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Medical physics

Medical physics

CIRS Zeus Phantom for E2E QA and testing of MRgRT systems

01 Jun 2021 Sponsored by CIRS

This webinar was held on 22 June 2021. Available to watch now, it explores how the Zeus Phantom provides complete end-to-end testing of MRgRT systems

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In this webinar, you will learn how the Zeus Phantom combines an MR-safe motion control platform with an MR-realistic body to provide complete end-to-end testing of MRgRT systems such as ViewRay’s MRIdian and Elekta’s Unity systems. In Zeus, piezoelectric motors move a cylindrical insert with an organic-shaped tumour through the phantom body in three dimensions. The Zerdine® gel-filled body also contains anthropomorphic lungs, liver, kidney and spine with a life-like shape, spatial relationship, and imaging contrast in both MR and CT. All organs except for the lungs offer ion chamber dosimetry cavities for completing an entire QA process.

The Motion Control software comes with multiple built-in motion profiles designed for use during commissioning and routine QA; it also allows for the import of complex patient-specific respiratory waveforms. These waveforms can be edited for amplitude, sample rate, cycle time, phase shift and baseline position. The software also allows users to set up independently controllable waveforms for linear and rotation motion of the insert. The inferior-superior motion of the insert/moving target can be gated-based on amplitude to allow verification of machine beam latency.

Finally, the motion controller box provides an interface (BNC physical input type) for the beam-on beam-off signal, which is read by the Motion Control software to calculate the beam latency specific to hybrid MRI-Linac systems.

Roy A Lowe is the corporate sales manager for CIRS, Inc. He is well known in the radiology and radiation therapy industry throughout the US and internationally. He has a clinical background as a registered radiation therapist and medical dosimetrist working in both university academic and community hospital healthcare institutions. Roy is a graduate of the University of Tennessee Graduate School of Medicine with a degree in radiation science and medicine. He is a member of the American Registry of Radiologic Technologists and the American Association Medical Dosimetrists.

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