DQE of wireless digital detectors: comparative performance with differing filtration schemes

Area of Science:

• Medical Imaging Physics
• Radiological Technology
• Detector Performance Evaluation

Background:

• Wireless flat panel detectors are increasingly used in portable medical imaging.
• Evaluating detector performance is crucial for optimizing image quality and patient safety.

Purpose of the Study:

• To evaluate and compare the performance of two wireless flat panel detectors against a conventional one.
• To assess detector performance using International Electrotechnical Commission (IEC) standards for modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE).

Main Methods:

• Acquired raw images from three detectors (DRX-1C, DRX-1, Pixium 4600) using a calibrated radiographic system.
• Employed two filtration schemes (aluminum and copper-aluminum) to meet IEC beam quality requirements (RQA5, RQA9).
• Measured MTF, NNPS, and calculated DQE according to IEC 62220-1 formalism at various exposure levels.

Main Results:

• All three DR systems exhibited comparable MTFs, with DRX-1 showing lower values at higher spatial frequencies.
• DRX-1C and Pixium detectors demonstrated superior noise performance compared to DRX-1.
• Zero-frequency DQE values were highest for DRX-1C (74% for RQA5, 50% for RQA9), followed by Pixium (63% RQA5, 42% RQA9) and DRX-1 (38% RQA5, 28% RQA9).

Conclusions:

• The DRX-1C detector displayed the best overall DQE performance.
• The alternative copper-aluminum filtration provided comparable detector ranking and practical benefits for field measurements.