TLD international intercomparision of secondary dosimetry standard for radiotherapy level in 2005

Objective: To check the consistency of SSDL radiotherapy dose level standard and international standard, SSDL in our institute participated in TLD international intercomparision organized by IAEA/WHO. Methods: SSDL irradiated the TLDs posted by IAEA and calculated the dose to be delivered to the TLDs, then returned the TLDs and results to IAEA dosimetry laboratory. IAEA gave the diviation of intercomparision. Results: The deviation for 60Co is -1.4%, and the deviation for high energy X rays is - 1.8 %. Conclusions: The requirement of deviation between IAEA and SSDL should be no more than ±3.5%. Therefore the results of this intercomparison are considered satisfactory. (authors)