JPH05208008A - Data collection processing method by x-ray ct scanner - Google Patents

Abstract

PURPOSE:To provide the data collection processing method of an X-ray CT scanner which can speedily process the scan data obtained through the high speed scan by using a reconstitution device efficiently. CONSTITUTION:During the scan by an X-ray CT scanner 1, reconstitution is carried out by a reconstitution device 4 on the basis of the front half of the scan data which is temporarily stored in a main memory 3, and the image data is obtained, and the rear half of the scan data and the above-described image data are stored in an outside memory device 5, and after all the scan is completed, the rear half of the scan data is reconstitued by using a reconstitution device 6 again, ands each tomogram is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data acquisition processing method in an X-ray CT scanner capable of quickly processing scan data obtained by high speed scanning by efficiently using a reconstruction device or the like.

[0002]

2. Description of the Related Art The scan mode of an X-ray CT scanner includes an S & V (scan and view) mode and an S / V (scan and view) mode.
& S (scan and scan) mode.

In the S & V mode, as shown in the time chart of FIG. 3, an image is reconstructed by using scan data in the main memory of the X-ray CT scanner while scanning, and one scan and an image are reconstructed. After the
The image data obtained by this is filed in an external storage device, for example, a magnetic disk, and the data is collected and processed in the step of proceeding to the next scan. Such a scan mode is not used when performing a large number of scans at high speed because one scan cycle takes about 3.5 seconds.

On the other hand, in the S & S mode, as shown in the time chart of FIG. 4, the scan is first performed continuously, and the scan data stored in the external storage device is read after the scan data is collected or after all the scans are completed. This is a data collection processing mode in which the image of each scan is reconstructed. For example, in the example shown in FIG. 4, the scan data is sent from the external storage device to the reconstruction device three times, the image reconstruction processing is performed, and then the image data is filed in the external storage device. Such a scan mode is frequently used because one scan cycle can be set to about 2 seconds, which enables high-speed scanning and shortens the examination time and the patient restraint time. Both scan modes have a scan time of 1 second and a scan data amount of 1.5M.
B, the image data amount is 0.5 MB, the reconstruction time of one image by the reconstruction device is 3 seconds, and the disk transfer rate is 1 MB /
It is assumed that sec is set, and that data transfer between the disk and the memory and image reconstruction processing can be performed at the same time.

[0005]

However, in the continuous rotation type high speed scanning X-ray CT scanner, the external storage device is almost exclusively used for filing the scan data at the time of the next scan after the scanning, so that It is difficult to reconstruct the image by calling the filed scan data and sending it to the reconstruction device.
There is a problem in that the reconstructing device cannot be used sufficiently during scanning and the reconstructing device is idle. Also, if it is desired to use the reconstruction device during scanning, X-ray CT
The scanner requires a large-capacity main memory or an external storage device capable of high-speed data transfer, which is problematic in terms of manufacturing cost.

The present invention has been made to solve these problems, and an object of the present invention is to provide a data acquisition processing method in an X-ray CT scanner that rapidly processes scan data obtained by high-speed scanning.

[0007]

An X-ray CT according to the present invention
The data collection processing method in the scanner is the first step of temporarily storing the first half of the scan data in the memory at the same time as the scanning, and immediately after the end of the first step, only the second half of the scan data is stored in the external storage device. At the same time, the second step of reconstructing an image based on the temporarily stored scan data to obtain the image data of the first half of the scan, and the first step of the next scan, the second step of the previous scan. A third step of storing the image data in an external storage device, a means for executing each of the steps for a set number of scans, and immediately after the completion of all scans, the data already stored in the external storage device is read into the memory, And means for reconstructing an image in each scan.

[0008]

According to the data collection processing method in the X-ray CT scanner of the above means, the image is reconstructed by the reconstructing device based on the first half of the scan data temporarily stored in the main memory,
The image data obtained by such reconstruction processing and only the latter half of the scan data are filed on a magnetic disk or the like, which is an external storage device, before the next scan is completed.
Therefore, the amount of scan data transferred to the external storage device can be halved, and the timing for transferring the image data to the external storage device can be sufficiently secured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a data acquisition processing method in an X-ray CT scanner to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a data acquisition processing system of an X-ray CT scanner.

In such a system, the X-ray C
When the pre-processing device 2 that performs amplification and A / D conversion (analog / digital conversion) of the signal sent from the T scanner 1 into scan data of a predetermined digital signal and arithmetic processing based on a program or the like, Main memory 3 for temporarily storing scan data, CPU 4 for controlling arithmetic processing and various devices based on a predetermined program or command signal, external storage device 5 including a magnetic disk for storing data, scan data A reconstructing device 6 for reconstructing an image, an operation unit 7 for inputting a processing command to be executed in the CPU 4 and setting a program to be executed, a display unit 8 for displaying image data as a tomographic image, and the like.

FIG. 2 is a time chart showing a scan mode executed by the X-ray CT scanner 1. In this scan mode, the scan time is 1 second, the scan cycle is 2 seconds, the scan data amount is 2 MB, the image data amount is 0.5 MB, and the image reconstruction time by the reconstruction device is 3 MB.
It is assumed that the disk transfer rate is 1 MB / sec and the data transfer between the external storage device 5 and the main memory 3 and the reconfiguration by the reconfiguration device can be performed at the same time.

In order to set the position of the imaging region of the patient (not shown) and the scan mode to be executed by the X-ray CT scanner 1 in the system, a scanogram or the like is displayed on the display unit 8, and the operation unit is referred while referring to this. It is performed by the operator using the keyboard of 7. X-ray CT
When the scanner 1 starts scanning based on a predetermined program that has already been set, scan data is sent out to the main memory 3 via the X-ray CT scanner 1 and the preprocessing device 2, and the data is saved by the following steps. Collected and processed.

First, at the same time as scanning, the main memory 3 stores
The first half of the scan data in the scan is temporarily stored (first step). Next, when the latter half of the scan data is sent to the main memory 3, the latter half of the scan data is sent as it is to the external storage device 5 in real time, and at the same time, the reconstruction device 6 temporarily stores it in the main memory 3. The scanned data is captured and the image is reconstructed (second step). The image data of the first half of the scan obtained by such reconstruction is stored in the external storage device 5 during the first step of the next scan (third step).

The above steps are executed for the number of scans set by the operator. Immediately after the completion of all the scans, the scan data and the like stored in the external storage device 5 are read out to the main memory 3 and the respective scans are executed. The reconstruction is finally done.

Since the reconstructing device 6 is always driven except when the image data is stored, the X-ray C
When the scanning by the T scanner 1 is completed, the reconstruction is almost completed.

Further, in the example of FIG. 2, since there is a spare disk transfer capacity for the scan cycle, if the image data is saved during the next reconstruction process, the scan cycle can be up to 1.5 seconds. Can be shortened. Even in this case, reconstruction is about half finished at the end of the scan,
The same effect as in the 2-second cycle can be obtained. On the other hand, if the scan cycle is shortened to 1.5 seconds in the example of FIG. 4, reconstruction during scanning cannot be performed at all, and all reconstruction processing must be performed after the end of scanning. Therefore, in such a case, the effect of the present invention is most significant.

[0017]

According to the data acquisition processing method in the X-ray CT scanner of the present invention, the first half of the scan data temporarily stored in the memory is reconstructed as image data, and the second half of the scan data is directly used as the scan data. Since the data is transferred to the storage device, the transfer amount of scan data can be halved. Therefore, without relying on hardware such as an external storage device capable of reading and writing at high speed, the image data is saved during scanning, so that sufficient time for accessing the external storage device can be secured.

As a result, even if the scanning speed of the X-ray CT scanner is increased, the reconstructing device can be efficiently used and the image data can be saved without pursuing the performance of the hardware. The required work time can be shortened.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment to which the present invention is applied.

FIG. 2 is a diagram showing a timing chart of a data collection process in a scan mode of the same embodiment.

FIG. 3 is a diagram showing a timing chart of data collection processing in the S & V mode.

FIG. 4 is a diagram showing a timing chart of data collection processing in the S & S mode.

[Explanation of symbols]

 1 X-ray CT scanner 2 Pre-processing device 3 Main memory 4 CPU 5 External storage device 6 Reconfiguring device

Claims (1)

[Claims] 1. A first step of temporarily storing the first half of scan data in a memory simultaneously with scanning, and immediately after the end of the first step, only the second half of scan data is stored in an external storage device, and at the same time, The second step of reconstructing an image based on the temporarily stored scan data to obtain the image data of the first half of the scan and the image data obtained by the second step of the previous scan during the first step of the next scan A third step of storing in the external storage device, a means for executing each of the steps for the set number of scans, and immediately after the completion of all the scans, the data already stored in the external storage device is read out on the memory, and in each scan An image reconstructing method in an X-ray CT scanner, comprising: a means for reconstructing an image.