Hello OCRA and Tabletop community, In this blog post I want to share our console power supply for the OCRA Tabletop MRI System. The console is driven by a Mean Well RT-50C switching mode power supply with a universal 110/230V AC input and +15V, -15 and +5V DC outputs. To connect the power supply to…
Gradient Coils for the OCRA Tabletop MRI System
Hello OCRA and Tabletop community, In this blog post I want to share our gradient coil design for the OCRA Tabletop MRI System. Gradients fields are necessary to encode spatial information to the spin signal. As the origin of the spin signal is the homogeneous magnetic field (B0) it is possible to variate this field…
Relax2.0, a graphical user interface for OCRA
Hello OCRA and Tabletop community, In this blog post, I will share the news about the first GitHub publication of my Relax2.0 graphical user interface (GUI) for OCRA. Relax2.0 is based on the original OCRA server for the Red Pitaya by Thomas Witzel and the PyQt GUI Relax by David Schote. Relax2.0 can be downloaded…
Testing the transmit and receive functionality of the OCRA Tabletop MRI System
Hello OCRA and Tabletop community, In this blog I will guide you on how to test the RF functionality of the OCRA Tabletop MRI System. We will test the functionality for receiving RF spin signals (RX) and transmiting RF pulses (TX). For the tests you need a pickup loop coil. The coil can be build…
RF-Coil for the OCRA Tabletop MRI system
Hello OCRA and Tabletop community, In this short blog I will share my radiofrequency (RF) -coil design for our OCRA Tabletop MRI system. The coil is a simple solenoid design. To make it sensitive to the measurement (Larmor) frequency it is built as an electrical resonator with parallel capacitance. To match its impedance to a…
Small Scale 600W Gradient Power Amplifier
Hello OCRA and Tabletop Community, I would like to introduce the low-cost 4-channel 600 W Gradient Power Amplifier (GPA) for our OCRA Tabletop MRI system. Basically, the GPA converts a voltage input coming for example from the OCRA1 (see blog post from Marcus) into currents to supply gradient coils. The GPA can handle gradient sequences (pulsed…
Transmit-Receive Switch for the OCRA Tabletop MRI system
Hello OCRA and Tabletop Community, In this blog I will share my Transmit-Receive (TR) switch design for our OCRA Tabletop MRI system. As it’s a general design, it also can be used for small RF-power applications in other MRI systems. The TR-switch is used to connect the RF-coil (antenna) to the RF Power-Amplifier (RFPA) in…
OCRA1 – SPI controlled 4 channel 18bit DAC and RF Attenuator
Hello OCRA Community, I would like to introduce you to one of the core elements of our OCRA Tabletop MRI console, the OCRA1. It’s a peripheral printed circuit board (PCB) that extends a Red Pitaya to a basic MRI console. All its components are controlled with the Serial Peripheral Interface (SPI) bus given by the…
The OCRA Project in Magdeburg, Germany
Hello OCRA Community! My name is Marcus Prier and I’m working at the Research Campus STIMULATE of the Otto-von-Guericke University Magdeburg (Germany). I’m a physicist and specialized in MRI RF electronics development. A few years ago, I had a short-term scholar at the Athinoula A. Martinos Center in Boston supervised by Larry Wald in Boston where I…
Porting RP-125 FPGA bitstream features to RP-122
My name’s Vlad Negnevitsky, and I’ve been working on OCRA part-time since mid-2019 on behalf of the MRILab at i3m in Valencia, Spain. I’m not an MRI physicist, and I’ll mainly be discussing the technical side of OCRA. OCRA is a multi-level project, bringing together lots of fun engineering at the electronics/hardware, FPGA firmware, embedded…