See the links below.

"The two types of badges that may be issued to workers are the *chest dosimeter* or *ring dosimeter*. The badges are tailored to a particular isotope of radioactivity that they are working with. Workers are given an annual exposure report detailing their annual exposure (if any) to radioactivity. "
http://tinyurl.com/24m9o

For more information on chest (whole body) dosimeter, please visit the following site:

"The whole body dosimeter should be worn on the upper chest area so that you are able to read the identification sticker. If lead aprons are worn, the badge should be clipped to the shirt collar or to the outside of the top of the lead apron to measure exposure to the eyes. Supplemental badges, if issued, may be worn under the lead apron but readings obtained from such badges do not accurately measure exposure to the eyes or thyroid.

If you should lose your dosimeter (radiation badge), another badge can be assigned."
http://www.hc-sc.gc.ca/hecs-sesc/nds/publications/booklet/no...

I also suggest you visit the following site for more information on ring (extremity) dosimeter.

"Extremity ring dosimeters shall be worn on the hand likely to receive the highest radiation dose, and positioned such that the TLD chip is exposed to the radiation source. To meet these conditions, extremity rings are typically worn on the dominate hand with the TLD facing the palm. "
http://www.oehs.wayne.edu/oeh&s/Personnel Monitoring.htm

Hope to have been of help!