��������

In Dr. Ramin Pashaie and Dr. Mahsa Ranji’s lab — both I-SENSE faculty fellows and professors in the �������� College of Engineering & Computer Science — two Ph.D. students are taking on a complex engineering challenge: building advanced imaging systems that can reveal early signs of disease in the brain.

Mehrnoosh Neghabi and Parisa Nategh, both Ph.D. candidates in electrical engineering, are leading the development of two tomography platforms for use in lab animals, one focused on brain imaging and the other on the retina.

Their goal is to make it easier to detect conditions like Alzheimer’s disease and diabetic retinopathy at earlier stages, when intervention could have the greatest impact. To do that, the systems combine two types of imaging that are not typically integrated into a single platform.

The first, optical coherence tomography (OCT), uses light waves to create high-resolution, three-dimensional images of tissue. It functions similarly to ultrasound, but with light rather than sound, allowing researchers to see the fine structure of layers in the brain or retina.

The second, fluorescence imaging, captures how cells are functioning. By exciting naturally occurring molecules in the body, the system detects subtle changes in metabolism. These changes can signal cellular stress or dysfunction before physical damage becomes visible.

Bringing these two methods together required building much of the system from scratch.

Neghabi and Nategh designed the optical architecture in Zemax, a specialized modeling software, to ensure the system could deliver and collect light with extreme precision. They engineered custom mechanical components in SolidWorks, then fabricated and assembled them in the lab and machine shop.

At the center of the system is a redesigned scanner head that allows both imaging methods to operate through a single objective lens. To make that possible, the students developed a series of optical pathways that separated and directed different wavelengths of light using components such as dichroic mirrors, which reflect some wavelengths while allowing others to pass through.

They also built out the full imaging pipeline, from the sample and reference arms of the OCT system to the excitation and emission paths used for fluorescence. The result is a platform that simultaneously captures both structural and functional data from the same region.

One of the biggest challenges came from imaging the mouse eye, where the small pupil size makes it difficult to deliver enough light and maintain alignment. Even after building the system based on simulations, the team initially struggled to capture clear images in live animals.

To solve this, they designed and built a custom aiming tool to precisely guide the optical beam. The process required multiple iterations, testing and adjustments before the system produced consistent, high-quality images.

Working through failed alignments and unexpected results, these students learned how to balance competing optical requirements, refine designs under real-world constraints and translate theoretical models into functioning hardware. They also built practical skills across optical design, mechanical fabrication and image processing, along with the confidence to diagnose and solve problems independently.

With both systems now operational, the work is moving into longitudinal studies to track how diseases develop over time in animal models. Because the retina is directly connected to the brain, changes observed in the eye may provide a window into neurological conditions like Alzheimer’s, opening the door to earlier and more accessible screening methods.

At the same time, the project reflects a broader goal of I-SENSE research: giving students the space to take ownership of complex problems and follow them through to working solutions.

“Embrace the troubleshooting phase,” they said. “The moments when the system doesn’t work are where the most meaningful learning happens. In engineering, theory is essential, but hands-on problem-solving is what brings it to life.”