Agfa Gevaert Nv

Agfa-gevaert

Gentil Verbeke

Gerard J Boeve

Walter Exelmans

Luc H Leenders

Jan A Van Den Bogaert

Frans Henri Claes

Kudolf Van Den Bergh

To minimize the adverse effects of flare in a photostimulable phosphor read out apparatus, the input face of a light guide for guiding light emitted upon stimulation has an elliptical cross section. It is positioned so that one of the foci of the ellipse defining the elliptical cross section coincides with the scan line. The second focus is positioned above the scan line and in the vicinity of the second focus a light beam reflection preventing means is provided so that stimulation light reflected by the input face of the light guide is extinguished. In an alternative embodiment the light guide has a circular cross section and is positioned so that the axis of a cylinder comprising the input face does not coincide with the scan line.

Radiation read out apparatus

A cassette (10) for photo-stimulable ('PSL') radiography, comprising a flat rigid base (12) and a cap (14) for the base which is releasably securable thereto so as lighttightly to cover a layer of PSL material applied to the inside face of the base, which cassette comprises a rigid removable PSL plate (13) which can freely rest on the base plate within the cap, and which is arranged for absorbing a portion of the X-ray radiation image which will expose the PSL layer on the base and which has four extensions (17) for its lifting, the cap (14) and the removable PSL plate (13) being arranged in such a way that both the cap alone, and the cap together with the PSL plate can be lifted from the base, in order to allow the separate reading-out of the image of the base and of the PSL plate.

Cassette for photo-stimulable radiography

An apparatus is described for reading an image from a stimulable phosphor sheet (1) carrying a radiation image thereon. The apparatus comprises exposing means (2) for exposing the sheet (1) to scanning stimulating radiation which causes the sheet (1) to emit light in the pattern of the stored image, the stimulating radiation being deflected into the trace direction by means of galvanometric deflection. Detecting means (13) photo-electrically detect the emitted light. Erasing means (22) progressively exposes the sheet (1) to erasing radiation during the retrace steps of the galvanometric deflection to erase any residual image on the sheet (1) to enable subsequent re-use thereof by exposure of the sheet (1) to erasing radiation.

Apparatus for reading an image from a stimulable phosphor sheet

A cassette for a photo-stimulable luminescence (PSL) radiography which comprises a flat rigid base having one surface of which a layer of PSL material is adapted to be supported, a cover for the flat base constituted of a top wall coextensive in area with the one surface of the flat base and a flange extending around the periphery of the cover top wall and projecting at an angle to the cover top wall, the peripheral flange of the wall being disposed in close-fitting relation to side edges of the base when the base and cover are assembled, and cooperating releasable detent means on the peripheral flange of the cover and the side edges of the base for securing the cover and base together, the cover being separable from the base upon release of the detent means to permit the base for radiographic exposure of the PSL layer. Preferably, the rigid base has significant thickness so that its side edges are in the form of side faces and the base side faces are inclined laterally with the side walls of the cover being correspondingly inclined in order to facilitate assembly of the cover on the base.

Cassette for PSL radiography

An image scanning apparatus has an apparatus sub-frame and a separate sub-frame which are adapted to rest upon a floor or like supporting surface independently of one another. The separate sub-frame includes a scanning station having means for scanning the thus-transported recording medium with a beam of radiation and the apparatus sub-frame has a conveyor for transporting an image recording medium towards and away from the scanning station. The apparatus sub-frame carries wheels which are adapted to be lowered into contact with the supporting surface in order to elevate the apparatus sub-frame above such surface. The apparatus and separate sub-frames have cooperating shoulders which are brought into abutment when the apparatus sub-frame is elevated and upon continued elevation of the apparatus sub-frame result in simultaneous elevation of the scanning station sub-frame above the supporting surface. The projections preferably are configured to bring about self-alignment of the two sub-frames relative to one another upon abutment thereof. The separate sub-frame preferably includes a separate conveyor for receiving the medium from the apparatus sub-frame conveyor and delivering the same to the scanning station to thereby isolate the scanning station from vibrations present in the apparatus sub-frame.

Image scanning apparatus

In a known method for radiographic imaging, a phosphor sheet capable of stimulation with radiation and carrying stored thereon an image pattern obtained e.g. by an X-ray exposure through a patient's body, is exposed to stimulating radiation, such as a laser beam, which causes the sheet to emit light in the pattern of the stored image and the emitted light is read-out photoelectrically. The stimulating radiation is applied to the sheet as a beam which is caused to scan the sheet linewise as the sheet undergoes relative movement in one direction with respect to the beam by means of galvanometric deflection which deflects the beam in one direction in a scanning step and then in the opposite direction in a retracing step to return the beam for the next scanning step. In the invention, the sheet is exposed to the beam at a significantly lower intensity level to cause the sheet to emit low level light corresponding to the image pattern. The low level light is read out as low level image signals which are then employed to control the sensitivity with which the light emitted as a result of the scanning step is read out photo-electrically, e.g. the gain utilized for such read-out. The opaque light chopper ordinarily employed to block the radiation beam during the retrace step is replaced with a chopper of limited light transmissivity, e.g. 5-10%, which reduces the intensity of the radiation beam during the retrace step so that the same light source can be used during both the scanning and retrace steps.

Radiation image read-out system

Scanning apparatus for scanning a cassette of the type used form photo-stimulable phosphor luminescence (PSL) radiography that includes a rigid base plate carrying a PSL layer thereon and a cover adapted to be releasably secured to the base plate in overlying relation to the PSL layer, in which a cassette is removed one-by-one from an input stack of a number of cassettes arranged with the plates thereof in generally vertical orientation and transported to a separating station for removal of the cover, to a scanning station for scanning of a PSL image thereon, to an erasing station for erasing the scanned image, and to a re-assembly station for re-assembly of the cover and base plate, all while the base plate is maintained in generally vertical orientation and preferably is displaced only within its own plane. The re-assembled cassettes are stacked vertically in an output stack for removal from the apparatus.

Scanner for the PSL radiographic cassette

A method for recording an image of ionizing radiation comprising the steps of:

Growing community of inventors

Edegem, Belgium

Gentil Verbeke