I was strapped to a hard metal sheet, and the technician had just bolted my head down using a black mask that had been heat-molded to the contours of my face. The sheet and I would slide first up and then back in an overhead arc that would send high-energy electrons into my head and neck from computerized data sets outlining my throat cancer and its spread into adjacent lymph nodes.

I wasn’t a doctor anymore. I was a patient.

That was almost three years ago. This spring, the Archives of Internal Medicine published a much-discussed study that showed that doctors might recommend different treatments for their patients than they would for themselves. They were far more likely to prescribe for patients a potentially life-saving treatment with severe side effects than they were to pick that treatment for themselves.

Understandably, people are worried that this means doctors know something they’re not telling their patients. But my own experience with illness taught me a simpler truth: when it comes to their own health, doctors are as irrational as everyone else.

I had squamous cell carcinoma of the throat, a pea-size lesion first, then the cancer spread to my lymph nodes. I knew that this was a bad actor; I’d seen the disease and its consequences many times while wearing a white coat, a stethoscope dangling from my neck, at a patient’s bedside.

At the beginning, I knew intellectually what was in store for me. I allowed myself to be a patient, to trust my doctors and let them lead me through the treatments and complications and side effects that rolled out with alarming regularity. I submitted to a brutal treatment regimen that had not changed in over 40 years. Two thousand units of radiation a day for 35 days, with high doses of platinum chemotherapy, followed, a year later, by a dissection of the right side of my neck to remove the lymph nodes in which the cancer had reappeared.

I soon realized I had no idea what kind of rabbit hole I had fallen into.

For my doctors, it was all about the numbers, the staging of my cancer, my loss of weight and strength. For me, too, it was about the numbers: the six feedings I pushed through the syringe into the plastic tube in my stomach every day; the number of steps I could take by myself; how many hours I had to wait before I could grind up the pill that allowed me to slip into unconsciousness.

But it was also about more: my world progressively shrinking to a small, sterile, asteroidal universe between the interminable nausea and the chemobrain that left my head both empty and feverish, between survival and death.

Survival was a percentage, and not a horrible one — 75 percent if I completed the treatment regimen, by the reckoning of my physicians. But more and more I found myself thinking about what would happen if I was in that 25 percent. If I completed the regimen and the tumor came back, there were no other treatment options. It was morphine and palliative care. I was 58 years old. Death was a 100 percent certainty, eventually. So did it matter?

During one particularly desperate hospitalization, after receiving blood transfusions and a drug to stimulate my white cells, I decided that I had had enough. I refused further radiation and chemotherapy. I lay in my bed and watched the events around me — the distress of my family, the helplessness of my doctors — without anxiety, comfortable that I had made the correct decision.

My doctors couldn’t override it or persuade me to change my mind, but, luckily, my wife, Diana, could and did. From my mental cocoon in the hospital bed, I could sense Diana at my side. “You’re going to finish the treatment,” she said softly. I did not have the energy, or perhaps the will, to disagree. She wheeled me down herself to finish my radiation treatments in the basement of the hospital.

My dreams of dying were not the products of anxious moments of terror. The life force had simply slipped away and made me ready to die. It had also rendered me incapable of making the right decision for myself. My disease was treatable and the odds were favorable. My doctors were professional and gentle but ultimately could not decide for me. When neither doctor nor patient can make the right decision, it is vital to have a caring family — though even here the legal and ethical issues are complicated.

Next week it will be three years since I first noticed the hoarseness that was a symptom of cancer, and I am back to work and a busy life. But my illness has changed me profoundly as a physician. Even having lived through this illness, I’m not sure that I would be any better prepared if I had to relive it again. No amount of doctoring can prepare you for being a patient.

If anything, it’s that recognition of vulnerability as well as expertise that makes me a better doctor today.

Eric D. Manheimer, the medical director of Bellevue Hospital Center, is the author of the forthcoming memoir “Twelve Patients.”