See into living tissue with MAX IV
Max IV will be a new tool to see into material, even living material! A particular beamline for biomedical imaging, MedMax, is being proposed for Max IV. With synchrotron radiation, images of tissue can be obtained using a sort of super-x-ray to visualise things that are very difficult to see with conventional methods.
LTH News joined a workshop at BMC where interested medics found out about the opportunities offered by technology. Crister Ceberg is a professor of radiation physics and part of the groups that are to collect as many users as possible from the faculties of medicine and science.
“So far, researchers are not exactly queuing up”, he observes. “It can take time for people to understand the potential”.
In addition to medicine and biology, researchers in paleontology, cultural heritage or other fields could be interested in this beamline which is proposed for the second phase of the decision. In the first phase, seven other beamlines were decided. In August, the medicine and science researchers’ proposal on MedMAX is to be ready. Max IV and the Swedish Research Council will decide in the autumn who will be allowed to take part.
“Naturally, there are other users throughout Sweden. This is after all a national facility”, Crister Ceberg points out. “However, the beamline will not be built for medical treatment; imaging will be its most important task”.
In order to design the plans, Danish researcher Martin Bech has been employed as an expert by the Faculty of Medicine.
“We want to be able to carry out in vivo imaging, i.e. imaging of living tissue. This is not possible with the highest resolutions, however, as blurring due to movement occurs”, he explained.
The length of the beamline tube out of the storage ring is among the factors that determine how large the items to be examined can be. In a short tube, objects that are millimetres in size can be studied, while a 100 metre-long tube allows for samples of several centimetres, meaning that whole small laboratory animals can be radiated.
“In MedMAX, imaging will mainly be done of extracted samples on a scale of millimetres to centrimetres. By rotating them and analysing the images mathematically, it is possible to generate 3D-images (tomography).”
With mono-energetic radiation, one can produce so-called “K-edge-imaging” and the use of contrasting agents enables a better quantification of the result compared to ordinary x-rays.
With coherent radiation, one can produce so-called “phase-contrast imaging” which reveals finer contrasts and clearer boundaries and structures in soft tissue. For example, one can distinguish between grey and white brain tissue. The detectors are also being continuously developed.
The areas which are being put forward in the proposal as being of particular interest for the technology include lung function, tumour imaging, bone, cartilage and neuroscience.
“It will also be possible to view changes over time, to ‘film’. Wild ideas such as obtaining images of the progress of sound waves through the inner ear have been aired. Bone and implants can be studied together”, says Crister.
A number of similar facilities, besides MAX-Lab in Lund, already exist in the world. One of them is in Grenoble: ESRF, European Synchrotron Radiation Facility. Concerning the potential uses, Franz Pfeiffer from Technische Universität München explained in the workshop that gold can be used as a contrast agent to increase image contrast. He showed in images how one can slice up an organ or a body, show the entire organ’s surface or the inside of it. He showed soft tissue and skeleton in the same image or a study of plaque in blood vessels.
Peter Cloethens from ESRF explained that his source at the moment is being rebuilt for both radiation therapy and image analysis. For better images, the beams can be focused. A biopsy of a femur can be studied, even showing the basic elements that are present on the image to study the mineralisation in a bone!
Pekka Sourtti from Helsinki gave examples of “K-edge imaging”. He had studied lung function in rabbits and found that a common asthma drug could be damaging to the deep alveoli.
“MedMax can fill the ’visualisation gap’ between the technologies that exist at LBIC, Lund University BioImaging Center: microCT/PET/MRI and the protein determinations that can be carried out at other beamlines”, asserts Crister Ceberg.
Text and images: MATS NYGREN