Jaramillo-Núñez A

Language: Spanish
References: 7
Page: 140-146
PDF size: 236.60 Kb.

ABSTRACT

Introduction. The qualities that digital x-rays possess, and which analog x-ray lack, are unquestionable. In an effort to obtain analogic x-rays that have the same qualities, we have implemented a technique that uses the photographic process and digital processing of images. Using them individually or simultaneously, depending on the problem, we have found that sensitivity can be increased to the point where it is possible to view details that would be difficult to see otherwise. At times high resolution is also needed, and thus far we have achieved 10 microns; however, that value can be improved in the near future using higher resolution detectors. We show the results of applying the technique in four cases.
Material and methods. The x-rays were photographed using a CCD (charge coupled device) camera and a fixed focal distance lens. Controlling the diameter of the diaphragm, we obtained contrasted images even when the x-ray is dark or bright. Changing the distance between the camera and the x-ray we controlled the size of the photographed area. The pixel size of the CCD camera is 3 microns and the size of the digitalized images is 3000 × 2200 pixels. The maximum resolution obtained is 10 microns for an x-ray area of 30 × 25 mm. To show some of the advantages of the technique, four cases were analyzed: rheumatoid arthritis, osteopenia, breast cancer, and calcifications.
Discussion. The first case shows how, when the diameter of the camera diaphragm is varied, a contrasted image can be obtained from a low-contrast x-ray. The second shows how, simultaneously using photographic technique and digital image processing, we can reach the extreme of making semi-quantitative evaluations of the information contained in the x-ray. The third case shows how, with the aid of the technique implemented, errors in x-ray interpretation can be avoided. It is important to emphasize the resolution achieved, because at times it is necessary to know the structure, shape, and dimensions of findings, and that is possible only with good resolution, which is the point of the fourth case.
Conclusion. The technique implemented, when combined with other mathematical tools, may be used, for example, to monitor advances in diseases such as bone metastasis, monitor the action of therapies, highlight desired information in mammograms, etc. To know the limits of application of the technique, it is necessary to analyze more x-rays containing information on other diseases.

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