JP2001008930A - Radio ct instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an radio CT instrument that enables an operator, even who has few skills and few experiences, to quickly and easily set up the most suitable imaging condition according to the proportion of a subject. SOLUTION: From a slice position for sectional imaging that is specified on the CR image of a subject M displayed on an image monitor 15, a CPU 13 finds the maximum size for the physical thickness of the subject M and compares it with a standard thickness. An imaging condition-physical thickness tables 14 memorizes a large number of proper imaging conditions according to imaging parts and the physical thickness of the subject. The CPU 13 reads a normal imaging condition when the physical thickness of the subject is a standard value, or in the case that the physical thickness of the subject is larger of smaller than the standard state, the CPU 13 respectively reads a proper imaging condition from the imaging condition-physical thickness table 14 and outputs the condition to a console 5. The console 5 performs the imaging control of the sectional image, based on the input imaging condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to
The present invention relates to an X-ray CT apparatus that performs tomographic imaging of a subject by processing data obtained by irradiating X-rays.

[0002]

2. Description of the Related Art An X-ray CT apparatus for obtaining a tomographic image is widely used as an apparatus for diagnosing a lesion in a subject.

When imaging an object using an X-ray CT apparatus, imaging conditions such as a tube voltage, a tube current, and an imaging time suitable for each diagnostic site, for example, head, chest, and abdomen, are set. Can be obtained.
In such a case, if these imaging conditions are set each time the subject is imaged, the imaging operation becomes extremely complicated, and the subject cannot be quickly imaged. Therefore, X
The X-ray CT apparatus is provided with a function for preliminarily storing imaging conditions suitable for a standard subject for each diagnostic region and setting necessary imaging conditions simply by selecting a button indicating the diagnostic region. .

[0004]

However, since the patients as subjects have different body shapes, the preset standard imaging conditions are not always suitable for obtaining an image suitable for diagnosis. Absent. For this reason, conventionally,
The operator manually corrected the preset standard imaging conditions so that an image suitable for diagnosis was obtained for each subject, but since these corrections require the operator's long experience and skill, However, it was not easy to obtain a good captured image depending on the subject.

[0005] Even if the imaging conditions are appropriately corrected by a skilled operator, correcting the imaging conditions for each subject requires a considerable amount of time and effort, and also requires a rapid imaging. Was difficult to do.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and the setting of optimum imaging conditions according to the body shape of a subject can be quickly and easily performed even by an operator without skill or experience. An object of the present invention is to provide an X-ray CT apparatus that can be easily performed.

[0007]

The present invention relates to an X-ray CT apparatus for performing tomographic imaging of a subject by processing data obtained by irradiating the subject with X-rays. A body thickness measuring means for measuring the body thickness of the subject from data on a plane image of the subject obtained by irradiating X-rays from one direction along the direction, and a subject having a body thickness deviating from the standard body thickness data. Imaging condition storage means for storing imaging conditions suitable for the specimen, comparing the body thickness data measured by the body thickness measurement means with the standard body thickness data, and the measured body thickness data is obtained from the standard body thickness data. If it is out of range, an imaging condition setting unit that reads out imaging conditions suitable for the body thickness from the imaging condition storage unit and performs necessary settings so that a tomographic image is captured based on the read out imaging conditions. It is characterized by the following.

[0008]

FIG. 1 is a diagram showing a schematic configuration of an X-ray CT apparatus according to the present invention. The X-ray tube 4 and the X-ray detector 3 are arranged on the gantry 2 so as to face each other, and the bed 1 is rotated by continuously rotating the gantry 2 while irradiating a fan-shaped X-ray FB from the X-ray tube 4. X-rays transmitted from multiple directions around the subject M placed on the X-ray detector are detected by the X-ray detector 3 in which a large number of X-ray detection elements 3a are arranged in an array. The detected data is subjected to processing such as conversion to digital data in the data collection unit 9 and then temporarily stored in the detection data memory 10, reconstructed into a tomographic image by the reconstruction means 11, and transmitted to the image monitor 15. Is displayed. The reconstructed tomographic image is stored in the image memory 12 so that diagnosis or the like can be performed at a later date.

The X-ray tube 4 irradiates X-rays with a high voltage applied by a high-voltage generator 7, and the operation of the high-voltage generator 7 is controlled by an X-ray controller 6. The rotation operation of the gantry 2 and the movement operation of the bed 1 are performed via the gantry table controller 8.

In the X-ray CT apparatus of this embodiment, the object M
In addition to the function of capturing a plane image (hereinafter, referred to as a “CR image”), the apparatus has a function of specifying an imaging region of a tomographic image to be captured on a CR image prior to capturing a tomographic image. C
The R image is obtained by continuously irradiating X-rays from the X-ray tube 4 in a state where the gantry 2 is stationary while moving the bed 1 along the body axis direction of the subject M, and data detected by the X-ray detector 3. Are synthesized by the reconstruction means 11.

The console 5 is provided with input means for instructing the operation of the entire X-ray CT apparatus, and the operator gives necessary imaging instructions, various image processing, and instructions for reading stored images. Through. Console 5
X-ray controller 6, gantry table controller 7, CP as needed, based on operation instructions given through input means
It controls each component of the X-ray CT apparatus such as U13.

The CPU 13 calculates the body thickness of the subject M from the obtained CR image based on an instruction from the console 5 and, based on the calculated body thickness data, sets an appropriate imaging condition in an imaging condition-body thickness table. 14 and outputs the read imaging conditions to the console 5. Console 5 is C
The whole apparatus is controlled so that the subject M is imaged based on the imaging conditions obtained from the PU 13.

FIG. 2 is a diagram showing a state in which the imaging conditions related to the body thickness stored in the imaging condition-body thickness table 14 are hierarchically stored. Imaging conditions-body thickness table 1
4 hierarchically stores imaging conditions according to the imaging region, the imaging direction of the CR image, and the body thickness. In each of the abdomen and the chest, a CR image of AP taken from the front of the subject and a CR of LATERAL taken from the side of the subject
It is divided into the case of an image.

In both cases where the abdomen and chest are imaged, A-
For the case of the CR image of P, the imaging conditions at the standard body thickness TA, when the measured body thickness is smaller than the standard body thickness TA,
And the imaging condition in the case of a large body is stored. Also, in the case of a lateral CR image, the imaging condition in the case of the standard body thickness TL, the case where the measured body thickness is smaller than the standard body thickness TL, and Each of the imaging conditions in the case of being large is stored. Further, the respective imaging conditions are such that when the measured body thickness is smaller than the standard body thickness TA, the X-ray intensity is lower than the imaging condition corresponding to the standard body thickness, and when the measured body thickness is larger, the standard body thickness is smaller. Is set so that the X-ray intensity becomes higher than the imaging condition corresponding to.

The table shown in FIG. 2 is configured to be able to store a plurality of imaging conditions for each body thickness. As shown in FIG. This is because, when a plurality of imagings are performed as indicated by the lines, imaging conditions for each imaging are stored. In the present embodiment, an example in which the same imaging condition is stored for each body thickness is shown.
In a normal chest or the like, as shown in FIG. 4, since there is a tendency to become narrower from the upper part to the lower part, it is possible to store, for example, such that the tube current is sequentially reduced.

The standard body thickness TA in the CR image of AP and the standard body thickness TL in the CR image of LATERAL
May be used as the body thickness of the subject having the average height and weight at the imaging site.

Next, the imaging condition is set based on the CR image.
The procedure automatically set in consideration of the body thickness will be described with reference to the schematic configuration shown in FIG. 1 and the flowchart shown in FIG.

First, the console 5 is operated by a CR
Based on the imaging instruction of the image, the imaging conditions of the CR image including the AP and the lateral imaging are set (S1), and the necessary components in the X-ray CT apparatus are controlled based on the set imaging conditions (S2). .

The captured CR image is stored in the image memory 12 and displayed on the image monitor 15. The operator observes the CR image displayed on the image monitor 15 while viewing FIG.
As shown in (3), slice positions 1 to 4 for capturing a tomographic image are specified by a mouse or the like provided on the console 5 (S3).

When the specification of the slice position is completed, the CPU
13 calculates the body thickness of the subject M for each set slice position, and measures the body thickness of the largest part as the body thickness T1 of the subject M (S4). Here, the measurement of the body thickness compares the data value of the CR image on the slice position for each slice position,
Since two points having rapidly different data values are considered to be the contours of the subject M, the calculation can be easily performed by calculating the distance between these two points.

When the measurement of the body thickness data T1 is completed, CP
U13 reads the imaging conditions required from the imaging condition-body thickness table 14 based on the comparison result of the imaging region, the type of the CR image, and the standard body thickness data TA or TL with the body thickness data T1, and outputs them to the console 5 ( S5). In the example shown in FIG. 2, the imaging region, the type of the CR image, and the body thickness data T
There are a plurality of imaging conditions specified by
Outputs the plurality of imaging conditions to the console 5, and the console 5 displays the plurality of conditions so that the operator can select an appropriate one.

When the imaging conditions are finally specified by the operator, the console 5 controls the entire apparatus so as to perform tomographic imaging under the specified imaging conditions (S5).
6).

In the above-described embodiment, when the measured body thickness TL is equal to the standard body thickness TA, or when the standard body thickness T
Although a plurality of imaging conditions are stored for each of the cases A and below, for parameters changed according to the body thickness of the subject M, for example, the relationship between the tube current and the body thickness as shown in FIG. A table indicating the relationship may be stored in advance, and a necessary tube current may be calculated for the measured body thickness T1 from the relationship of the table.

The above-mentioned standard body thickness TA is usually configured as a value having a predetermined width. For example, CR of AP
In the case of an image, it can be 40 cm to 50 cm or the like.

Further, the standard body thicknesses TA and TL are separately set for the gender of the patient and for adults and children, and appropriate imaging conditions are stored for cases where the standard body thickness deviates from the standard body thickness and for the standard body thickness. You may.

As a method of measuring the body thickness, it is possible to measure the approximate body thickness from the profile data of the detector 3 or the data collection unit 9 obtained at the time of capturing the CR image. In this case, profile data that is a standard value for each body thickness is set as a comparison target, and imaging conditions can be read for each body thickness by comparing the profile data with actual imaging data.

[0027]

According to the present invention, appropriate imaging conditions can be automatically set according to the body shape of the subject, so that even an operator with little skill or experience can make a diagnosis according to the body shape of the subject. An appropriate tomographic image can be obtained. In addition, since it is not necessary to correct the imaging conditions for each subject, the imaging operation is facilitated and quick imaging is possible.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an X-ray CT apparatus of the present invention.

FIG. 2 is a diagram showing imaging conditions hierarchically stored according to an imaging region, a CR image, and a body thickness of a subject.

FIG. 3 is a flowchart illustrating an operation of setting an imaging condition according to a body thickness of a subject.

FIG. 4 is a diagram showing a procedure for obtaining a body thickness of a subject on a CR image.

FIG. 5 is a diagram showing a relationship between tube currents to be set according to body thickness.

[Explanation of symbols]

 1 bed 2 gantry 3 X-ray detector 15 image monitor

Claims (1)

[Claims] 1. An X-ray CT for performing tomographic imaging of a subject by processing data obtained by irradiating the subject with X-rays from the periphery of the subject.
In the apparatus, a body thickness measuring means for measuring the body thickness of the subject from data on a planar image of the subject obtained by irradiating X-rays from one direction along the body axis direction of the subject, a standard body thickness Imaging condition storage means for storing imaging conditions suitable for a subject having a body thickness deviating from data, and comparing the body thickness data measured by the body thickness measurement means with the standard body thickness data, and measured. When the body thickness data deviates from the standard body thickness data, an imaging condition suitable for the body thickness is read from the imaging condition storage means, and necessary settings are made so that a tomographic image is captured based on the read imaging condition. An X-ray CT apparatus, comprising: an imaging condition setting unit for performing the operation.