Dosimetry experts in laboratories and hospitals in 50 countries can now better control the accuracy of radiation measurements, thanks to a recent workshop on Uncertainty Estimations for Radiation Measurements held at the IAEA.
Dosimetry is the science of measuring radiation dose, which is crucial for diagnosing several diseases and treating cancer: too little radiation can be ineffective, while too much can be harmful. Accurate treatment delivery and radiation protection of staff and patients is achieved through the use of calibrated dosimeters. Estimating uncertainty in dosimetry helps get the radiation dose right.
“Now I can use my knowledge of uncertainties and apply it when working with patients,” said Shada Wadi-Ramahi, Chief Medical Physicist at the King Faisal Specialist Hospital and Research Center in Riyadh, Saudi Arabia, who participated at the workshop in Vienna last month. “In fact, we have just commissioned a new treatment technique in the clinic that combines a simultaneous treatment of High Dose Rate brachytherapy with radiosurgery. We calculated the uncertainty of our measurements from this new clinical technique using the method I learned.”
This workshop, through lectures, discussions and practical sessions, offered theoretical and practical training on methods used for estimation of various uncertainty components in radiation measurement. Eighty physicists from calibration laboratories and hospitals learnt how to prepare uncertainty estimations for measurements and calibrations.
The quantities used for radiation dose measurements are established in Primary Standards Dosimetry Laboratories (PSDLs). These laboratories provide calibrations for reference dosimeters of Secondary Standards Dosimetry Laboratories (SSDLs). SSDLs in turn calibrate dosimeters of end users, such as hospital staff. This entire process is called the traceability chain. This workshop covered uncertainties in the whole chain from PSDL to end user measurement.
“Dosimeters used to measure radiation in practice must be calibrated against a national standard to ensure that measurement results are consistent with the International System of Units,” said Paula Toroi, medical radiation physicist and SSDL Officer at the IAEA. “The IAEA provides calibrations and bilateral comparisons for SSDLs. Uncertainty estimation is an important part of these activities which are used to ensure that the determined dose levels in different countries are internationally comparable.”
The IAEA maintains the Dosimetry Laboratory in Seibersdorf, Austria, which is the central laboratory of the SSDL network created in 1976 to ensure coherence in dosimetry measurement standards internationally. The network has 85 member laboratories from 70 countries around the world.
