====== ☢️ 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⁺)**.

===== 🔬 Physical Characteristics =====
  * **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)

===== ⚡ Biological Effects =====
  * 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**

===== 🛡️ Penetration and Shielding =====
  * Cannot penetrate skin
  * Stopped by **a sheet of paper**, skin, or a few centimeters of air
  * Dangerous **only if inhaled, ingested, or injected**

===== 🧪 Medical Relevance =====
  * 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

===== 🧠 Summary =====
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.