All radiation physicists, individual allowed working with ionizing radiation e.g. X, Gama, Alpha, Beta and Neutron and licensed radioactive Centers, maintain by law to collect accurate records of radiation exposure by Film Badge or Thermoluminescent dosimeter (TLD).
A Thermoluminescent dosimeter (TLD) is different than film badge. A TLD measures ionizing radiationexposure by measuring the intensity of visible light emitted by crystals Lif:Mg,Ti (TLD-100, TLD 600, TLD-700) inside the detector when the crystal is heated. All processing is fully-automated, reducing the chance of human error and misidentification. Proprietary algorithms provide for exceptionally accurate dosimetry. Thermoluminescent dosimetry (TLD) is a method for dosimetry in medical applications due to the small size of the detectors and their low effective atomic number (Z eff ) similar to that of soft biological tissues Z eff = 7.4. Therefore, there is no energy correction factor, as result we witness rise of accuracy. 
Other characteristics of TLDs, which make appropriate for dosimetry, are the following:
1) Good tissue equivalence
2) Low fading
3) High sensitivity
4) Good precision and accuracy
5) Good stability under standard environmental conditions (temperature and humidity)