X-ray or gamma ray systems or devices – Specific application – Computerized tomography
Reexamination Certificate
1998-10-23
2001-09-11
Church, Craig E. (Department: 2882)
X-ray or gamma ray systems or devices
Specific application
Computerized tomography
Reexamination Certificate
active
06289073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an X-ray CT apparatus which has a compact and lightweight structure in comparison with the conventional X-ray CT apparatus.
2. Description of Related Art
There is a known X-ray CT apparatus of a so-called “helical-scanning” type, as shown in FIG.
1
. The shown X-ray CT apparatus includes a frame
100
in the form of a box. Disposed at the center of the frame
100
is a radiographic port
101
into which a patient laid on a not-shown bed is to be inserted. About the radiographic port
101
, an X-ray tube and an X-ray detector opposing thereto are adapted so as to rotate along the periphery of the port
101
together with a part of power processing components and signal processing components, providing a rotating part
102
. In operation, by irradiating X-ray against the patient inserted into the radiographic port
101
while the rotating part
102
rotates, the X-ray apparatus is so constructed as to pick up an image of tomographic layer of a desired part of the patient. Further, the frame
100
is provided, on a bottom part
100
a
thereof, with a suction port
103
. On an upper part
100
b
of the frame
100
, cooling fans
104
b
are disposed to discharge air sucked through the suction port
103
for circulating the interior of the rotating part
102
, thereby cooling down the X-ray tube and power circuits etc. which are heated by scanning.
The interior constitution of the frame
100
are shown in
FIGS. 2A and 2B
.
In the rotating part
102
, a rotary base
110
is equipped with the X-ray tube, the X-ray detector and a high-voltage generator. The rotary base
110
is arranged on a fixed base
112
through the intermediary of a bearing
111
.
A drive motor
113
for rotating the rotating part
102
, and electric components
114
a
to
114
c
, such as baseplates and power circuits, for controlling a dose of X-ray and other parameters are arranged on the fixed base
112
. Due to the weightiness of the drive motor
113
, it is disposed on a lower part of the frame
100
. The electric components
114
a
,
114
b
are arranged on both shoulders of the frame
100
, while the component
114
c
is provided on the lower part of the frame
100
. Thus, as a natural result of the above-mentioned arrangement of the electric components
114
a
,
114
b
on both shoulders of the frame
100
, a cover
117
for covering the whole of the frame
100
is shaped in the form of a box.
The fixed base
112
, the drive motor
113
and the electric components
114
a
to
114
c
constitute a fixed part of the apparatus. By a stand
115
through tilting supports
116
, the fixed part is carried so as to tilt by predetermined angles. Owing to this arrangement, it is possible for the whole frame
100
to tilt about the supports
116
as fulcrums by the predetermined angles, thereby allowing the apparatus while tilting the frame
100
to scan the patient.
From
FIG. 2B
where the frame
100
is viewed from its wiring side, it will be understood that a power line
120
approaches the interior of the apparatus by way of the backside of the frame
100
. This is because the not-shown bed for mounting the patient is provided on the front side of the frame
100
.
The power line
120
is connected to the rotating part
101
and the electric components
114
a
to
114
c
of the fixing part through the intermediary of various kinds of breakers and electric filters in the stand
115
. Of course, in the rotating part
110
, the electric power is supplied to the high-voltage generator and the X-ray detector through so-called “slip rings” (not shown).
Next, a signal line
121
for transmitting various control signals from console units or the like is wired by the way of the backside of the frame
100
, as similar to the above-mentioned power line
120
. Being wired side by side with the power line
120
as shown in
FIG. 2B
, the signal line
121
is also connected to the electric components
114
a
to
114
c
. Further, the signal line
121
for transmitting signals processed by the electric components
114
a
to
114
c
is divided into a signal branch line for controlling the drive motor
113
and signal branch lines for controlling the action of the bed and the X-ray system. It is noted that radiographic (pick-up) signals generated by the X-ray detector are transmitted to the console units through optical transmitting parts arranged in the rotating part
102
and the fixed part.
By the way, it should be noted that the X-ray CT apparatus and the other medical instruments have been developed in performance for recent years and their applications have been enlarged with the improvement of performance. Additionally, being involved in an information-oriented society, the above-mentioned medical instruments have been subjected to the application of electronic instruments, such as moving telephones.
Therefore, there has been caused a problem that the medical instruments operate erroneously due to radio waves and noises produced from the electronic instruments. Under such a situation, it is eagerly required to prevent the noise from generating from the medical instruments and avoid their erroneous operation.
In the above-mentioned prior art X-ray CT apparatus, however, it has a problem of increasing the length of wiring since the power line
120
and the signal line
121
have to be wired to various parts through the stand
115
and the supports
110
in order to allow the tilting operation of the frame
100
. Consequently, there is a possibility of picking up unnecessary internal and external radio waves or noises due to the electrical wiring of the power line
120
and the signal line
121
etc. acting as antennas. Thus, the longer the wiring length of the medical instrument becomes, the broader the instrument can pick up the radio waves and the noises disadvantageously. Especially, since there is established a severe standard about the electromagnetic noise in IEC (international electrotechnical comission) standard which is an international standard for electrical instruments, it is required to take strong measures to cope with the IEC standard.
In addition, since the electric components
114
a
to
114
c
of the prior art X-ray CT apparatus are dispersed in the frame
100
, it is difficult to take the measures for electromagnetic noise and the assembling process is apt to be complicated. Further, in assembling of the apparatus, the arrangement of the electric components
114
a
to
114
c
requires spaces for the establishment of the components
114
a
to
114
c
. Thus, the conventional X-ray CT apparatus has a problem that it is large-sized due to the frame
100
in the form of a box. Such a large-sized apparatus is apt to overawe the patient to be inspected and makes it difficult to ensure a space required for establishing the apparatus in a hospital.
When taking the tomography image of the patient by the oblique scanning in the conventional X-ray CT apparatus, the whole frame
100
is tilted as shown in FIG.
3
. In such a case, there is a possibility that an operator's operations to adjust the position of the patient and to puncture etc. are interrupted by the projecting lower part of the slanted frame
100
, thereby causing a great hindrance to the operator working about the apparatus.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an X-ray CT apparatus which is capable of taking strong measures for electromagnetic noise and making the apparatus itself to be small-sized. It is an additional object of the present invention to provide an X-ray CT apparatus which is also capable of preventing the frame having the lower part projected forward by the tilting operation, from disturbing the working of the operator. These objects of the present invention described above can be accomplished by an X-ray CT apparatus comprising: a frame having a substantially circular radiographic port formed so as to allow an object to be inspected laid on a bed to be inserted thereinto; a radiographic unit accom
Sasaki Tomiya
Tachizaki Hisashi
Church Craig E.
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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