Dozymetria

Dozymetria, known in English as dosimetry, is the science of measuring and assessing the dose absorbed by matter, especially living tissue, from ionizing radiation. It covers the estimation, measurement, and calculation of energy deposited by radiation in materials and organisms and underpins radiation protection, medical imaging, and radiation therapy.

The field uses several quantities and units. The absorbed dose is measured in grays (Gy), where 1 Gy equals 1 joule of energy deposited per kilogram of matter. For health-related risk assessment, the equivalent dose and effective dose are expressed in sieverts (Sv). The equivalent dose accounts for the biological effectiveness of different radiation types, while the effective dose combines this with tissue-specific weighting factors to reflect varying radiosensitivity.

Dosimetry methods are categorized into external and internal approaches. External dosimetry employs instruments such as ionization chambers, semiconductor detectors, film, and dosimeters for workplace or patient exposure. Common personal dosimeters include thermoluminescent dosimeters (TLDs) and optically stimulated luminescence (OSL) devices. Internal dosimetry evaluates dose from radionuclides inside the body using biokinetic models and organ- and tissue- specific dose calculations.

Applications span medical and safety domains. In radiology and radiotherapy, dosimetry guides dose optimization and treatment verification. In nuclear medicine, it estimates patient-specific radiation doses from radiopharmaceuticals. In occupational and environmental protection, dosimetry monitors worker exposure and ambient radiation levels, supporting regulatory compliance and risk assessment.

Historically, dosimetry emerged with early radiation research and evolved through the establishment of standardized units (gray and sievert) and calibration protocols by international bodies. It remains essential for ensuring safe and effective use of ionizing radiation.