The Mobius AIRO mobile CT for image-guided proton therapy: Characterization & commissioning

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Imaging Systems

Background:

• The integration of advanced imaging systems is crucial for precise image-guided radiation therapy.
• Mobile CT systems offer potential advantages in workflow and accessibility for various clinical applications.

Purpose of the Study:

• To characterize the Mobius AIRO Mobile CT System for its utility in localization and image-guided proton therapy.
• To evaluate the AIRO system's performance in the context of proton therapy, marking its first known application in this modality.

Main Methods:

• CT images of a Catphan phantom were acquired using the AIRO Mobile CT System and compared with other CT simulators (Philips, Siemens) and a Varian EDGE cone-beam CT.
• Image quality parameters including spatial resolution, contrast, uniformity, and dose were analyzed using DoseLAB software.
• Localization accuracy was assessed using phantoms (MIMI, Stereophan) and compared between 3D and 2D imaging systems.

Main Results:

• The AIRO system demonstrated a spatial resolution of 0.21 lp mm⁻¹, lower than other CT simulators and CBCT systems.
• Significant scaling discrepancies were observed between the AIRO and other systems (AIRO/Siemens: 191.2%, AIRO/Philips: 145.8%).
• Localization accuracy was found to be within 0.6° and 0.5 mm, with maximum shifts of 0.2 mm in the z-direction.

Conclusions:

• The Mobius AIRO Mobile CT System exhibits localization accuracy suitable for image-guided proton therapy, achieving sub-millimeter precision.
• Despite having slightly lower overall image quality compared to conventional CT systems, the AIRO system is deemed accurate and reliable for proton therapy applications.