Photoacoustic image generation apparatus

1. A photoacoustic image generation apparatus, comprising:

an insertion needle that has an outer needle having an inner cavity and an inner needle removably inserted into the inner cavity of the outer needle, the inner needle including a light emitting portion that emits light guided from a light source and a photoacoustic wave generating portion that absorbs the light emitted from the light emitting portion to generate photoacoustic waves;

acoustic wave detection unit for detecting the photoacoustic waves emitted from the photoacoustic wave generating portion;

photoacoustic image generation unit for generating a photoacoustic image based on the detected photoacoustic waves;

image output unit for displaying the photoacoustic image on image display unit;

insertion and removal detection unit for detecting that the inner needle has been removed from the outer needle; and

processing switching unit for changing image display so as to be different from image display before it is detected that the inner needle has been removed in a case where it is detected that the inner needle has been removed.

2. The photoacoustic image generation apparatus according to claim 1 , wherein the insertion needle is configured to be insertable into a subject in a state in which the inner needle has been inserted into the outer needle.

3. The photoacoustic image generation apparatus according to claim 1 ,

wherein the processing switching unit changes a display color of the photoacoustic image displayed on the image display unit before and after it is detected that the inner needle has been removed.

4. The photoacoustic image generation apparatus according to claim 1 , further comprising:

a sound source position detection unit for detecting a position of a generation source of the photoacoustic waves in the insertion needle based on the photoacoustic image,

wherein the image output unit displays a marker indicating the detected position of the generation source of the photoacoustic waves on the image display unit, and

the processing switching unit changes a display color of the marker displayed on the image display unit before and after it is detected that the inner needle has been removed.

5. The photoacoustic image generation apparatus according to claim 1 ,

wherein the acoustic wave detection unit further detects reflected acoustic waves of acoustic waves transmitted into a subject, and

reflected acoustic wave image generation unit for generating a reflected acoustic wave image based on the detected reflected acoustic waves is further provided.

6. The photoacoustic image generation apparatus according to claim 5 ,

wherein the image output unit displays an image, in which the photoacoustic image is superimposed on the reflected acoustic wave image, on the image display unit before it is detected that the inner needle has been removed, and displays the reflected acoustic wave image on the image display unit after it is detected that the inner needle has been removed.

7. The photoacoustic image generation apparatus according to claim 6 ,

wherein the image output unit displays an image, in which a photoacoustic image generated before it is detected that the inner needle has been removed is superimposed on the reflected acoustic wave image, on the image display unit after it is detected that the inner needle has been removed.

8. The photoacoustic image generation apparatus according to claim 5 , further comprising:

movement detection unit for detecting a movement of the insertion needle based on a reflected acoustic wave image at a time before it is detected that the inner needle has been removed and a reflected acoustic wave image at a current time after it is detected that the inner needle has been removed.

9. The photoacoustic image generation apparatus according to claim 8 ,

wherein the movement detection unit detects a movement of a needle tip of the insertion needle based on a difference between a total value of pixel values in the reflected acoustic wave image at the time before it is detected that the inner needle has been removed and a total value of pixel values in the reflected acoustic wave image at the current time.

10. The photoacoustic image generation apparatus according to claim 9 ,

wherein the movement detection unit calculates the total values of the pixel values after performing distal end emphasis processing, which is for emphasizing a distal end portion of the insertion needle, for each of the reflected acoustic wave image at the time before it is detected that the inner needle has been removed and the reflected acoustic wave image at the current time.

11. The photoacoustic image generation apparatus according to claim 9 ,

wherein the movement detection unit calculates a total value of pixel values in a region including a position of the photoacoustic wave generating portion in the photoacoustic image.

12. The photoacoustic image generation apparatus according to claim 8 , further comprising:

warning unit for warning a user in a case where an amount of movement detected by the movement detection unit is equal to or greater than a threshold value.

13. The photoacoustic image generation apparatus according to claim 8 ,

wherein, in a case where an amount of movement detected by the movement detection unit is equal to or greater than a threshold value, the image output unit changes a display color of the photoacoustic image to a different display color from a display color before the amount of movement detected by the movement detection unit reaches the threshold value or more.

14. The photoacoustic image generation apparatus according to claim 13 ,

wherein, when the amount of movement detected by the movement detection unit becomes smaller than the threshold value after the amount of movement reaches the threshold value or more, the image output unit returns the display color of the photoacoustic image to the display color before the amount of movement reaches the threshold value or more.

15. The photoacoustic image generation apparatus according to claim 8 , further comprising:

needle distal end extraction unit for extracting a distal end candidate of the insertion needle from the reflected acoustic image,

wherein the image output unit displays a marker, which indicates a position of a distal end candidate of the insertion needle extracted by the needle tip candidate extraction unit, on the image display unit in a case where an amount of movement detected by the movement detection unit is equal to or greater than a threshold value.

16. The photoacoustic image generation apparatus according to claim 15 ,

wherein the image output unit stops the display of the marker when the amount of movement detected by the movement detection unit becomes smaller than the threshold value after the amount of movement reaches the threshold value or more.

17. The photoacoustic image generation apparatus according to claim 15 ,

wherein the needle tip candidate extraction unit ends the needle tip candidate extraction processing in a case where the movement detection unit detects that the insertion needle has moved by a predetermined amount or more in a direction in which the insertion needle is removed.