Characterization and potential applications of a dual-layer flat-panel detector

Area of Science:

• Medical Imaging Physics
• Detector Technology
• Radiological Sciences

Background:

• Dual-energy (DE) x-ray imaging offers enhanced material differentiation in radiography, fluoroscopy, and CT.
• Existing DE methods like kV switching are susceptible to motion artifacts.
• A dual-layer (DL) flat-panel detector (FPD) offers a potential solution for motion-robust DE imaging.

Purpose of the Study:

• To characterize a prototype DL FPD and evaluate its DE imaging capabilities.
• To assess its performance in 2D radiography/fluoroscopy and 3D cone-beam CT (DE-CBCT).
• To compare DE fluoroscopy with single-energy (SE) fluoroscopy for lung tumor tracking.

Main Methods:

• A DL FPD with two CsI scintillator layers and amorphous silicon (aSi) sensors was constructed.
• Detector performance metrics (MTF, NPS, DQE) were measured.
• Phantoms were used for 2D DE imaging, fluoroscopic lung tumor tracking, and 3D DE-CBCT material decomposition.

Main Results:

• The DL FPD achieved high-quality material-specific images and superior lung tumor tracking accuracy (>10x RMSE reduction).
• Accurate DE-CBCT material decomposition was demonstrated with <5% error for iodine and calcium inserts.
• Optimal virtual monoenergetic (VM) imaging was determined at 60 keV.

Conclusions:

• The prototype DL FPD successfully performs single-exposure DE radiography, fluoroscopy, and DE-CBCT.
• DL detectors offer superior image registration and simplified acquisition sequences for advanced DE imaging.