Radiography is carried out using X-rays or Gamma rays. Radiographic testing (RT) is one of the most reliable and widely used NDT methods. RT works on the principles of differential absorption of radiation, and is used to detect internal flaws in castings and welds.

Gamma Radiography

Is a technique which uses gamma-rays to produce the image of an object onto film. The source of radiation is either a gamma-ray tube, which is normally described by the electrical voltage with the higher the voltage the higher the penetrating power of the radiation or a pellet of radioactive material emitting gamma-rays: Iridium 192, Cobalt 60, Selenium 75, Ytterbium 169. Applications include wall loss detection and sizing in pipes and plate through to manufacturing defects in welds, forgings castings etc. Radiography provides a quality, cost effective, permanent record with high volume capabilities due to simple operation and portability.

Digital Microfocus Radiography

Digital radiography is a form of X-ray imaging, where digital X-ray sensors are used instead of traditional photographic film. Advantages include time efficiency through bypassing chemical processing and the ability to digitally transfer and enhance images. Also less radiation can be used to produce an image of similar contrast to conventional radiography.
Instead of X-ray film, digital radiography uses a digital image capturing device. This gives advantages of immediate image preview and availability; elimination of costly film processing steps; a wider dynamic range, which makes it more forgiving for over- and under-exposure; as well as the ability to apply special image processing techniques that enhance overall display of the image.

Computed Tomography

Computed Tomography (CT) uses very similar equipment to conventional radiography except that in place of a film to create the image, an imaging plate (IP) made of photostimulable phosphor is used. The imaging plate housed in a special cassette and placed under the body part or object to be examined and the x-ray exposure is made. Hence, instead of taking an exposed film into a darkroom for developing in chemical tanks or an automatic film processor, the imaging plate is run through a special laser scanner, or CT reader, that reads and digitizes the image. The digital image can then be viewed and enhanced using software that has functions very similar to other conventional digital image-processing software, such as contrast, brightness, filtration and zoom.