JPS60199432A - Computer tomographic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a computerized tomography device (Comp
A combicoater tomography system (hereinafter referred to as CT) with a vertical patient positioning mechanism is used.

(Prior Art) Placing the subject 4i1 at the scanning rotation center in the gun 1-1, that is, centering, is important in preventing overrange of the detection data collection system and obtaining a high-quality tomographic image. FIG. 1 is an explanatory diagram regarding centering. In this figure, 1 indicates a subject and 2 indicates an effective visual field area.

For centering, move the subject 1 appropriately in the X direction (horizontal direction) and Y direction (vertical direction) so that the sliced part of the subject falls within the effective visual field area 2 and becomes the center of scanning rotation, and accurately center the subject. It is necessary to mark the position in both directions.

In this case, in the X direction, the table on which the subject is placed is placed at the center of the gun, and if the subject is placed in the middle of the table, it can be centered in the X direction almost accurately. However, in the Y direction, it is difficult to perform accurate hinting that matches the shape of the subject. This Y direction centering has conventionally been performed in the following manner.

■As shown in Figure 2, apply positioning lines 1 to 3 to the scanning position of the subject 1, and position them at the center of the scan.
Adjust the height of the table so that it is the center of scan rotation for the subject.

■After adjusting the approximate table height, perform one scan and observe the reconstructed image. If the reconstructed image is not appropriate
If J, the deviation from the scan center in the reconstructed image is measured, and the table height is readjusted by the deviation.

■For the C1-device equipped with a table height display device, calculate the rough table height based on the shape of the subject and the scanning area, and find the required height (after moving the table table, perform the scan). Observe the reconstructed image and repeat the readjustment in the same manner as in (2) above.

However, in case (2), accurate centering cannot be expected because the shape of the subject is not uniform and the line of sight of the operator making the adjustment is higher than the adjustment position.

Also, in ■ and ■, in order to perform accurate centering, skill l? There is a problem in that the X-ray exposure has to be repeated and the exposure to X-rays increases.

(Objective of the Invention) The present invention has been developed with these points in mind.The object of the present invention is to easily, accurately, and safely position a subject in the vertical direction without causing radiation exposure. The object of the present invention is to provide a CT system with patient positioning im that can be obtained.

(Structure of the Invention) To achieve such an object, the present invention uses a light emitting element disposed at a position where light runs horizontally within the screen plane near the first edge of a centered subject. means for detecting the phase of the light receiving element and the height of the table on which the subject is placed;
arithmetic processing means for calculating the vertical dimension of the object based on the table height signal and the signal from the light receiving element and determining the table height for centering; Receive control l signal to do it
a driving means for moving the table up and down kr with the table [-
The present invention is characterized in that it is equipped with a group of operation/instruction buttons for performing immobilization, and is configured so that the subject to be examined can be positioned at the center of scan rotation.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 3 is a main part configuration diagram showing an embodiment of the patient positioning mechanism of the present invention, in which (a) is a side view and (b) is a front view.

In the figure, 1 indicates a subject (patient). 20 is a gantry having an X-ray source that generates radiation (hereinafter referred to simply as X-rays in the case of X-rays) and an X-ray detector that detects the transmitted X-ray intensity; 13 is a light-emitting element, and 14 is a light-receiving element. This pair of light-emitting and light-receiving elements is arranged horizontally within the scan plane 4, and the distance from the scan rotation center 6 is the same as that of the subject 1. It is placed at approximately 1/2 of the vertical dimension (for example, 100 m).In addition, this set of light emitting and light receiving elements can be used for a wide range of subject shapes (patient body sizes).
Multiple arrays may be used to cover the following. 40 is a table height detection circuit that detects the height of the table 30;
50 is a table that can move the pull 30 up and down, l-a table that can be moved up and down;
It is a wh device. Reference numeral 60 denotes an operating device having an operating button and an indicator, which is operated by an operator for accurate centering. FIG. 4 shows an example of the push button and indicator group of the operating device 60, and the centering.

There are push buttons 61, 62, 63 for ``Ul'', □own''
l) ” and “D o w n ” indicators 64 and 65, respectively. 70 is a performance frame processing unit, which includes a light emitting element 13, a table height detection circuit 40, and an operating device 6.
0 signal is received, arithmetic processing is performed, and control/instruction signals are sent to the operating device 60 and table vertical movement drive 8/50.

The operation in such a configuration will be explained next using FIGS. 3 and 4.

Here, the distance between the position of the light emitting/light receiving element and the scan rotation center is [, and the height from the bottom end of the table to the scan rotation center is 1-1.

First, the height of the table 30 is adjusted to an appropriate position, the subject 1 is sent into the gantry 20, and the centering button of the operating device 60 is pressed. At this time, if the light receiving element 14
If '1''<light is not blocked), operate device 60
The 'Up' indicator lights up. Look at it and press button 62 on the controller to move the table up and down.
The drive device 50 operates, and the 7-bull 30 moves in the -F direction.

If you continue to press the Up button 62 until the 'Up' indicator 64 goes out, the light receiving element 14 will change to '1'.
From 'O' to 'U' (where the light is blocked)
I') "The indicator 64 goes out and the upward movement of the table 30 stops.

If the table height at this time is h, the value of h is detected by the table height detection circuit 40, and the signal IJ
The signal is supplied to the arithmetic processing section 70. Since the vertical dimension of the object 1 in the vertical direction () is expressed by f-(+l-h), the appropriate pink ring height Δ can be expressed by the following equation.

A = l-1-(I"+ L-h) / 2-(
I-(-L+h)/2 Here, since 1-1 and [ have already been input to the arithmetic processing unit 70 as constants, A can be immediately determined from the above equation. Subsequently, this A and the table height h are compared, and if I is equal, the operating device 60 is set to ""up" or '[
) own''' indicator.The operator presses the button corresponding to the blinking indicator and continues to press it until the indicator disappears.When the table height is centered (Qff&), the table vertical movement will stop. Then, the flashing indicator goes out. Through these operations, the proper pink ring position is determined and the operation is completed.

If the light receiving element is 0 when you press the first centering button.
'', the operator 600゛' □ o w n '' indicator lights up, and when you press the Down button after looking at it, the table 30 moves downward, and the light receiving element 14 changes from ``Opa'' to ``1''. At the point when it is covered, the indicator disappears and the movement of the table is stopped4.Knowing the table height h at this time, it is possible to determine the centering table height Δ based on the above formula and perform appropriate pink ringing.

Accurate centering can be performed with such simple operations. Furthermore, even if the vertical spacing between the plurality of light receiving elements is coarse, by moving the table up and down until the state of the light receiving elements 7- changes as described above, the vertical dimensions of the object can be accurately measured. . Furthermore, by making the vertical spacing of the light receiving elements finer and increasing the number thereof, it is possible to reduce the vertical movement of the table for measuring the size i1 of the subject, and it is possible to cover a wide range of thinking physiques.

Here, the present invention is not limited to the structure in which the light emitting/light receiving elements are provided on the four-tone surface (this is referred to as internal positioning). It may also be configured to be provided at a position that is a certain distance (for example, 30 cm) from the main surface (this is called external positioning). In that case, the set of light emitting and light receiving elements may be provided at the position of the external positioning light instead of at the scanning surface. In this case, if the light-emitting/light-receiving element is integrated with the delta mechanism system of the gantry, l cos θ-[) sin θ (however, D
is the distance between the scan plane and the external positioning position, and θ is the delta angle).

<Effects of the Invention> As explained above, according to the present invention, it is possible to accurately determine the scan point of a subject by simple operation according to the operation guide such as indicator display from the arithmetic processing section. By moving the table up and down to measure the vertical direction of the object, accurate positioning is possible even with a small number of object size measurement detectors, and this eliminates unnecessary X-ray skin tone. It eliminates the need for repetition and minimizes patient radiation exposure.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram regarding centering to align the subject to the scan position, Fig. 2 is an explanatory diagram showing an example of conventional centering, and Fig. 3 is a main part configuration showing an embodiment of the patient positioning mechanism according to the present invention. 4 are explanatory diagrams showing operation buttons and indicator groups of the operation device according to the present invention. 1... Subject 13... Light emitting element 14... Light receiving element 20... Gun 1 edge -30...
・Table 4o... Table height detection circuit 50... Table vertical movement drive device 60... Operator 70... Actual processing section -11-

Claims (1)

[Scope of Claims] A combination of a light emitting element and a light receiving element arranged at a position where light runs horizontally in the scan plane near the upper edge of a centered subject, and the height of a table on which the subject is placed. a calculation processing means for calculating the vertical dimension of the subject based on the table height signal and the signal from the light receiving element to determine the table height for centering; and the calculation processing means The table is provided with a driving means for vertically moving the table in response to a control signal for performing the downward movement of the table F, and a group of operation/instruction buttons for vertically moving the table. A tomographic imaging apparatus configured so that a subject can be positioned at the center of scan rotation.