Compensators for dose and scatter management in cone-beam computed tomography

Area of Science:

• Medical Physics
• Radiological Imaging
• Radiation Therapy

Background:

• Scattered X-rays are a major challenge affecting image quality in cone-beam CT (CBCT).
• CBCT is increasingly used for image guidance in radiation therapy, highlighting the need for dose reduction and image quality improvement.
• Compensators, such as bow-tie filters, are explored to mitigate scatter and patient dose.

Purpose of the Study:

• To investigate the effectiveness of simple compensators (bow-tie filters) in reducing scatter and patient dose for kV cone-beam CT.
• To assess the potential of these compensators for practical implementation in CBCT systems.
• To quantify scatter and dose reduction under various CBCT imaging scenarios.

Main Methods:

• Construction of simple compensators with a design suitable for implementation on CBCT systems.
• Evaluation of compensator performance under different CBCT imaging conditions.
• Measurement of X-ray scatter reduction at the detector and patient dose reduction.

Main Results:

• The implemented compensators demonstrated a reduction in X-ray scatter reaching the detector.
• Patient dose was reduced by the compensators.
• Reductions in both scatter and dose exceeded a factor of 2 in various tested situations.

Conclusions:

• Simple bow-tie filters are effective in reducing X-ray scatter and patient dose in kV cone-beam CT.
• These compensators show promise for improving CBCT imaging performance and patient safety in radiation therapy.
• Further optimization of compensator design could lead to even greater reductions in scatter and dose.