The IAEA/WHO TL Dosimetry Service for Radiotherapy Centres 1969–1987

Abstract

The International Atomic Energy Agency (IAEA) started a postal dosimetry service in 1966 using lithium fluoride (LiF) thermoluminescent dosimeters (TLD). The World Health Organization (WHO) joined the programme in 1968. Dosimeters were sent on 29 occasions to primary standards laboratories or to the ‘Bureau International des Poids et Mesures' to guarantee the traceability to primary standards of absorbed dose. The mean deviation was −0.26 ± 0.18% (1% SD of the mean). One SD for a single result was about 1%. The number of intercomparisons made during the whole period is about 2000 from about 700 radiotherapy centres in 89 countries. To date only ⁶⁰Co machines have been included. The mean deviation of all the results from the centres was −0.25, and 1% SD for a single result 6.7%. About 5% of the centres had deviations larger than 30%, at least on one occasion. It is shown that the accuracy in dosimetry improves considerably for those departments participating more than once in the TL dosimetry service.