JPH0434479Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a radiation filter device used by being attached to a radiation diaphragm device.

(B) Conventional technology For example, when performing coronary angiography of the heart, the subject is the left coronary artery, and even if the aperture device is operated so that the center of the X-ray irradiation area is located there, the center of the X-ray irradiation area is The body protrudes from the heart, and as it is unavoidable that X-rays pass through tissues such as the lungs, which have high X-ray transmittance, halation occurs in part of the X-ray image, affecting the subject's own X-ray image.
make it unclear. In order to eliminate such inconveniences, a radiation filter is attached to the aperture device to weaken the X-rays incident on areas with high X-ray transmittance, thereby eliminating the significant difference in brightness on the X-ray image plane. It was designed to suppress the occurrence of halation.

Conventionally, this type of radiation filter device has at least one filter inside the diaphragm main body, which is moved between a position where it traverses a radiation cone and a position where it does not traverse it, by an appropriate drive mechanism. equipped with a radiation filter (for example,
No. 56-75144), the X-ray filter can be positioned at any position within the X-ray irradiation area by remote control in a short time while observing the X-ray fluoroscopic image, preventing halation and reducing the It is designed to minimize radiation exposure.

However, the area to be imaged of a subject that requires a radiation filter during X-ray photography is not limited to the heart mentioned above, but includes various areas such as the head and neck, and the shape of each of these areas as well as the adjacent areas. The X-ray transmittance of the exposed parts also varies. For this reason, simply positioning a filter with a constant X-ray absorption rate at an arbitrary position on the X-ray cone cross section, as in the radiation filter device described above, is not sufficient to deal with this, and of course, the radiation filter itself can be replaced as appropriate. Must. Therefore, for example, Jitsukaiaki
In the radiation filter device according to the invention of Publication No. 59-58400, the radiation filter is screwed so that it can be replaced.

However, in such a method, it is inevitable that replacing the filter is troublesome and requires a considerable amount of time.

(c) Purpose This invention was made in order to solve the above-mentioned problems with conventional radiation filter devices, and it is possible to easily and quickly create a radiation filter that is suitable for any part of the subject. The object is to provide a radiation filter device that can be replaced.

(D) Structure The radiation filter device according to this invention has at least one radiation filter which is movable between a position where the radiation cone crosses and a position where it does not cross, by a drive mechanism, inside the main body of the diaphragm device. In a radiation filter device provided with a filter, the radiation filter is connected to and held by the drive mechanism, the thin ferromagnetic plate is connected to the drive mechanism, and the whole or at least the bottom part is formed of a sheet-shaped rubber magnet, and the ferromagnetic plate is It is composed of a filter that is adsorbed and held by the
positioning the filter together with the ferromagnetic plate acting as a part of the radiation filter at an arbitrary position on the radiation cone cross section by the driving mechanism;
Furthermore, the filter provided with the suction means can be replaced easily and in a short time depending on the subject.

(E) Embodiment FIG. 1 is a partial perspective view showing the main parts of an embodiment of the device according to this invention. However, the radiation filter is shown in a removed state for convenience of illustration.
The main parts of the device of this embodiment are housed inside the aperture device, and have a radiation cone window in the center, and a fixed base (not shown) provided at right angles to the radiation cone axis. All of the above-mentioned essential parts are mounted on a rotary disk (not shown) which is rotatably mounted on this fixed base, also has a radiation cone window in the center, and can be rotated by external operation. It is being That is, a pair of guide rods 2, 2' which are parallel to each other are fixed at both ends to the rotary disk and to supports arranged symmetrically with respect to the center of the radial cone window. Sliding members 3, 3' are slidably engaged with the guide rods 2, 2', respectively. Reference numeral 4 denotes an extremely thin ferromagnetic plate (for example, a steel plate) whose portion near the axis of the radial cone has a concave arc shape, and is fixed to the bottom surfaces of the sliding members 3, 3' at the left and right ends.
The sliding member 3 is secured to the endless belt 5 via the steel plate 4 joined to the bottom surface thereof. The endless belt 5 is attached to a driven pulley 6 that is rotatably supported in a cantilever manner by a bearing (not shown) fixed to the rotary disk, and to an output shaft of a motor 7 that is also installed on the rotary disk. The guide rod 2 is spanned between the guide rod 2 and a drive pulley 8, and is made to travel in a vertical plane parallel to the guide rod 2 by rotating the motor 7. Therefore, by driving the motor 7 clockwise or counterclockwise toward the drive pulley 8, the ferromagnetic plate 4 can be moved in parallel in the direction of arrow A or in the opposite direction. be.

The filter 1 is a sheet-shaped rubber magnet with an aluminum equivalent of 0.5 to 10 mm per mm.
By appropriately selecting its material and thickness, it can be used as an X-ray compensation filter having a desired X-ray absorption rate. The reason why the concave arc shape and this arc surface is an inclined surface is because the subject,
For example, this is to bring the intensity of transmitted X-rays at the edge of the heart closer to that near the center and to equalize the brightness of the X-ray image plane. When in use, the filter 1 is attracted and fixed to the ferromagnetic plate 4 by its own attractive magnetic force, but since the area of attraction with the ferromagnetic plate 4 is relatively large, sufficient fixing force is required. arise. In this case, the ferromagnetic plate (steel plate) 4 is extremely thin.
Since it also acts as a radiation filter, it is necessary to take into consideration the aluminum equivalent of the steel plate 4 when selecting the material and thickness of the filter 1.

Next, the operation of this device will be explained.

A filter 1 of material and thickness corresponding to the part of the subject to be imaged is prepared. When preparing this, if a sheet magnet with the desired X-ray absorption rate is not available, as shown in FIG. are used as a composite filter having a desired X-ray absorption rate by bonding them together with an adhesive, or by attaching a plurality of sheet-shaped magnets 1 with an adhesive to a third
They may be used by bonding them together as shown in the figure.

The filter 1 prepared in this way is attached to a ferromagnetic plate 4.
The filter 1 is held at an arbitrary position on the radial cone cross section by adsorbing and fixing the filter 1 on the top of the radial cone, and by appropriately combining the rotational movement of the rotary disk and the parallel movement of the ferromagnetic plate 4 driven by a motor. I can come. Therefore, for example, while observing an X-ray fluoroscopic image of a subject, the radiation filter can be easily and quickly positioned at any position within the X-ray irradiation area by remote control, thereby preventing halation.

In particular, in this apparatus, when a radiation filter suitable for the part to be imaged of the subject is replaced as appropriate, the replacement can be done easily and in a short time. In addition, when forming the recess along the outline of the subject, if the filter 1 is formed of a sheet magnet or a stack of magnets, the machining is easy and can be done simply by cutting with a knife. This can be significantly lower than that of lead-containing acrylic sheets, which have been used for many years.

Note that this invention is not limited to the embodiment described above, but may include another filter 1 including a drive mechanism and a ferromagnetic plate 4 provided on the guide rods 2 and 2' facing these members described above. You can also do this.

(f) Effects In the radiation filter device according to this invention, it is possible to easily and quickly replace and install a radiation filter suitable for the imaging site of the subject. Further, it is also easy to mold a part of the filter into a shape that follows the outline of the subject, if necessary.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing the main parts of a radiation filter device that is an embodiment of this invention, and FIGS. 2 and 3 are two views of the radiation filter installed in the device.
FIG. 3 is an external perspective view showing two examples. 1... Radiation filter (sheet-shaped rubber magnet),
2, 2'...Guide rod, 3, 3'...Sliding member, 4...Ferromagnetic plate.

Claims (1)

[Scope of utility model registration request] A radiation filter device comprising at least one radiation filter provided inside the main body of the radiation aperture device, the radiation filter being movable by a drive mechanism between a position where it traverses the radiation cone and a position where it does not cross the radiation cone.
The radiation filter is composed of a thin ferromagnetic plate connected and held to the drive mechanism, and a filter whose entirety or at least a bottom portion is formed of a sheet rubber magnet and which is attracted and held by the ferromagnetic plate. Radiation filter device.