Design and manufacturing of embedded air-muscles for a magnetic resonance imaging compatible prostate cancer binary manipulator
By: Miron, Geneviève
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Contributor(s): Girard, Alexandre.
Publisher: New York ASME 2013Edition: Vol.135(1), Jan.Description: 1-10p.Subject(s): Mechanical EngineeringOnline resources: Click here
In:
Journal of mechanical designSummary: Magnetic resonance imaging (MRI) compatible robots can assist physicians with the insertion of biopsy needles and needle-like therapeutic instruments directly into millimeter-size tumors, using MR images as feedback. However, MRI systems present a challenging environment with high magnetic fields and limited space, making the development of MRI-compatible robots complex. This paper presents an MRI-compatible pneumatic actuation technology consisting of molded polymer structures with embedded air-muscles operated in a binary fashion. Along with its good positioning accuracy, the technology presents advantages of compactness, perfect MRI-compatibility, simplicity and low cost. Here, we specifically report the design and validation of a transperineal prostate cancer manipulator prototype that has 20 embedded air-muscles distributed in four star-like polymer structures. These compliant structures are made of silicone elastomer, using lost-core injection molding. Low motion hysteresis and good precision are achieved by designing molded joints that eliminate sliding surfaces. An effective design method for such embedded polymer air-muscles is proposed, using a manipulator model and four air-muscle design models: geometrical, finite elements, uniaxial analytic, and experimental. Binary control of each air-muscle ensures stability and accuracy with minimized costs and complexity. The prototype is found MRI-compatible with no observable effects on the signal-to-noise ratio and, with appropriate image feedback, is found to reach targets with precision and accuracy under 0.5 mm. The embedded approach reveals to be a key feature since it reduces hysteresis errors by a factor of ≈7 compared to a previous nonembedded version of the manipulator.
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School of Engineering & Technology Archieval Section | Not for loan | 2024-0634 |
Magnetic resonance imaging (MRI) compatible robots can assist physicians with the insertion of biopsy needles and needle-like therapeutic instruments directly into millimeter-size tumors, using MR images as feedback. However, MRI systems present a challenging environment with high magnetic fields and limited space, making the development of MRI-compatible robots complex. This paper presents an MRI-compatible pneumatic actuation technology consisting of molded polymer structures with embedded air-muscles operated in a binary fashion. Along with its good positioning accuracy, the technology presents advantages of compactness, perfect MRI-compatibility, simplicity and low cost. Here, we specifically report the design and validation of a transperineal prostate cancer manipulator prototype that has 20 embedded air-muscles distributed in four star-like polymer structures. These compliant structures are made of silicone elastomer, using lost-core injection molding. Low motion hysteresis and good precision are achieved by designing molded joints that eliminate sliding surfaces. An effective design method for such embedded polymer air-muscles is proposed, using a manipulator model and four air-muscle design models: geometrical, finite elements, uniaxial analytic, and experimental. Binary control of each air-muscle ensures stability and accuracy with minimized costs and complexity. The prototype is found MRI-compatible with no observable effects on the signal-to-noise ratio and, with appropriate image feedback, is found to reach targets with precision and accuracy under 0.5 mm. The embedded approach reveals to be a key feature since it reduces hysteresis errors by a factor of ≈7 compared to a previous nonembedded version of the manipulator.
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