X-ray ct apparatus

• US 20040264624A1
• Filed: 06/09/2004
• Published: 12/30/2004
• Est. Priority Date: 12/10/2001
• Status: Active Grant

• Current Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Tanaka, Kazuhiro, Hibino, Atsushi, Okabe, Kuniyoshi
• Granted Patent: US 7,269,242 B2
• Time in Patent Office: Days
• US Class Current: 378/4
• CPC Class Codes: A61B 6/0478 Chairs
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4441 the rigid structure being a C-arm or U-arm
• CPC Class Codes: A61B 6/469 for selecting a region of interest [ROI]
• CPC Class Codes: A61B 6/51 for dentistry

Abstract

An X-ray CT apparatus is capable of obtaining an image of arbitrary size for an arbitrary part of an object to be examined. The X-ray CT apparatus prepares two-dimensional data and three-dimensional data from a plurality of X-ray information obtained by driving an X-ray tube and an X-ray information detector through one rotation around a patient in a range between a lower jaw and the eyes of the patient, and it displays a tomographic image based thereon on a display unit. A rotational mechanism is fitted to a support, a U-shaped arm is mounted on the support with the X-ray tube and the X-ray information inputting means facing each other and fitted, and the image of an arbitrary size of an arbitrary part of the patient is collected and displayed as the patient is supported in a chair which is capable of being electrically-driven in the vertical direction.

Claims

1. An X-ray CT apparatus comprising:

X-ray generating means for generating X-rays;

X-ray detecting means arranged opposite to the X-ray generating means for two-dimensionally detecting a dose of X-rays passing through an object to be examined;

means for holding the X-ray generating means and the X-ray detecting means so that the object is located therebetween;

rotation driving means for driving the holding means to rotate around the object;

image processing means for producing a tomogram of the object based on the X-ray dose detected by the X-ray detecting means; and

display means for displaying the tomogram,

further comprising means for changing an FOV size of the X-ray detecting means in accordance with a detected portion of the object displayed by the display means.

2. An X-ray CT apparatus according to claim 1, wherein the FOV size changing means includes X-ray converting means for converting the X-rays into visible light;

light receiving means for converting the visible light converted by the X-ray converting means into electrical signals; and

means for changing a portion of the visible light converted by the X-ray converting means necessary for creating the tomogram.

3. An X-ray CT apparatus according to claim 1, wherein the X-ray detecting means is a two-dimensional X-ray flat sensor for converting X-rays into electrical signals, and the FOV size changing means includes means for changing a portion of the electrical signals converted by the two-dimensional X-ray flat sensor necessary for creating the tomogram.

4. An X-ray CT apparatus according to claim 1, wherein the FOV size changing means includes means for inputting a desired FOV size by moving a cursor of a pointing device onto an FOV size changing switch displayed on the display means and control means for changing an FOV size to the size input by the inputting means.

5. An X-ray CT apparatus according to claim 1, further comprising means for controlling conditions of X-ray generation of the X-ray generating means in accordance with the FOV size changed by the FOV size changing means.

6. An X-ray CT apparatus according to claim 1, further comprising means for adjusting a size of the tomogram displayed by the display means.

7. An X-ray CT apparatus according to claim 6, wherein the adjusting means includes means for adjusting a distance between the X-ray generating means and the X-ray detecting means on the holding means.

8. An X-ray CT apparatus according to claim 6, wherein the adjusting means adjusts the distance between the X-ray generating means and the X-ray detecting means by extending and retracting a part of the holding means.

9. An X-ray CT apparatus according to claim 6, wherein the holding means is a U-shaped arm provided with the X-ray generating means and the X-ray detecting means respectively on the ends, and the rotation driving means rotates the holding means around an intermediate portion of the U-shaped arm being the center.

10. An X-ray CT apparatus according to claim 6, further including means for expanding the tomogram obtained with the FOV size changed by the FOV size changing means.

11. An X-ray CT apparatus according to claim 1, further comprising means for determining a position of the object so that an arbitrary portion of the object is located on the rotation center of the X-ray generating means and the X-ray detecting means.