2.  To provide an overview of external and internal dosimeters used for accupationl radiation protection 

3. Types of Dosimetry Services External Dosimetry Services EPD (FBD) (TLD) (OSL) Internal Dosimetry Service Thyroid Scanning WBC

4. Film emulsion is made a AgBr crystals Film has been used to determine personal Exposure to photons betas and thermal neutrons Measured doses between (0.1mSv- 2Sv)

5. . The thermoluminescence mechanism is complex. Some TL materials are nearly tissue – equivalent.Dosimeters have excellent long term stability. Dose evaluation is rapid and dosimeters are reusable. Measured doses between (0.2mSv-

6. Evaluate possible radiation exposure quickly. Sensible to gamma only. Located in Emergency kits. Advantages: Direct read-out: Self-reading Records dose Disadvantages Sensitive to gamma only Extremely sensitive to shock

7. Activated using the Electronic Dosimeter reader Self-reading, digital display of accumulated dose and dose rate Visual and audible alarms for accumulated dose and dose rate Silicon diode detector to detect gamma radiation (sensitive to gamma only) Resistant to shock Downloads dose and dose rate data to Radiation Exposure Control database when deactivated by the ED reader

8.  Measuring radionuclide in human body directly Whole body counting  Only γ-ray or characteristic X-ray from human body using whole body counter  It is needed to remove (decontamination) the radionuclide such as take off clothing or take a shower  Stand up type whole body counter : Large two NaI(Tl) detectors)  Bed scanning type whole body counter : two HPGe detectors (25% relative efficiency)

10.  Detector : 2x2 in. NaI(Tl) scintillation detector Lead shield : 1.5 cm  Distance (Detector -Neck surface) : 12 cm Counting time : 600 s . MDA : 200 Bq for I-131

11.  Thank you for your attention