U.S. Philips Corporation

Kai-Michael Ludeke

Olaf H Dossel

Volker Rasche

Michael Harald Kuhn

Peter Bornert

Johann E Kruger

Gert Rabe

Wolfgang Hoppe

Rolf U Kobs

Jurgen Kohler

Wilfried Edeler

Bernd R David

The position of an object, for example a catheter, in a body to be examined is determined so as to enable monitoring of its movement through the body at the same time that information concerning the anatomy in the surroundings of the object is to be acquired. An as high as possible temporal and spatial resolution should be achieved for this purpose. To this end, the nuclear magnetization in the surrounding region of the object is determined by means of a micro-coil which is mounted on the inserted object, it being possible to determine the position of the object from the nuclear magnetization. Subsequently, an RF coil system is used to perform a line scan around this position in order to determine the nuclear magnetization in a line-shaped region.

MR method and arrangement for carrying out the method

An image synthesizing method and apparatus for forming a composite image from basic images with complex image values acquired by sensors having sensitivities which vary differently across the area to be imaged, includes the deviation of complex image values of the composite image from the image values of the basic images which have been weighted in dependence on the complex values of the sensitivity of the sensors. The complex sensitivity values are determined according to the invention in that the sensitivities of the sensors are estimated on the basis of the basic images themselves by determining the sensitivity of each sensor from the basic image acquired thereby.

Image synthesizing method for forming a composite image from basic images

A shielding sleeve (19) for SQUID-magnetometers which serves to shield from electromagnetic interference fields, consists of an electrically conductive shielding material so as to obtain adequate RF shielding in conjunction with a low noise contribution, completely envelops a non-shielding cryostat (10), has a predetermined sheet resistance and consists of at least one layer of the shielding material in order to avoid an increase of the magnetometer overall noise.

Squid magnetivity having a totally enclosing electromagnetic shield with

A miniaturized SQUID module (10), notably for multi-channel magnetometers, for measurement of varying magnetic fields in a field strength range below 10.sup.-10 T, includes superconducting and shielded connections between a SQUID chip (19) and a gradiometer (12). The module can be mounted in the lower part of a cryostat and enables a large number of measurement points per unit of surface area. The SQUID chip (19) is arranged on a fully shielded supporting plate (18) which has a width of only a few millimeters and which is provided with electronic circuitry (23), the SQUID chip (19) being connected in a superconducting manner, at least by soldering, to the wires (11) of the gradiometer (12) via a superconducting, solderable and bondable intermediate support (27).

Miniaturized squid module having an intermediate super conducting

A method of suppressing current distribution noise in a DC SQUID comprising two Josephson junctions (12) in a superconducting current. This current distribution noise is caused by individual fluctuations of the critical currents of the two Josephson junctions used for measuring weak magnetic fields. A DC SQUID is connected to a device which comprises a control device (14) for generating a periodic bias current (I.sub.b), a modulation device (15) for generating a flux modulation via an induced AC current in the loop (11), and a signal detection device (17) for forming a mean output voltage (V.sub.ges). The polarity of the bias current (I.sub.B) is reversed by the control device (14) with the modulation frequency and a time shift of one quarter of the period duration of the modulation frequency, so that the SQUID assumes different bias states. In the case of suitably weighted signal detection in the signal detection device (17), the current distribution noise signals stemming from fluctuations of the critical currents eliminate one another in the signal sum taken over four bias states.

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Hamburg, Germany

Kai-Michael Ludeke