Abstract: The invention relates to a method of localizing an object in a turbid medium. After measurement of the intensities for a plurality of light paths between the light sources and the detectors, the measured intensities are normalized. Subsequently, an image of the interior of the turbid medium is reconstructed on the basis of the measured intensities. In order to counteract artefacts in the reconstructed image, the combination includes a weighting factor which reduces the effect exerted on the reconstructed image by the measured intensities with a high noise factor in comparison with the effect exerted thereon by the measured intensities with a low noise factor.

Abstract: An integrated circuit includes electrostatic discharge (ESD) protection circuits coupled to protect I/O pins and or operational circuits from damage due to ESD events. The ESD protection circuits are coupled to fuses which in turn are coupled to external program pin(s) of the IC. The fuses can be opened via the external program pin(s) to substantially completely remove the capacitive loading on the I/O pins as well as any internal circuitry within the IC. The ESD circuits may protect against ESD damage during testing, packaging, shipping and installation into a system, and then be subsequently removed via the external program pins, such as upon first application of power to the IC via the system. Because fuses are used, the added capacitive loading of the deselection circuit is substantially zero and much less than active switching elements. The ESD deselection structure is beneficial for very high frequency RF circuits, where capacitive loading problems are particularly acute.

Abstract: The MRI apparatus includes an actively shielded gradient system (40) with primary gradient coils and shielding coils (56). Despite the active shielding, such a system inevitably causes a magnetic field to some extent outside the shielding, so that eddy currents are generated in the conductive structures of the main magnet, said eddy currents causing heat dissipation and annoying noise. According to the invention, the gradient system also includes an eddy current shield (48) which consists of an electrically conductive, substantially closed plate; furthermore, the primary gradient coil (60) and the shielding coil (56) are arranged within the eddy current shield (48) and these three elements together constitute a mechanically rigid unit. As a result, eddy currents are avoided in the main magnet and annoying noise is strongly reduced.

Abstract: The light to be generated by a light source in a device for localizing an object in a turbid medium is successively coupled into the turbid medium from different directions by use of an optical detection unit. The light coupled in is transported in different directions through the turbid medium. A part of the light emanating from the turbid medium is measured by use of photodetectors. An image of the interior of the turbid medium is reconstructed by optical tomography on the basis of the measured intensities. The device includes structure which reduces variations in the intensity of the light coupled into the turbid medium from the same direction in order to reduce errors occurring on repeated executions of the measurements for successively localizing the object.

Abstract: The invention relates to a computed tomography apparatus which includes a radiation source, a detector device and an analog-to-digital converter for converting the detector output signals into digital values. In order to realize a computed tomography apparatus in which the number of binary positions required for the encoding of the signal entering the analog-to-digital converter is reduced while using simple components which operate with a high degree of reliability, use is made of a read-out amplifier (1) which precedes the analog-to-digital converter (10), has a plurality of gain factors and a control system (12) for the relevant gain factor which, when a predetermined limit value of the integrated input signal is reached, automatically selects an appropriate, each time lower gain factor for the step-wise linear approximation of a proportional ratio between the digital values and the square root of the detector output signals.

Abstract: Current mirror circuit including a current input terminal (2), a current output terminal (6), a common terminal (8), a first transistor (T1) arranged between the current input terminal (2) and the common terminal (8), a second transistor (T2) arranged between the current output terminal (6) and the common terminal (8), a transconductance stage (TS) having an input terminal coupled to the current input terminal (2), and an output terminal coupled to the common terminal (8), and a bias source (22) for biasing the control electrodes of the first and second transistors (T1, T2). This configuration provides a large bandwidth independently of the input current, accurate current transfer and a single pole system.

Abstract: Objects of this invention include provision of magnetic resonance (MR) imaging methods, MR apparatus, and radio-frequency (RF) receiving coil devices permitting interactive MR examination of a patient. In particular, this invention includes means for generating MR images by a moveable RF coil which can be moved across a patient during an MR examination. The MR apparatus includes a position detection system which detects the current position and orientation of the moveable RF coil. The coil can be hand held for manual movement or can be attached to mechanical manipulators for controlled movement. The imaging methods determine and generate magnetic gradient and RF pulse sequences to excite nuclear magnetization in a 3D region determined with respect to the current 3D position and 3D orientation of the moveable RF coil. The invention also includes moveable RF coils for receiving and transmitting which are configured and sized for convenient manipulation by an operator.

Abstract: A reduced-complexity automatic frequency control (AFC) loop to match the frequency of a receiver to that of a transmitter. A received input signal is multiplied with the sine and cosine signals of a voltage-controlled-oscillator, digitized and filtered, and the sign (the most significant bit) of the cosine function of the received input signal is sliced off by a sign slicer circuit to provide an input to two sign gates. The outputs of the two sign gates are added to produce an estimate of the frequency error, which is used to control the voltage-controlled-oscillator to match the received signal's frequency. The required number of multiplier circuits required to implement the AFC loop is reduced from prior art AFC loops by the use of the sign slicer circuit and the use of the sign gates.

Abstract: An X-ray examination apparatus is provided with a DC voltage source which is to be connected to a maines voltage and whereto there are connected an accumulator with a charging circuit for this the accumulator as well as a high voltage generator for an X-ray tube. The accumulator is charge in a standby mode; the accumulator can be discharged via the high voltage generator. There is provided a power gate circuit via which power up to a maximum value can be drawn from the mains, the accumulator being chargeable for as long as this maximum value has not yet been reached; when a power beyond said maximum value is required, the surplus beyond this maximum value is delivered by the accumulator via said power gate circuit.

Abstract: An x-ray examination apparatus comprises an x-ray source for generating an x-ray image and an image analysis system derives brightness variations from the x-ray image and derives a dose control signal dependent on said brightness variations in order to control the x-ray source. The image analysis system derives a distribution of said brightness variations and derives the dose control signal from the distribution of brightness variations. Preferably, the image analysis system is arranged to derive the brightness variations from the processed image and a histogram analysis is employed to derive the dose control signal.

Abstract: An X-ray examination apparatus includes an X-ray detector for deriving an image signal from an X-ray image. The X-ray detector has an essentially elongate X-ray-sensitive surface. The X-ray sensitive surface of the X-ray detector corresponds notably to a relevant part of the object to be examined.

Abstract: A computer tomograph detector for the detection of electromagnetic radiation transmitted by an object, which detector includes at least one detector row which consists of a plurality of detector elements, each detector element including a scintillator for converting radiation of a first energy level into radiation of a second energy level, as well as a photosensor for converting the radiation into an electrical current, each photosensor being associated with an amplifier element, is extended in such a manner that it can include a plurality of detector rows while the electronic noise is nevertheless reduced and at the same time a higher DQE is obtained; this is achieved by arranging a plurality of photosensors and the associated amplifier elements on the same substrate in integrated semiconductor technique.

Abstract: The invention relates to an X-ray diagnostic device in which the dose applied to a patient is determined and in which the effective dose which is of relevance for the radiation load is calculated from this dose as well as from a weighting factor which is fetched in dependence on the relevant anatomical region to be examined.

Abstract: The invention relates to a method of manufacturing a filter which includes a number of ducts formed by a number of deformable foils. The foils have electrically insulating outer sides, with electrically conductive bands which are separated from one another by electrically insulating bands. The electrically conductive bands on a first outer side of the foil are arranged so as to be offset relative to the electrically conductive bands on the second outer side of the foil. The foils are stacked. The oppositely situated electrically insulating bands of the oppositely situated foils are interconnected. The foils are ultimately moved away from one another in a direction transversely of the foils in order to form the ducts between the interconnected foils. At least one detached, electrically insulating section is situated in a prolongation of at least one electrically conductive band and is not connected to an oppositely situated foil.

Abstract: An X-ray examination apparatus includes an X-ray source (1) for emitting an X-ray beam, an X-ray detector (6) for detecting an X-ray image and converting it into an optical image, and a video extractor (8) which is coupled to the X-ray detector (6) via optical coupling means (9). The optical coupling means (9) is provided with an optical pick up (11) for feeding a fraction of the light flux to a photosensor (12) which produces a control signal for adjusting the X-ray flux from the X-ray source (1). The photosensor (6) is provided with an array of pixels, with weighting means for the signals detected in or by each of said pixels, and with means for determining a mean value of the detected and weighted signals, yielding a control signal which is fed back in order to adjust the X-ray flux from the X-ray source (1).

Abstract: The invention relates to an imaging method for medical examinations, notably MR examinations, in which a set of measurement values is acquired from measuring points which are irregularly distributed in the frequency domain (or in the k-space). Before an image in the space domain is generated from these measurement values by a Fourier transformation, the measurement values must be weighted in dependence on the density of the measuring points in the frequency domain. To this end, the measurement values are weighted in conformity with the magnitude of the Voronoi cells.

Abstract: The invention relates to a magnetic resonance method for determining a perfusion image of a portion, which method comprises the following steps: generation of a control pulse sequence in a first portion of the body and measurement of a control data set by generation of an MR-image sequence for imaging of an third portion of the body, generation of a labelling pulse sequence in a second portion of the body wherein a fluid flows towards the third portion, and measurement of the labelled data set by generation of the MR-image sequence for imaging the third portion of the body, and reconstruction of the perfusion image of the fluid in a mass of the third portion of the body from a combination of the control data set and the labelled data set.

Abstract: The invention relates to a computed tomography method in which the examination zone is scanned along a circular path by means of a conical radiation beam. The computation required for the reconstruction of the absorption distribution in the examination zone can be reduced by taking the following steps: a) rebinning of the measuring data so as to form a number of groups, each group containing a plurality of planes which extend parallel to one another and parallel to the axis of rotation, each plane containing a respective fan beam, b) one-dimensional filtering of the data, produced by the rebinning, of each group in the direction perpendicular to the direction of the planes, and c) reconstructing the spatial distribution of the absorption from the filtered data of different groups.

Abstract: The invention relates to a computed tomography method where the examination zone is scanned by means of a conical radiation beam. The reconstruction volume can be enlarged by reconstructing the absorption of voxels in a first sub-volume by means of a first reconstruction algorithm and that of voxels in a second sub-volume by means of a second reconstruction algorithm, the assignment of the voxels to the sub-volumes being performed in such a manner that the secondary conditions for the reconstruction algorithms used for these sub-volumes are satisfied.

Abstract: A method and apparatus for checking/updating existing software on a user's computer utilizes a graphical user interface (GUI). The GUI enables the user, without knowing what software exists on the computer, to download a text file from a remote server and check whether the software on the remote server is contained on the user's computer. The user can also download and automatically install a new or updated program via the GUI.