Seeing Radiation: How VR Makes the Inverse Square Law and Shielding Concepts Click for Real-World NDT

Seeing Radiation: How VR Makes the Inverse Square Law and Shielding Concepts Click for Real-World NDT

If you’ve ever tried explaining radiation to someone just getting started in radiography, you probably know how tough it can be. Diagrams, lectures, and even videos can only take you so far. Radiation isn’t something you can see or feel until it’s too late—and that’s exactly why it needs to be understood before exposure, not after. That was the mindset behind building a new VR training simulation that brings radiation, shielding, and the inverse square law to life.

This VR experience was designed with one goal in mind: to help learners see how every little decision, like where you stand, how far you are from the source, whether you’ve placed shielding properly, can dramatically affect dose rates. It’s not just theory. It’s a hands-on way to learn radiation safety and exposure control by actually moving around and interacting with the scene in real time.

The Core Experience: A Radiation Sandbox

The heart of the simulation is a glowing sphere in the middle of the room that represents a gamma source. It behaves like a real one, based on inverse square law logic. Using the Meta Quest 3 or a Piko headset and your controllers, you can reach out, grab the source, and move it wherever you want in the room.

Your right hand holds the current dose rate and your distance from the source. Everything’s dynamic. Move closer? The dose rate spikes. Step away? It drops like it should. It’s simple but powerful when you see it happen in real time with just your distance.

Real-Time Shielding: Lead, Steel, Concrete

To help teach the effect of shielding, there are three movable plates in the scene made of lead, steel, and concrete. These are physically accurate representations of half-value layers (HVL). When you place a plate between the source and your body, it cuts the dose in half and reflects on your right hand, that's giving constant feedback. Stack two? Now you’re at a quarter. Add a third? Eighth. It’s all happening live, and you can immediately see the result on your dose rate and on the room’s heatmap.

There’s even a collimator object that acts like a 4-HVL shield. It doesn’t just lower the dose; it directs it. So, learners can see how proper use of directional shielding keeps radiation focused where it needs to go—and keeps everyone else safe.

A Heatmap That Paints the Risk

The entire room is wrapped in a reactive heatmap: floor, ceiling, all four walls. Areas near the source glow red, medium zones turn blue, and safer spots show green. But green doesn’t mean safe—it means less dangerous. That nuance becomes clear when learners realise how distance and shielding influence the whole space.

The heatmap updates in real time. As the source moves or shielding is added, the “radiation shadows” shift. These aren’t just visuals—they reflect actual exposure differences. You can use shielding to create safer pockets behind walls or build protected zones for people or equipment.

Why It Matters

Radiation is unforgiving. The best techs in the field are the ones who see the shot before it happens. They don’t guess; they calculate. They think ahead, plan barricades, set up shielding, and keep the public safe. This VR experience helps build that mindset early.

It’s especially helpful for visual learners. Some folks don’t grasp radiation from reading charts or hearing a lecture—but the moment they see the dose rate drop by half after adding shielding, or spike when they lean a little closer, it clicks.

What’s Next: Turning Training Into a Game

Right now, the VR sim is an open sandbox: move the source, adjust shielding, and experiment. But I'm looking at turning it into a structured training experience with challenges and progression.

Imagine starting with a simple “stay under 200 mR/hr” task and working your way up through increasingly complex rooms. Maybe you have to protect a group of virtual civilians behind a wall. Or maybe you only get one lead plate, and you’ve got to make it count. And to unlock that plate? You’ve got to solve an inverse square law problem first.

The idea is to create scenarios that mimic the real creativity needed in field radiography. Sometimes, you have to work with limited tools in complex environments. This VR sim can be a safe space to learn those critical problem-solving skills.



Final Thoughts

If we want better-trained NDT professionals, we have to meet them where they are—and sometimes that’s in a headset. Radiation isn’t something to learn through trial and error. It should be understood clearly, before a source is ever energized.

This VR tool makes that possible.

If you're an NDT instructor, radiation safety trainer, or radiographer looking to bring real clarity to your classroom or team, experiences like this are the future. They don’t replace field work, but they sure make the first time in the field a whole lot safer.

Author note: This article is based on real experience building and testing the VR training using the Meta Quest 3 headset. The way radiation and shielding work in the VR is based on real physics and safety rules, like half-value layers. Some parts may still be improved, but the goal is to help people see radiation in a new, clearer way.

Watch Video

Author: Daniel Hoke