Improving Structure Delineation for Radiation Therapy Planning Using Dual-Energy CT

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Oncology

Background:

• Conventional CT imaging presents limitations in soft tissue contrast and artifact reduction for radiation therapy (RT) planning.
• Dual-energy CT (DECT) offers multi-parametric data acquisition, enabling advanced image post-processing.
• Exploiting energy-dependent X-ray attenuation is key to overcoming conventional CT limitations.

Purpose of the Study:

• To present the clinical advantages of using dual-energy CT (DECT) for radiation therapy (RT) planning.
• To demonstrate the utility of DECT-derived images in improving simulation workflow and structure delineation.
• To evaluate the impact of DECT on image quality and artifact reduction in RT planning.

Main Methods:

• DECT data were acquired from 20 patients using simultaneous dual-source and sequential single-source scanners with 80 and 140-kVp X-ray beams.
• Iodine maps, fat maps, and mono-energetic images (MEIs) were derived from 40 to 190 keV.
• Analysis focused on comparing DECT-derived images with conventional CT for RT planning applications.

Main Results:

• Mono-energetic images (MEIs) at 40 keV enhanced soft tissue contrast by a factor of 2.8.
• Tumor contrast and contrast-to-noise ratio improved significantly (up to 60%) for cholangiocarcinoma.
• Artifacts from titanium implants were reduced by over 95% using 190 keV MEIs, and photon starvation was eliminated.

Conclusions:

• DECT provides clinically significant benefits for radiation therapy (RT) simulation.
• Enhanced structure delineation and improved simulation workflow are key advantages of DECT in RT planning.
• DECT represents a valuable advancement for optimizing radiation therapy planning.