Patent Application
20070297571
The invention relates to an X-ray emitter and a method for creating and displaying X-ray images.
DE 3632878 A1 discloses an apparatus for positioning the head of a patient for the purpose of producing X-ray images, particularly a dental panoramic tomogram, by means of which apparatus the head of the patient is aligned with the display of the recorded silhouette of the patient's head. A video camera and a video monitor are used for this purpose, the stored position being brought into register with the current position on the video monitor. The video camera is adjusted in such a way that its optical axis coincides with that of the central ray of the X-ray emitter. This apparatus appears to be independent of the actual X-ray device.
DE 10148412 A1 discloses a process and an apparatus for imaging the head region of a patient, which apparatus is disclosed for both cephalometric X-ray and photographic images of objects to be X-rayed. The imaging position of the X-ray emitter is adjusted according to the photographic image. Both modes of imaging can be performed concurrently, wherein a photographic camera is arranged in a mirrored arrangement laterally to an X-ray source. The beam path of the photographic camera is deflected by the mirror so as to coincide with the X-ray beam.
It is an object of the invention to provide information, from a single panoramic rotation around an object to be X-rayed, concerning the relationship of the X-ray images and the visible surface of the object.
Another object is to provide a method by means of which not only an X-ray image is produced but also further information concerning the object being examined is acquired and finally displayed.
This object is achieved with the X-ray emitter according to the invention, which comprises an X-ray source disposed in a housing comprising an emission aperture, a diaphragm being provided, which is located at a distance from the emission aperture and which delimits the X-rays emitted through the emission aperture so as to form an X-ray fan beam. Means for deflecting light waves in the visible range, which are transparent to X-rays, are accommodated in the space between the emission aperture and the diaphragm.
The term “transparent to X-rays” means that the X-rays are not attenuated to such an extent that they become unsuitable for producing the required image of the object to be examined.
Even in the case of tomographic imaging, it is possible, when using the X-ray emitter according to the invention, to produce such images of the visible surface of the object to be X-rayed, as described above. When creating such images, the X-ray emitter must be positioned very close to the object to be X-rayed, as opposed to cephalometric images. Thus the space available for accommodating additional optical components as may be necessary for imaging the visible surface of the object is very small. Accommodating these components, including the required deflection means, in front of the primary diaphragm makes it unnecessary to modify the imaging geometry.
Further advantageous embodiments are evident from the subclaims.
In an advantageous embodiment of the X-ray emitter, the deflection means form a component of the emission aperture. This ensures that the space available is optimally utilized.
In another advantageous embodiment of the X-ray emitter, the deflection means can be pivoted into the beam path of the X-rays. It is then possible to move the deflection means into the beam path only when it is desired to create an image of the visible surface of the object to be X-rayed.
The deflection means advantageously consist of a vacuum-metalized element of plastics material showing low X-ray absorption. In this case, the deflection means can always remain in the beam path and a pivoted mechanism becomes unnecessary.
Furthermore, is has proven to be advantageous if the image recorder is aligned on a plane between the emission aperture and the diaphragm with its imaging direction extending at right angles to, and/or obliquely to, the direction of the X-ray fan beam. The image recorder can thus be accommodated within the housing of the X-ray emitter.
Advantageously, in the X-ray emitter according to the invention, the geometry of the surface image created by light in the range of visible wavelengths is substantially the same as the geometry of the region which is X-rayed. This substantially facilitates the formation of an association between the X-ray image and the visible surface of the object being X-rayed.
It has proven to be particularly advantageous if the area to be X-rayed coincides exactly with the video image delimited by the diaphragm. An automatic computer-aided overlap of the two images is thus made possible.
The process according to the invention is explained with reference to the drawings, in which:
The X-ray emitter 1 shown in
Regarded from the X-ray source 3, deflection means 5 in the form of a mirror are located downstream of the emission aperture 4. These deflection means 5 are likewise permeable to X-rays. However, this mirror 5 is substantially opaque to light waves in the optically perceivable range of wavelengths. The mirror 5 is arranged so as to cooperate with an image recording device 6 for light waves in the visible range which is disposed in front of the emission aperture. The X-ray fan beam 7, which is deflected by the mirror 5, is recorded by means of the camera 6. Said X-ray fan beam is directed towards the object to be examined, here a patient 8, and illuminates the surface present thereon. The beam path of the light reflected from the object 8 to the image recording device 6 is illustrated by way of example by means of a central ray 9.
A cross section of the X-ray emitter 1 is shown in
An X-ray image, which is produced when the X-ray emitter and an sketched image detector 15 for the radiation passing through the object 8 rotates around the object 8 being X-rayed, shows structures, for example, bones, teeth and fillings existing under the surface of the object 8.
The surface of the object to be examined is videographed using the camera 6, which is disposed away from the X-ray fan beam 14 of the X-rays and the beam path of which is aligned by the deflection means 5 such that the beam path 7 with its central ray 9 substantially coincides with the X-ray fan beam 14 and images the same area of the object 8.
At a pre-defined distance of a focus 16 from the diaphragm 13, there is usually sufficient installation space in the emission aperture 4 to accommodate the deflection means 5 and the camera 6. A minimum distance between the focus and the diaphragm is expedient due to the finite expansion of the focus for preventing any disturbing influences of the penumbra on the image detector 15.
In addition, the deflection means can be designed such that they can be moved into and out of the beam path of the X-ray fan beam 14. This can be effected either by means of a motor or manually, for example, using a rod arrangement (not illustrated), which is accessible from outside the housing 2. This is explained in detail below.
The emission aperture itself is made of a material permeable to X-rays and the design of the surface located in the beam path affects the quality of the X-rays in the X-ray fan beam by not more than the extent that may be tolerable for the creation of X-ray images.
The deflection means 5 are inserted along the guides 18, 19 laterally into the beam path by a spindle driven by a motor 17, as illustrated in
In
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 020 370.9 | Apr 2004 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP05/51764 | 4/21/2005 | WO | 10/20/2006 |
