Markus Koerner MD, Presenter: Nothing to Disclose

Marcus Treitl MD, Abstract Co-Author: Nothing to Disclose

Ulrich Linsenmaier MD, Abstract Co-Author: Nothing to Disclose

Klaus-Juergen Pfeifer MD, Abstract Co-Author: Nothing to Disclose

Maximilian Reiser MD, Abstract Co-Author: Nothing to Disclose

To evaluate possible dose reduction in plain film radiography of the extremities using a newly developed needle structured image plate (NIP) compared to a powder structured image plate (PIP) and a flat-panel digital radiography system (FPD) at different dose levels.

72 plain film radiograms of 6 human foot specimen were obtained at 4 different dose levels (63, 40, 20, and 10 µGy, patient entrance surface dose) on 3 different systems: (1) NIP (Prototype, AGFA, Belgium), (2) PIP (MD 40, AGFA), and (3) FPD (Trixell Pixium 4600, Siemens Medical Systems, Germany). The reference image of each specimen (80 µGy entrance surface dose) was obtained using a PIP. Tube voltage (50 kV) and detector-focus-distance (115 cm) were kept constant, dose level was set by altering the tube current and the exposure time. Images were printed on film and produced on a standardized light box for reading. Image evaluation was performed by 5 independent, blinded radiologists. The visualization of details was rated for cortical bone, trabecular bone, and soft tissue in comparison to the reference image using a five-point scale. The same scale was used for rating artefacts and the noise impression. The overall image quality was also rated independently of the reference. Wilcoxon’s test (significance level 0.05) was used for statistical analysis.

NIP images at 63, 40, and 20 µGy were rated superior compared to the reference image as well as to PIP and FPD images at same dose levels concerning cortical and trabecular bone, soft tissue, and noise. Artefact rate of NIP and FPD images was slightly higher. FPD images at 63 µGy were rated superior compared to the reference images regarding cortical bone, trabecular bone, and noise. Image quality of NIP images was rated optimal (63, 40, and 20 µGy) and good (10 µGy). Image quality of FPD and PIP images was rated good (FPD: 63, 40, 20 µGy; PIP 63, 40 µGy) and sufficient (FPD: 10 µGy; PIP 20, 10 µGy).

Dose reduction up to 50% can be realized in clinical skeletal imaging using NIP without any loss of information, a reduction to 25% seems possible for certain indications (e.g. detection of foreign bodies). For FPD images dose reduction is possible to 75%.

M.K.: This study was partially funded by a grant of the AGFA-Gevaert Company.

Koerner, M, Treitl, M, Linsenmaier, U, Pfeifer, K, Reiser, M, Dose Reduction in Digital Radiography: Comparison of Needle Structured Storage Phosphors, Powder Structured Storage Phosphors and a Flat-Panel Detector at Different Dose Levels.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4412050.html