The IAEA/WHO TLD postal programme for radiotherapy hospitals

Background and purpose: Since 1969 the International Atomic Energy Agency ( IAEA), together with the World Health Organization (WHO). has performed pos tal TLD audits to verify the calibration of radiotherapy beams in developin g countries. Materials and methods: A number of changes have recently been implemented t o improve the efficiency of the IAEA/WHO TLD programme. The IAEA has increa sed the number of participants and reduced significantly the total turn-aro und time to provide results to the hospitals within the shortest possible t ime following the TLD irradiations. The IAEA has established a regular foll ow-up programme for hospitals with results outside acceptance limits of +/- 5%. Results: The IAEA has. over 30 years, verified the calibration of more than 3300 clinical photon beams at approximately 1000 radiotherapy hospitals. O nly 65% of those hospitals who receive TLDs for the first time have results within the acceptance limits, while more than 80% of the users that have b enefited from a previous TLD audit are successful. The experience of the IA EA in TLD audits has been transferred to the national level. The IAEA offer s a standardized TLD methodology, provides guidelines and gives technical b ack-up to the national TLD networks. Conclusion: The unsatisfactory status of the dosimetry for radiotherapy, as noted in the past, is gradually improving; however, the dosimetry practice s in many hospitals in developing countries need to be revised in order to reach adequate conformity to hospitals that perform modern radiotherapy in Europe, USA and Australia. (C) 2000 Elsevier Science Ireland Ltd. All right s reserved.