JPS6230983A - Image display for scintillation camera - Google Patents

Abstract

PURPOSE:To enable easy and accurate setting of optimum conditions, by removing the maximum integrated part from an image data on an image memory to convert the image data in the contrast on the basis of the upper and lower limit of the remaining data. CONSTITUTION:An image data with a scintillation camera 1 is converted 2 into digital from analog to be written into an image memory 4. Then, by a processing through a CPU 7 or the like, the image data is added separately in directions X and Y orthogonal to each other to determine the parts BX and BY above cut off levels LX and LY in the addition profile as the maximum integrated part of the image data by the integration with a radio isotope. These parts BX and BY are removed from the image data to determine the upper and lower limit values of the remaining image data in the memory 4 and a contrast conversion of the image data is performed based on the upper and lower limit values. This enables easy and accurate setting of optimum conditions thereby assuring an easy-to-view indication of a display image with a converted contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image display method using a scintillation camera that detects radiation (gamma rays) emitted from a radioisotope administered into the body of a subject and displays a scintigram thereof. In particular, the present invention relates to an image display method using a scintillation camera that can clearly display images of bones or lesion areas, particularly in the case of whole-body imaging.

Conventional technology The image display method of conventional scintillation cameras is as follows:
The image data collected from the subject was converted to gradation using its maximum and minimum values, and the image was displayed on the display with this gradation width. For example, as shown in Figure 5,
Assume that the maximum value of the count of image data collected for a certain subject is "1. OOO", and the minimum value is LL.
In the case of OI+, the gradation is converted between the maximum value and the minimum value with a gradation width of 256 steps, for example from "0" to "255", and the maximum value "1000" is set to 255 gradations, and the minimum value “0” was displayed as 0 gradation. Generally, when a radioisotope is administered into the subject's body and a whole body bone scintigram is taken, the radioisotope after traveling around the body accumulates in the bladder, which is shown with diagonal lines in Figure 5. Part A indicates the maximum value of image data "1000".

Problems to be Solved by the Invention However, in such an image display method, if an extremely large amount of radioisotope accumulates in a specific region of the subject, for example, bladder region A, and the maximum value of the image data appears there. The gradation was converted using a predetermined gradation width using the maximum value indicated by the specific region. Here, apart from the case where there is a lesion in the bladder part A, if there is a lesion in other than the bladder part A, the lesion part has a count of "50" in the image data in FIG.
However, since the gradation has been converted to 256 steps with the maximum value of the bladder area A, ``i o o o'', the gradation level for the lesion area ``2'' is half that, ``0'', to 11127. Therefore, the image of the lesion part that you actually want to observe in detail is displayed in rough shading, making it difficult to obtain a clear image, which may not be useful for diagnosis. To deal with this, a count of the image data is set in advance to, for example, '500'', the part above this count is cut off, and the remaining part is displayed after converting the gradation to 256 levels. . However, in this case, the count number set in -1- is based on experience and intuition, and
The number of counts that should be set varies depending on the radioisotope administration site, imaging conditions, and individual differences, so it is difficult to set optimal conditions and display a good image. Therefore, an object of the present invention is to solve such problems.

Means for Solving the Problems The means of the present invention for solving the above problems is to detect radiation emitted from the body of a subject and transfer the collected image data to an image memory. Add the above image data pixel by pixel in the X direction and Y direction to create an addition profile in each direction, determine the maximum accumulation part of the image data from the cutoff level of the addition profile in each direction, and then add the image data to the image memory. Exclude the most accumulated part in I from L, calculate the second limit value and lower limit value for the remaining image data, and then use the upper and lower limit values to transform the image data into gradations. This is done by displaying an image on a display with a range of gradations.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flow chart showing the steps of an image display method for a scintillation camera according to the present invention, and FIG. 2 is a block diagram showing an apparatus used to implement this image display method. The above device includes a scintillation camera 1 that collects image data of the subject by detecting gamma rays emitted from a radioisotope administered into the body of the subject and converting the detected gamma rays into electrical signals; an A/D converter 2 that digitizes the image data collected in step 1; a storage device 3 such as a magnetic disk that stores the already collected image data;
an image memory 4 that stores image data from the A/D converter 2 or the storage device 3; an adder circuit 5 that adds counts to the image data on the image memory 4 for each pixel in the X direction and the Y direction; It has a display 6 such as a CRT that displays image data, and a central processing unit w (CPtJ) 7 that controls these components.

Now, assume that the scintillation camera 1 is moved along the body axis of the subject to take a whole-body bone scintigram. First, the scintillation camera is gradually moved from the subject's head, for example, along the body axis toward the legs. During that time, gamma rays emitted from the subject's body are detected and converted into electrical signals, and image data of the subject's whole body is collected. Then, convert this image data to A/
I) Image memory 4 after being digitized by converter 2
(Step ('T') in Figure 1). In addition,
If the collection of image data for the subject has already been completed and the image data to be displayed is stored in the storage device 3, the image data in this memory bag W3 is stored in the CP.
It may be read out via U7 and transferred to the image memory 4. Next, when the whole body imaging of the subject is performed in this manner, the image data in the image memory 4-1 is added pixel by pixel in the X direction (see FIG. 3) in the adding circuit 5, and As shown in Figure 3, an addition profile Px in the X direction is created (step ■). In the same manner, the image data in the image memory 4'' is added pixel by pixel in the Y direction to create an addition profile py in the Y direction as shown in FIG. 3 (step 2).

In addition, in FIG. 1, the addition in the X direction is shown as step 2, and the addition in the Y direction is shown as step 2, but the present invention is not limited to this, and the addition in the Y direction may be performed first. Next, in the addition profiles Px and Py in the X and Y directions, the cutoff level I of the boundary showing an extremely large count number,
Find x, T, y and set these cutoff levels Lx, L
By finding the address where y cuts the addition profiles Px and Py in the X and Y directions in the X and Y directions,
As shown in Figure 3, the maximum accumulation part B of image data
Determine x and By (step ■). The region of the subject 8 corresponding to the maximum accumulation portions Bx and By corresponds to the bladder 9. Thereafter, the maximum accumulation portions Bx and By are removed from the image memory 4-[-, and two limit values and a lower limit value are calculated for the remaining image data (step 2).

In other words, as shown in FIG. 4, for example, in the addition profile Px in the ”, then
When this count is 500 or more, the shaded area in the figure becomes the maximum accumulation area Bx. Therefore, the image data whose count number is 500 or more is discarded,
For the remaining image data, for example, set the second limit value to 50.
0'', and the lower limit value is calculated as 0.Next, using the upper and lower limit values calculated in this way, the image data is gradation-converted and an image is displayed on the display 6 with the gradation width. In other words, as shown in FIG.
The gradation is converted and displayed using a stepwise gradation width. Although only the X direction is shown in FIG. 4, the operations of step (2) and step (2) are performed in exactly the same way for image data in the Y direction. As a result, the above cutoff level T, x
Images of bones and lesions that appear below , Ly are displayed in fine shading, making it possible to clearly display images of the parts that you actually want to observe in detail. Note that the calculation operations in each of the above steps are automatically controlled by the CPU 7.

Furthermore, in FIG. 2, the image data on the image memory 4 is shown as being added for each pixel in the X and Y directions by the adding circuit 5, but the present invention is not limited to this, and the adding circuit 5 is not used. The program for the CPU 7 causes the CPU to
1. An addition operation may be performed using J7. In this case, processing time will be slightly slower.

Effect of the Invention 8 = As explained above, the present invention excludes the maximum accumulated portions Bx and By above the cut-off levels L, x, r, and y from the image memory 4, and at the same time processes the remaining image data. ■ By calculating the second limit value and lower limit value, and then using the -L limit value and lower limit value to convert the gradation of the -h image data, the image of the bone or lesion part that you actually want to observe in detail can be created with a wide gradation level. It can be displayed in fine gradation. Therefore, an image of the bone or lesion can be clearly displayed, and effective diagnostic information can be provided. In addition, the cutoff level LX, ■, the maximum integration portion Bx, By of 7 or more is obtained by adding the image data of the image memory 41 for each pixel in the X direction and the Y direction to obtain the addition profile Px, Py in each direction. Since it is determined automatically by creating the image, the optimal display conditions are automatically set to produce a good image without relying on the operator's experience or intuition, and without being affected by shooting conditions or individual differences. can be displayed. Therefore, the operability of the scintillation camera is also improved.
-Can be done.

[Brief explanation of the drawing]

FIG. 1 is a flowchart 1 to 1 showing the steps of an image display method for a scintillation camera according to the present invention, FIG. 2 is a block diagram showing an apparatus used to implement this image display method, and FIG. An explanatory diagram showing an addition profile for data. Figure 4 is a graph showing the state of gradation conversion when the maximum accumulation part of image data is excluded. Figure 5 is a graph showing the gradation of image data in a conventional image display method. It is a graph showing the state of conversion. 1... Scintillation camera 2... A/I) converter 3... Storage device 4... Image memory 5... Addition circuit 6... Display 7... Central processing unit Px, Py... Addition profile Lx, T,, y...Cutoff level 1l-Bx, By...Maximum accumulation part

Claims (1)

[Claims] Image data collected by detecting radiation emitted from the subject's body is transferred to an image memory, and the image data on this image memory is moved in the X direction and Y direction, respectively.
Add each pixel in each direction to create an addition profile in each direction, determine the maximum accumulation part of the image data from the cutoff level of the addition profile in each direction, and then exclude the maximum accumulation part from the image memory. A scintillator characterized in that an upper limit value and a lower limit value are calculated for the remaining image data, and then the upper limit value and the lower limit value are used to convert the image data into gradations, and an image is displayed on a display with the gradation width. How to display images on a digital camera.