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For Gregory Loan, fake blood and silicone body parts are all part of the job.

But he doesn’t work for a Hollywood special effects studio. He’s part of the Boston Children’s Hospital Simulator Program (SIMPeds), which creates body parts and mannequins, called trainers, for clinicians to practice on.


“I basically use every kind of tool known to man,” said Loan, a simulation engineer, whose equipment includes a 3-D printer, a table saw, and even a Dunkin’ Donuts Boston cream doughnut (“my very secret pus recipe”).

He sculpts veins and body parts out of clay and silicone and designs robotic mechanisms that go underneath the skin, allowing the trainers to respond to physicians.

“Whether that’s a heartbeat or it’s breathing or it’s a pulsing vein or artery, these things will help break down that barrier and make people believe that they’re working on a real patient,” Loan said.


Loan used to do special effects for films and theme parks before leaving to study robotics and earn a master’s degree at Harvard Extension School.

One of his more recent projects at SIMPeds is a trainer with eyes that respond when physicians shine a light on it. To house the eyes, he’s sculpting a girl’s head out of clay.

“Squeamishness is not helpful in this line of work,” Loan said. “When I start working on a new project, I have to familiarize myself with the anatomy. In fact, I have to become an expert in that one piece.”

Clinicians can ask the SIMPeds team for any kind of trainer, including ones for medically complex cases. The team works closely with the medical staff to craft highly realistic models.

Unlike in Hollywood, not only do body parts have to look right, sutures and scalpels have to pass through the material and feel like how it does in real life.

“I’ve had situations in the past where even after we call time out, the clinicians will continue to work on the patient to try and save the patient’s life,” Loan said. “That, for us, is the absolutely best possible outcome because it means that we’ve done our job.”