Résumé
Since 1969 the International Atomic Energy Agency and the World Health Organization (along with the Pan American Health Organization, working with countries in Latin America and the Caribbean) have operated postal dosimetry audits based on thermoluminescent dosimetry (TLD) for radiotherapy centers. The purpose of these audits is to provide an independent dosimetry check of radiation beams used to treat cancer patients. The success of radiotherapy treatment depends on accurate dosimetry. Over the period of 1969 through 2003 the calibration of approximately 5 200 photon beams in over 1 300 radiotherapy centers in 115 countries worldwide was checked. Of these audits, 36 percent were performed in Latin America and the Caribbean, with results improving greatly over the years. Unfortunately, in several instances large TLD deviations have confirmed clinical observations of inadequate dosimetry practices in hospitals in various parts of the world or even accidents in radiotherapy, such as the one that occurred in Costa Rica in 1996. Hospitals or centers that operate radiotherapy services without qualified medical physicists or without dosimetry equipment have poorer results than do hospitals or centers that are properly staffed and equipped. When centers have poor TLD results, a follow-up program can help them improve their dosimetry status. However, to achieve audit results that are comparable to those for centers in industrialized countries, additional strengthening of the radiotherapy infrastructure in Latin America and the Caribbean is needed.