Device for determining the spatial absorption distribution in a plane of examination
AssigneeU.S. Philips Corporation
InventorWolfgang Wagner
Life of this patent
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Abstract
The device in accordance with the invention comprises detectors, a first part of which is not struck by radiation during measurement of the useful signal, whilst a second part which is struck directly by the radiation during the measurement of the useful radiation, is shielded during a next measurement. During the last measurement, the first detector part is struck by scattered radiation. From the two signals thus formed, a signal free from scattered radiation can be obtained by subtraction.
Claims4
In a device for determining a spatial absorption distribution in an object, comprising a plurality of radiation sources which are arranged in a plane of examination and which irradiate the plane of examination from different directions, and also comprising a large plurality of detectors which are arranged on an arc of a circle in the plane of examination and which serve to measure the intensity of radiation which passes through the object, at least some of said detectors being struck by radiation from more than one direction, the improvement wherein:
- the detectors comprise a first zone (831, 832) which is active to produce a first signal;
- and
- an adjoining second zone (830) which is disposed in the plane of examination and detects radiation which passes along straight lines between at least one source and the detectors in said second zone, and is active to produce a second signal;
- and
- the device further comprises shielding means which function to shield the first zone from radiation which passes along straight lines between the sources and the detectors in said first zone.
Dependencies are inferred from the claim text.