The IAEA/WHO TL dosimetry service for radiotherapy centres 1969-87

Area of Science:

• Medical Physics
• Radiation Dosimetry

Background:

• The International Atomic Energy Agency (IAEA) initiated a postal dosimetry service in 1966.
• The World Health Organization (WHO) joined this initiative in 1968.
• Lithium fluoride (LiF) thermoluminescent dosimeters (TLD) were utilized.

Purpose of the Study:

• To ensure traceability to primary standards of absorbed dose.
• To assess the accuracy of radiotherapy dosimetry across numerous centers globally.
• To evaluate the effectiveness of the IAEA's postal dosimetry program.

Main Methods:

• 2,000 dosimeter intercomparisons were conducted over several decades.
• Dosimeters were sent to primary standards laboratories, including the 'Bureau International des Poids et Measures'.
• Thermoluminescent dosimeters (TLD) were used for measurements from radiotherapy centers in 89 countries, focusing on 60Co machines.

Main Results:

• The IAEA's dosimetry service demonstrated high accuracy, with a mean deviation of -0.26% ± 0.18% for traceability checks.
• Radiotherapy centers showed a mean deviation of -0.25% with a 6.7% SD for single results.
• Approximately 5% of centers occasionally exceeded 30% deviation, but accuracy improved with repeated participation.

Conclusions:

• The IAEA's postal dosimetry service effectively ensures traceability and improves radiotherapy dosimetry accuracy.
• Repeated participation in the TLD service significantly enhances the accuracy of dosimetry departments.
• The program has successfully involved around 700 radiotherapy centers worldwide, contributing to radiation safety.