Abschlussarbeiten, Bachelor- und Masterarbeiten

02.08.2024, Abschlussarbeiten, Bachelor- und Masterarbeiten

Overview

Computed Tomography (CT) imaging is widely used in medical scenarios. A significant advancement in CT technology over the last decade is the increased availability of scanners that capture more than one energy level during the same exam. Commonly used software for medical image visualization often combines this data to create a single virtual monoenergetic image. In this project, we aim to give users more control over how the different energy levels are combined and displayed. We want to develop a virtual reality (VR) prototype that allows users to freely choose the transfer function and other colorizations for each energy level, highlighting details that might otherwise be lost in a monoenergetic image. We have a prototype implementation for color mixing that will be extended

Background & Motivation

Multiple energy levels in a CT scan can be achieved through various technical implementations, with two energy levels being the most common. A key benefit of CT scanners that can capture more than one energy readout is that different tissues and contrast agents react differently at different energy levels, allowing for the disambiguation of otherwise indistinguishable tissues [1]. Typically, these levels are combined into a single virtual monoenergetic image [2]. While this approach is user-friendly, it limits the user's ability to find better visualizations with more control over which energy level is displayed and which transfer function is used for colorization [3]. Medical volumes are usually displayed using direct volume rendering, which maps the acquired density in a CT volume to predefined colors using transfer functions [4]. Giving users more control over this mapping when multiple energy levels are present could help highlight small details.

Student’s Task

Students are tasked with extending an existing prototype that allows users to mix and display multiple energy levels with different transfer functions in virtual reality. Tasks include:

• Reviewing the relevant literature
• Researching (with users) the functionality needed to best highlight tissue compared to virtual monoenergetic data
• Extending the prototype with additional functionality
• Evaluating the prototype with expert users

Technical Prerequisites

Students should have strong programming experience. The existing prototype is developed in the Unity Game Engine and scripted with C#, so proficiency in both is essential. Experience with shader programming is a plus. Students should be interested in working with medical data and developing VR applications for data visualization. Students should further be comfortable with interacting with users of the system to acquire insights and possibly run a study with expert users.

Please send your transcript of records, CV and motivation to: Constantin Kleinbeck (constantin.kleinbeck@tum.de) with CC to hex-thesis.ortho@mh.tum.de

Literature
[1] T. R. C. Johnson, “Dual-Energy CT: General Principles,” American Journal of Roentgenology, vol. 199, no. 5_supplement, pp. S3–S8, Nov. 2012, doi: 10.2214/AJR.12.9116.
[2] L. Yu, S. Leng, and C. H. McCollough, “Dual-Energy CT–Based Monochromatic Imaging,” American Journal of Roentgenology, vol. 199, no. 5_supplement, pp. S9–S15, Nov. 2012, doi: 10.2214/AJR.12.9121.
[3] P. Ljung, J. Krüger, E. Groller, M. Hadwiger, C. D. Hansen, and A. Ynnerman, “State of the Art in Transfer Functions for Direct Volume Rendering,” Computer Graphics Forum, vol. 35, no. 3, pp. 669–691, 2016, doi: 10.1111/cgf.12934.
[4] K. Engel, M. Hadwiger, J. M. Kniss, and C. Rezk-Salama, “Real-Time Volume Graphics,” 2006, Accessed: Dec. 30, 2021. [Online]. Available: https://diglib.eg.org:443/xmlui/handle/10.2312/egt.20061064.0595-0748

Kontakt: hex-thesis.ortho@mh.tum.de, constantin.kleinbeck@tum.de