Kiiritusannuse

Kiiritusannuse is Estonian for radiation dose and refers to the amount of energy from ionizing radiation deposited in a unit of mass. It is used to quantify exposure and assess potential health risk in medical, industrial, environmental, and research settings. The concept includes several related measures that describe how radiation interacts with matter and organisms.

The primary quantity is the absorbed dose, measured in gray (Gy). One gray equals one joule of energy deposited per kilogram of matter. For risk assessment and protection, two additional dose concepts are used: the equivalent dose and the effective dose, both expressed in sieverts (Sv). Equivalent dose multiplies the absorbed dose by a radiation weighting factor that reflects radiation type. Effective dose adds tissue weighting factors to account for varying sensitivity across body tissues, providing a single value that correlates more closely with overall risk.

Measurement and dosimetry employ a range of devices. Personal dosimeters such as thermoluminescent dosimeters (TLDs) and optically stimulated luminescence (OSL) dosimeters monitor occupational exposure. Ionization chambers measure dose in laboratory or clinical settings, and in vivo dosimetry is used during radiotherapy to estimate dose delivered to patients.

Applications and interpretation: kiiritusannuse guides planning and safety in radiotherapy, diagnostic imaging, and radiopharmaceutical therapies. It also underpins environmental monitoring and occupational protection programs, helping to compare procedures, optimize protection, and comply with regulations.

Safety and regulation: Radiation protection relies on justification, optimization (ALARA), and dose limits for workers and the public. International and national guidelines, such as those from ICRP, inform practice, governance, and dose reporting to minimize unnecessary exposure while enabling beneficial uses of radiation.