As restrictions on in-person gatherings and meetings continue, GMW invites you to connect with us virtually for technical and sales discussions on instrumentation used in the Radiology and Medical Physics fields.

GMW supports Radiology and Medical Physics with products used for:

  • MRI B0 Measurements and Magnetic Field Mapping
  • Magnetic Field Site Survey and Fringe Field Measurements
  • High Field Magnets: Field Measurement and HTS Current Leads
  • Current Measurement
  • Non-destructive Beam Current Measurement

Brian Richter

Brian Richter

Ludo Letourneur Headshot

Ludovic Letourneur, Ph.D.
Senior Applications Engineer

MRI B0 Measurements and Magnetic Field Mapping

MRI Research & Development | MRI Production | MRI Installation

Metrolab PT2026 Precision Teslameters are a versatile, ultra-high-precision instrument — perfect for measuring the B0. The PT2026 is  suitable for simple hand-held field-strength checks, for example, during rampingas well as sophisticated long-term stability studies, simultaneous measurements at several locations, or even a simple field map.

Metrolab MFC2046 multi-point NMR arrays allow computational models to be verified to a high order, thanks to their ultra-high precision, their geometry adapted to the magnet, a high density of measurement points, and rapid acquisition time. The same field maps form the basis for a robust and fast shimming procedure that can handle even the relatively poor field quality of a prototype.

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Magnetic Field Site Survey and Fringe Field Measurements

Background Magnetic Field Survey | Fringe Field Mapping and Safety Measurements

Bartington Spectramag-6 and Mag-13 are used to record magnetic field variations over time at the site of the proposed installation. The period of time depends on the interference of interest, but for DC the longer the survey the better, in order to obtain a more representative view of daily facility activity. Sources of disturbance for DC and low frequencies include passing traffic and lifts; for AC the mains network and electromechanical equipment may contribute.

Metrolab THM1176/TFM1186 handheld digital  USB telsameters (gaussmeters) are a family sensors with different measurement ranges (8 mT to 14 T), resolutions (nT to mT), and sizes (0.5x2x42 to 16.5×5.0×2.3 mm). Choose the model best suited to your application – all are low-power, portable, 1 KHz bandwidth, and fully software compatible. The THM1176-LF (Low Field Probe) is particularly suited for 5G-line measurements.

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High Field Magnets: Field Measurement and HTS Current Leads

High field NMR | High field MRI

Group3 DTM 151 is the highest performance Hall effect teslameter (gaussmeter) commercially available with digital linearity and temperature correction to provide 0.01% accuracy, resolution to 2ppm, and a temperature stability of 10ppm/°C. Group3 probes are now available with calibration to 6T and 9T for precise measurements at or near the magnet bore.

Metrolab THM1176-HF is a 3-axis handheld digital USB telsameter (gaussmeter) calibrated to 14T with an accuracy of 1% and resolution of 0.3mT, for high field BX, BY, BZ and BTotal measurements.

HTS-110 CryoSaverTM Current Leads use High Temperature Superconducting (HTS) tape to create a robust, reliable lead. The leads deliver significantly improved performance, with lower heat leak than vapor-cooled leads. Applications include MRI, NMR, and beam-line magnets as well as driven (non-persistent) superconducting magnets.

Also available are HTS-110 Sapphire Heat Sink Kits for use on all standard leads to optimize the thermal contact between lead and heat sink.

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Current Measurement

MRI Gradient Amplifiers | High Voltage X-Ray Cables | RF Current Measurement

Danisense Zero-flux Current Transducers are used within gradient amplifies for precise, repeatable and stable control of the output current. Danisense DCCTs have very high absolute amplitude and phase accuracy from dc to over 1kHz, low signal output noise, enhanced electrostatic shielding to increase rejection of primary dV/dt coupling with full scale current ranges from 20A to over 10000A. A model particularly suited for gradient amplifiers is the DS600-P1300, which has a linear range to 1300A in a compact, integrated package.

Bergoz IPCT is a large aperture, DC Current Transformer widely used for X-ray installations for leakage current or applications requiring high resolution DC measurements. IPCTs have full scale range from ±1mA to ±20A and DC to 3.8 kHz (-3dB) response.

Bergoz FCT (Fast Current Transducer) is a wide-band AC transformer with a rise time down to 175ps and a bandwidth up to 2GHz, useful for RF Current Measurement.

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Non-destructive Beam Current Measurement

Medical Cyclotrons | Flash Therapy

Bergoz CWCT is a current transformer with strict limits on lower and upper cut-off frequencies, tailored to the beam RF. Its lower cut-off assures negligible droop between bunches. Yet, droop is high enough to allow fast differentiation. CWCT can be used for non-destructive beam current measurements in medical cyclotrons where currents have traditionally been too low for accurate, non-destructive measurement.

Bergoz ACCT being used in development of Flash Therapy for measurement of short beam pulses. As an example, a partnership between PMB and University Hospital of Lausanne, Switzerland has announced “First patient treated with FLASH-radiotherapy.”

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