Evaluation of a chest phantom for CT nodule densitometry

Area of Science:

• Medical Imaging
• Radiology
• Physics

Background:

• Pulmonary nodule densitometry is crucial for diagnosing lung conditions.
• Accurate CT scanner characteristics are essential for reliable nodule densitometry.
• Evaluating phantom performance is key to validating CT scanner capabilities.

Purpose of the Study:

• To assess the performance of a chest phantom for CT nodule densitometry.
• To determine the operating characteristics of a GE CT 9800 scanner for this application.
• To evaluate the impact of phantom inserts and positioning on CT numbers.

Main Methods:

• Utilized a GE CT 9800 scanner with a chest phantom.
• Scanned reference rods in various lung field positions and chest wall thicknesses.
• Incorporated liver/spleen inserts and tested CT attenuation values of different rods.

Main Results:

• Rod size was the primary factor influencing CT numbers (1-83 HU).
• Standard rods lacked measurable calcium or other minerals.
• Positioning, chest wall thickness, and inserts had minimal impact on CT numbers.

Conclusions:

• The GE CT 9800 scanner demonstrates improved characteristics for pulmonary nodule densitometry.
• Further evaluation with simplified phantoms is recommended for nodule densitometry.
• The phantom and scanner show potential for accurate CT nodule densitometry.