Dual- and multi-energy CT for particle stopping-power estimation: current state, challenges and potential

Area of Science:

• Medical Physics
• Radiotherapy
• Medical Imaging

Background:

• Range uncertainty in particle radiotherapy limits its physical potential, primarily due to inaccuracies in estimating particle stopping power (ρ).
• Current methods using single-energy CT (SECT) and Hounsfield look-up tables (HLUT) are sensitive to variations in elemental composition and patient-specific tissue differences.

Purpose of the Study:

• To review and accelerate the clinical implementation of dual-energy CT (DECT) and multi-energy CT (MECT) for improved particle stopping power estimation in radiotherapy.
• To provide a comprehensive overview of existing DECT/MECT methods, their uncertainties, and clinical implementation aspects.

Main Methods:

• Review of various DECT and MECT methodologies proposed for particle stopping power estimation.
• Analysis of the strengths, weaknesses, and uncertainties associated with these advanced CT techniques.
• Discussion of factors influencing the clinical translation and implementation of DECT/MECT in radiotherapy planning.

Main Results:

• DECT has demonstrated effectiveness in reducing range uncertainty compared to SECT by providing additional material-specific information.
• MECT offers higher dimensionality of material-specific information, potentially further enhancing the accuracy of particle stopping power estimation.
• Despite proven benefits, DECT and MECT methods are not yet widely adopted in routine clinical practice.

Conclusions:

• Advanced imaging techniques like DECT and MECT hold significant promise for improving the accuracy of particle stopping power estimation in radiotherapy.
• Addressing uncertainties and practical implementation challenges is crucial for the broader clinical adoption of these technologies.
• Future applications of DECT/MECT extend beyond stopping power estimation, offering broader potential in radiotherapy.