Computed radiography in scoliosis. Diagnostic information and radiation dose.
ABSTRACT The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis.
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ABSTRACT: To present results of optimising scoliosis examination by changing from a conventional film/grid (F/G) to air-gap technique using computed radiography (CR), and to evaluate different methods for estimating effective radiation doses. Forty-nine children and adolescents were examined with an F/G technique, and 21 with air-gap and CR techniques. Entrance surface doses (ESD) were determined with lithium fluoride thermoluminescence dosimeters. For all patients, the effective radiation doses were determined using a hermaphrodite PCXMC computer program. For all F/G radiographs, the effective doses were also determined according to the NRPB-R279 report, and for 22 children (>9 years and/or >40 kg) also with the ODS-60 program, which allows separate gender calculations. Accumulated doses for 37 children examined more than once with F/G examinations were assessed. For F/G techniques, the ESDs for both frontal and lateral views varied with age and were significantly correlated to the patients' thickness. The calculated effective doses using the PCXMC program and the NRPB-R279 did not differ significantly for all frontal and lateral radiographs, respectively, but ODS-60 gave significantly higher values in female subjects. With air-gap and CR techniques, the mean effective doses were reduced by a factor over 10. The mean accumulated effective dose for 37 children with a mean of seven F/G examinations was 6.1 mSv, implying a risk of death of about 1:2,000 for boys and at least 1:1,000 for girls. Paediatric scoliosis radiography should be considered a specialised procedure, which has to be optimised using a non-grid technique.Pediatric Radiology 12/2003; 33(11):752-65. · 1.57 Impact Factor
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ABSTRACT: The wide dynamic range of the digital detectors and the capabilities of post-processing allow obtaining more information from the radiographic images and avoiding retakes. Using phosphor plates in the image formation process, it has been possible to lower the dose to the patient. In digital radiography, several authors report the possibility to substantially lower the radiation dose to the patient while maintaining or even increasing the image quality. In conventional radiography, increased patient dose results in a dark image. In digital radiography the brightness of the image does not depend on patient dose. High patient doses can result in low-noise, high-contrast digital images; therefore, optimization of examinations is of vital importance in digital radiography. Special emphasis should be directed to paediatrics. The digital technique is very useful in reducing the dose both in fluoroscopy and radiography; however, special procedures for children are needed.European Radiology Supplements 02/2004; 14:50-58.
Article: The physics of computed radiography.[Show abstract] [Hide abstract]
ABSTRACT: Cassette-based computed radiography (CR) systems have continued to evolve in parallel with integrated, instant readout digital radiography (DR) systems. The image quality of present day CR systems is approaching its theoretical limits but is significantly inferior to DR. Further improvements in CR image quality require improved concepts. The aim of this review is to identify the fundamental limitations in CR performance. This will provide a background for the development of new approaches to improve photostimulable phosphor CR systems. It will also guide research in designing better CR systems to possibly compete with DR systems in terms of image quality parameters such as detective quantum efficiency and yet maintain CR convenience in being portable and more economical.Physics in Medicine and Biology 01/2003; 47(23):R123-66. · 2.70 Impact Factor