My dad flew to California in the spring to meet his grandson, who was about five months old at the time. He wasn’t that interested in baby care. He mostly wanted to sight-see and spend the evenings watching TV. One weekday morning, he ventured out on a hike alone, while I was at work. He left at 9 a.m. and never came home.

We live at the base of a dusty mountain range. Mount San Jacinto rises 10,000 feet above the Coachella Valley floor. The mountains are beautiful, molding the dramatic desert light through the day. But they are dangerous — and sometimes deadly. My husband and I started to worry as it got dark, and dad still wasn’t home. But he’d been out late before, so we didn’t immediately panic. He called on his flip phone. He could see the lights of town from the mountain, and he thought he could make it down in an hour.

Hours later, he called to say that he could see the lights of town, and he might be home in 2 hours. Then he turned his phone off.

Hours after he’d lost the trail, he stumbled down/ across the rocky slope. His poor eyesight betraying him, he fell. He was unprepared for a night on the mountainside. He brought no food or water. He left his sweater on the bike I lent him that morning, at the steep, dusty trailhead below. He spent a 40-degree night in short sleeves, crouching for warmth.

He fell many times, trying to make it down. He later admitted to the trauma surgeon that he may have dropped 20 feet. What would that even feel like in the dark? I shuddered.

By the time he was found and airlifted from the mountain by helicopter, rescue hikers had spent hours trying to locate him, based on his descriptions of where he thought he might be.

He broke multiple ribs against a boulder. The ribs punctured his lung. Muscle breakdown products flowed through his blood, their units measured in thousands.

Yet more seriously, he had a small hemorrhage in front of his brainstem. This uncommon type of subdural versus epidural blood collection could have expanded to compress my dad’s brainstem — killing him. If the problem had gone unnoticed, and dad had turned or flexed his head just so, he may not have survived it. Many imaging experts could have missed this subtle finding, but Dr. Henry Jones saw it. A radiologist saved my dad’s life.

Most people walking down the street would not be able to tell you what a radiologist does. A radiologist is a physician who is educated through four years of undergraduate study, four years of medical school, and five years of residency. Most radiologists specialize further, training an additional one to three years. This additional training is called fellowship. As radiologists, or “rads,” we can see people’s insides. It’s a humbling privilege, fascinating work, and a high-stakes enterprise. You need to find everything that could threaten a person’s life, whether in five minutes or five years. These, sometimes, ominous discoveries can be buried in hundreds or even thousands of images.

Dr. Jones saves people on a daily basis through this work. He knows it, but not many other people do. He diagnoses treatable problems all day, every day — and rarely receives any recognition for it. I thanked him some days later, for making that critical discovery, for preventing my father’s premature death. Thank you, Henry.

Barbara Hamilton is an interventional radiologist and can be reached at Tired Superheroine and on Twitter @TSuperheroine.

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