A Pneumatic-Driven Robot for MR-Guided Prostate Therapy

With the capability of providing images of suspicious lesions inside soft tissues including the prostate, brain, and breast, Magnetic Resonance Imaging (MRI) has been widely used for cancer diagnosis and treatment. Traditional methods of cancer treatment require physicians to site a needle into the target area for biopsy, ablation, or brachytherapy. However, this has potential disadvantages including low accuracy, long procedure and postoperative recovery time, and low detection rates. In contrast, the utilisation of robots that can work in the Magnetic Resonance (MR) environment enhances MR-guided operations. Utilising high-resolution MR images, targeting accuracy can be improved, with detection rates increased significantly. However, there remain technical challenges to the deployment of robots in MRI scanners. Due to the strong magnetic field generated, ferromagnetic materials are prohibited from use, and with only limited use of paramagnetic materials. The material that is MR safe needs to be nonmagnetic, nonmetallic, and nonconductive. Another challenge is the confined space inside the scanner bore, which requires the robot working inside to be compact. Several MR conditional robots have been proposed 1, 2. Owing to the complicated structure and power transfer system, their large size limits application within the narrow closed bore. As such, this study proposes a new robot that has a compact size, allowing it to be easily placed within the MRI bore. The pneumatic actuators used are inherently MR- safe. With four degrees of freedom (DoFs), the needle can be inserted into the target point at various orientations.