X-ray Technology and Applications Update
The invention of the x-ray by Roentgen in 1895 created an amazing step forward in the history of medicine. Today we see  X-ray technology used in many different fields as a non-invasive inspection tool and not least in the field of security where x-rays are used for baggage scanning at airports, mailscanning in postrooms, vehicle scanning at border controls and more recently through body x-ray scanners for identifying contraband, weapons and IEDs concealed on a person.  For field use, specially adapted portable systems have been developed to meet the different investigative needs of military theatres and national military and civil search.
X-ray technology today uses the same basic principles in that x-rays are passed through an object and a latent shadow image is captured on an imaging panel placed behind it. Different materials will absorb different numbers of photons so that the relative densities of the object can be seen as differences in grey scales when viewed on a screen.
Pre 9/11 many field based x-ray systems were still operating manual Polaroid film technology
where an x-ray source was placed in front of the object requiring scanning and a cassette placed behind. The x-ray generator was manually fired by the operator and then the target area would be reapproached for the film to be retrieved for chemical processing. 
Although the resulting image was fairly good, it could be quite a time consuming process as the processing itself could take up to 2 minutes and if the development was not carried out in the correct conditions, several attempts were often needed before  getting a picture of sufficiently good resolution. Each attempt meant another sheet of Polaroid film which involve significant weight and cost factors when carrying out multiple x-rays of a large target.
In addition film had dead areas where edges of cassettes were joined or unexposed and where potentially an IED could go unseen. If dead areas are found additional x-rays need to be taken which increases time on target for EOD personnel.
The range of portable x-ray equipment available in the security market is growing. Conventional Polaroid film systems are gradually being replaced by “real time” systems wh
ere images are displayed in digital form on a laptop or other portable device.
Fundamentally there are  2 primary technologies available off the shelf to upgrade older Polaroid film systems to a digital platform whilst operating the same safe, tried and tested x-ray generators.
The first is DR – Direct (Digital) Radiography which use either a rugged CCD X-ray Imager or a very high resolution amorphous silicon (aSi)  flat panel imager to capture x-ray images before sending them directly back to a laptop and the second is known as  CR – Computed Radiography which utilises very flexible reusable digital film and an image plate processor that scans the x-ray image onto the laptop via a USB data connection.
Each  has its own benefits dependent on the requirements of the job but all of the imaging panels described in this article are lightweight and can be handled easily even by someone wearing heavy body armour.
If we look first at the picture in overseas theatres such as Iraq and Afghanistan, their needs
will be quite different from the requirements of a postal inspector needing to check a suspect package or a special projects team carrying out a room search.
The homemade IED is the extremist’s deadliest weapon and our troops' biggest challenge.  In 2003 there were 81 recorded IEDs in Afghanistan. In 2009 there were over 8,000. Half of all soldiers killed in Iraq were killed by IEDs and currently in Afghanistan it is two thirds.
Early detection (or better, prevention) of IEDs is mission critical which is why current Counter IED methodology is focused on Defeat the Device (finding the weapon and protecting against its effects) Attack the Network (identify what an IED cell looks like so that the networks can be identified and attacked) and Train the Force.
Detection of IEDS is a daunting challenge. IEDS are being concealed in everyday items such as drinks cans, toy cars, key rings and mobile phones and can be very easily disguised in rubbish, potholes and craters and a high percentage are frequently spotted by soldiers noticing something doesn’t look right. In this instance x-ray equipment may be deployed as a confirmatory tool or to remotely diagnose the insides of an object without pic
king it up.
In such instances where the equipment is going to be used regularly by someone often operating on foot, for Special Forces a highly portable lightweight system that can be carried in a backpack would be the key requirement. A CCD imaging system also represents a very cost effective solution.
xposedA real time CCD x-ray system is combination of camera and x-ray source at the target and laptop or other viewing console at the control point. CCD systems produce a latent x-ray image on photoluminescent screen. A camera sends the image back to the laptop directly down a cable or by wireless transmission and multiple exposures can be made to gain the best possible image without having to return to the target.

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