A technique for extending the dynamic range of medical X-ray image that uses multi-scale image decomposition is proposed to extend the dynamic range of digital radiology equipment with either image intensifier or charge coupled device. Two images obtained at different tube voltages are decomposed by multi-scale image decomposition

and the resulting components are then recombined to reconstruct an image with extended dynamic range. Experiments show that the image processed by the technique contains 3 or more regions of interest(ROI)regions while the original image contains 2 ROI regions. Total surface dose in two exposures is 2.646×10

-4

Gy/cm

2

that does not cause any increase in patient dose. The technique can improve the utilization of digital radiology equipment using either image intensifier or charge couple device.