Abstract
In the diagnostic workup of breast cancer, the biopsy is crucial to determine the malignancy of a lesion. Its success rate mainly depends on accurate lesion localization and needle placement. Especially when lesions are magnetic resonance imaging (MRI)-visible only, there are limitations in the accuracy, which can negatively impact the biopsy outcome.
Robotic assistance can take place inside and outside the magnetic resonance (MR) bore and potentially improves the biopsy procedure's accuracy. For outside the MRI, the MRI and Ultrasound Robot-assisted biopsy (MURAB) project presents a robotic setup to assist the radiologist with an ultrasound-guided biopsy on an MR-detected lesion. The robotic setup consists of a seven-degrees-of-freedom robotic arm holding an end-effector positioned under a patient bed. The patient lies on this bed with the examined breast through a hole such that it is freely accessible by the robot. The robot achieves an accurate notion of the lesion position by combining the preoperatively acquired MRI images with stereo vision and intraoperatively acquired ultrasound images. Additionally, a patient-specific biomechanical model is built utilizing elastography to predict deformations caused by needle insertion. For inside the MRI, an entirely plastic MR safe pneumatic robot was developed, which autonomously takes a biopsy based on the MRI images.
In this thesis, several aspects of these setups are worked out in detail. For the MURAB project, an end-effector design containing an actuated needle guide, an ultrasound probe, stereo cameras, a projector and lighting is presented. A compliant controller is introduced, limiting the robot's energy in the null space, optimizing the joint positions relative to their limits, and avoiding the joint limits. Furthermore, the work shows how ultrasound feedback is taken advantage of during ultrasound acquisitions and the biopsy procedure. For the MR safe robot, a position sensor is developed based on a spectrophotometer.
Robotic assistance can take place inside and outside the magnetic resonance (MR) bore and potentially improves the biopsy procedure's accuracy. For outside the MRI, the MRI and Ultrasound Robot-assisted biopsy (MURAB) project presents a robotic setup to assist the radiologist with an ultrasound-guided biopsy on an MR-detected lesion. The robotic setup consists of a seven-degrees-of-freedom robotic arm holding an end-effector positioned under a patient bed. The patient lies on this bed with the examined breast through a hole such that it is freely accessible by the robot. The robot achieves an accurate notion of the lesion position by combining the preoperatively acquired MRI images with stereo vision and intraoperatively acquired ultrasound images. Additionally, a patient-specific biomechanical model is built utilizing elastography to predict deformations caused by needle insertion. For inside the MRI, an entirely plastic MR safe pneumatic robot was developed, which autonomously takes a biopsy based on the MRI images.
In this thesis, several aspects of these setups are worked out in detail. For the MURAB project, an end-effector design containing an actuated needle guide, an ultrasound probe, stereo cameras, a projector and lighting is presented. A compliant controller is introduced, limiting the robot's energy in the null space, optimizing the joint positions relative to their limits, and avoiding the joint limits. Furthermore, the work shows how ultrasound feedback is taken advantage of during ultrasound acquisitions and the biopsy procedure. For the MR safe robot, a position sensor is developed based on a spectrophotometer.
| Original language | English |
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| Qualification | Doctor of Philosophy |
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| Award date | 21 Feb 2022 |
| Place of Publication | Enschede |
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| Print ISBNs | 978-90-365-5322-3 |
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| Publication status | Published - 21 Jan 2022 |