I switched on the machine, and it shot a square of light onto the table. I lay on my back and angled my left breast into the square.

Our town had been irradiated; how much was unclear, but I knew it was super rare for someone my age to get breast cancer. In one of my mom’s books, I read that 80 percent of lumps were benign and that teenage breasts can be lumpy. Well, that was exactly the sexiest thing I’d ever heard.

So why was I scared shitless?

The machine didn’t have a timer—it wasn’t designed for taking your own X-rays—so this would be tricky. Through trial and error, I learned that there was a three-second delay between hitting the button and the machine taking a picture.

For the first effort, I didn’t make it back onto the table fast enough, and the image was a blur. The second attempt was decent, if a bit fuzzy, but the third looked good, as did the fourth, which I took just in case.

Back on the office computer, I pulled up the images after moving them into a folder titled “Maggie Homework” and deleting the originals from the X-ray machine. I pulled out Mom’s medical encyclopedia and looked up a “normal” chest X-ray.

That image was clear. Mine was cloudy. Some of the clouds were low, down by my liver and spleen. I couldn’t see even an outline of my breasts, and I wondered: If X-rays go through skin and tissue, would they show a tumor? The medical encyclopedia made me think they would, at least to some extent.

On my images, I could see a blob that looked similar to the encyclopedia’s tumor pictures, but it was hard to be sure. Even doctors often needed to refer such matters to specialists.

I pulled up the first two X-rays I’d taken, the ones that didn’t come out right. The first was a mass of clouds, no doubt stemming from my movement as I tried to position myself on the table. The other one was a little clearer but showed the right side of my body: arm, shoulder, and collarbone.

Wait, what was that?

Leaning closer to the screen, I stared at a single spot of bright white on my upper arm. I’d seen such things in veterinary X-rays, when dogs still had their collars on. A spot like that would have to be something dense, like metal or plastic. Maybe something on the table or my T-shirt got in the picture?

None of the other three images showed that arm.

The clock read 8:00 p.m. Mom wouldn’t be home for another hour at least. I went back into the exam room and looked all over the table for something that might leave that pill-like mark. Nothing. Maybe I’d knocked the object off the table when I was rushing to get back under the X-ray beam, but I found nothing on the floor, either.

I took two more X-rays of my upper arm, breathing deep and trying to be as motionless as possible. When I opened these images, it was clear that something was in my right deltoid.