Seeing Through You: How X-rays Capture What’s Inside

-Karthik Gurumurthy

So you’re wondering how X-rays manage to show your bones but not all the squishy stuff around them? It’s actually pretty clever!

Think about what happens when you go for skiing and break your leg (ouch!). When they take an X-ray, your bones show up super bright against a dark background – here’s why that happens:

X-rays are basically super-powered particles that blast right through most of your body. Your flesh is mostly water, so those energetic X-ray particles zip through it like it’s barely there, leaving only a faint shadow on the film.

But your bones? They’re dense as heck and packed with heavy elements like calcium that the X-rays can’t easily penetrate. The bones actually absorb the X-rays instead of letting them pass through. That’s why a crack in your tibia shows up dark on the film – it’s literally showing where the bone isn’t stopping the X-rays anymore.

The way the image gets captured is pretty cool too. The X-ray machine fires electrons at a plate covered with special silver halide crystals that react to light. Your injured leg gets positioned between the X-ray source and this plate. When an electron makes it through your body and hits the plate, it turns a crystal black. The areas where no electrons hit (because your bones blocked them) stay transparent or white when the plate is developed.

So basically, X-rays work because different parts of your body are different at playing “blocker” to these high-energy particles. Your bones are champion blockers, while your flesh is basically letting everyone through the door!