28 X-Ray Safety K. Personnel Monitoring A number of devices and methods exist for assessing an individual’s exposure to ionizing radiation. Whether one or more of these personnel monitoring methods is employed for a given situation will depend upon a number of factors, including amount of time spent working with the devices. Personnel Dosimeters State and federal laws require that any individual likely to receive a dose in excess of 10% of the limits be monitored. There are numerous types of materials or devices that are used to assess an individual’s cumulative external radiation dose. These are collectively termed “dosimeters.” Dosimeters are issued to monitor both whole-body and extremity exposures. Periodically, dosimeters are exchanged by Environmental Health and Safety (EH&S) and forwarded to the vendor’s laboratory for analysis. Whole Body Whole-body dosimeters are issued for work with or near sources emitting penetrating radiation (energetic beta particles, x-rays, gamma rays or neutrons). Whole body dosimeters monitor external radiation exposures. Extremity/Ring Ring dosimeters are worn by individuals who’s hands may be exposed to the x-ray beam. Examples are aligning the x-ray beam or using fluoroscopy. Ring dosimeters monitor extremity exposures or exposures to limbs beyond the elbow and knee. A whole body badge will be worn on the front of the torso between the shoulders and the waist near the portion of the body that is most likely to receive the maximum radiation exposure and under any protective clothing. If a protective apron is worn, the dosimeter should be near the midline of the body under the apron. An additional dosimeter will be worn for the purpose it was issued such as eye, upper extremity or fetal monitoring. A dosimeter issued to monitor the eyes will be worn on the collar. A dosimeter issued to monitor an upper extremity exposure will be worn on the sleeve. Further instruction on proper dosimeter use and storage can be found on the EH&S website.