Experimental realization of dynamic fluence field optimization for proton computed tomography

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image Reconstruction

Background:

• Proton computed tomography (pCT) is crucial for accurate proton therapy planning, providing relative stopping power (RSP) maps.
• Current pCT methods can be optimized for dose efficiency and noise reduction.

Purpose of the Study:

• To investigate the experimental feasibility of fluence-modulated pCT (FMpCT) for tailored image noise reduction.
• To validate FMpCT's ability to achieve prescribed noise distributions in proton therapy imaging.

Main Methods:

• Developed and implemented an optimization algorithm for fluence modulation in pCT.
• Interfaced a clinical proton beam line to deliver dynamically modulated fluence.
• Acquired pCT images using uniform fluence, constant noise prescription, and FMpCT protocols with three phantoms.
• Proposed and applied a correction method for acquisition artifacts.

Main Results:

• FMpCT successfully achieved satisfactory agreement with planned noise distributions.
• Relative stopping power (RSP) accuracy of FMpCT was comparable to standard pCT.
• Identified technical areas for improvement in future experimental acquisitions.

Conclusions:

• FMpCT optimized for specific image noise prescriptions is experimentally feasible.
• FMpCT offers a promising approach for dose reduction in proton therapy imaging.