Types of Dosimeters: Which is the Most Common and Why?

Optically Stimulated Luminescence (OSL) dosimeter is the most common type of personnel dosimeter used in the monitoring of occupational radiation exposure in today's diagnostic radiology. This type of dosimeter is lightweight, durable, and easy to carry. Radiation workers often use an electronic personal dosimeter (EPD), which is placed on the torso and displays the immediate dose and dose rate on the small monitor. Electronic personal dosimeters use a metal oxide semiconductor field-effect transistor (MOSFET or MOS transistor) that triggers an alarm when radiation levels exceed regulatory compliance.

UTHealth uses two badges for most employees: Luxel by Landauer (aluminum oxide dosimeter) and TLD (thermoluminescent dosimeter). The Luxel badge measures whole-body dose from x-radiation, gamma radiation, and beta-radiation. The TLD measures the dose in the extremities (fingers, hands, etc.) and is housed in a plastic ring for carrying in the dominant hand. The main purpose of a dosimeter is to keep an occupational dose as low as possible (ALARA).

Diodes are increasingly being used to complement cameras, especially for dosimetry measurements in small fields. The effective dose, E, can be estimated from the reading of a single dosimeter placed under the platform, Hw, using a conversion factor to account for partial body shielding. Dosimeters inform and alert people when radiation levels are too high for them to evacuate the exposure area and avoid radiation poisoning. In addition to photoelectric measuring devices, UV dosimeters based on biological or chemical reactions have been employed for various applications.

They can also be given to short-term visitors for whom monthly (or three-monthly) dosimeters make no sense and to pregnant staff to avoid exposure to an unexpected source of activity. Personal film dosimeters Open film support showing metal filters and openings that distinguish different radiation qualities. Anyone who is occupationally exposed to ionizing radiation and who is likely to receive a dose greater than 10 percent of the applicable annual allowable limit will receive a radiation monitoring device (radiation dosimeter). Fetal dosimeters have a monthly frequency and should be worn at waist height under any lead garment.

The results of prior personal monitoring can be used as an indication, noting that the external radiation dose to the fetus is unlikely to exceed 25% of the personal dosimeter measurement (ICRP, 2000). This is necessary in order to be able to properly estimate the reflected pressure and, therefore, the true pressure felt by the surface underlying the assembled dosimeter.