The authors designed a multichannel system for noninvasive measurement of the extremely weak magnetic fields generated by the brain and the heart. It uses a flat array of 37 superconducting magnetic field-sensing coils connected to sophisticated superconducting quantum interference devices. To prevent interference from external electromagnetic fields, the system is operated inside a shielded room. Complete sets of coherent data, even from spontaneous events, can be recorded. System performance was evaluated with phantom measurements and evoked-response studies. A spatial resolution of a few millimeters and a temporal resolution of a millisecond were obtained. First results in patients with partial epilepsy and investigations of the cardiac conductive pathway indicate that biomagnetism is now ready for a systematic clinical evaluation. Interpretation of measurements was facilitated by highlighting biomagnetically localized electrical activity in three-dimensional digital magnetic resonance images.
%675$&7We demonstrate for the first time the feasibility of Coherent Scatter Computed Tomography (CSCT) with a fan geometry primary beam. CSCT allows superior tissue characterization and diagnosis by reconstructing the structure function rather than the attenuation properties as in regular CT. To study the feasibility of CSCT, Monte-Carlo based simulations of scatter distributions of technical phantoms were carried out. The projection data were used as input for a novel algebraic reconstruction technique (ART) which takes account of the details of the measurement geometry. First results are discussed showing the potential of CSCT. The influence of achievable angular collimation quality is investigated and an outlook on future work is given.
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