Dose optimization of 2D X-ray image acquisition protocols in image-guided radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Diagnostic Imaging

Background:

• Patient positioning accuracy in radiotherapy is crucial and relies on kilovoltage (kV) imaging.
• Current kV imaging protocols may expose patients to unnecessary radiation dose.
• Optimizing these protocols is essential for patient safety without compromising diagnostic quality.

Purpose of the Study:

• To optimize planar kV imaging acquisition protocols in radiotherapy.
• To reduce patient radiation dose while maintaining diagnostic image quality.
• To evaluate the efficacy of dose-optimized protocols in clinical settings.

Main Methods:

• Image quality and radiation dose were assessed using test objects and phantoms with various kV/mAs settings.
• Dose-optimized protocols were compared against default protocols on an anthropomorphic phantom and 51 patients.
• Organ and effective doses were estimated using Monte Carlo simulations.

Main Results:

• Dose-optimized protocols achieved significant dose reductions (up to 48.0% for AP head, 30.0% for lateral head, 28.4% for AP pelvis, 27.0% for lateral pelvis).
• Effective dose reductions were 54% for head and 29.6% for pelvic acquisitions.
• Image quality was subjectively evaluated as equivalent to default protocols, with no compromise in positioning accuracy.

Conclusions:

• Dose-optimized kV imaging protocols can substantially reduce patient radiation dose in radiotherapy.
• These optimized protocols maintain image quality and patient positioning accuracy.
• Routine implementation of dose-optimized protocols is recommended to enhance patient safety.