Master Thesis Motion Compensation in CBCT-imaging

Cone-beam CT (CBCT) supports patient positioning and adaptive radiotherapy, but movement during scanning can introduce artifacts and reduce image quality. This thesis at Elekta will explore motion compensation methods, focusing particularly on respiratory motion. The goal is to improve image quality and treatment accuracy while keeping computation efficient and limiting scan time and patient radiation dose.

The assignment

• Review published methods for motion compensation in CBCT imaging.
• Develop or adapt a motion compensation algorithm and produce a prototype suitable for integration into Elekta’s CBCT reconstruction pipeline.
• Test the algorithm and assess image quality, computational efficiency and robustness.
• Compare the prototype with existing approaches to identify strengths and limitations.
• Deliver the implementation source code and a report covering the methods, results and conclusions.

Who we are looking for

• Have a strong foundation in physics, medical imaging and machine learning.
• Experience with Python or similar programming languages, along with image processing libraries and frameworks, is preferred.
• Be motivated, attentive to detail and able to work both independently and with others in a research setting.
• Be comfortable combining theoretical research with practical algorithm development and evaluation.

What we offer

• Supervision by Niklas Gunnarsson.
• An opportunity to develop a prototype for Elekta’s CBCT image reconstruction pipeline in a radiotherapy research context.

Practical details

Location: Elekta AB, Stockholm. Planned start: spring 2027, with the exact date agreed individually. Supervisor contact: Niklas Gunnarsson, niklas.gunnarsson@elekta.com.