CT and MRI compatibility of flexible 3D‐printed materials for soft actuators and robots used in image‐guided interventions

Abstract

Purpose Three‐dimensional (3D) printing allows for the fabrication of medical devices with complex geometries, such as soft actuators and robots that can be used in image‐guided interventions. This study investigates flexible and rigid 3D‐printing materials in terms of their impact on multimodal medical imaging. Methods The generation of artifacts in clinical computer tomography (CT) and magnetic resonance (MR) imaging was evaluated for six flexible and three rigid materials, each with a cubical and a cylindrical geometry, and for one exemplary flexible fluidic actuator. Additionally, CT Hounsfield units (HU) were quantified for various parameter sets iterating peak voltage, x‐ray tube current, slice thickness, and convolution kernel. Results We found the image artifacts caused by the materials to be negligible in both CT and MR images. The HU values mainly depended on the elemental composition of the materials and applied peak voltage was ranging between 80 and 140 kVp. Flexible, nonsilicone‐based materials were ranged between 51 and 114 HU. The voltage dependency was less than 29 HU. Flexible, silicone‐based materials were ranged between 60 and 365 HU. The voltage‐dependent influence was as large as 172 HU. Rigid materials ranged between −69 and 132 HU. The voltage‐dependent influence was <33 HU. Conclusions All tested materials may be employed for devices placed in the field of view during CT and MR imaging as no significant artifacts were measured. Moreover, the material selection in CT could be based on the desired visibility of the material depending on the application. Given the wide availability of the tested materials, we expect our results to have a positive impact on the development of devices and robots for image‐guided interventions.

Tissue mimicking materials for imaging and therapy phantoms: a review

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Recent Trends and Innovation in Additive Manufacturing of Soft Functional Materials

“…Soft robots and/or actuators are highly compliant devices with multiple degrees of freedom that enable object manipulation with minimal damage. Due to their interesting material properties such as flexibility and compliance, soft robotics have gained a significant attention in the fabrication of diverse types of grippers for manufacturing [ 133 ], nature inspired actuation [ 134 , 135 ], sea exploration [ 136 ], surgical devices [ 137 , 138 ], and rehabilitation devices [ 133 , 139 ]. Actuation of soft robots occurs usually through the application of pneumatic or hydraulic pressure [ 133 ], temperature [ 134 , 135 , 140 ], UV light [ 135 , 141 ], magnetic fields [ 134 ], or electric fields [ 137 , 138 ].…”

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