Novel On-line PET Imaging for Intra-Beam Range Verification and Delivery Optimization: A Simulation Feasibility Study

Area of Science:

• Medical Physics
• Radiotherapy
• Nuclear Imaging

Background:

• Current on-line PET imaging for particle therapy uses low-dose initial beams to measure particle beam range (BR), risking inaccurate measurements due to low image counts.
• Inaccurate BR measurements can lead to deviations in dose delivery, compromising treatment efficacy and patient safety.

Purpose of the Study:

• To evaluate the feasibility of a novel on-line PET imaging method for measuring BR at the mid-plane of a target volume using portions of high-dose therapy beams.
• To assess the potential of this method for verifying BR and guiding adaptive radiotherapy replanning in real-time.

Main Methods:

• Simulations of proton beam radiation therapy were performed on a human brain phantom with a tumor.
• Positron emission tomography (PET) images were generated at the target mid-plane using initial beams, and activity range was measured.
• Simulations incorporated range-shift compensation and delivery of subsequent therapeutic beams.

Main Results:

• The novel on-line PET method achieved an approximate 1.1 mm mid-plane BR measurement accuracy under simulated conditions.
• The delivered range-shifted compensated dose distribution closely matched the planned dose distribution.
• The method demonstrated potential for accurate real-time monitoring and adaptation of particle therapy.

Conclusions:

• The proposed on-line PET imaging method shows promise for significantly improving the accuracy of particle therapy.
• Utilizing parts of high-dose therapy beams for mid-plane BR measurement offers a more accurate approach compared to low-dose initial beams.
• This technique could enhance adaptive treatment strategies, leading to better clinical outcomes in proton therapy.