Auslesen von supraleitenden Fluss-Quantenbits
Final Report Abstract
Superconducting quantum interference devices (SQUIDs) are very sensitive detectors of magnetic flux. They combine the physical phenomena of flux quantization and Josephson tunneling. SQUIDs are used as ultra-sensitive flux detectors for a variety of applications ranging from quantum computing to medical applications. The use of SQUIDs as building blocks and readout devices for flux quantum bits is subject of current research. Examples for medical applications of SQUIDs include magnetoencephalography (MEG), magnetocardiography (MCG) or liver susceptometry. The use of SQUIDs to detect nuclear magnetic resonance (NMR) signals enables Magnetic Resonance Imaging (MRI) at magnetic fields on the order of the Earth's magnetic field without the use of large, expensive superconducting magnets. We have developed a MRI system that combines prepolarization in a field up to 300 mT with SQUID detection at fields around 100 microtesla and is capable of acquiring MR images of peripheral parts of the human body. We have used this system to acquire images of a human arm with an in-plane resolution of about 2 mm. The best resolution achieved on water phantom is well below 1mm. A major advantage of this system is that it could be marketed for a substantially lower price than conventional MRI, thereby potentially lowering the cost of imaging significantly. Because this novel MRI system uses very low magnetic field strength it is very open and could readily be combined with other modalities like MEG. The absence of susceptibility artifacts at microtesla fields makes this system an ideal candidate to be used for image-guided interventions like, for example, imageguided biopsies. The unique strength of microtesla MRI, however, is the substantially higher T1-weighted contrast achievable in microtesla fields as compared to the fields on the order of 1.5 T and higher used in conventional MRI. This enhanced contrast could have significant impact in the use of MRI for tumor imaging. SQUID-detected microtesla MRI would combine better discrimination of tumors with lower costs and could therefore be used as a novel low-cost device to detect, for example, prostate or breast tumors.
Publications
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SQUID-Detected Magnetic Resonance Imaging in Microtesla Magnetic Fields. J. Low Temp. Phys. 135, 793 (2004)
R. McDermott, N. Kelso, S-K. Lee, M. Mößle, M. Mück, W. Myers, B. ten Haken, H.C. Seton, A.M. Trabesinger, A. Pines and J. Clarke
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Correction of concomitant gradient artifacts in experimental microtesla MRI. J. Mag. Res. 177, 297-307 (2005)
Whittier R. Myers, Michael Mößle, and John Clarke
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Microtesla MRI detected with a superconducting quantum interference device. Proc. Intl. Soc. Mag. Res. Med. 13(2005)
M. Mößle, W.R. Myers, S-K. Lee, N. Kelso, M. Hatridge, A. Pines, John Clarke
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SQUID-detected in vivo MRI at microtesla magnetic fields. IEEE Trans. Appl. Supercond. 15, 757 (2005)
M. Mößle, W.R. Myers, S-K. Lee, N. Kelso, M. Hatridge, A. Pines, John Clarke
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SQUID-detected MRI at 132 μT with T1-weighted contrast established at 10 μT-300 mT. Magnetic Resonance in Medicine 53, 9 (2005)
Seung Kyun Lee, Michael Mößle, Whittier Myers, Nathan Kelso, Andreas H. Trabesinger, Alexander Pines and John Clarke
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SQUID-detected microtesla MRI in the presence of metal. J. Magn. Reson. 179:146-51 (2006)
M. Mößle, S. Han, W. Myers, S-K. Lee, N. Kelso, A. Pines and John Clarke
