# Absorbed Dose
**Entity class:** Radiation quantity
## Definition
**Absorbed dose** is the energy imparted by ionizing radiation per unit mass of matter. It is distinct from the ambient radiation field and from biological-effect quantities that apply radiation weighting or tissue response.
## Relationships
- **derived from:** [[wiki/Radiation Transport Field|Radiation Transport Field]], exposure duration, geometry, shielding, and receptor properties.
- **evaluated within:** [[wiki/Receptor Layer|Receptor Layer]].
- **supports:** [[wiki/Person-Scale Exposure Estimation|Person-Scale Exposure Estimation]] and survivability analysis.
## Sources / Provenance
- [NIST — SI Units: Radiation Dose](https://www.nist.gov/pml/owm/si-units-radiation-dose)