X-ray dose reduction using additional copper filtration for dental cone beam CT

Area of Science:

• Medical Physics
• Radiological Imaging

Background:

• Dental cone beam computed tomography (CBCT) is crucial for diagnosis.
• Optimizing radiation dose and image quality in CBCT is an ongoing challenge.

Purpose of the Study:

• To quantitatively assess the impact of additional copper-filters (Cu-filters) on radiation dose and contrast-to-noise ratio (CNR) in dental CBCT.
• To determine optimal parameters for Cu-filter use in CBCT imaging.

Main Methods:

• CBCT imaging was performed on a phantom using varying Cu-filter thicknesses (0.00-0.20 mm) and tube voltages (70-90 kV).
• Contrast-to-noise ratios (CNRs) were calculated for aluminum, air, and bone equivalent material (BEM).
• Volumetric CT dose index (CTDIvol) was measured using standard CTDI test objects.

Main Results:

• Higher CNR was observed with increased tube voltage and tube current, while CNR decreased with increasing Cu-filter thickness.
• A tube voltage of 90 kV demonstrated superior CNR performance across all materials.
• CTDIvol increased with tube voltage and current but decreased with added Cu-filter thickness.
• At a fixed CNR, using a 90 kV Cu-filter reduced CTDIvol by 8.7% compared to no filter.

Conclusions:

• Copper-filters show potential for reducing patient radiation dose in dental CBCT.
• The addition of Cu-filters can achieve dose reduction while maintaining diagnostic image quality (CNR).
• Optimized Cu-filter use in CBCT represents a significant advancement in radiation safety.