Image quality evaluation of a desktop computed radiography system

Area of Science:

• Medical Imaging Physics
• Radiologic Technology
• Diagnostic Imaging

Background:

• Computed radiography (CR) systems are essential in modern diagnostic imaging.
• Performance evaluation of CR readers is crucial for ensuring diagnostic image quality.
• The Lumisys ACR-2000 and Fuji AC-3 are widely used CR systems.

Purpose of the Study:

• To quantitatively assess and compare the imaging performance of the Lumisys ACR-2000 CR reader.
• To evaluate the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of the Lumisys ACR-2000.
• To benchmark the Lumisys ACR-2000 against the Fuji AC-3 CR system.

Main Methods:

• Measured the one-dimensional (1D) modulation transfer function (MTF) using a sharp edge.
• Derived the 1D noise power spectrum (NPS) from a two-dimensional (2D) NPS of a uniform field.
• Estimated the ideal input signal-to-noise ratio (SNR) of x-ray beams using published spectra and attenuation data.
• Acquired measurements using Agfa, Fuji, and Kodak storage phosphor plates under varying kVp and mR exposures.

Main Results:

• The detective quantum efficiency (DQE) of the Lumisys ACR-2000 was measured across different exposure levels (0.10, 1.0, 10.0 mR) and x-ray beam qualities (70 and 120 kVp).
• The Lumisys ACR-2000 exhibited a lower system DQE compared to the Fuji AC-3 CR system.
• The use of Fuji storage phosphor plates resulted in the highest system DQE for the Lumisys ACR-2000.

Conclusions:

• The Lumisys ACR-2000 CR reader demonstrates a lower overall DQE performance when compared to the Fuji AC-3 system.
• Storage phosphor plate type significantly influences the DQE of the Lumisys ACR-2000, with Fuji plates yielding the best results.
• Further optimization may be needed for the Lumisys ACR-2000 to achieve comparable DQE levels to established systems like the Fuji AC-3.