X-RAY IMAGING APPARATUS AND PROGRAM

• US 20130182822A1
• Filed: 01/10/2013
• Published: 07/18/2013
• Est. Priority Date: 01/12/2012
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: SAKAGUCHI, Takuya, Tanaka, Manabu, Ishikawa, Takayuki, Takemoto, Hisato, Watanabe, Koichiro
• Granted Patent: US 9,095,258 B2
• Time in Patent Office: Days
• US Class Current: 378/42
• CPC Class Codes: A61B 6/022 Stereoscopic imaging
• CPC Class Codes: A61B 6/4464 the source unit or the detector unit being mounted to ceiling
• CPC Class Codes: A61B 6/487 involving fluoroscopy
• CPC Class Codes: A61B 6/503 for diagnosis of the heart
• CPC Class Codes: A61B 6/5288 involving retrospective matching to a physiological signal
• CPC Class Codes: A61B 6/542 involving control of exposure

Abstract

According to one embodiment, an X-ray imaging apparatus includes an X-ray generation unit, an X-ray collimator, a dose detection unit, and a dose reduction rate calculation unit. The X-ray generation unit irradiates the object with X-rays. The X-ray collimator limits an X-ray irradiation range of the X-ray generation unit. The dose detection unit detects the X-rays that have passed through the X-ray collimator. The dose reduction rate calculation unit calculates a reduction rate of an exposure dose of the object based on a value detected by the dose detection unit in X-ray imaging before the X-ray irradiation range is limited by the X-ray collimator and a value detected by the dose detection unit in X-ray imaging after the X-ray irradiation range is limited by the X-ray collimator.

Claims

1. An X-ray imaging apparatus for performing X-ray imaging of an object and acquiring an X-ray fluoroscopic image, comprising:

an X-ray generation unit configured to irradiate the object with X-rays;

an X-ray collimator configured to limit an X-ray irradiation range of the X-ray generation unit;

a dose detection unit configured to detect the X-rays that have passed through the X-ray collimator; and

a dose reduction rate calculation unit configured to calculate a reduction rate of an exposure dose of the object based on a value detected by the dose detection unit in X-ray imaging before the X-ray irradiation range is limited by the X-ray collimator and a value detected by the dose detection unit in X-ray imaging after the X-ray irradiation range is limited by the X-ray collimator.

2. The apparatus according to claim 1, wherein the dose reduction rate calculation unit calculates, as the reduction rate, a value G2/G1 when an exposure dose rate detected by the dose detection unit in the X-ray imaging before the X-ray irradiation range is limited by the X-ray collimator is defined as a reference value G1, and an exposure dose rate detected by the dose detection unit in the X-ray imaging after the X-ray irradiation range is limited by the X-ray collimator is defined as a current value G2.

3. The apparatus according to claim 2, wherein the dose reduction rate calculation unit calculates, as the reduction rate, a value Σ

2/Σ

1 when a cumulative value of the exposure dose detected by the dose detection unit in X-ray imaging for a predetermined time is defined as a measured cumulative value Σ

2, and a product of the predetermined time and a dose rate detected by the dose detection unit in X-ray imaging performed without causing the X-ray collimator to limit the X-ray irradiation range before execution of the X-ray imaging for the predetermined time is defined as a reference cumulative value Σ

1.

4. The apparatus according to claim 1, further comprising a display unit configured to display the reduction rate together with the X-ray fluoroscopic image.

5. The apparatus according to claim 1, further comprising a display unit configured to display a graph based on the reduction rate.

6. The apparatus according to claim 5, wherein the graph includes

a reference value graph representing the exposure dose rate detected by the dose detection unit in the X-ray imaging before the X-ray irradiation range is limited by the X-ray collimator, and

a graph representing a time-rate change in the exposure dose rate detected by the dose detection unit in the X-ray imaging at a current time after the X-ray irradiation range is limited by the X-ray collimator.

7. The apparatus according to claim 5, wherein the graph includes

a graph representing a time-rate change in the reference cumulative value of the exposure dose of the object when assuming that the X-ray imaging is continued up to the current time without causing the X-ray collimator to limit the X-ray irradiation range, and

a graph representing a time-rate change in the cumulative value of the exposure dose detected by the dose detection unit during a time in which the X-ray imaging is continued up to the current time while executing limiting of the X-ray irradiation range by the X-ray collimator continuously or intermittently.

8. The apparatus according to claim 5, wherein the graph includes

a graph representing a time-rate change in the cumulative value of the exposure dose of the object up to the current time, and

a graph representing a time-rate change in the cumulative value of the exposure dose of the object, which is calculated assuming that the X-ray imaging at an exposure dose rate corresponding to the X-ray irradiation range limited to a predetermined area by the X-ray collimator is performed from the current time.

9. The apparatus according to claim 8, further comprising:

a storage unit configured to store an upper limit of the cumulative value of the exposure dose permitted for the object; and

an imaging enable time calculation unit configured to calculate a time needed until the cumulative value of the exposure dose of the object changes from a value at the current time to the upper limit when assuming that the X-ray imaging at the exposure dose rate corresponding to the X-ray irradiation range limited to the predetermined area by the X-ray collimator is performed from the current time,

wherein the display unit displays a graph representing the upper limit and the time needed to reach the upper limit.

10. A program that causes a computer to function as an X-ray imaging apparatus for acquiring an X-ray fluoroscopic image of an object by X-ray imaging, the program causing the computer to implement:

a function of irradiating the object with X-rays;

a function of limiting an X-ray irradiation range;

a function of, when the irradiation range is limited, detecting the X-rays that irradiate the object after the limiting the X-ray irradiation range, and when the irradiation range is not limited, detecting the X-rays have irradiated; and

a function of calculating a reduction rate of an exposure dose of the object based on a value detected in X-ray imaging before the irradiation range is limited and a value detected by a dose detection unit in X-ray imaging after the irradiation range is limited.