Flat-panel x-ray detector using amorphous silicon technology. Reduced radiation dose for the detection of foreign bodies.
OBJECTIVE
The authors evaluate a new flat-panel x-ray detector (FD) with respect to foreign body detection and reduction of radiation dose compared with screen-film radiography.


METHODS
Flat-panel x-ray detector is based on amorphous silicon technology and uses a 1 k x 1 k photo-detector matrix with a pixel size of 143 x 143 microns and 12-bit digital output. A thallium-dotted cesium iodide scintillation layer converts x-rays into light. An ex vivo experimental model was used to determine the detectability of foreign bodies. Foreign bodies with varying sizes were examined: glass with and without addition of lead, bone, aluminium, iron, copper, gravel fragments, and graphite. Four hundred observation fields were examined using conventional radiography (speed, 400; system dose: 2.5 microGy) as well as FD with a simulated speed of 400, 800, 1200, and 1600, corresponding to a detector dose of 2.5 microGy, 1.25 microGy, 0.87 microGy, and 0.625 microGy, respectively. Four independent radiologists performed receiver operating characteristic analysis of 8000 observations.


RESULTS
Flat-panel x-ray detector with a simulated speed of 400 was significantly superior (P = 0.012) to screen-film radiography (speed, 400). At a simulated speed of 800 and 1200 FD yielded results equivalent to screen-film radiography. Flat-panel x-ray detector was significantly inferior to screen-film radiography at a simulated speed of 1600 (P = 0.012).


CONCLUSIONS
Flat-panel x-ray detector technology allows significant reduction in radiation dose compared with screen-film radiography without loss of diagnostic accuracy.
Völk
M
M
Department of Radiology, University Hospital of Regensburg, Germany. markus.voelk@klinik.uni-regensburg.de
Strotzer
M
M
Gmeinwieser
J
J
Alexander
J
J
Fründ
R
R
Seitz
J
J
Manke
C
C
Spahn
M
M
Feuerbach
S
S
D005547:Foreign Bodies / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D012372:ROC Curve; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation*