X-ray or gamma ray systems or devices – Electronic circuit – With display or signaling
Reexamination Certificate
1999-01-28
2001-04-24
Porta, David P. (Department: 2882)
X-ray or gamma ray systems or devices
Electronic circuit
With display or signaling
C378S095000
Reexamination Certificate
active
06222906
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an X-ray diagnostic apparatus sing an X-ray flat panel detector and a method for controlling the same X-ray diagnostic apparatus.
2. Description of the Prior Art
In a field of X-ray image diagnosis, instead of radiography with conventional X-ray film, an image intensifier (I.I)-TV system has been widely used. The I.I-TV system has such advantages that X-ray image diagnosis can be performed immediately without a wait time for development unlike the silver salt film, real-time fluoroscopy as well as radiography can be carried out, and management, storage, transporting and copying of an image are facilitated by converting an image to digital data by video capture.
FIGS. 1A
,
1
B show a conventional X-ray diagnostic apparatus utilizing such an I.I-TV system.
In this X-ray diagnostic apparatus, X-ray is projected from an X-ray source
100
to a patient and an an X-ray image passing through the patient is intensified by I.I
101
and converted to an optical image. This optical image is taken by a TV camera
103
via an optical system
102
and subjected to a predetermined image processing by an image processing portion
104
and then supplied to a monitor device
105
. As a result, the X-ray image can be observed via the monitor device
105
.
In this X-ray diagnostic apparatus, magnification for the X-ray image is variable inside the I.I
101
. If an entire X-ray image irradiated to an input surface of the I.I
101
is required to be observed, this entire X-ray image is focused on an output surface of the I.I
101
as an optical image by controlling an electronic lens provided inside the I.I
101
. If part of the X-ray image irradiated to the input surface of the I.I
101
is required to be observed, this part of the X-ray image is focused on the output surface of the I.I
101
as an optical image by controlling the electronic lens as shown in FIG.
1
B.
The X-ray diagnostic apparatus provided with the I.I
101
is capable of changing the magnification for the X-ray image by the electronic lens. Further, by narrowing an observation region for the X-ray image irradiated to the input surface of the I.I, a high resolution optical image can be obtained easily.
The size of the imaging region of the I.I-TV system is determined by a bore of the an I.I. Recently, I.I having a bore as large as 16″ has been produced to meet a demand for enlargement of an imaging region. However, if the bore of the I.I is increased, a depth of its detecting system as well as the imaging region is increased, so that its weight also naturally increases. As a result, such an X-ray diagnostic apparatus becomes difficult to use. Further, the service life of the X-ray diagnostic apparatus is short because of tube structure.
Thus, an X-ray diagnostic apparatus utilizing a thin type X-ray flat panel detector has been regarded as a hopeful alternative to compensate for such disadvantages of the I.I-TV system.
The X-ray flat panel detector is capable of reading an X-ray strength distribution projected on a plane as data in each pixel. This X-ray flat panel detector is classified to two types. One is an indirect type in which the X-ray is converted to a light wavelength which can be detected by an photoelectric conversion element by using a fluorescent material, and the other one is a direct type in which the X-ray is directly detected by a semiconductor such as selenium. Both types of the X-ray flat panel detectors are produced by applying fine processing technology like semiconductor production technology, liquid crystal display panel production technology or the like and a panel of about 40 cm×40 cm can be produced now.
Recently, a case using the X-ray radiography to grasp a patient's condition has been increased in an emergency field such as an accident or disaster. In the conventional X-ray diagnostic apparatus, because its radiography region is relatively small, positioning for taking a region of interest within that radiography region must be achieved in even an emergency case or a number of radiographs must be taken to radiograph an entire field of the region of interest.
However, in case of the conventional X-ray diagnostic apparatus, if its X-ray source and X-ray detector are connected to each other in the system, detection of the position thereof and control of the position thereof must be carried out so as to place the X-ray detector at a position on which the X-ray is irradiated, so that labor and time are needed for this positioning.
Further in the conventional X-ray diagnostic apparatus, if the X-ray source and X-ray detector are not connected in the system, the position thereof must be determined by a number of pre-irradiation to place the detector at a position on which the X-ray is irradiated. Thus, in addition to the above problem, there is another problem that exposure to the X-ray is increased.
Further in a case of an X-ray diagnostic apparatus utilizing a large vision field X-ray flat panel detector, because entire pixel data of that X-ray detector are collected, it takes a long time to collect the data, and further it takes time and labor to extract and display data including an interest position from the collected data. That is, there is still another problem that high speed and detailed radiography is impossible.
From another point of view, the X-ray diagnostic apparatus is demanded to satisfy the following two points. One of them is ability to observe a wide region at a relatively low spatial resolution. The other is the ability to observe at a relatively high spatial resolution although the area is small. To satisfy these two requirements, an X-ray diagnostic flat panel detector having as high a spatial resolution as possible and as wide a vision field as possible is demanded to be produced.
However, if such an X-ray flat panel detector having the high spatial resolution and large vision field is used, data amount per frame output from the X-ray flat panel detector increases tremendously, thereby producing an inconvenience that its image processing circuit at a next step is burdened with a large load. Particularly, in case where X-ray consecutive image data (e.g., 30 frames/second) is collected, data transmission and processing at a very high data rate must be carried out, so that an expensive unit needs to be provided as a signal transmission system and signal processing system.
In a field of X-ray image diagnosis, angiography has been important for diagnosis on a circulatory organ such as the heart and blood vessel. According to this angiography, a tube called a catheter is inserted into a blood vessel up to near an object artery of a patient under fluoroscopy and then X-ray contrast medium is injected into the blood vessel through the catheter. The X-ray contrast medium flowing in the blood vessel is radiographed at a high speed with the X-ray diagnostic apparatus. As a result, the condition of the blood in the blood vessel is visualized.
Particularly, this inspection is carried out for diseases of the circulatory organ like myocardial infarction, cerebral infarction. Because the tube is inserted into the blood vessel, this inspection is conducted in a relatively clean inspection room. In this case, a patient lies on a diagnostic bed for the catheter and an operator and several assistants stand around him. A pair or two pairs of the X-ray sources and X-ray TV units (hereinafter referred to as X-ray TV chain) for obtaining X-ray images are placed just beside the patient (see FIG.
2
).
In such an environment, a supporting device supporting the X-ray tube and X-ray TV unit is brought near to the patient as required from various angles like the head portion, leg, right hand side, left hand side to ensure a better access to the patient (see
FIG. 3
)
Conventionally, when the I.I.-TV camera is used as the X-ray TV system, even if the direction for approaching the I.I to the patient is changed, the X-ray image is obtained with a constant direction by turning the image by, for example, image processin
Nishiki Masayuki
Sakaguchi Takuya
Tsukamoto Akira
Watanabe Naoto
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Porta David P.
LandOfFree
X-ray diagnostic apparatus using an X-ray flat panel... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with X-ray diagnostic apparatus using an X-ray flat panel..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray diagnostic apparatus using an X-ray flat panel... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499404