Digital X-ray has Become a Mainstream Tool for Bomb Squads
Published in the June 2011 issue of Intersec magazine
By: Eliyahu Dayan, Ofra Kleinberger-Riedrich, Rachel Lieberman
Portable Digital X-ray systems have become a mainstream tool for bomb squads in recent years. With major large events coming up (2012 Olympics in UK, 2014 football World Cup in Brazil and the Winter Olympics in Russia just to name a few), the portable digital radiography systems market is on the move! Eliyahu Dayan & Ofra Kleinberger explore the hottest X-ray technology out there.
The security measures taken for securing major events, like the royal wedding of HRM Prince William and Miss Kate Middleton in April 2011 or the upcoming Olympic Games in London in 2012, are of huge proportions. The equipment used is varied and security units need to stay updated due to the fact that cutting-edge technological developments often serve to facilitate the discreet fulfillment of their tasks. In events of this size it is important for security teams to combine advanced means with low visibility, thus achieving maximum public security with minimal awareness of the security measures taken for its protection.
The purpose of the EOD/IED team operating at such large events is to acquire the ability to deal with any detected threat quickly. A key product to achieve this aim is a portable X-ray system packed in a single backpack along with its accessories, which can also serve as an operational platform in the field. This system enables the bomb tech to be discreetly located at the scene along with such equipment where he can remain relatively inconspicuous while inactive, but he is instantly available to deal with any actual on-site threat.
A digital X-ray equipment review conducted by the US military, which was recently published on the web (X-ray test report #060309 from the US army corps of engineers), defined several factors as important in a desired portable digital X-ray inspection system: Most important were portability, battery life, field readiness, fast and easy set-up, penetration capabilities, operating efficiency and operator safety. Other qualities named were homogeny in images combined with high resolution and high-image quality, as well as user-friendly software with many advanced features. All these attributes can be grouped into five major factors that should be considered when researching which of the many systems available is the best investment. These five factors are reviewed below in detail:
True mobility – not every system that looks portable is really field worthy. Your first question should be: Is the system really mobile? Can the system actually be carried on foot to any location, such as an underground station or even rough terrain (like Afghanistan or Iraq)? Or perhaps a large system in a vehicle can adequately meet your needs?
The system must be light enough to be trekked on foot by a single individual (just think of a bomb tech needing to make his way in a stadium full of people). It must be packed in one casing that also includes a working platform, allowing for convenient work with a ruggedized computer in field conditions. The system must be able to operate on batteries for extended periods of time, thus eliminating the need to change a battery down range during a potentially dangerous inspection. The system must allow for conducting the entire inspection from a safe distance.
Wireless communication provides greater set-up flexibility, thus increasing field worthiness. The transition from film to digital X-ray first enabled integration with robots. A digital X-ray system that can be integrated to work in full compatibility with an ROV enables greater portability and increased versatility when combating terrorist threats.
Providing the bomb tech with X-ray eyes:
X-ray penetration is the key to a clear and informative image
X-ray image - Digital X-ray flat panel based systems have introduced a new level of X-ray visibility. This enhanced visibility has been achieved due to the ability of the amorphous Silicon (a-Si) flat panel to detect the X-rays that hit it following the penetration of the suspect object. This technology enables the X-ray of hard-to-penetrate objects (like improvised EOD shells, IEDs located in thick steel containers, full car petrol tanks etc.), because the panel is capable of detecting the few X-rays that go through. While the image will be relatively dark (as very little X-ray has been detected), it will still display valuable information; several easy-to-use software enhancement tools enable the user to "open up" the dark image and extract details. Another aspect of this characteristic is that when using an a-Si flat panel system for X-ray inspection, the X-ray dose (meaning the actual energy level of the X-ray beam) can be decreased considerably and exposure time can be shortened. This means less exposure of the bomb techs and the public to X-ray and greater overall safety.
Not every off-the-shelf a-Si panel is suitable for high levels of penetration. The trick is to integrate all of the components of the portable X-ray system to be able to exploit the panel’s full potential penetration of over 80 mm of steel* is possible with a-Si, even in the field). You need to make sure the manufacturer is offering you a system that is indeed able to make the most of the panel.
Time to image - is a key factor in keeping bomb techs safe. Fast set-up of equipment is crucial to shortening the time down range as much as possible. The incorporation of simple components such as a single cable that pushes both power and data down the line, or built–in wireless communication modules makes the fully suited bomb tech’s walk down-range much less cumbersome and the set-up process easier.
Digital Radiography based on a-Si panels provides an X-ray image on the laptop screen with only a single approach to the suspect object (in order to place the X-ray source and flat panel next to it). The image is then generated immediately on the computer screen and is available for instant analysis. Computerized Radiography (CR), a technique which also generates a digital X-ray image, requires two approaches down range – one to place the Image Plate (IP) and X-ray source and another to retrieve the IP for scanning. In addition, time is also lost on the scanning procedure (and on cleaning the plates in preparation for re-use).
The a-Si flat panel provides high-resolution images of the entire active imaging area in just seconds, while scanners require much more time to scan the inspection area and will inevitably provide either a small high-resolution image or a large poor-resolution image. The high dynamic range of the a-Si technology combined with excellent Signal to Noise Ratio (SNR) enable generating images with thousands of grey levels**. The latter contain an equal number of layers of information, enabling the detection of the tiniest details (even with low X-ray exposure) and allowing for immediate yet informed decision making regarding necessary action. In Digital Radiography once the system is set up, capturing another image merely requires another click of a button on your laptop.
Flat a-Si panels with larger imaging areas are highly popular in the market of digital X-ray because they enable examination of larger items in a shorter time frame. It can be compared to looking through an open door, rather than peering through the keyhole when the door is closed. The size of the imaging area of currently available flat a-Si panels has increased in the last year [with the appearance of products like FlashX (Vidisco) and GE-DXR 250V (General Electric) on the market], but it is limited nevertheless. The trend of “going big” has become very relevant as bomb techs and custom officials aspire to shorten the inspection time spent on large objects (such as suitcases and even vehicles). Today, in order to X-ray a suitcase (for example), the operator must approach the suspect item repeatedly, moving the imager in relation to the item to acquire more than one shot. Cars can only be X-rayed in sections – e.g. a door and then a seat – again necessitating the repeated approach down-range. In such cases, both speed and safety are impaired.
Manufacturers are therefore seeking a solution that will enable the achievement of several consecutive X-ray shots automatically. One such solution is a so-called “Slider” device***. This method enables the attachment of a flat a-Si panel with a simple click. The panel and “Slider” are carried down-range as an integrated unit and placed behind the suspect object. The device then “slides” the panel into four consecutive imaging positions; consequently, advanced software automatically stitches the images into a large image. There is no need to return to the suspect item. A single approach has enabled the capture of four consecutive images.
Prolonged quality - When purchasing a portable digital X-ray system, it is important to ensure that the quality of imaging generated by the system will be maintained over time. Digital Radiography systems based on a-Si continuously provide top-quality images and are geared to do so even after many years of use, unlike CR technology, where the Image Plates may feature scratches and wear out faster.
Cost –efficiency ratio - The most inexpensive system is not always your best option. In many areas of life a cheap purchase can become a very expensive one over time. Digital X-ray flat panels may initially be more costly than other technologies (such as CCD or CR) but they provide images of the highest quality. There are no added expenses for repeated shots. Hardly any maintenance is required due to the fact that there are no moving parts and cleaning or developing chemicals are unnecessary. Amorphous Silicon is the most advanced digital X-ray technology available today. By placing such superior detection capabilities in the hands of the bomb squad, anti-terrorist deterrents become that much greater. The cost of the portable X-ray system is minute in comparison to the toll that a successful terror attack at a major event would take.
Let us summarize the crucial role that a portable digital system can play in securing a large event: Fast and efficient operation is a life saving parameter when securing a major event. Speed ensures the safety of both the bomb tech and the crowd surrounding him. True portability can enable EOD/IED teams to reach the site of a threat without delay. Simple set up capabilities further shortens onsite operation time. Penetration capabilities of the digital X-ray systems ensure the immediate availability of a clear image including valuable information regarding the exact nature of the threat. Increased Probability of Detection (POD) is achieved despite the speedy operation. Accurate analysis based on high-quality images can lead to rapid action to dismantle or neutralize a threat. The bomb tech can take informed decisions quickly and act upon them. The inspection site can then “return to normal” as soon as possible and the event can proceed as planned.
- Eliyahu Dayan is a member of the founding group of the Bomb Disposal Division in the Israeli Air force (special IDF EOD unit). He has over 20 years of experience in the field of EOD/IED disposal and is a senior developer at Vidisco Ltd.
- Ofra Kleinberger-Riedrich is the Marcom Manager at Vidisco Ltd.
- Rachel Lieberman is a Marcom Writer at Vidisco Ltd.
*Vidisco FlashX system with XRS-3 can penetrate over 80mm of steel (and 2mm of lead will be visible in the X-ray image).
** 16 bit (65,535 grey levels) with FlashX
*** The Vidisco SLIDER2x2 is the first product of its kind to offer a comprehensive solution. The panel is moved automatically into the 4 required positions, the image is automatically stitched together and the whole process is controlled by the operator from a safe distance.