Chicago’s reputation as a center for technology companies is gaining strength. Among the medical, biotech and digital manufacturing firms moving operations here is Brainlab, which creates technology used in neurosurgery, radiation oncology and spine, trauma and head and neck surgeries.

The company, based in Munich with 1,200 employees in 17 offices worldwide, has 90 people working at its U.S. headquarters in Westchester and recently chose the Wrigley Building for its design, marketing and education offices. Nearly half the company’s yearly $330 million in revenue comes from the United States.

The education division, Brainlab Academy, hosts neurosurgeons, physicists and radiation oncologists at the Wrigley Building for training.

Brainlab founder and CEO Stefan Vilsmeier, 47, spoke with Sun-Times reporter Sandra Guy. An edited transcript follows.

Question: How did you get started writing software for brain surgeons?

Answer: Growing up in a suburb of Munich, when I was 15, a fellow student gave me a two-hour demonstration of his Commodore 64 computer. I was fascinated. For me, the computer was initially an instrument of artistic expression, something that could drive my creativity.

I thought I’d be the worst person to manage a company. Even selling was against my natural instinct. I’m a complete introvert. I make sure the people I hire do a better job than me.

Q: Describe Brainlab?

A: Most of our revenue comes from our cranial navigation product — a GPS system for the brain.

Seventy-five percent of the top 1,000 cancer centers worldwide use Brainlab technology.

We are working on better treatments for strokes and spinal tumors that would focus radiation from 100 angles onto just one tumor and increase the dose tenfold.

Q: Why did you choose Chicago for Brainlab Academy?

A: Chicago is the design capital of the United States, whether it’s in aesthetics or architecture. We hired a marketing firm here in 1996. It took four months to hire away all of the talented people from that firm.

Logistically, Chicago is easy to reach. It has the best airport and is similar in style and culture to Munich.

And Chicago has the best opera house — way better than the Metropolitan Opera — as well as better restaurants than New York.

Q: You started the company with proceeds from a book you wrote at 16 about 3D graphics.

A: I took vector geometry in school. Thinking of things in three dimensions appealed to me.

I wrote software that got the attention of a magazine called Computer Software of the Month. I wrote an article about my software, and the [editors] asked me to write a book. It sold 50,000 copies instead of the 4,000 anticipated and generated $75,000 in sales.

After mandatory military service, I started Brainlab in 1989. I dropped out of university. I am more of an autodidact. To hear someone lecture on the basic principles of computer science, I really hated.

At that time in Germany, entrepreneurs were thought of as people who abused workers and stuffed money in their pockets. That never discouraged me.

In 1990, Brainlab demonstrated the company’s first commercial, mouse-controlled surgical navigation software, letting surgeons see and control where their instruments were located inside the patient’s skull during surgery.

Q: You hid inside a convention hall and set up your own exhibitor’s booth?

A: A company in the United States had designed a product already [to do the same thing as Brainlab’s product]. I was essentially doomed.

Even when Brainlab was growing, the [first clients] were late to pay. We had $2.5 million in accounts receivable. I had to fund it with bank loans. I had to personally guarantee those loans.

So, in September 1992, I took the remaining $10,000 I had, packed up 850 pounds for an exhibit structure, took a flight to Washington, D.C., hid in a convention center so we could build our own exhibit booth at the Congress of Neurological Surgeons annual scientific meeting. We couldn’t afford the $69 union-labor fee. We had four people in one hotel room, staying in a Motel 6 in Maryland for $18.95 a night. I had breakfast at Shoney’s.

I had to push our first product — simple software to plan angles for a mechanical device that would reach a certain pathway with high precision for brain surgery. I took the highest price I could think of, multiplied it by two — and charged $14,000.

I’m very good at turning negative energy into positive.

Q: What do you do for fun?

A: I spend time with my parents and enjoy becoming the favorite uncle to my nieces and nephew.

I like opera. I take my parents to the opera.

I do sports. My workout is a combination of yoga and Pilates.

I have started cooking. I looked at various ways to make creme brulee. I tried 50 versions. I settled for something that required a combined steam-and-convection oven. The consistency is perfect. I’m a perfectionist.