☢️ Alpha Particle

An alpha particle (α) is a type of ionizing radiation consisting of two protons and two neutrons — the same as a helium-4 nucleus (⁴He²⁺).

• Massive compared to other radiation (about 7,000–8,000 times heavier than an electron)
• Charge: +2
• Energy: High energy (typically 5–8 MeV)
• Range in tissue: Very short (~50–100 micrometers)

• Causes dense ionization along its short path
• Induces double-strand DNA breaks
• Highly effective at killing cells with a few particles per cell
• Due to short range, must be delivered directly to or near cancer cells

• Cannot penetrate skin
• Stopped by a sheet of paper, skin, or a few centimeters of air
• Dangerous only if inhaled, ingested, or injected

• Used in Targeted Alpha Therapy (TAT)
• Paired with tumor-targeting molecules for highly selective cancer treatment
• Examples of alpha-emitting isotopes: ^^213^^Bi, ^^225^^Ac, ^^211^^At

Alpha particles deliver high-energy, localized damage to cells, making them powerful tools in cancer therapy when precisely targeted. Their short path and high cytotoxicity are key advantages in modern radionuclide therapies.