Positioning accuracy of a new image-guided radiotherapy system

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image-Guided Interventions

Background:

• Advancements in image-guided radiotherapy (IGRT) are crucial for precise cancer treatment.
• Accurate patient positioning is fundamental to the efficacy and safety of IGRT.

Purpose of the Study:

• To assess the accuracy of the patient positioning function of the MHI-TM2000, a novel image-guided radiotherapy system.
• To evaluate the performance of the system's integrated image guidance capabilities.

Main Methods:

• Utilized a cube phantom with a central steel ball to measure isocenter discrepancies across lasers, MV beams, and kV imaging (X-ray and CBCT).
• Performed off-isocenter measurements (50 mm) to verify coordinate system accuracy.
• Conducted image fusions using anthropomorphic phantoms to evaluate positional and rotational accuracy.

Main Results:

• Isocenter alignment achieved sub-millimeter accuracy (within 0.5 mm) across all axes.
• Geometrical errors for kV X-ray and CBCT at 50 mm off-isocenter were within 0.2 mm and 1.0 mm, respectively.
• Image fusion accuracy demonstrated errors within 1.0 mm translation and 1.0 degree rotation, with no significant difference between chest and pelvis phantoms.

Conclusions:

• The MHI-TM2000 system demonstrates high accuracy in isocenter alignment.
• The automatic image fusion function provides sufficient accuracy and precision for clinical image-guided radiotherapy applications.