title: Development and Evaluation of the Volumetric Image-Matching Environment for Radiotherapy (VIMER) Thesis
Creators: name: Byrd, BK
Publisher: name: University of Liverpool Repository
Year: 2019

description: Abstract: Development and Evaluation of the Volumetric ImageMatching Environment for Radiotherapy (VIMER) submitted by Brook Kennedy Byrd A novel 3D immersive virtual environment (3D IVE) image matching application, referred to as the VIMER ( V olumetric I mage M atching E nvironment for R adiotherapy), was developed and evaluated as a potential tool for Image Guided Radiotherapy (IGRT). The VIMER aimed to address a significant problem within IGRT, i.e. manual image matching. As part of IGRT pretreatment verification, automated imagematching processes can fail in cases where anatomic boundaries are indistinct or where human clinical judgement is needed. During a manual image match, the clinician currently is restricted to working with one orthogonal plane at a time. In attempts mediate this process, the VIMER renders both the primary and secondary patient CT datasets as volumes in the same virtual space. The tool facilitates a dynamic cycle of inspecting matched dataset alignment and performing positional readjustments with complete spatial freedom. By doing so, additional spatial information is accessible for manual image matching compared to orthogonal 2D slices. The user interface replaced the traditional 2D orthographic matching planes with nonrestrictive volumetric matching surfaces within a 3D IVE. Unique manipulation and slicing tools enabled inspection of the matching boundaries between the two datasets at any location. Additional tools allowed the user to perform intuitive 6 degree of freedom image matching adjustments manually in the 3D virtual space. A qualitative study was conducted in effort to answer the central question: “Are there any potential benefits in performing a manual imagematch within VIMER over the conventional 2D planar image matching methods?” Data collection comprised of a 15 minute training session, a 15 minute simulation session, and a 15 minute individual interview session with a sample group of six University staff members with clinical experience in image matching. After training had been completed, the users were tasked with performing two image match operations between two datasets with random offsets (i.e. a parotid case and a bladder case). Following the inductive thematic analysis, three major themes were identified from the extracted interview data. First, the VIMER was capable of facilitating satisfactory image matching solutions amongst all users even with a large change in the learned image matching technique. As to be expected, the learning curve was strongly speculated to be surmountable with sufficient time and experience. Even during the user acclimation process, the users were still able to identify achievable and tangible benefits, including increased spatial anatomic understanding, matching efficiency, clinician confidence, and satisfaction in the quality of the match solution using VIMER. In conclusion, the VIMER served as a valid proof of principle for developing a more intuitive 3D IVE image matching tool with clear potential clinical benefits. From these results, development will continue in refining VIMER into a clinically useful image matching tool.