In this paper, the question about automatic brightness control for x-ray imaging systems based on CCD camera is discussed, and the structure and principle of an auto brightness control loop are analyzed along with the working procedure of the x-ray imaging system. A kind of digital brightness controller about a typical device and the designing idea of the computer brightness intelligent control software is introduced.
Algorithms ; Image Processing, Computer-Assisted ; Radiation Protection ; Radiographic Image Enhancement ; instrumentation ; Radiography ; instrumentation ; X-Ray Intensifying Screens

A kind of rural digital radiography systems is introduced In this paper, including its design, constructural characteristics, and the implementing methods. Meanwhile time, it is pointed out that detail considerations should be given to the system features, key components selection and clinical workflow. Serviceability and ease of as for developments of rural digital radiography systems are also mentioned.
China ; Equipment Design ; Humans ; Image Processing, Computer-Assisted ; methods ; Radiographic Image Enhancement ; instrumentation ; Rural Health ; X-Ray Intensifying Screens

Using the present cone beam reconstruction formula for general trajectory, we have investigated the issue of detector efficiency for non-helical trajectory. The results reveal that the two factors dominating the detector efficiency are detector geometry and filtering directions. The methods for to higher detector efficiency are proposed, and the reliability and feasibility are tested by simulation results.
Cone-Beam Computed Tomography ; instrumentation ; methods ; Humans ; Image Processing, Computer-Assisted ; methods ; Radiographic Image Enhancement ; methods ; Scattering, Radiation ; X-Ray Intensifying Screens

OBJECTIVE: To investigate the clinical feasibility of dual energy subtraction (DES) imaging to improve the delineation of the vocal cord and diagnostic accuracy of vocal cord paralysis as compared with the anterior-posterior view of flat panel detector (FPD) neck radiography. MATERIALS AND METHODS: For 122 consecutive patients who underwent both a flexible laryngoscopy and conventional/DES FPD radiography, three blinded readers retrospectively graded the radiographs during phonation and inspiration on a scale of 1 (poor) to 5 (excellent) for the delineation of the vocal cord, and in consensus, reviewed the diagnostic accuracy of vocal cord paralysis employing the laryngoscopy as the reference. We compared vocal cord delineation scores and accuracy of vocal cord paralysis diagnosis by both conventional and DES techniques using kappa statistics and assessing the area under the receiver operating characteristic curve (AUC). RESULTS: Vocal cord delineation scores by DES (mean, 4.2 +/- 0.4) were significantly higher than those by conventional imaging (mean, 3.3 +/- 0.5) (p < 0.0001). Sensitivity for diagnosing vocal cord paralysis by the conventional technique was 25%, whereas the specificity was 94%. Sensitivity by DES was 75%, whereas the specificity was 96%. The diagnostic accuracy by DES was significantly superior (kappa = 0.60, AUC = 0.909) to that by conventional technique (kappa = 0.18, AUC = 0.852) (p = 0.038). CONCLUSION: Dual energy subtraction is a superior method compared to the conventional FPD radiography for delineating the vocal cord and accurately diagnosing vocal cord paralysis.
Absorptiometry, Photon/*instrumentation/*methods ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Feasibility Studies ; Female ; Humans ; Male ; Middle Aged ; Observer Variation ; Reproducibility of Results ; Sensitivity and Specificity ; Subtraction Technique ; Vocal Cord Paralysis/*radiography ; Vocal Cords/radiography ; *X-Ray Intensifying Screens ; Young Adult