Solvay Specialty Polymers has expanded its range of PEEK resins for use in implantable medical devices. A new radio-visible compound grade, Zeniva ZA-520, provides image contrasting capabilities for visualisation with x-ray CT and MRI imaging systems. Zeniva ZA-520 compound provides visibility of an implant without the artefacts common with competitive metal-based materials, according to Solvay. The new compound is available in resin form - for injection moulding - and rod stock which can be high-precision machined. On the basis of biocompatibility testing to ISO 10993 standards, Zeniva PEEK is claimed to demonstrate no evidence of cytotoxicity, sensitisation, irritation or acute systemic toxicity.