Design and Optimization of Four-Dimensional Cone-Beam Computed to mography In Image-Guided Radiation Therapy

<p>The influence of respiratory motion on patient anatomy poses a challenge to accurate radiation therapy, especially in lung cancer treatment. Modern radiation therapy planning uses models of tumor respiratory motion to account for target motion in targeting. The tumor motion model can be verified on a per-treatment session basis with four-dimensional cone-beam computed tomography (4D-CBCT), which acquires an image set of the dynamic target throughout the respiratory cycle during the therapy session. 4D-CBCT is undersampled if the scan time is too short. However, short scan time is desirable in clinical practice to reduce patient setup time. This dissertation presents the design and optimization of 4D-CBCT to reduce the impact of undersampling artifacts with short scan times. This work measures the impact of undersampling artifacts on the accuracy of target motion measurement under different sampling conditions and for various object sizes and motions. The results provide a minimum scan time such that the target tracking error is less than a specified tolerance. This work also presents new image reconstruction algorithms for reducing undersampling artifacts in undersampled datasets by taking advantage of the assumption that the relevant motion of interest is contained within a volume-of-interest (VOI). It is shown that the VOI-based reconstruction provides more accurate image intensity than standard reconstruction. The VOI-based reconstruction produced 43% fewer least-squares error inside the VOI and 84% fewer error throughout the image in a study designed to simulate target motion. The VOI-based reconstruction approach can reduce acquisition time and improve image quality in 4D-CBCT.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation (PhD)

Year dc:date.available

2012

Author dc:creator

• Ahmad, Moiz

Contributors dc:contributor

• Tinsu Pan
• George Starkschall
• Peter Balter

• Medical imaging
• lung imaging
• radiation therapy
• IGRT
• image reconstruction
• cone-beam CT
• 4D imaging
• 4D-CBCT
• VOI
• GSBS
• Analytical, Diagnostic and Therapeutic Techniques and Equipment
• Medicine and Health Sciences
• Numerical Analysis and Scientific Computing
• Physics

Repository record dc:identifier

https://digitalcommons.library.tmc.edu/utgsbs_dissertations/312

OAI identifier oai:identifier

oai:digitalcommons.library.tmc.edu:utgsbs_dissertations-1346