A cell hit by a proton beam is like a city after a pinpoint bombing: some blocks are leveled, others just have broken windows. Whether the city survives depends on which buildings are hit and how the strikes are distributed. In the past, doctors gauged the damage by the overall intensity of the bombardment, but that's not enough: two identical doses can leave very different destruction.

The new model works like a meticulous damage assessor, looking not only at the force of the explosions but also at their locations. It analyzes how particle energy is distributed across different scales, from tiny clusters a few nanometers wide (where DNA strands break) to micrometer tracks (the trails left by particles in tissue). The model decides on its own which details to focus on and shows them to humans, like a translator who underlines key words in a document.

The most interesting part: no single scale turned out to be dominant. To make accurate predictions, you need all of them — from nanometer damage to micrometer tracks. But the smaller the scale, the greater its contribution. The usual LET metric (linear energy transfer — how much energy a particle deposits along each millimeter of its path) turned out to be secondary. It's like assessing bomb damage by which specific houses are hit rather than the total bomb yield.

This approach could change how radiation therapy is planned: instead of rough averages, doctors would get a map of a tumor's vulnerable spots. The model also helps explain why some cells die from radiation while others survive, and how to protect healthy tissue during treatment.