Lada Bumbure

Quality of the Computed Radiography Image Acquired with Decreased Doses

Decrease of radiation dose to patients and its management is important for modern radiographic imaging procedures. Computed radiography (CR) provides broader dynamic range and high potential for post-processing, lower radiation dose while maintaining usual image quality could be promoted. There is sufficiency of experiments, which finds clinical possibilities of patient dose reduced from usage of CR systems. However the experiments correlating radiation dose and x-ray image quality have not been found. Therefore the current research is directed to find ways to reduce patient dose keeping up the quality of x-ray image using CR system. The quality of image was evaluated as the contrast and lateral resolution. The Plexiglas phantom and test plate “ETR-1” were in use as the radiated objects. The x-ray machine “Bucky Diagnost” was employed to supply radiation flow. The digital images were provided both the Automatic Exposure Control (AEC) and manual modes. The voltage range from 40 to 90 kV was in use. The radiation dose was varied because of the mA·s control. The dose was estimated because of detected Air Kerma (microGy·m2) by the DAP meter. The results demonstrated that the dose could be decreased on for 40–75% keeping the quality of image.

X-Ray Radiation Statistics towards Quality Assurance in Digital Radiography

Most of diagnostic radiography today is digital. Therefore there is a great possibility to make an express check of an x-ray beam quality using digital approach. The flux of the x-ray photons detected is governed by the Poisson statistics. The deviation of the radiating technique modes leads from the Poisson statistics. Because the single element of a digital detector matrix produces the signal that is directly proportional to the number of the absorbed photons, the brightness distribution is in use to estimate the statistics of the photons. This is demonstrated to evaluate quality of x-ray beam of the digital x-ray diagnostic equipment.

Statistics of digital x-ray image brightness histograms

An x-ray digital imaging technology in use in xray diagnostics makes it possible to achieve a digital evaluation of image quality. Histograms on image brightness over the pixels were processed. Variance and an average of the histograms correlated to a contrast. This approach demonstrates a simple, fast method for evaluating the quality of a digital x-ray image.