Document Type : Research Article
Authors
1 Radiation Application Research School, Nuclear Science and Technology Research Institute, P.O. Box 31485-498, Karaj, Iran
2 Atomic Energy Organization of Iran, Secondary Standard Dosimetry Laboratory (SSDL)
3 Department of Physics, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
Abstract
The International Atomic Energy Agency (IAEA), sends dosimeters annually to Secondary Standard Dosimetry Laboratories (SSDL) around the world, to calibrate their radiation field. Therefore, they mainly send thermo-luminescent dosimeters as transfer dosimeters to the SSDL laboratories, to be irradiated under the requested conditions and sent back to the IAEA laboratories for reading. In this way, by reading the dosimeters, the uncertainty of the dosimetry carried out by SSDL and, consequently, the calibration of its radiation fields is determined. In this research, with the aim of feasibility of comparative dosimetry program by SSDL laboratory for radiation therapy centers, this program was carried out for a number of centers. In this way, TLD-700 thermoluminescence dosimeters were irradiated in the same conditions in the SSDL laboratory and also in the selected centers to a certain amount. After reading and applying the correction coefficients and calibration factors, the obtained results were compared with the measurement results using ion chamber reference dosimeter. In this work the uncertainty of the dosimetry using TLD tablet was less than 1.12% in comparison to the reference ionization chamber dosimeter and was within the acceptable range of less than 3%.
Highlights
- Feasibility of conducting a comparative dosimetry audit program for medical centers, by SSDL, has been investigated.
- Using TLD-700 chips, instead of its powder, has Sufficient precision for therapeutic photon beam dosimetry.
- This work can be conducted annually, in order to control the amount of dose delivered to the patients.
Keywords
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