Research of Ways and Development of Magnetoresonance Tomograph with a Pulsed Magnetic Field
Tech Area / Field
- MED-DID/Diagnostics & Devices/Medicine
3 Approved without Funding
Kurchatov Research Center, Russia, Moscow
- NIIIT (Pulse Techniques), Russia, Moscow
- Forschungszentrum Karlsruhe Technik und Umwelt / Tritium Laboratory, Germany, Karlsruhe\nUniversity of California / Department of Radiological Sciences, USA, CA, Irvine\nIntermagnetics General Corporation (IGC), USA, NY, Latham\nBruker Medizintechnik GmbH, Germany, Karlsruhe
Project summaryProject is dedicated to development of magnetoresonance tomograph based on the nuclear magnetic resonance (NMR) and intended for medical research. Tomograph is distinguished from the well-known systems by the fact that it uses a pulsed magnetic field. In the magnetoresonance tomographs the image quality of slice-tomograms and speed of their formation depend to a large measure on the magnetic field strength. To create a magnetostatic field of tomographs the different magnetic systems are applied. For fields with induction up to 0.2 Т both the so-called resistive electromagnets as solenoids or design with an iron yoke and permanent magnets made from the special-purpose alloys are used. To achieve higher fields (up to 1 Т and more) the superconductor magnetic systems should be applied. But their cost is enough high (millions of dollars). Necessity for liquid helium for their operation hampers the use of this equipment at the sites remote from the industrial centers.
NMR tomograph with a resistive pulsed magnet, field of which increases and drops slowly and has a flat top with induction of 0.5 T, will be developed as a result of execution of the given Project. Power consumption is not high; in the average it is not more than 1-2 kW. Method of the stable in time magnetic pulse forming is presented in Patent RU 20.47871 C1 of the Russian Scientific Center, Kurchatov Institute. It lies in the fact that the capacitor storage is discharged through a solenoid to create the magnetic field; in this case the bell-shaped top of magnetic pulse is compensated with a field of special coil, through which the control currents go. Method is characterized by its high efficiency; energy required for forming of a flat top of magnetic pulse does not exceed several percent of energy being given up by storage. Low lag of control system provides fast setting of the resonance value of field. It should be pointed out that at present tomographs with induction of 0.5 T are produced only with superconducting magnets and their cost is far beyond that of proposed system.
Tomograph enables one to obtain NMR-tomograms by fast methods, such as FLASH-method with a low angle of nutation ensuring imaging in seconds or EPI-echoplanar imaging in tenth fractions of a second. In this case tomograms are free of artifacts caused by organ motions. This method allows one to carry out "filming" and to retrace the processes in dynamics. Thanks to a large volume of information, high speed of imaging and low operating expenses it is possible that tomograph with a high pulsed field will be also effective in those research where another instruments are presently used, for example, ultrasonic ones, etc.
To develop the magneto-resonance tomograph with a pulsed magnetic field, it is necessary to perform large volume of research and design work, which would conclude, with production of a prototype. Acquired experience will allow the partner-enterprises jointly with industry to manufacture a production model. Tomograph with a pulsed magnetic field will be reasonable not only for diagnostic centers, but also for small clinics and hospitals. This instrument can be used in the field conditions in the regions of natural calamities where fast diagnostics is especially important. These tomographs can be located in the cars. It is not inconceivable that, in time, the reasonably portable pulsed tomographic instrumentation with low power consumption will be used in the cosmic research too. Taking into consideration the continuous progress in the field of energy storage facilities, in the near future NMR pulsed tomographs will be able to be produced with induction of 1.5-2 Т and more. This will permit the spectrometric measurements considerably extending the diagnostic capabilities to be carried out.
It should be pointed out that method being developed in Project in order to receive high and stable in time pulsed magnetic field for NMR-tomography can also be used in other fields of science and technology, such as thermonuclear investigations, accelerators, etc. This will enable one to abandon the usage of very expensive high power pulse generators in some equipment.
When carrying out the present Project it would be well to involve collaborators being representatives of firms operating in the field of tomographic equipment. Experience of firms producing both resistive and superconductive systems is especially of significance when developing tomograph with a pulsed magnetic field. Collaborators representing such firms, e.g. Bruker, can take an active part in development of pulsed tomograph, in which the resistive electromagnet is used and induction conforms to the superconductive system. Turbo - RARE (Rapid Acquisition Relaxation Enhanced) Method of rapid imaging can be used in the present Project too. It is obvious that consultation of firms will be of advantage when developing the time sequences and gradient devices. In its turn collaborators will be interested in obtaining the experience when developing the economical pulsed system. It is possible we shall purchase the low - and high - frequency powerful amplifiers of a firm - collaborator.
In the project participate:
1. Winner of State premium USSR and premiums of Ministerial Council USSR — A. Tsitovich.
2. Twice the winner of the State premiums USSR — V. Keylin.
3. Winner of premium of Government РФ — V. Molochkov.
4. Winner of State premium USSR — S. Tsvetkov.
5. Winner of State premium USSR — V. Chernikov.
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