Dose reduction in CT by anatomically adapted tube current modulation. II. Phantom measurements

Area of Science:

• Medical Imaging
• Radiological Physics
• Radiation Dose Reduction

Background:

• Patient dose in computed tomography (CT) is a significant concern.
• Theoretical studies suggest dose reduction is achievable via tube current modulation.
• Modulating tube current based on X-ray attenuation can maintain image quality while lowering dose.

Purpose of the Study:

• To validate simulation findings on dose reduction through phantom studies.
• To evaluate the effectiveness of attenuation-based versus sinusoidal tube current modulation.
• To assess the potential for clinical application of online tube current control.

Main Methods:

• Used cylindrical, oval, and elliptical phantoms (mathematical and physical) to simulate human anatomy.
• Employed prototype hardware for real-time tube current control on a clinical CT scanner.
• Compared dose reduction achieved with attenuation-based and sinusoidal modulation strategies at various amplitudes.

Main Results:

• Simulation and phantom measurements showed agreement within 10%.
• Dose reductions ranged from 8% to 56%, depending on phantom and modulation type.
• Attenuation-based modulation consistently outperformed sinusoidal modulation, achieving up to 56% dose reduction in specific phantom configurations.
• Measured dose reduction exceeded mAs reduction estimates, indicating a conservative approach.

Conclusions:

• Attenuation-based online tube current control effectively reduces patient dose in CT.
• This technology offers significant potential for widespread clinical adoption.
• Further validation through patient studies confirms the efficacy and safety of the method.