External exposure is typically caused by radiation from sources located outside the body. Which radiation type is a common external source?

External exposure is typically caused by radiation from sources located outside the body. Which radiation type is a common external source?

• A. Neutron radiation
• B. Alpha particles
• C. Gamma & X-ray
• D. Beta particles

Answer: (C)

External exposure refers to radiation reaching you from sources outside the body. The radiation type most commonly encountered in this way is gamma rays and X-rays. These are high-energy photons with strong penetrating power, so they can travel through air, clothing, and body tissue and still deliver dose to someone standing nearby or in line with the source. That’s why medical imaging devices, industrial radiography, and natural background radiation are major sources of external exposure. In contrast, alpha particles have very short reach and are stopped by a small amount of material (even the outer layer of the skin or a sheet of paper), so they’re mainly a concern when the source is inside the body. Beta particles penetrate more than alpha but are still relatively easy to shield, so external exposure is less significant in typical environments. Neutron radiation is also highly penetrating and dangerous, but it’s less common as an everyday external exposure source and requires specialized shielding; gamma and X-rays remain the most common external hazards due to their widespread production and penetrating ability.

External exposure refers to radiation reaching you from sources outside the body. The radiation type most commonly encountered in this way is gamma rays and X-rays. These are high-energy photons with strong penetrating power, so they can travel through air, clothing, and body tissue and still deliver dose to someone standing nearby or in line with the source. That’s why medical imaging devices, industrial radiography, and natural background radiation are major sources of external exposure.

In contrast, alpha particles have very short reach and are stopped by a small amount of material (even the outer layer of the skin or a sheet of paper), so they’re mainly a concern when the source is inside the body. Beta particles penetrate more than alpha but are still relatively easy to shield, so external exposure is less significant in typical environments. Neutron radiation is also highly penetrating and dangerous, but it’s less common as an everyday external exposure source and requires specialized shielding; gamma and X-rays remain the most common external hazards due to their widespread production and penetrating ability.