U.S. Philips Corporation

Petrus W Linders

Lambertus G Fokkink

Marcel Rene Bohmer

Rudolf Kemner

Nicolaas P Willard

Wilhelmus J Welters

Herman Stegehuis

Michael J Severens

Johanna A Sondag-Huet-Horst

Andre R De Wit

Frans J Berkers

Christianus Glm Nederpelt

An X-ray examination apparatus includes an X-ray source (1) for emitting X-rays. An object to be radiologically examined is arranged in an examination space. An X-ray detector (2) derives an image signal, for example an electronic video signal, from an X-ray image of the object. An X-ray filter locally attenuates the X-rays partly. The X-ray filter is arranged between the X-ray source and the X-ray detector and the X-ray filter is provided with filter elements whose X-ray absorptivity can be adjusted on the basis of an amount of X-ray absorbing liquid present within the individual filter elements. The X-ray examination apparatus includes an X-ray collimator for locally intercepting the X-rays. The X-ray collimator is arranged between the X-ray source and the examination space and is provided with collimator elements which can be switched between an X-ray transmitting state and an X-ray intercepting state. Individual collimator elements are filled with an X-ray intercepting liquid in the X-ray intercepting state. The amount of X-ray absorbing liquid present in the filter elements is controlled by application of an electric voltage to the relevant filter elements. The collimator elements are switched between the X-ray intercepting state and the X-ray transmitting state by means of an electric voltage which is applied to the relevant collimator elements.

X-ray examination apparatus including an x-ray filter

An X-ray examination apparatus in accordance with the invention includes a filter (4) for limiting the dynamic range of an X-ray image which is formed on an X-ray detector (4) by irradiation of an object (3), for example a patient to be examined, by means of X-rays (15). The filter (4) includes filter elements (5), being capillary tubes (5), one end of which communicates with an X-ray absorbing liquid. The adhesion of the X-ray absorbing liquid to the inner side of the capillary tubes is adjustable by means of an electric voltage which can be applied to an electrically conductive layer (36) provided on the inner side of the capillary tubes (5). The filling of the capillary tubes (5) with the X-ray absorbing liquid is adjusted on the basis of the period of time during which the electric voltage is applied. This period of time can be subdivided into a number of fractions and individual rows of capillary tubes are then filled with the X-ray absorbing liquid partly in parallel.

X-Ray examination apparatus comprising a filter

An X-ray apparatus is provided with a filter (12) for limiting the dynamic range of an X-ray image formed on an X-ray detector (4) by exposure of an object (3), for example a patient to be examined, to X-rays (2). The filter (12) has filter elements (13) including one or more capillary tubes (13), one end of which communicates with a reservoir with an X-ray absorbing liquid. The adhesion of the X-ray absorbing liquid to the inner side of the capillary tubes can be adjusted by means of an electric voltage applied to an electrically conductive layer provided on the inner side of the capillary tubes (13). The degree of filling of the capillary tubes (13) with the X-ray absorbing liquid is adjusted by way of the electric voltage value. The X-ray absorption profile is adjusted within a very short period of time, for example within one second, by adjustment of the electric voltages applied to the capillary tubes (13).

X-ray apparatus comprising a filter

An X-ray examination includes a filter for limiting the dynamic range of an X-ray image formed on an X-ray detector by irradiation of an object, for example a patient to be examined, by means of X-rays. The filter has a number of electrodes and grains or powder particles containing an X-ray absorbing material and suspended in a suspension liquid. When a voltage is applied to electrodes, X-ray absorbing material in the suspension will move to the excited electrodes under the influence of electrophoresis. A distribution with a desired X-ray absorption profile is adjusted by application of a suitable voltage pattern. The electrodes may have dimensions of, for example 0.5.times.0.5 mm, enabling an X-ray absorption profile to be obtained with a high spatial resolution. The X-ray absorption profile can be changed within a brief period of time, for example within one second, by changing the voltage pattern on the electrodes.

X-ray examination apparatus comprising a filter

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Eindhoven, Netherlands

Petrus W Linders