Bioengineering student makes waves in MRI research with a 3D printed ghost head

Ghosts are not just ghostly figures of our imagination, they are also digital or physical models that represent human characteristics and provide an inexpensive way to test electromagnetic applications. Sossena Wood, Ph.D. in bioengineering candidate at the University of Pittsburgh, has developed a realistic ghost head for magnetic resonance research at the Swanson School of Engineering.

Wood began her tenure at Pitt as an undergraduate student in the Department of Electrical and Computer Engineering where she met with Tamer Ibrahim, an associate professor of bioengineering. She began researching her laboratory, the Radio Frequency (RF) Research Center, in her last year and is currently completing her PhD by integrating similar research as a graduate student in the Department of Biological Engineering.

Ibrahim envisioned designing a 3D-printed ghost head for use with UHF technology uniquely designed in his lab. "In the RF research facility, we use a 7 Tesla Magnetic Resonance Imager for the whole body (MRI 7T), which is one of the most powerful human clinical MRI devices in the world," he said. declared Ibrahim. The 7T ultra-high field technology is a powerful tool, but unfortunately, this type of imaging has some disadvantages.

"As we move from lower fields to higher fields, the images produced become less uniform and localized heating becomes more widespread," Ibrahim explained. "We wanted to develop an anthropomorphic ghost head to help us better understand these problems by providing a safer way to test imaging. "

Researchers are currently using numerical simulations to study the effect of electromagnetic fields (EM) on biological tissues at different frequencies. Wood said: "EM numerical modeling has been a standard in analyzing these interactions, and we wanted to create a ghost that would look like the human form to validate EM modeling, thus providing a more realistic environment for the EMs. tests. "

Before Wood could print the 3D structure, she had to do some math work to build the model of the model. She began with a set of 3T MRI data on a healthy man, characterized by segmentation and dividing into eight tissue compartments, a feature that differentiates his model from other basic ghost heads. According to Wood, these compartments help to improve image accuracy by acting as a kind of "retarder" in the field.

After the computer preparations, Wood used an MRI scanner to produce a 3D digital image of a healthy man's head and used his model through computer-aided design, a software used to create, edit, analyze and optimize a design.

The next step was to print the prototype, which was to last three semesters. "We used a plastic developed by DSM Somos for our printing equipment because it allowed us to create durable and detailed parts with conductivity similar to that of the human body," Wood said. "To help the model mimic a real environment, we've created fill ports on the prototype where we can drop fluids that look like different types of tissue."

Now that Wood has a fully printed anthropomorphic ghost head, she is able to assemble it and start testing. The ghost has many applications, including tests to see if certain implants are able to penetrate an MRI or detect temperature rise in different tissues according to various RF instruments.

"With magnetic resonance imaging, the power of RF exposure turns into heat in the patient's tissues, which can have adverse effects on the patient's health, particularly with implants if the scanner does not explain it ". "With our ghost head, we can test the safety of our imaging by placing probes inside certain areas of the head and measuring the effects," Ibrahim said.

Ibrahim and Wood hope that this model will eventually be developed commercially and will provide others with the ability to pursue research without resorting to human testing.

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