Lumius

Lumius is a Y Combinator-backed company that fast, smart, accessible 3D ultrasound for everyone. Based in Durham, USA, the company participated in the Spring 2026 batch of Y Combinator.

Ultrasound today is still mostly 2D. Clinicians have to imagine the 3D anatomy in their head while also moving the probe at the same time. This makes procedures like vascular access hard to learn and perform consistently, especially for beginners. ~50% fail on their first attempt. Hospitals also spend millions each year on 2D ultrasound training. Meanwhile, existing 3D ultrasound devices can cost >10× as much.

Lumius was part of Y Combinator's Spring 2026 cohort, has a team of approximately 4 employees, and is actively operating.