U.S. patent application number 10/609646 was filed with the patent office on 2004-04-08 for x-ray diagnosis apparatus.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Ogawa, Kenichi.
Application Number | 20040066885 10/609646 |
Document ID | / |
Family ID | 30437192 |
Filed Date | 2004-04-08 |
United States Patent
Application |
20040066885 |
Kind Code |
A1 |
Ogawa, Kenichi |
April 8, 2004 |
X-ray diagnosis apparatus
Abstract
An X-ray diagnosis apparatus is configured to control at least
one of the X-ray diaphragm which restricts the irradiation range of
the X-ray and the compensation filter which attenuates the amount
of the X-ray based on at least one of the rotation position or the
position parallel to the body axis of the X-ray source.
Inventors: |
Ogawa, Kenichi;
(Tochigi-ken, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
30437192 |
Appl. No.: |
10/609646 |
Filed: |
July 1, 2003 |
Current U.S.
Class: |
378/42 |
Current CPC
Class: |
A61B 6/06 20130101; A61B
6/544 20130101; A61B 6/542 20130101 |
Class at
Publication: |
378/042 |
International
Class: |
A61B 006/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 8, 2002 |
JP |
2002-198148 |
Claims
What is claimed is:
1. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a diaphragm
configured to restrict an irradiation range of the X-ray; a
detector configured to detect the X-ray penetrated through the
object; a movement apparatus configured to move a position of the
X-ray source in a first direction along the object; and a
controller configured to control the diaphragm based on the
position of the X-ray source in the first direction.
2. The X-ray diagnosis apparatus according to claim 1, wherein the
movement apparatus is configured to move the position of the X-ray
source in a longitudinal direction of the object.
3. The X-ray diagnosis apparatus according to claim 1, wherein the
controller comprises: a memory configured to store data of the
irradiation range corresponding to the position of the X-ray
source; and a main controller configured to read the data from the
memory based on the position of the X-ray.
4. The X-ray diagnosis apparatus according to claim 3, wherein the
memory is configured to store the data of the irradiation range
corresponding to a plurality of positions of the X-ray source.
5. The X-ray diagnosis apparatus according to claim 1, further
comprising an operation unit configured to set the irradiation
range on an X-ray fluoroscopic image.
6. The X-ray diagnosis apparatus according to claim 1, wherein the
movement apparatus is configured to move the position of the X-ray
source along a flow direction of a contrast agent injected into the
object, at a desired speed.
7. The X-ray diagnosis apparatus according to claim 1, further
comprising a bed on which the object is positioned.
8. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a diaphragm
configured to restrict an irradiation range of the X-ray; a
detector configured to detect the X-ray penetrated through the
object; a rotation apparatus configured to rotate a position of the
X-ray source around the bed; and a controller configured to control
the diaphragm based on the position of the X-ray source.
9. The X-ray diagnosis apparatus according to claim 8, wherein the
controller comprises: a memory configured to store data of the
irradiation range corresponding to the position of the X-ray
source; and a main controller configured to read the data from the
memory based on the position of the X-ray.
10. The X-ray diagnosis apparatus according to claim 9, wherein the
memory is configured to store the data of the irradiation range
corresponding to a plurality of positions of the X-ray source.
11. The X-ray diagnosis apparatus according to claim 8, further
comprising an operation unit configured to set the irradiation
range on an X-ray fluoroscopic image when the X-ray stops being
irradiated.
12. The X-ray diagnosis apparatus according to claim 8, further
comprising a bed on which the object is positioned.
13. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a compensation
filter configured to attenuate an amount of the X-ray; a detector
configured to detect the X-ray penetrated through the object; a
movement apparatus configured to move a position of the X-ray
source in a direction along the object; and a controller configured
to control the compensation filter based on the position of the
X-ray source.
14. The X-ray diagnosis apparatus according to claim 13, wherein
the movement apparatus moves the position of the X-ray source in a
longitudinal direction of the object.
15. The X-ray diagnosis apparatus according to claim 13, wherein
the controller comprises: a memory configured to store data of an
amount of the X-ray corresponding to the position of the X-ray
source; and a main controller configured to read the data from the
memory based on the position of the X-ray.
16. The X-ray diagnosis apparatus according to claim 14, wherein
the memory is configured to store the data of the amount of the
X-ray corresponding to a plurality of the positions of the X-ray
source.
17. The X-ray diagnosis apparatus according to claim 13, further
comprising an operation unit configured to set the amount of the
X-ray on an X-ray fluoroscopic image.
18. The X-ray diagnosis apparatus according to claim 13, wherein
the movement apparatus is configured to move the position of the
X-ray source along a flow direction of a contrast agent injected
into the object at a desired speed.
19. The X-ray diagnosis apparatus according to claim 13, further
comprising a bed on which the object is positioned.
20. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a compensation
filter configured to attenuate an amount of the X-ray; a detector
configured to detect the X-ray penetrated through the object; a
rotation apparatus configured to rotate a position of the X-ray
source around the object; and a controller configured to control
the compensation filter based on the position of the X-ray.
21. The X-ray diagnosis apparatus according to claim 20, wherein
the controller comprises: a memory configured to store data of an
amount of the X-ray corresponding to the position of the X-ray
source; and a main controller configured to read the data from the
memory based on the position of the X-ray.
22. The X-ray diagnosis apparatus according to claim 21, wherein
the memory is configured to store the data of the amount of the
X-ray corresponding to a plurality of positions of the X-ray
source.
23. The X-ray diagnosis apparatus according to claim 20, further
comprising an operation unit configured to set the amount of the
X-ray on an X-ray fluoroscopic image.
24. The X-ray diagnosis apparatus according to claim 20, further
comprising a bed on which the object is positioned.
25. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a compensation
filter configured to attenuate an amount of the X-ray; a detector
configured to detect the X-ray penetrated through the object; a
movement apparatus configured to move a position of the X-ray
source in a first direction parallel to the object; and a
controller configured to control the compensation filter to move in
a second direction, opposite to the direction of movement of the
X-ray source, at a same speed as the movement of the X-ray
source.
26. A method for obtaining an X-ray image, comprising: irradiating
an X-ray to an object; restricting an irradiation range of the
X-ray; detecting the X-ray penetrated through the object; moving a
position of the X-ray source in a direction taken along the object;
and controlling a diaphragm based on the position of the X-ray
source in the direction.
27. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a diaphragm
configured to restrict an irradiation range of the X-ray; a
detector configured to detect the X-ray penetrated through the
object; a movement apparatus configured to move a position of the
X-ray source in a first direction along the object; and means for
controlling the diaphragm based on the position of the X-ray source
in the first direction.
28. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a diaphragm
configured to restrict an irradiation range of the X-ray; a
detector configured to detect the X-ray penetrated through the
object; a rotation apparatus configured to rotate a position of the
X-ray source around the bed; and means for controlling the
diaphragm based on the position of the X-ray source.
29. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a compensation
filter configured to attenuate an amount of the X-ray; a detector
configured to detect the X-ray penetrated through the object; a
movement apparatus configured to move a position of the X-ray
source in a direction along the object; and means for controlling
the compensation filter based on the position of the X-ray
source.
30. An X-ray diagnosis apparatus, comprising: an X-ray source
configured to irradiate an X-ray to an object; a compensation
filter configured to attenuate an amount of the X-ray; a detector
configured to detect the X-ray penetrated through the object; a
rotation apparatus configured to rotate a position of the X-ray
source around the object; and means for controlling the
compensation filter based on the position of the X-ray.
31. A computer program product storing instructions for execution
on a computer system, which when executed by the computer system,
causes the computer system to perform the method recited in claim
26.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an X-ray diagnosis
apparatus and a method for creating an X-ray image.
BACKGROUND OF THE INVENTION
[0002] A conventional X-ray diagnosis apparatus irradiates an X-ray
from an X-ray tube to a patient, and detects the X-ray penetrated
through the patient with an image intensifier (hereinafter referred
to as I.I.), which changes the X-ray into a light and an imaging
tube or a charge coupled device changes the light into an
electronic signal or a flat panel detector (hereinafter called as a
FPD) directly changes the X-ray into the electronic signal. Thus,
an X-ray fluoroscopic image is obtained. The X-ray apparatus
enables an operator to observe flow and movement of a contrast
agent inside the patient on a display. Moreover, the fluoroscopic
image is stored in a memory and used for various image processes,
such as enlargement/contrast adjustment/space filter processes or
minimum/maximum trace processes or subtraction process or adding
process for removing a noise, and the like.
[0003] The subtraction process for obtaining a subtraction image of
a part of the patient using the X-ray diagnosis apparatus is
explained below. In order to perform the subtraction process, the
fluoroscopic image, a mask image, and a contrast image are
obtained. The fluoroscopic image is used for setting a position of
an X-ray diaphragm and a compensation filter. The mask image and
the contrast image are basic images to create the subtraction
image. Hereinafter, an imaging for obtaining the fluoroscopic image
is called a fluoroscopic imaging, and an imaging for obtaining a
mask image and a contrast image is called a main imaging. In the
fluoroscopic imaging, the operator sets X-ray fluoroscopic terms
(X-ray tube voltage, X-ray tube current, fluoroscopic time, etc.),
considering patient information, such as a patient age, sex, the
portion of the body being imaged and other factors (such as, but
not limited to, patient condition, pregnancy status, medical
conditions, allergy to the contrast agent, specific needed nursing
care). The X-ray is irradiated to the patient based on the
fluoroscopic factors, and the fluoroscopic image is displayed on
the display. The operator adjusts a position of a supporting unit
for supporting the X-ray tube and the I.I., in order to position an
imaging area at an appropriate part of the patient. The operator
sets positions of the X-ray diaphragm and the compensation filter,
observing the fluoroscopic image.
[0004] The main imaging starts after the X-ray diaphragm and the
compensation filter are set. In the main imaging, the mask image
and the contrast image are obtained in order. The mask image is
aligned to the contrast image, and the subtraction process between
these images is performed. The subtraction image is displayed on
the display in a real time.
[0005] In the conventional X-ray diagnosis apparatus, the X-ray
diaphragm and the compensation filter are fixed at such a position
that the imaging area is adequate during the main imaging, such as
during a bolus chase imaging where the X-ray and the I.I.
automatically move. That is, wherever the X-ray tube and the I.I.
move within the imaging area, the X-ray irradiated to the patient
is not blocked or attenuated. However, since the X-ray diaphragm is
fixed during the main imaging, the irradiation range of the X-ray
is wide, the amount of the X-ray irradiated to the patient
increases, and the influence of scattered X-ray appears. Moreover,
since the compensation filter is fixed during the main imaging,
X-ray halation partially remains. However, it is difficult to
manually adjust the position of the X-ray diaphragm or the
compensation filter according to a contour of the patient during
the main imaging where the X-ray tube and the I.I. automatically
move.
SUMMARY OF THE INVENTION
[0006] The present invention intends to solve the above-mentioned
problems. One aspect of the present invention is an X-ray diagnosis
apparatus including an X-ray source configured to irradiate an
X-ray to an object, a diaphragm configured to restrict an
irradiation range of the X-ray, a detector configured to detect the
X-ray penetrated through the object, a bed configured to support
the object, a mechanism configured to move a position of the X-ray
source in a direction taken along the bed, and a controller
configured to control the diaphragm based on the position of the
X-ray source in the direction.
[0007] Another aspect of the present invention is an X-ray
diagnosis apparatus including an X-ray source configured to
irradiate an X-ray to an object, a diaphragm configured to restrict
irradiation range of the X-ray, a detector configured to detect the
X-ray penetrated through the object, a bed configured to support
the object, a mechanism configured to rotate a position of the
X-ray source around the bed, and a controller configured to control
the diaphragm based on the position of the X-ray source.
[0008] Another aspect of the present invention is an X-ray
diagnosis apparatus including an X-ray source configured to
irradiate an X-ray to an object, a compensation filter configured
to attenuate an amount of the X-ray, a detector configured to
detect the X-ray penetrated through the object, a bed configured to
support the object, a mechanism configured to move a position of
the X-ray source in a direction taken along the bed, and a
controller configured to control the compensation filter based on
the position of the X-ray source in the direction.
[0009] Another aspect of the present invention is an X-ray
diagnosis apparatus including an X-ray source configured to
irradiate an X-ray to an object, a compensation filter configured
to attenuate an amount of the X-ray, a detector configured to
detect the X-ray penetrated through the object, a bed configured to
support the object, a mechanism configured to rotate a position of
the X-ray source around the bed, and a controller configured to
control the compensation filter based on the position of the
X-ray.
[0010] Another aspect of the present invention is an X-ray
diagnosis apparatus including an X-ray source configured to
irradiate an X-ray to an object, a compensation filter configured
to attenuate an amount of the X-ray, a detector configured to
detect the X-ray penetrated through the object, a bed configured to
support the object, a mechanism configured to move a position of
the X-ray source to parallel to the bed, and a controller
configured to control the compensation filter to move in an
opposite direction to a direction of movement of the X-ray source
at the same speed as the movement of the X-ray source such that the
compensation filter relatively stops to the bed.
[0011] Another aspect of the present invention is a method for
obtaining an X-ray image including irradiating an X-ray to an
object, restricting an irradiation range of the X-ray, detecting
the X-ray penetrated through the object, moving a position of the
X-ray source in a direction taken along the bed, and controlling
the diaphragm based on the position of the X-ray source in the
direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more complete appreciation of the invention and many of
the attendant advantages thereof will be readily obtained as the
same becomes better understood by reference to the detailed
description when considered in connection with the accompanying
drawings. Wherever possible, the same reference numbers will be
used throughout the drawings to refer to like parts. In the
drawings:
[0013] FIG. 1 is a block diagram of an X-ray diagnosis apparatus in
a first embodiment;
[0014] FIG. 2 is a top view of an X-ray diaphragm unit of the X-ray
diagnosis apparatus in the first embodiment;
[0015] FIG. 3A is a sectional view of a compensation filter
unit;
[0016] FIG. 3B is a top view of the compensation filter;
[0017] FIG. 4 is a flow chart for setting an X-ray diaphragm and a
compensation filter in the first embodiment;
[0018] FIG. 5 is an illustration of an example displayed on a
display unit in the first embodiment;
[0019] FIG. 6 is a table stored in a diaphragm and compensation
filter memory in the first embodiment;
[0020] FIG.7 is a flow chart for obtaining a contrast image in the
first embodiment;
[0021] FIG.8A is an illustration for explaining an operation of the
X-ray diaphragm in the first embodiment;
[0022] FIG.8B is an illustration for explaining an X-ray image in
the first embodiment; and
[0023] FIG. 9 is an illustration for explaining an operation of the
compensation filter.
DETAILED DESCRIPTION OF THE INVENTION
[0024] A first embodiment of the present invention is explained
referring to the figures. FIG. 1 is a block diagram of an X-ray
diagnosis apparatus. The X direction is approximately parallel to a
width direction of a patient, the Y direction is approximately
parallel to a body axis of the patient, and the Z direction is
approximately parallel to a thickness direction of the patient. As
shown in FIG. 1, an X-ray diagnosis apparatus includes a supporting
unit 16 and a main control unit 12. The supporting unit 16 includes
a C-arm and a bed 17. An X-ray tube 11 that irradiates an X-ray is
mounted on one side of the C arm, and an X-ray diaphragm unit 13
that blocks the X-ray irradiated to an unnecessary area is provided
on a patient P side of the X-ray tube 11. A compensation filter
unit 15 that attenuates the X-ray to restrain halation is also
provided on the patient P side of the X-ray tube 11. On the
opposite side of the C-arm to the bed 17, an X-ray grid 4, which
cuts a scattering X-ray penetrated through the patient P; an
I.I.19, which changes the remaining X-ray to an optical image; an
optical unit 21, which corrects a size of the optical image; and a
TV camera (or CCD, for example) 23, which changes the optical image
to a TV image signal, are mounted.
[0025] The main control unit 12 includes a system control unit 25;
an X-ray control unit 29, which controls a high voltage generating
unit 31 to generate high voltage impressed to the X-ray tube 11; an
X-ray diaphragm control unit 33, which controls the degree (X, Y
direction) of opening between X-ray diaphragms; and a compensation
filter control unit 35, which controls a position (X direction); a
rotation angle 4, and a type of a compensation filter in the
compensation filter unit 15. Moreover, the main control unit 12
includes a supporting control unit 37 that controls a position (Y
direction) of the C-arm to the bed 17, an I.I. control unit 39 that
controls the I.I. 19, a camera control unit 41 that controls the TV
camera 23, an image memory 44 that stores an X-ray image obtained
by the TV camera 23. Furthermore, the main control unit 12 includes
a display unit 43 that displays the X-ray image obtained by the TV
camera 23, a diaphragm, and compensation filter memory 14 that
stores a position, etc. of the X-ray diaphragm and the compensation
filter, a virtual diaphragm/compensation filter creation unit 18,
which creates a graphic image of the X-ray diaphragm and the
compensation filter on the display unit 43, and an operation unit
27 (for example, a keyboard and a mouse, or the like), which allows
an operator to input instructions.
[0026] The X-ray diaphragm unit 13 is explained in detail,
referring to FIG. 2, which is a top view of the X-ray diaphragm
unit 13 from the X-ray tube 11. The X-ray diaphragm unit 13 has a
plurality of X-ray diaphragms 45, 47, 49, and 51. These diaphragms
may be made of lead, for example, which limits the X-ray. The X-ray
diaphragm 45 and 49 symmetrically move, and the X-ray diaphragms 47
and 51 symmetrically move. In FIG. 2, the X-ray diaphragms 47 and
51 are arranged at a back side and the X-ray diaphragms 45 and 49
are arranged at a near side. An area (indicated as dotted lines)
surrounded by the X-ray diaphragms shows an area where the X-ray
irradiated from the X-ray tube 11 passes, and the X-ray diaphragms
45, 47, 49, and 51 symmetrically and asymmetrically move to extend
or narrow the pass area. Thus, the irradiation area of the X-ray to
the patient P may be controlled.
[0027] With reference to FIGS. 3A and 3B, the compensation filter
unit 15 is explained in detail. The non-limiting illustration of
FIG. 3A shows a sectional view of the compensation filter unit 15
from the body axis of the patient P, and FIG. 3B shows a top view
from the X-ray tube 11. The compensation filter unit 15 includes a
plurality of types of the compensation filters 15a, 15b, and 15c,
which are arranged along the direction of the X-ray irradiation
(indicated as dotted lines). The compensation filter 15c is far
from the X-ray tube 11, and the compensation filter 15a is near the
X-ray tube 11. Generally, each compensation filter is made of, for
example, acrylic or the like. Forms of the compensation filters 15a
through 15c may be different from each other.
[0028] For example, the compensation filter 15b may have an
elliptical form and the compensation filter 15c may have a
rectangular form. In the non-limiting illustration of FIG. 3B, the
compensation filter 15a is illustrated in the shape of a trapezium.
These compensation filters 15a, 15b, and 15c move in the X and Y
directions and rotates on a X-Y plate (the rotation angle is shown
as .phi.). One or more of the compensation filters move to
interrupt and attenuate the X-ray. In FIG. 3A, the case where the
compensation filter 15a interrupts the X-ray is shown.
[0029] Next, an operation of the X-ray diagnosis apparatus is
explained in the order of the fluoroscopic imaging, a setup of the
X-ray diaphragm/compensation filter, and the main imaging.
[0030] The fluoroscopic imaging and the setup of the X-ray
diaphragm/compensation filter is explained with reference to the
non-limiting illustration of FIG. 4, which is a flow chart. In the
first embodiment, so-called bolus chase imaging is explained as one
example. The bolus chase imaging is that the C-arm slides along a
longitudinal direction of the bed 17 without rotation, and a
contrast agent injected into the patient P is imaged. In Step 61 of
FIG. 4 showing the fluoroscopic imaging, the operator (generally a
doctor or a radiological technician) checks information (such as a
patient name or other relevant information) about the patient P,
the operator inputs suitable X-ray fluoroscopic terms (such as
X-ray tube voltage, X-ray tube current, fluoroscopic time, or other
appropriate parameters) for the patient P via the operation unit
27, and the operator puts the patient P on the bed 17.
[0031] In general, the X-ray tube current in the fluoroscopic
imaging is lower than that of the main imaging, and is set up to an
appropriate value by auto brightness control (ABC). The system
control unit 25 controls the X-ray tube 11 to irradiate the X-ray
to the patient P on the bed 17 via the X-ray control unit 29 and
the high voltage generating unit 31. At that time, the X-ray
diaphragm control unit 33 controls the X-ray diaphragms 45, 47, 49,
and 51 of the X-ray diaphragm unit 13 so that the pass area of the
X-ray is the maximum. Similarly, the compensation filters 15a
through 15c of the compensation filter unit 15 are held at
positions such that the X-ray is not attenuated.
[0032] The X-ray penetrates through the patient P, and the
scattered X-ray is cut by the X-ray grid 4. The remaining X-ray is
irradiated to the I.I.19. In the I.I. 19, the optical signal
corresponding to the amount of the incident X-ray is generated, and
after the optical signal is corrected by the optical unit 21, the
corrected optical signal is changed to the electric signal as the
TV image signal by the TV camera 23. The TV image signal is changed
to a digital signal by an A/D converter and the image processing
performs on the digital signal. The processed digital signal is
converted to a TV image signal to be displayed on the display unit
43 as the X-ray fluoroscopic image. Observing the X-ray
fluoroscopic image on the display unit 43, the operator may move
the C-arm from (for example) an abdomen to a lower leg of the
patient P by the operation unit 27 and the supporting control unit
37. At that time, the X-ray continues to irradiate the X-ray to the
patient P, and the fluoroscopic image from the abdomen to the lower
leg of the patient P is displayed on the display unit 43 in a real
time. The X-ray fluoroscopic image is stored in the image memory
44. A similar operation is performed in the main imaging.
[0033] Setup (Step 62 through Step 65 in FIG. 4) of the X-ray
diaphragm unit/compensation filter are explained. When the setup is
performed, the X-ray is not irradiated from the X-ray tube 11. In
Step 62 for replaying the fluoroscopic image, the fluoroscopic
image data is read out from the image memory unit 44 to be
displayed on the display unit 43.
[0034] FIG. 5 shows an example displayed on the display unit 43.
The fluoroscopic image replays in a center of a monitor as a
circular image. In Step 63, the virtual X-ray diaphragm and virtual
compensation filter are created on the fluoroscopic image 72 by the
virtual diaphragm/compensation filter creation unit 18. The virtual
X-ray diaphragm is a graphic displayed on the display unit 43, and
one example is indicated by dotted lines 74 in FIG. 5. The virtual
compensation filter is a graphic displayed on the display unit 43
similarly, and one example is indicated by dotted lines 73 in FIG.
5. A scale of the virtual X-ray diaphragm and virtual compensation
filter correspond to a scale of the X-ray fluoroscopic image. When
the X-ray fluoroscopic image is enlarged, the virtual X-ray
diaphragm and virtual compensation filter are similarly enlarged.
In Step 64, the operator sets X and Y positions of the X-ray
diaphragms.
[0035] In detail, the operator adjusts a size of the virtual X-ray
diaphragm 74 on the monitor, by the operation unit 27. According to
the size of the adjusted virtual X-ray diaphragm 74, X and Y
position data of the X-ray diaphragms is calculated, and the
position data is stored in the diaphragm and compensation filter
memory 14 with the position data of the supporting unit 16. In Step
65, a position, an angle, and a sort of the compensation filter is
set up. In detail, the operator selects one virtual compensation
filter among candidates shown as icons 71 on the monitor.
[0036] The case where a virtual compensation filter in the center
of the candidates is selected is explained below. The selected
virtual compensation filter is displayed near the fluoroscopic
image 72 on the monitor. The operator adjusts the X position of the
virtual compensation filter 73 and also adjusts the angle of the
virtual compensation filter 73. The type, position, and angle of
the virtual compensation filter is stored in the diaphragm and
compensation filter memory 14 with the position data of the
supporting unit 16. Similarly, the operation unit 27 is used for
selecting or adjusting the type, position, and angle of the virtual
compensation filter.
[0037] After the setup is completed, the operator sets the X-ray
diaphragm and compensation filter on another replayed fluoroscopic
image of a different position. The operator sets the X-ray
diaphragm and compensation filter on a whole imaging area (or only
on a desired area). Thus, the X-ray diaphragm and compensation
filter may be set, and a table of data (as shown, for example, in
FIG. 6) is stored in the diaphragm and compensation filter memory
14. The Y position of the supporting unit may be a position of the
X-ray tube 11 which may be an absolute position which is not
related to the bed 17 or a relative position to the bed 17. The Y
position of the X-ray tube may be a position of the I.I. or the
C-arm, etc.
[0038] An operation of the main imaging is explained below. As
described above, the main imaging is performed to obtain the mask
image and the contrast image used for the subtraction process. The
imaging for obtaining the mask image starts based on the
instruction of the operator and is performed before the contrast
agent is injected into the patient P. The X-ray tube 11 and the
I.I. 19 automatically move from the abdomen to the lower leg or
from the lower leg to the abdomen. After the mask image is
obtained, the imaging for obtaining the contrast image starts. The
imaging starts immediately after the contrast agent is injected
into the patient P, based on the instruction of the operator. In
the imaging for obtaining the contrast image, the X-ray tube 11 and
the I.I. 19 move along the flow of the contrast agent at an
arbitrary speed based on the instruction of the operator. The mask
image is aligned to the contrast image and the subtraction process
is performed. A trace of the contrast agent, namely a blood vessel,
may be emphasized.
[0039] Differences between the mask image and the contrast image
include the following points, for example. The mask image is
obtained before the contrast agent is injected to the patient P,
while the contrast image is obtained after the contrast agent is
injected to the patient P. The imaging for obtaining the mask image
is automatically performed, while the imaging for obtaining the
contrast image is performed at arbitrary speed to chase the flow of
the contrast agent, and other operations are similar to each other.
Additionally, the direction of the imaging for obtaining the mask
image may be opposite to or the same as the direction of the
imaging for obtaining the contrast image. The imaging for obtaining
the contrast image is explained below. An explanation of a similar
operation for fluoroscopic imaging is omitted.
[0040] FIG. 7 shows a flowchart of operation for obtaining the
contrast image. In Step 81, the Y position of the supporting unit
16 is detected by the system control unit 25. In Step 82, the X and
Y position of the X-ray diaphragm is searched in the system control
unit 25. In detail, the first and second nearest data to the
detected Y position is searched from the table shown in FIG. 6, and
the X-ray diaphragm data corresponding to the first and second
nearest data is specified.
[0041] In Step 83, the position, angle and sort of the compensation
filter are searched in the system control unit 25. In detail, the
data of the compensation filter within a field of view of the I.I.
19 is specified based the detected Y position of the supporting
unit 16 and a field of view data of the I.I. 19, which is
pre-stored. In Step 84, the X-ray diaphragm and the compensation
filter are controlled based on the specified data.
[0042] The control of the X-ray diaphragm is explained with
reference to FIGS. 8A and 8B. The controls of the X-ray diaphragm
and the compensation filter may be independently performed
simultaneously. FIG. 8A shows the fluoroscopic image from the
abdomen to the lower leg. In this case, four virtual X-ray
diaphragms are set on the fluoroscopic image by the operator. If
the detected position of the supporting unit 16 is the position
near the abdomen in FIG. 8A, the data 74a and 74b are searched as
the X-ray diaphragm data in Step 82. In detail, as shown by solid
lines of FIG. 8B, the actual X-ray diaphragms 45, 47, 49, and 51
are controlled as the virtual X-ray diaphragms 74a and 74b, and are
connected smoothly. The portions shown as the dotted lines of FIG.
8B indicate the virtual X-ray diaphragms 74 shown as the solid
lines of FIG. 8A.
[0043] Since the X-ray diaphragm may be controlled as described
above, the desired imaging area set by the operator receives
adequate X-rays, while the X-ray is appropriately blocked from
extraneous areas. In the above explanation, the four virtual X-ray
diaphragms are overlapped from the abdomen to the lower leg as
shown in FIG. 8A; however, the virtual X-ray diaphragm may be
partially set. Where the virtual X-ray diaphragm is not set, the
pass area of the X-ray between the X-ray diaphragms may be set as
the maximum. That is, the X-ray diaphragm may not block the X-ray,
if the virtual X-ray diaphragm is not set as well as the
fluoroscopic imaging.
[0044] The control of the compensation filter is explained with
reference to FIG. 9, which shows the fluoroscopic image from the
abdomen to the lower leg. The non-limiting example where three
virtual compensation filters 73 are set on the fluoroscopic image
by the operator is shown in FIG. 9. The specified data of the
compensation filter in Step 83 is used for controlling the
compensation filter as the virtual compensation filter 73 is set.
When the X-ray tube 11 moves to the lower leg from the abdomen, the
compensation filter moves from the lower leg to the abdomen at the
approximately same speed as the X-ray tube 11. The movement of the
compensation filter may continue until the compensation filter is
beyond the field of view of the I.I 19. Thus, since the
compensation filter is controlled to move in an opposite direction
to movement direction of the X-ray tube 11 at the approximately
same speed, the attenuation of the X-ray is minimized.
[0045] After the main imaging, the operator performs an operative
treatment on an affected area of the patient P, such as a closed
blood vessel, after the operator confirms the affected area on the
subtraction image obtained by the main imaging. In detail, while
the X-ray is irradiated to the patient and the I.I. detects the
X-ray to create the fluoroscopic image again, the operator inserts
a catheter into the patient P. During the insertion of the
catheter, the operator confirms a position of the catheter on the
X-ray fluoroscopic image.
[0046] After the operative treatment is completed, the main imaging
is preformed on the affected area again. In the main imaging after
the operative treatment, the X-ray diaphragm and the compensation
filter data used in the main imaging before the operative treatment
may be used again. Thus, the operator performs the main imaging
after the operative treatment to confirm a result of the operative
treatment. The operative treatment may be performed immediately
after the operative treatment or may be performed a few days after
the operative treatment, for example.
[0047] In the first embodiment, since at least one of the X-ray
diaphragm and the compensation filter is controlled on the
fluoroscopic image according to the position of the X-ray tube, the
X-ray diagram or the compensation filter can be set at an
appropriate position. In addition, since the virtual X-ray diagram
or the virtual compensation filter is used, the X-ray irradiation
to the patient may be stopped during setting the X-ray diagram or
the compensation, and the amount of the X-ray irradiated to the
patient can be reduced.
[0048] The present invention is not limited to the above
embodiments, and various modifications may be made without
departing from the spirit or scope of the general inventive
concept. For example, although the X-ray tube and the I.I. move to
the bed which is fixed in the first embodiment, the bed may move
during the fluoroscopic or main imaging. However, it is more
desirable to move the X-ray tube and the I.I. than to move the bed,
since the contrast agent may move unusually as a result of the
movement of the bed. Moreover, although the X-ray diaphragm can be
set in both of the X direction which is perpendicular to the body
axis of the patient and the Y direction which is parallel to the
body axis of the patient in the first embodiment, the X-ray
diaphragm may be set in at least one direction. For example, the
X-ray diaphragm data may be stored in only the Y direction of the
X-ray diaphragm. Furthermore, although the X-ray diaphragm and the
compensation filter are controlled according to the position in the
body axis direction (Y direction) of the C-arm in the first
embodiment, the C-arm may be fixed in the Y direction and may
rotate instead. The X-ray diaphragm and the compensation filter may
be controlled according to an angle of the rotation of the C-arm.
Thus, a 3-dimensional subtraction process (so-called a rotation
DSA) may be applied.
[0049] Although the virtual X-ray diaphragm and the virtual
compensation filter are set on the replayed fluoroscopic image to
set the X-ray diaphragm and the compensation filter in the first
embodiment, the X-ray diaphragm and the compensation filter may
also be set on the fluoroscopic image displayed in a real time
while the X-ray is irradiated to the patient.
[0050] As described above, since at least one of the X-ray
diaphragm and the compensation filter is controlled according to
the position of the X-ray tube, the X-ray diaphragm or the
compensation filter can be set at an appropriate position.
Therefore, the amount of the X-ray irradiated to the patient is
reduced or a halation on the X-ray image may be restrained.
* * * * *