Described is a device comprising a dosimeter reader including an RFID tag reader for retrieving andor updating all or a portion of the data stored in the non-volatile memory of an RFID tag on a dosimeter sled that is part of a radiation dosimeter. 6 to 10 and a fraction insoluble in xylene at 25\xb0 C. The motor may have a longitudinal axis substantially aligned with a longitudinal axis of the roller frame. The second selection circuit receives the external output data output from the second combinational circuit and an operation result data output from the third combinational circuit, and outputs any of them to the second memory element. An example method includes capturing an image of a body region in a first frame; and when a second frame different from the first frame includes the image of the body region, incrementing a first count of persons in the second frame.