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A close-up view of X-ray scanning

Almost everybody has been through a body scanner at an airport or other sensitive locations. Similarly, most of us have been subject to a bag scanner to ensure we are not transporting stolen goods or weapons of some sort into or out of a venue or aeroplane.

Yet, while familiarity with these devices is common, few of us spend much time figuring out how they work or what the consequences are of subjecting oneself to their scrutiny. There are many stories in the public domain regarding the apparent danger of X-ray radiation and other risks of scanners of this sort. But are these stories based on fact or do they just make good reading? What do these body and asset ­scanners really do?

Hi-Tech Security Solutions asked two experts in the field to tell us about the scanners we see today, and what new technology we could be seeing in future. Our experts are:

• Neil Cameron, general manager, Johnson Controls Building Efficiency, and

• Andy Hudson, relationships manager at HISSCO.

Hi-Tech Security Solutions: Asset and people scanning has been around for ages. How have these systems changed over time and how do you expect them to evolve in future?

Neil Cameron: In the past, systems were focused around a manual approach. The intervention was driven by manpower; a person would sit in front of a scanner projection and monitor the images for discrepancies. Today, the systems have become far more efficient as they remove the element of human error by in­corporating automation. The technology is engineered to scan for a particular substance, shape and density, enabling the security personnel to identify if contraband is being smuggled on or in the person.

This is far more accurate and efficient in comparison to the past technologies where a person would have to manually scan up to 400 images a day and physically notice items to be flagged. The latest technologies compare a previous scan with a latest scan to automatically flag any changes in any area of the full body scan, creating a physical signature that will automatically be processed for immediate detection and action.

Andy Hudson: We can put X-ray ­scanning technologies for the screening of mail, goods, luggage and cargo into two categories. Firstly, advanced systems using X-ray and computer tomography for an automated decision as to whether or not a threat item was present in items being screened. Secondly, conventional X-ray systems that require an operator to make a determination as to the composition of the contents of an item being examined.

Up to now, advanced systems have comprised of similar technology to Cat-Scans used in hospitals for MRI scans. These systems are normally operated in airports throughout the world for the exclusive purpose of detecting organic substances within luggage that have a similar characteristic to explosives. Using a series of complex and secret algorithms, these units determine whether or not the mass, density and shape of items have a composition that could contain an explosive substance. The downside of using this type of equipment is that it can be slow, and is extremely expensive to purchase and maintain. The operation of a gantry spinning at a significant RPM (revolutions per minute) to take slices of huge volumes of items being screened means that the wear and tear on this equipment is substantial.

A new technology has just been released that will improve the speed and accuracy of the screening process and significantly reduce the servicing/spare parts required over the lifetime of the equipment. This system still uses computer tomography, but instead of a rotating gantry to take slices, as the item(s) to be screened pass through, a number of pulses positioned inside the machine take multiple X-rays and create a three dimensional image for processing. To provide some idea as to how this works, imagine walking through a crowd of people with lots of people taking flash photographs of you from all sides.

This equipment also allows for quicker throughput as the belt runs at 0.5 metres per second. This is the normal operating speed of baggage belts at airports worldwide.

For conventional systems, in the past all of these types of X-ray machines that you often see at airport check points have provided an oper­ator with one image of the bag going through the unit. This is because there was only one X-ray source – so effectively only one picture was taken. A few years ago, manufacturers developed a dual-view system that allowed for two images to be taken of a bag or item to be screened at two separate angles. Many countries now mandate that for aviation security applications, only dual view technology can be used for the screening of baggage and or cargo.

The latest news is that systems are now being offered with three or more views all of which are to assist an operator in making a decision as to the contents of an item being screened. Manufacturers are also working on improving the levels of penetration and resolution (image quality) with these X-ray machines. It used to be that an X-ray could penetrate 25 mm of steel with a resolution whereby you could pick up a thin strand of wire. Today, penetration values have increased to over 40 mm of steel with a much thinner strand of wire being seen on the image.

As far as body scanners are concerned, the future is in the use of low frequency radio waves. Whilst there may be limitations with this technology, it is being improved all of the time. Unlike exposure to ionising radiation caused by X-rays this technology is ideal for multiple screening activities and is completely safe in application. At this stage it is still an expensive screening system but within the next ten years will undoubtedly be used to replace archway metal detectors.

Hi-Tech Security Solutions: What about health concerns? Many people fear the radiation could cause cancer or some kind of disease. Is this a realistic fear today?

Neil Cameron: It is correct that in the past, medical grade X-ray machines were utilised in the scanning process. These machines transmitted X-rays which bombarded the body with high-energy electromagnetic radiation. However, new technologies have seen the eradication of such methods. The technology used today is known as ‘back­scatter’ scanning.

Backscatter scanning uses ionising radiation, which means that rays are flung at the body rather than penetrating through bones and skin. The radiation scatters as it hits the body tissue; ricocheting the rays back towards the sensors of the machine. This in turn creates a picture (it more or less functions on the same concept as echolocation or bio sonar).

Although the potential risks are very low per scan (a person is subjected to the same amount of radiation if they were to sit next to a pile of 20 bananas), there are important safety regulations that are rigorously maintained. Each person’s scan is logged and a sensor monitors the actual record of exposure to any type of radiation, which is then put into a report and maintained for medical purposes and made accessible to the Department of Health.

Andy Hudson: Radiation is simply not a realistic fear for either operators or persons passing through these X-ray systems. Because our bodies are made up of water, medical X-rays need to be far stronger because X-rays absorb water. To penetrate the human body, the X-rays need to be powerful. In the case of conventional systems used for screening, these are very low-dose (emitting about 5000 times less radiation that the average medical X-ray).

Hi-Tech Security Solutions: When it comes to asset scanning, what is new in the market? As technology is able to discover and differentiate between different materials, so the criminal or terrorist element finds new ways to bypass scanners. What is the industry doing to make discovery more reliable and faster?

Neil Cameron: The technology that industry has implemented relies on item specific scanning. Each scanner is customised according to the client’s exact need; for example, should the scanner be implemented in a platinum mine, the scanner will pick up the smallest amount of platinum anywhere on that person’s body, whether it be under a finger nail or in a shoe.

The technology is so advanced that it is impossible to smuggle any substance that the scanner is programmed to detect. The scanner can even detect machinery, tools and items or traces of an item that has been hidden in an attempt to later be smuggled. This means that if a screw for a tool has been replaced with an identical screw made of platinum it will be detected. The success is in the customised, item specific scanning.

Andy Hudson: The answer to this is simple. The industry is combining multiple technologies and new hardware including X-ray, computer tomography, quadrupole resonance, low frequency radio waves, metal detection and developing complex software algorithms for threat determination.

Hi-Tech Security Solutions: What products does your company supply to market?

Neil Cameron: The Johnson Controls P2000 X-Ray solution takes a standard X-ray machine and adds intelligence. Designed in conjunction with a local platinum group to improve the effectiveness and control of full body X-ray scans, the solution is integrated into Johnson Controls’ P2000 access control platform. As such, it makes integration into enterprise systems, such as HR, health and safety, security (CCTV, access control, etc.) and time and attendance systems possible. This is an important differentiator, facilitating development of intelligent algorithms to assess and minimise risk, meet health regulations, and improve process speed and efficiency. Rolled out over a year ago at the mine’s production facility, it has proven itself highly beneficial.

Andy Hudson: HISSCO sells all of the technologies that have been mentioned above. The new MV3D is the latest advanced Cat-Scan system that does not use a rotating gantry. We also supply the ProScan low frequency body scanner and an entire range of single and multiple view conventional X-ray systems. These can all be viewed on our website www.hissco.co.za.

For more information contact:

Johnson Controls, +27 (0)11 921 7141, neil.cameron@jci.com, www.johnsoncontrols.com

HISSCO, + 27 (0)11 397 1323, andy@hissco.co.za, www.hissco.co.za.

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