which type of ionising radiation is the most dangerous if swallowed?

Alpha radiation is the most dangerous type of ionising radiation if a radioactive source is swallowed and ends up inside the body.

Quick Scoop

When radiation is inside the body (for example, swallowed or inhaled), the key issue is how strongly it ionises nearby cells and how far it travels. Alpha particles have very high ionising power but only travel a tiny distance in tissue, so all their energy is dumped into a very small volume of cells, causing intense local damage and a higher cancer risk. Beta and gamma are still harmful internally, but they are less ionising and more likely to pass through cells rather than stop and deposit all their energy in one spot, so they are generally less dangerous per unit of activity when ingested.

If this question is related to personal exposure or a real incident, urgent assessment by medical and radiation safety professionals is essential, because risk depends on the specific radionuclide, amount swallowed, and how long it stays in the body.