Exploring forensic medical imaging
Medical imaging techniques are not just used for diagnosing disease and assessing treatment; they can also be used as evidence in court
Meredith Thomas met Mark Viner, a registered forensic practitioner, to hear more about how these methods are used in a legal setting.
What is forensic radiology?
Forensic medical imaging is the application of medical imaging techniques, such as X-ray or MRI scanning, to legal questions. In the medical sense, we are generally looking at questions that apply to an individual. You could be looking at how or why they died or you may be trying to establish issues of identity. You may have people who are living and claiming to be older or younger than they really are.
Because of the way medical technology has moved on, we no longer need to cut living people open to find out what is wrong. In the past we used to do an operation to look in the abdomen, where we now simply do a scan. We can use the same technology to provide answers about the dead without having to do an autopsy (post mortem). In a lot of cases, the cause of death could be determined by doing a scan. If it’s inconclusive, an autopsy could then be done if necessary.
Computed tomography (CT) is one of the best examinations that can be done. It can give you a 3D image, unlike an X-ray, which gives you a 2D image. Having said that, an X-ray is a lot cheaper and a lot easier to access, so it has its advantages. Magnetic resonance imaging (MRI) is also good, particularly in cases of sudden death in babies and small children. However, this has an added disadvantage, particularly in forensic cases: if there is any ferrous [iron-containing] metal involved, it will move in the scanner’s large magnet.
Does forensic radiology have uses in criminal pathology as well?
It does, because you can record and examine a lot more information. For example, if someone has been shot, you will want to find out where the bullet is. You cannot assume that it has come out, even if you have an exit wound, which is why bodies should always be X-rayed. Bullets can end up in the most amazing places. Sometimes they will go into the body and actually enter the bloodstream. Even though you have an entry wound in the chest, the bullet can sometimes end up in the leg because it has travelled down the arteries.
In addition, in what we call mass fatality incidents – for example, a bomb going off – you can use radiology to identify people. If someone has had a fracture previously, there will be X-rays of that. We can compare those with X-rays we take of the deceased and see whether it’s the same individual. You can also use the radiography to look for minute fragments of the bomb mechanism.
What do you think the future of forensic radiology is going to be?
I think forensic radiology is going to expand exponentially over the next 20 years. In this country we are going to see its increasing use to replace autopsies, particularly in non-suspicious sudden death. I think we are also going to see an increasing reliance on it for forensic cases, including murders.
We will need to adapt imaging techniques to meet this new requirement. The more decomposed the body is, obviously, the less soft tissue it has. You’ve got to think about how the CT scanner is set up. If the tissue is no longer there, it is no longer absorbing the radiation. You have to programme the machine accordingly, so that it reconstructs the information in the right way.
There are also issues around training and education. For example, in this country, pathologists are often not familiar with looking at and reading CT scans. The problem has always been that when these new medical technologies come out, the dead are often the last people to have access to them. In other countries (like Denmark, Switzerland, Japan and, increasingly, the USA), they already have CT scanners in their public mortuaries. So we are a little bit behind, really.
How did you become interested in forensic radiology?
I trained as a diagnostic radiographer and then I started working in clinical practice. In most large hospitals, you do occasionally get asked to undertake forensic examinations of one form or another. We used to get involved in X-raying the dead and bits of dead bodies that were discovered in woods.
Then, in the early 1990s, there were several terrorist attacks in London. I just seemed to be in the wrong place at the wrong time in different hospitals. I was involved in dealing not only with the living that came from those incidents but also the deceased, and I became aware of a training issue within our own profession. People just didn’t have a clue what they were supposed to do. Taking an X-ray to find out whether there might be an item of evidence means that the radiograph you take is potentially going to be scrutinised in a court. We did not understand that at all.
What was it like to work in the Balkans?
In the mid-1990s, I took a call from a pathologist who I used to work with in the hospital. He was looking for radiographers to assist the United Nations in the Balkans [an area of south-eastern Europe where several wars were fought during the 1990s]. They were exhuming bodies from mass graves. Over the next few years, we set up protocols and trained people to go out and X-ray the human remains. We were operating out there, usually from April to October each year, working as part of a team with pathologists, scenes of crime officers and various scientists.
We use a thing called a fluoroscope, which is like a video X-ray. We would open body bags and screen the remains of individuals who had been exhumed from mass graves after three or four years. We were looking for bullets and bullet fragments, as well as any other items of evidence. When you bury a body in the ground for several years and then dig it up, everything looks the same colour. The advantage of using X-ray is that all the metallic stuff really stands out. It’s quite important with ballistic material to be able to get it out without damaging it because you can then trace it back to the gun that fired it.
The aim of the exercise was to determine the cause of death and the identities of people in the graves. The charge was that all these guys of fighting age had been rounded up, taken to the woods and shot. Could there be any charge that they had died fighting? This defence does not stand if the bodies had their hands tied behind their back, had blindfolds on and had been shot in the back of the head.
We found a lot of incidents of blindfolds and ligatures, and investigators would find bullet casings by the sides of the graves. These people had been lined up along the sides of the grave, had been shot and had fallen in. All of the evidence put together made sense of what you, as an individual, were finding.
I went out numerous times – probably 13 to 14 times over six years. It was rewarding from a personal and professional perspective. I think everybody was affected by it to one degree or another. You can’t deal with that sort of scale of macabre criminality without being affected. I think the key thing is to remember that you are doing a scientific job and you have to just focus on the science. Once you start putting names, faces and personalities to these individuals, it actually becomes very difficult to deal with.
How do you become involved in forensic radiology?
You have to train as a radiographer or a radiologist. There are probably only 20 or 30 people who are regularly involved in forensic radiology in the UK, so it would be very, very competitive to get into doing it full-time. As with any forensic specialty, you need a day job that allows you to become an expert. It is very rare to do a degree in forensic science and then walk out of the door and get a job, but it is an interesting sideline.