Patent Number: 
Section: claims

1. An X-ray device comprising:an X-ray source;a settable collimator;an X-ray detector; anda data processing unit which calculates a reduction in radiation dose brought about by the collimator. 2. The X-ray device of claim 1 further comprising a display unit for displaying the calculated reduction in radiation dose. 3. The X-ray device of claim 2 wherein the reduction in the radiation dose is quantified by the ratio of the radiation cross-sectional areas with and without the collimator. 4. The X-ray device of claim 2 wherein the reduction in the radiation dose is quantified by the ratio of the area dose products with and without the collimator. 5. The X-ray device of claim 1, wherein the data processing unit calculates the reduction in the radiation dose (DR) by using the relationship:DR=DAPb/DAP0·100%where DAPb is an area dose product with filters in place, and DAP0 is an area dose product with a completely open shield. 6. The X-ray device of claim 2, further including:an imaging region for receiving a subject to be imaged;a reconstruction processor that reconstructs received x-rays into an image representation of the subject, wherein the display unit displays the image representation and the reduction in dose concurrently. 7. An X-ray device, comprising:a) an X-ray radiation source;b) a settable collimator for limiting, locally damping and/or filtering a bundle of X-rays;c) an X-ray detector; andd) means for detecting a reduction in the radiation dose brought about by the collimator. 8. An X-ray device as claimed in claim 7, further comprising a data processing unit for controlling the generation of images and for processing recorded X-ray images, which data processing unit is connected to the X-ray radiation source, the collimator and the X-ray detector and is set up for the purpose of detecting the current setting of the collimator and determining therefrom the reduction in the radiation dose brought about by the collimator. 9. An X-ray device as claimed in claim 7, further comprising a display unit for displaying a recorded X-ray image, and displaying the detected reduction in the radiation dose as text and/or as graphics. 10. An X-ray device as claimed in claim 7, further comprising a display unit for displaying imaging parameters, and displaying the radiation dose as text and/or as graphics. 11. An x-ray device as claimed in claim 7, wherein the collimator includes a shutter, and iris for limiting cross-sectional area of an x-ray beam from the x-ray source, and filter elements with adjustable x-ray transparency for adjusting a spectrum of the x-rays. 12. A method of setting the collimator of an X-ray device, wherein, based on the current setting of the collimator and possibly other components of the X-ray device, the reduction in the radiation dose brought about by the collimator is determined and displayed. 13. A method as claimed in claim 12, wherein the reduction in the radiation dose is quantified by the ratio of the radiation cross-sectional areas with and without the collimator. 14. A method as claimed in claim 12, wherein the reduction in the radiation dose is quantified by the ratio of the area dose products with and without the collimator. 15. A method as claimed in claim 14, wherein the area dose product with collimator is calculated as a function of characteristics of the X-ray radiation source of the X-ray device. 16. A method as claimed in claim 12, wherein the reduction in the radiation dose is displayed as text and/or as graphics. 17. A method as claimed in claim 12, wherein the reduction in back-scattering of the X-ray radiation and/or the improvement in image quality is determined from the reduction in the radiation dose. 18. A method as claimed in claim 12, wherein the radiation dose reduction is displayed during a patient examination to indicate the reduction in radiation dose in real time during the examination. 19. A method as claimed in claim 16, further including:disposing a subject in an imaging region of the x-ray device;reconstructing received x-rays into an image representation;displaying the image representation and the reduction in dose concurrently. 20. The method of claim 12, wherein the step of determining the radiation dose (DR) brought about by the collimator includes using the relationship:DR=DAPb/DAP0·100%where DAPb is an area dose product with filters in place, and DAP0 is an area dose product with a completely open shield.