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Author: Thomas Witzel

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Articles

18 May

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…
Continue reading “Testing the transmit and receive functionality of the OCRA Tabletop MRI System”…
18 Apr

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…
Continue reading “RF-Coil for the OCRA Tabletop MRI system”…
15 Dec

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…
Continue reading “Small Scale 600W Gradient Power Amplifier”…
30 Sep

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…
Continue reading “Transmit-Receive Switch for the OCRA Tabletop MRI system”…
27 Nov

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…
Continue reading “OCRA1 – SPI controlled 4 channel 18bit DAC and RF Attenuator”…
05 Nov

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…
Continue reading “The OCRA Project in Magdeburg, Germany”…

Welcome to the OCRA blog!

Posted on: July 23, 2020 Last updated on: July 23, 2020 Written by: Thomas Witzel Comments: 0
What started in a little corner of my tiny Boston apartment, and then later advanced with the help of numerous students that shall be listed soon on this page has now become a project bigger than just my hobby, with users and contributors in both Europe and the USA. In order to keep the community…
Continue reading “Welcome to the OCRA blog!”…

Recent Posts

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…
Continue reading “Testing the transmit and receive functionality of the OCRA Tabletop MRI System”…

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…
Continue reading “RF-Coil for the OCRA Tabletop MRI system”…

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…
Continue reading “Small Scale 600W Gradient Power Amplifier”…

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…
Continue reading “Transmit-Receive Switch for the OCRA Tabletop MRI system”…

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…
Continue reading “OCRA1 – SPI controlled 4 channel 18bit DAC and RF Attenuator”…

Recent Comments

  • Luna on Transmit-Receive Switch for the OCRA Tabletop MRI system
  • Marcus Prier on Transmit-Receive Switch for the OCRA Tabletop MRI system
  • luna on Transmit-Receive Switch for the OCRA Tabletop MRI system
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