Jurgen E.M. Mourik PhD, Presenter: Nothing to Disclose

Pieternel van der Tol, Abstract Co-Author: Nothing to Disclose

Wouter J. H. Veldkamp PhD, Abstract Co-Author: Nothing to Disclose

Koos Geleijns PhD, Abstract Co-Author: Nothing to Disclose

Wireless detectors are more frequently used in digital radiography. The advantages of wireless detectors are greater flexibility and better hygiene. The purpose of this study was to compare dose and image quality of wireless detectors for digital chest radiography.

A chest phantom was developed from perspex, aluminium, foam (air) and a contrast-detail phantom (CDRAD). Entrance dose at both the detector (EDD) and phantom (EPD) were measured with a solid-state dosimeter. Dose and image quality (CDRAD) were measured for wireless detectors of 5 different vendors (A-E). Both the actual clinical protocols and a standard reference protocol (120kV, EDD: 4 μGy) were evaluated. For image quality, 6 successive images were acquired for each protocol and analyzed with automated software yielding averaged inverse image quality figures (IQFinv). In addition, dose corrected contrast-to-noise ratios, defined as CNR/√EDD, were assessed for the cylindrical holes on the first row of the CDRAD phantom. As the cylindrical holes vary in depth, this leads to an approximate linear relationship between CNR/√EDD and the depth of the cylindrical holes.

All wireless detectors used a CsI scintillator and differed mainly in size [34-43cm] and pixel size [125-200 µm]. Main differences in clinical protocols involved tube voltage [90-125 kV], tube current [0.5-1.4mAs], the use of a small (D and E) or large focus and the use of additional filtration (D and E). For the clinical protocols, large differences in EDD [A: 1.8; B: 5.6; C: 4.4; D: 7.0; E: 2.0 µGy] and EPD [A: 21.7; B: 68.8; C: 58.3; D: 54.2; E: 17.3 µGy] were observed. IQFinv varied between 2.4 (E) and 4.1 (C) for the clinical protocol and between 2.1 (B) and 3.8 (C) for the reference protocol. For both clinical and reference protocol, largest CNR/√EDD were found for vendor A (slope: 0.6, intercept: 0.6) and smallest for vendor B (slope: 0.3, intercept: 0.2) and D (slope: 0.3, intercept: 0.4).

Large differences in acquisition parameters, entrance dose and image quality were observed between the 5 different systems. Further improvement of imaging technology and acquisition protocols is warranted for optimization of wireless digital chest radiography.

Wireless detectors offer greater flexibility and better hygiene but further improvement of imaging technology and acquisition protocols is warranted for optimization of wireless chest radiography.

Mourik, J, van der Tol, P, Veldkamp, W, Geleijns, K, Comparison of Wireless Detectors for Digital Radiography Systems: Image Quality and Dose.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007855.html