Technological Breakthrough: New Scanner Could Revolutionize Cancer Diagnosis
By Cinthia Briseño in MunichScientists in Germany have developed an innovative new scanner that could revolutionize cancer diagnosis. The technology carries out two different types of scans at the same time, making an examination quicker and exposing patients to less radiation. But whether the new device will ever be cost-effective is still an open question.
Worried-looking patients wait outside a ward, while white-coated doctors dash along the corridors. At the big open foyer by the entrance, people try to make sense of the many signs or ask a patient porter where to go. For visitors to this Munich hospital, the place initially seems confusing.
The press spokesperson knows exactly where to go, however. First we turn left down a long corridor, then into another part of the building, to the stairs and, at some stage, veer right. There is plenty of time to chat on the extended stroll to our destination. Who would ever guess that in this labyrinth of a building, somewhere in the depths of the nuclear medicine department, would lurk a revolutionary new invention that has amazed doctors and researchers?
All of a sudden the walls are gleaming and white; you can almost smell the fresh paint. The rooms are spartan. One contains a narrow desk, on which stand two simple computer screens. Then our attention is grabbed by a futuristic blue glare from behind a glass screen. That is the innovation: a massive new scanner, the pride of the Munich doctors.
Biograph mMR is the name of Siemens' newest high-tech machine. The company calls its creation "a pioneering achievement in medical imaging." It is more commonly known as MR-PET, a description of what the technology actually does, namely simultaneously provide both PET and MRT images. The two techniques offer a way to look inside the body and have been in use for a long time.Cracking the Problem
The first of these techniques is called positron emission tomography, PET for short. It highlights cancer cells by detecting their increased metabolic activity. The other, magnetic resonance tomography (MRT), also known as magnetic resonance imaging (MRI), creates detailed images of internal organs. By combining the two techniques, doctors can, for the first time, check the position of internal organs within the body, their function and the patient's metabolism using just one image. Until now, two separate and costly examinations were needed, as it seemed impossible to create a machine that would combine both techniques.
The reason is the physics behind the techniques. Alexander Drzezga, a senior consultant for nuclear medicine at the Technical University in Munich and one of the first doctors to test the system in real life, explains how it works using simple sketches. The PET method measures low levels of radiation. When patients are injected with a slightly radioactive substance, the PET scan shows where in the body it accumulates. An MRT image, on the other hand, works with radio waves and a strong magnetic field. "This would however affect the electronic measurement of the radioactivity in PET," Drzezga explains.
The doctor draws another sketch, with dots representing electrons, small squares standing for crystals and numerous arrows, that shows how Siemens researchers managed to crack the problem. It involves a series of technical refinements which are barely comprehensible for non-scientists. Simply explained, at the heart of the invention are special photodiodes that prevent the magnet from disturbing the PET detectors.
The German Research Foundation (DFG) has spent more than €12 million ($16 million) on the project. In total, four MR-PET scanners will be installed in Germany. Alongside the Munich trial, Leipzig, Essen and Tübingen should all get one of the new machines this year for clinical tests. In Munich, a whole consortium is working on developing clinical applications for the scanners. Radiologists and nuclear medicine specialists from two Munich universities are involved in the research.Potential Future Market
Doctors are investing high hopes in the new combination tomography. "Until now, the PET-CT machine has been the traditional option for hybrid imaging," Drzezga says. "But the CT process has a number of disadvantages in diagnosis versus MRT."
PET-CT can also locate cancer cells in the body and show where tumors are. But CT, or X-ray computed tomography, is not equally effective for all human tissue. "Good images can be made of bones and the lungs, but the soft tissues of the brain cannot be so easily differentiated," says Drzezga. Apart from that, patients are also exposed to more radiation during a CT scan, he explains.
MR-PET should eradicate a number of these disadvantages. MRT does not have the high impact of X-rays: Indeed, magnetic resonance tomography is considered harmless. "In addition, MR-PET gives us much more information," says Heinz-Peter Schlemmer, department head at the German Cancer Research Center in Heidelberg. For example, doctors can identify how much blood is supplied to tumor-affected tissue, or check a patient's bone density -- important information for certain types of cancer.
Given these possibilities, doctors hope that the new scanner can be used to detect cancers at an early stage. It should also enable close monitoring of tumor growth, which would allow the development of a specific treatment plan for individual patients. The machines will answer questions as to whether the tumors are responding to treatment, and if the medicine works. Better aftercare for cancer patients should also be possible due to the reduced exposure to radioactivity.
Medical technology firms see the new scanners as a market with great potential. Nevertheless, it is yet to be seen whether the machines will ever be used as a routine procedure. "It is still completely unclear whether the technology will be efficient on a cost-benefit basis," says Schlemmer, who has already carried out cost-effectiveness calculations for full-body MRT and PET-CT scans. 'A Long Way to Go'
Schlemmer started with a simple calculation: As well as the purchase of the new technology, there are running costs, plus the costs of the personnel and the radioactive substances injected into the patient ahead of the PET scan. On the other side are the costs covered by the patients or their health insurance companies.
These costs remain huge, however: At present, a 90-minute full-body scan with a PET-CT scanner costs a public health insurance company over €1,100. The benefit of the scan entirely depends on the individual case, according to what sort of tumor a patient has, where it is located and how advanced it is.
Experts are divided over the question of when PET and PET-CT scans should be used. Most public health insurance companies in Germany remain skeptical about the benefits of the scanning technique and only pay for it in a few specific cases. In comparison to other European countries which have more enthusiastically adopted the technology, the German system "is hard to understand," says Alexander Drzezga. He hopes that MR-PET's advantage of shorter examination times compared to two separate scans will help brush aside doubts about the technology.
The sums still need to be done to work out what an MR-PET scanner and an individual examination will cost (a PET-CT scanner currently costs €2.5 million). It's a complex analysis that will take some time to complete, Schlemmer explains. At the end of the day, the analysis will hinge on how many patients can be scanned per day with the device and if this could really cost less than two separate examinations.
Specially qualified personnel will also be needed -- an additional cost factor. Training specialists who know how to use PET as well as MRT is a challenge in itself. One would have to know exactly what one wants to examine, Schlemmer says.
The extra information revealed by the high-tech scans will also have to be analyzed by the doctors and adequately remunerated. "The income and expenses will have to be very soberly calculated," says Schlemmer. "We have a very long way to go before the method can become a routine procedure."