A digital image is basically an array of numbers of pixels where each pixel represents the brightness of a point of an image- Digital imaging is a mathematical transformation of these pixels. Digital imaging brings about improvement in the following:

• Quantitative measurements

• Image enhancement

• Object recognition

• Segmentation

• 3D Construction

• Tomography

In the field of medical imaging, similar objects can give rise to different image patterns thus a flexibility must be build into the process. The flexibility is generally built into the function which attempts to match the image patterns. In the flexible matching pattern templates are used to match the data in an image by using a set of parameters e. g. A circular template can be described by three parameters i. e. Radius and the X and Y coordinates of its centre. Object recognition can be done by identifying the region of interest on the image on the basis of its brightness, then computing the values for the various measures of that region and classifying accordingly. By the use of imaging software 2-D or 3-D images can be constructed on a monitor screen for further analysis to achieve the objectives of medical imaging.

Due to the recent advances in digital imaging a radiography can be transmitted from a remote place in the world to any leading radiologist for diagnosis without the patient having to move from place to place.

This is made possible because of the following:

• High Resolution Scanner with a Resolution of 5 micron plus

• Digital Camaras in place of Conventional CCD Cameras

• Data storage devices like CD-Rom drive which can store data upto 150 MB plus or PD drives which can store data upto 650 MBs. This is a very important considering the fact that each digital image depending upon the resolution can occupy a data space of 1 MB to 3 MB.

• Data transfer devices like high speed modems which are used extensively in Networking, etc.

• High Resolution Monitors with 2000 plus horizontal scan lines.

The above equipment is being used today to transfer medical radiographs in digital form from various remote places to hospitals and this data can be successfully reconstructed into a radiographic image without loss of sensitivity wherever required.

Some of the benefits of the above technology are:

• Efficient film archive management with computerised digital retrieval/storage facility

• Faster retrieval times locally and remotely

• Film diagnostic tool for Radiologists for reporting and fast distribution to concerned users

• Significant reduction in storage space thus releasing of valuable space for other purposes

• Loss less image transfer. Stored images do not change with time and the life span is greater than normal 30 years.