Personal dosimeters are used to measure the dose of ionizing radiation received by an individual. The personal dosimeter is of fundamental importance to monitor the ionizing radiation damage to the human body which is cumulative, and related to the total dose received. The personal dosimeter is used to estimate the radiation dose deposited in an individual wearing the device. Dosimeters can be worn to estimate a whole body dose or can be localized to measure exposure of specific body parts such as the fingers. There are several types of dosimeters with varying characteristics and capabilities appropriate for different applications. They differ in sensitivity, energy range, and species of radiation to which they respond. Some can be read out directly by the wearer, while others must be sent to a specially equipped facility to determine the dose.