to perform quality control.