This is because the particles or rays become more spread out. The thicker the substance, the more the radiation is absorbed. Alpha, beta and gamma radiations penetrate materials in different ways.

After emitting an alpha or beta particle, the nucleus will often still be ‘excited’ and will need to lose energy. It does this by emitting a high energy electromagnetic wave called a gamma ray.

Metastatic melanoma is the most aggressive form of skin cancer. In an effort to achieve targeted therapy for metastatic melanoma, researchers recently developed a new radioactive drug that emits alpha ...