Radiant energy – Invisible radiant energy responsive electric signalling – Semiconductor system
Reexamination Certificate
2000-01-27
2002-08-13
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
Semiconductor system
C250S363020, C250S367000, C250S370110, C250S385100
Reexamination Certificate
active
06433341
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for photographing radiation images by using a radiation detection cassette comprising an image memory and a solid-state radiation detector, and also to the radiation detection cassette used therefor.
2. Description of the Related Art
In today's radiography aimed at medical diagnoses or the like, radiation image photographing apparatuses using solid-state radiation detectors (whose main part comprises semiconductors; hereinafter, simply called a “detector” or a “radiation detector” in some cases) for outputting an image signal by detecting radiation have been known. As the solid-state radiation detectors used therein, various types have been proposed and put into practice.
With respect to an electric charge generating process in which radiation is converted into an electric charge, solid-state radiation detectors of different types, such as optical conversion type detectors (see Japanese Unexamined Patent Publication Nos. 59(1984)-211263 and 2(1990)-164067, PCT International Publication No. WO92/06501, and SPIE Vol. 1443 Medical Imaging V; Image Physics (1991), p. 108-119, for example) and direct conversion type detectors (MATERIAL PARAMETERS IN THICK HYDROGENATED AMORPHOUS SILICON RADIATION DETECTORS, Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. 94720 Xerox Parc. Palo Alto, Calif. 94304, Metal/Amorphous Silicon Multilayer Radiation Detectors, IEEE TRANSACTIONS ON NUCLEAR SCIENCE. VOL. 36. NO.2. APRIL 1989, and Japanese Unexamined Patent Publication No. 1(1989)-216290, for example), have been known. In an optical conversion type detector, light emitted from a phosphor by exposing the phosphor to radiation is detected by a photoelectric conversion device and a signal charge thereby obtained is stored in a capacitor of the device. The stored electric charge is then converted into an image signal (electrical signal) and the signal is output. In a direct conversion type detector, a signal charge generated within a radiation conductive material by exposing the material to radiation is collected by an electric charge collecting electrode and stored in a capacitor. The stored electric charge is then converted into an electrical signal and the signal is output.
With respect to an electric charge reading process in which a stored electric charge is read out, solid-state radiation detectors of other types, such as TFT reading type detectors which read the charge by scanning TFT's (Thin Film Transistors) connected to capacitors and optical reading type detectors in which a charge is read by irradiation of reading light (an electromagnetic wave for reading) thereon have been known.
The present assignee has proposed radiation detectors of improved direct conversion type (see Japanese Patent Application Nos. 10(1998)-232824 and 10(1998)-271374). A radiation detector of improved direct conversion type means a radiation detector employing both the direct conversion method and the optical reading method. The radiation detector of improved direct conversion type comprises a first conductive layer which is transparent to radiation for recording, a photoconductive layer for recording exhibiting photoconductivity (or radiation conductivity, more accurately) when receiving the radiation for recording which has passed through the first conductive layer, an electric charge transport layer which acts as an insulator to an electric charge having the same polarity as the electric charge charged in the first conductive layer while acting as a conductor to an electric charge having the reversed polarity, a photoconductive layer for reading presenting photoconductivity (or more accurately, electromagnetic wave conductivity) by receiving an electromagnetic wave for reading, and a second conductive layer which is transparent to the electromagnetic wave for reading, with these layers being stacked in this order. A signal electric charge (latent image electric charge) representing image information is stored at the interface (the capacitor) between the photoconductive layer for recording and the electric charge transport layer. The first and the second conductive layers function as electrodes. The photoconductive layer for recording, the electric charge transport layer, and the photoconductive layer for reading comprise the main part of the solid state detector of this type.
Various kinds of cassette for radiation detection containing in a case a radiation detector and an image memory as recording means for recording an image signal output from the detector have been proposed (for example, see U.S. Pat. Nos. 5661309 and 5773839, and Japanese Unexamined Patent Publication Nos. 6(1994)-342099 and 7(1995)-140255). The cassette described in U.S. Pat. No. 5661309 uses an image memory having a recording capacity for a plurality of images, and stores image data for one image in the image memory each time the image has been detected.
A radiation image photographing apparatus using this cassette records image data for a plurality of images obtained by successive photographing in the image memory, and reads the data of the images from the image memory to collectively output the image data to a signal processing unit located outside the cassette. In this way, it becomes unnecessary to output (transfer) the image data to the external signal processing unit each time one image is detected (photographed). Therefore, efficient successive photographing becomes possible, and processing time between signal detection and signal processing can be reduced.
Meanwhile, upon photographing a radiation image, a photographer generally carries out photographing in an order determined based on a photographing menu such as patient information and photographing information displayed on an image/information display apparatus (hereinafter, simply called display apparatus) controlling photographing.
In the case where the cassette containing the image memory having recording capacity for a plurality of images is used for photographing, the image data read from the image memory do not correspond to the photographing menu used at the time of obtaining the image data, if photographing is carried out in an order different from the order determined in advance, (that is, if the order of photographing is changed during the successive photographing) and if there is no means for relating the photographing menu and the actual images represented by the image data in the image memory. Therefore, appropriate diagnoses cannot be carried out.
For example, in the case of mass medical examination of people's chests, it is common practice for subjects to be related to a photographing order in advance and a number of plate indicating the order is provided to each subject. A photographer carries out photographing in accordance with the number plates. If photographing is carried out according to the number plates, the photographed images can be related to the subjects. Otherwise, the photographed images do not correspond to the subjects, which causes a problem on diagnosis. The same problem occurs if the cassette to be used is misplaced.
Furthermore, in the field of recent medical diagnosis, networking has been in progress. A work flow is determined based on a diagnosis of a clinician, and the work flow is transferred to each consulting room via a network. Various kinds of processing are then carried out based on the work flow. A photographing menu is included in the work flow. However, processing may be carried out in a flow different from the work flow, due to convenience of a consulting room. Therefore, the likelihood of carrying out processing procedures different from the predetermined processing procedures is growing.
Therefore, realization of means for properly relating a photographing menu to image data recorded in an image memory has been desired so that no problem occurs even when a procedure different from a predetermined work flow is taken in a network environment.
SUMMARY OF THE INVENTION
The presen
Fuji Photo Film Co. , Ltd.
Hannaher Constantine
Israel Andrew
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