In this project, I will build a desktop-sized MRI that is inexpensive and can be built by anyone.
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My goal is to build an MRI that can be used for simple physics experiments, and to make the design process data public so that anyone can build an MRI.
The following is an overview of current progress.
First of all, I was able to obtain my first 2D image by MRI on 2/24 2022. The following images are from that time.
My goal is to build an MRI that can be used for simple physics experiments and to publish data on the design process.
Let me explain our current progress.
First of all, I was able to obtain my first 2-D MRI image on 2/24. The following images are from that time.
The image quality is coarse and blurred, but the image shows that an approximate shape can be reconstructed.
This two-dimensional image was acquired using the spin-echo method. The image type is proton density-weighted.
After this image was acquired, various improvements were made, and the image quality has now improved to the level shown below.
My current MRI has three problems.
■ The first is the poor signal-to-noise ratio of the signal and the resulting image quality.
This problem is exacerbated by switching noise and urban noise in the power supply to the detection system, including the preamplifier.
In principle, the lower limit of MRI noise is determined by the thermal noise of the detection coil, and the noise cannot be further reduced.
However, various types of noise are introduced into the detection system of my current MRI, adversely affecting the image quality.
■Second, as I am a novice in FPGAs, the HDL code for the FPGA that makes up the MRI sequencer is poor.
The MRI sequencer uses REDPITAYA, which is implemented with Zynq.
REDPITAYA is equipped with a 2-channel ADC and DAC as well as an Ethernet terminal for communication, but I have not been able to make full use of it.
I have implemented a UART module on my own and communicate with a PC using an RS232C-USB cable.
Due to this slow communication speed, the current MRI can only capture proton density-enhanced images.
■Third, the Z-axis gradient coil has not yet been implemented. Commercial MRIs can scan in three dimensions, but without a Z-axis gradient coil, they can only produce a two-dimensional projection image, similar to an x-ray.
Home Made MRI will continue to be improved.
A low cost solution to improve the thermal noise in the detection coil is by -improving the coil's quality factor (Q) by tuning and matching the coil's impedance to the preamplifier's input impedance using high-permeability materials, such as ferrites(or meta materials)
-Reducing the coils Resistance by increasing the coil's cross section will contribute to improving thermal noise.
Cooling the coil to lower temperatures, such as liquid nitrogen (77 K) or liquid helium (4.2 K), to reduce the thermal agitation of the electrons is another solution.
There are other viable solutions too. I haven't sourced any of the materials, but I would assume they are pretty expensive. Another way to reduce the coils resistance is using low-resistance materials, such as superconductors or high-temperature superconductors (HTS)
- Using cryogenic preamplifiers that operate at low temperatures and have low noise figures, such as high electron mobility transistors (HEMTs) or superconducting quantum interference devices (SQUIDs)
Good Luck. If you have any questions, I'll try my best to answer.
Very nice!
You may find some resources on how to design gradient coils from the OSI2 website: https://www.opensourceimaging.org/projects/
This is a community of open-source hardware people who work in MRI and ultrasound. There are lots of stuff there that may interest you!
Actually this looks very similar to the first clinical MRI scanner ever made (which is a good sign for you!) Link here: https://www.ghat-art.org.uk/mark-1-the-worlds-first-whole-body-mri-scanner/
I hope there will be more news soon :)
I have always wanted to do this. I'm happy to see you paving the way.
The device looks like an electronic spin resonance imager, which is related to nuclear magnetic resonance imagers. The difference being that ESRI identifies atoms via their electron spin characteristics where as NMRI identifies via nucleus mass. Both types of resonance imagers work the same way, just differ in which atomic characteristics are measured.
Does that imply that this technique would have trouble differentiating between elements in the same column of the periodic table? I'm a fair chemist, but I didn't know that "ESRI" was a thing until 5-minutes ago.
I can't wait to build this for myself. I am SUPER interested.
Amazing. I look forward to building one, if/when instructions become available.
What is the max intensity of B_0 that you can generate with this design?
When will you consider a person-size MRI? Head-size?
Do you plan on providing details - theory of design, references to design sources, thoughts behind why you chose your particular design (particularly interested in the field-coils and the theory behind them), Interaction of the coils with the gradient coil and the other coils top/bottom and side of the chamber, the math, the software. Deets, dude. Deets.
https://hackaday.io/project/182802/gallery#ad4c9c2247661101b7fbfafa9d41750c awesome! Your design looks super solid and hope you take it all the way
yashiro
G.Vignesh
null1
ajc150
It has been three years since I asked my question above. Are you planning to share the details?