Abstract: An information system comprises a master station (2, 10) controlling information to be displayed on a number of information units (30, 40) arranged remotely from said master station. The master station broadcasts instructions by modulated infrared signals, and these signals are detected by a photodiode within each information unit (30, 40), said information unit also comprising a receiver and logic circuitry. The information unit (30, 40) further comprises an emitter diode in order that it is capable of acknowledging the receipt of instructions. Information is presented on LCD-type displays, e.g. digits, a graphic field, or other information fields, all being implemented in LCD-type displays. The display units are, in particular, applicable in shops or warehouses, e.g. supermarkets, where a display unit may be arranged adjacent each item of merchandise, serving the purpose of displaying e.g. the unit price on the information unit.

Abstract: Inherent non-uniformities in a gamma camera system are compensated for by reducing the sensitivity for some locations on the detector. The tradeoff between image uniformity improvement and loss of camera sensitivity is maximized. Since the energy correction offsets direct the energy spectra downwards (or the energy window upwards). Scatter rejection is also improved.

Abstract: In a nuclear imaging tomographic scanner, a drive mechanism is included to selectively move the patient in an axial plane to thereby maintain a close proximity to the detector for the purpose of increasing resolution. In this way, the actual movement of the camera head is in a simple circle whereas the relative movement of the camera head with respect to the patient is one wherein the detector tends to follow the general contour of the patient by the movement within an oval path.

Abstract: A gamma camera is provided with a bidirectional switching network between each of its photomultiplier tubes and its surrounding tubes, such that each tube may inform its neighboring tubes when it has acquired a scintillation event. All of those tubes which have so acquired a scintillation event are then treated as a cluster with one of the tubes acting as a coordinator for the entire cluster. Provision is made for validation of the signals within the cluster, and the outputs of the individual photomultiplier tubes within the cluster are then synchronously and collectively applied to the signal-processing circuitry for display. In this way, it is possible to process plural valid events which occur simultaneously to thereby increase both the current rate and the validity rate of an anger-type system.