University of Twente Student Theses


Autonomous ultrasound scanning for breast cancer screening in the presence of a designed breast holder

Rodrigues, P. (2017) Autonomous ultrasound scanning for breast cancer screening in the presence of a designed breast holder.

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Abstract:The MURAB project aims to provide an efficient and effective solution for the breast cancer screening in patients with high risk of developing breast cancer. In order to do so, MURAB combines the accuracy of the MRI with the real-time evaluation and reduced discomfort of an US-guided biopsy, turning this technique into an easily repeatable procedure with very little margin for error by automating the whole process with an KUKA LBR iiwa robotic arm. The work developed in this master assignment focused on two topics within the MURAB project. On one hand, the thesis attempted to develop an autonomous ultrasound trajectory using the KUKA LBR iiwa 14 R820 that could be adaptable to surface of the breast (in this case a breast phantom) maintaining contact with it and conducting the motion through impedance control. On the other hand, so that the deformation induced on the breast by the US scan is reduced, it was also attempted to design a breast holding structure that could make the breast as whole stiffer in the response to the US transducer. In terms of trajectory design and implementation, it was possible to generate a robot controlled motion that could react compliantly to its surroundings, though the adjustability to the breast surface is still to be attained in future work. The current situation uses an algorithm that can generate the trajectory points necessary to scan over the breast after an MRI scan provides its 3D model, which assures a high level of position and contact accuracy provided that the breast position is not changed during the scan. From the second task, it was possible to design a breast holding structure made out of PVC that was able to fulfil all the pre-established requirements. In order to design the complete structure, some characteristics were established as optimal: the mesh structure should be about 35 mm thick, with squared holes with 4x4mm. In addition, through this design process, a thorough evaluation of other candidate materials was conducted though it was concluded that they were not US compatible. Despite being able to successfully reduce deformation in one of the experiments, this reduction was still not very pronounced. Lastly, the design and the trajectory are brought together to evaluate how the response of one changes in function of the other. From this, it was observed that the two can coexist without compromising image quality but the trajectory is not entirely smooth if the forces applied by the transducer in the direction perpendicular to the surface suffer a significant increase. Though this effect can be counteracted if certain adjustments are made both to the trajectory program and/or the breast holder’s setup.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Programme:Electrical Engineering MSc (60353)
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