Low-Contrast Detail Phantom: Proof of Concept

Area of Science:

• Medical Imaging Physics
• Radiological Sciences
• Phantom Development

Background:

• Conventional contrast detail phantoms (CDP) utilize air gaps, limiting their ability to simulate realistic patient body attenuation levels.
• Accurate assessment of image quality in planar radiology requires phantoms that can represent a wider range of subject contrasts.

Purpose of the Study:

• To investigate filling air gaps in conventional CDPs with various contrast media concentrations.
• To develop variable attenuation-level differential phantoms for improved contrast measurements in specific radiology applications.

Main Methods:

• Digital radiography was used to image a traditional CDP (Perspex/air) and a novel CDP with air holes replaced by attenuating materials (water, 30% iodine-based contrast medium).
• Image quality was quantitatively assessed using automated processing to calculate the image quality factor (IQF)_inv.

Main Results:

• Phantom studies revealed lower contrast levels when CDP holes were filled with water or 30% contrast media compared to traditional air/Perspex CDPs.
• For a 5-mAs beam, IQF_inv values decreased from 5.32 (air-filled) to 2.55 (water-filled) and 2.83 (30% contrast-filled).
• Extended contrast scales were achieved, encompassing ranges more realistic for patient anatomy.

Conclusions:

• The modified CDP allows for discernment of smaller contrast changes due to minimal attenuation differences between subject materials and the phantom.
• The developed low-form CDP serves as a valuable tool for evaluating image quality in planar radiology, particularly for low-subject contrast imaging requirements.