Overview
The purpose of the Human Imaging Core’s Electronics Shop is to…
- Create and maintain the custom electronics used in the human MRI bays,
- Create custom electronics or give advice to research groups at Martinos/MGH, and
- Occasionally repair out-of-warranty equipment around the center.
If you have a request for a custom device or consultation, get in touch. Anything from precision analog to RF to power to high-speed digital is fair game. Projects completed or currently in progress for various labs include:
- Experimental in-bore miniaturized shim amplifiers
- 48-channel temperature logger
- Arbitrary-waveform class-D TMS amplifier
- 10kA pulsed discharge system
Human MRI Bay Documentation
See here for documentation on the trigger signals, 10 Mhz clock, cable runs from control room to pen panel, and other non-Siemens hardware in each human MRI bay.
Non-Magnetic Parts List
A list of non-magnetic parts suitable for use inside the MRI bays is here.
MRI Tools and Descriptions
These proven general-purpose designs are freely available to reproduce.
All designs were created in KiCAD 5, which is free and open-source. Each zip file contains documentation and technical notes.
- Optical-signaling toolkit: Collection of devices for converting and testing optical signals on the cheap/easily-available 1mm POF (plastic optical fiber) as used in our Siemens MRI scanners
- Includes “Trigger pulse stretcher”: Extends the <100µs Siemens trigger pulse to a multi-ms pulse suitable for use on data loggers and other user equipment that needs a scanner trigger signal
- Low-field T/R switch with reed relays:
- Usage guide – what you need to know to build and use the T/R switch: read this first!
- Design files
- 1x tx relay (2.3)
- 1x tx relay, through-hole (2.2) – for those without the soldering equipment or expertise to handle SMT parts
- 4x tx relays (2.3)
- 6x tx relays (2.3)
- (1x tx relay, with speed-up option, 2.2) – only for experimentation
- Design guide – details of calculations and why certain design choices were made
- Test data summary only
- Test data, full (not including raw switching-time data for size)
- Raw switching-time data, binary (~4 GB)
- Raw switching-time data, text (~10 GB)
- Low-field T/R switches with MOSFETs: a design guide
- Optical SERDES: Receives and transmits 24 bits of digital data full-duplex, with only two optical fibers, for equipment inside the magnet room that needs heavy data exchange with the outside world
- Button box and interface (part 1, 2, 3): Patient-feedback button boxes for use in fMRI experiments, and the interface electronics that convert button presses to simulated USB keyboard signals (split into 3 parts because of WordPress file size limitations)
- 8-channel PIN diode driver: Drives 8 channels of PIN diodes @ 100 mA on/-15V off, with on/off state determined by sensing a single PIN diode channel – useful for massively-parallel MRI coils where the scanner doesn’t have enough PIN diode driver channels
