Personal dosimetry, employed to gauge an individual’s exposure to ionizing radiation, is classified into two primary categories. Both methods contribute to upholding safety standards in environments where radiation exposure is a concern: 
- Active dosimetry: Offers real-time data on radiation exposure
- Passive dosimetry: Logs radiation exposure over a duration, subsequently interpreted at a later time
Operational dosimetry, also referred to as active dosimetry, offers real-time measurement of radiation exposure as it unfolds. It serves as a crucial tool for monitoring the dosage received by workers in nuclear power plants handling radioactive materials and in various sectors such as nuclear medicine, healthcare, industry, defense, and security. In particular, it facilitates the identification of areas where overexposure is occurring, enabling prompt intervention. This capability is provided by an electronic device known as a personal electronic dosimeter, which is capable of measuring both whole-body dose and monitoring radioactive zones. These devices are worn on the body, typically at chest level, and record dose information from various ionizing radiation sources such as X-rays, gamma rays, beta rays, and neutrons.
Active dosimeters offer immediate readings of exposure levels on-site, whereas passive or delayed-reading dosimetry devices gauge a cumulative dose over the duration of use. Unlike operational dosimeters, passive dosimeters do not provide immediate readings. An individual operational dosimeter furnishes the wearer with an immediate indication of the ambient dose equivalent rate Hp(10). It includes adjustable visual and audible alarms, along with data logging functions.
