Dosimetry and Medical Radiation Physics (DMRP)

Programme Activities of the IAEA's Sub-Programme on Quality Assurance and Metrology in Radiation Medicine

The objective of the IAEA Subprogramme in Dosimetry and Medical Radiation Physics is to assure controlled radiation dosages in radiation medicine in Member States. This is achieved by operating the IAEA/WHO Network of Secondary Standards Dosimetry Laboratories, by providing mailed dosimetry auditing services for medical centres, by developing and disseminating dosimetry techniques among the Member States (e.g., dosimetry codes of practice), by supervising quality assurance programmes in radiotherapy dosimetry, and by organizing education programmes in Medical Radiation Physics.

The experimental work of the subprogramme is carried out in the IAEA's Dosimetry Laboratory, located at the IAEA's Seibersdorf Laboratories.

The subprogramme consists of four projects:

Quality Audits in Radiotherapy Dosimetry

The successful application of nuclear technology in the health care sector, particularly in the case of radiotherapy treatment of cancer patients, depends strongly on assuring accuracy in dose measurements and dose delivery. A key element in quality assurance is an independent verification or audit of radiation dose delivery at the end-user institution, i.e. a radiotherapy hospital. In response to requests by Member States, the Agency provides dose quality audits to over 1500 end-user institutions in regions that have no other means to participate in a dose verification process. Thermoluminescent dosimetry (TLD) is used as the basis of the Agency’s dose audits in radiotherapy since it offers adequate precision and reliability of operation to serve the auditing purpose well. An integral part of the auditing process is resolving discrepancies that are discovered. The Agency’s audit services are co-ordinated with national audit networks operating in some Member States and with NGOs that provide dose audits in industrialized countries. Organizations such as the WHO and PAHO are active partners with the Agency in providing these services.

Radiation Metrology Supporting the Network of SSDLs

In order to utilize nuclear technology for the safe and effective diagnosis and treatment of disease, Member States must be able to measure ionizing radiation including the radiation protection quantities of interest for occupationally exposed persons and for protection of the general public. Although several Member States have the capability to provide calibrations of radiation measuring equipment, those who are not members of the Meter Convention have no means, other than the Agency, to get traceability and/or verify the quality of their calibration and measurement capabilities (CMCs). The Agency operates the central dosimetry calibration laboratory at Seibersdorf to provide Member States with radiation measurement calibration services through a network of Secondary Standards Dosimetry Laboratories (the SSDL Network). To be able to function as a calibration laboratory, it is necessary for the Agency to maintain its own calibrated measurement standards, to compare them at the level of the Consultative Committee for Radiation Measurement (CCRI) and to operate a quality assurance system. The Agency is supported in these activities by international collaborators, for example, the WHO, the Bureau International des Poids et Mesures (BIPM), the International Commission on Radiation Units and Measurements (ICRU) and several Primary Standards Dosimetry Laboratories (PSDLs). The ultimate beneficiaries are patients undergoing diagnostic tests or radiation therapy, and radiation workers utilizing nuclear technology.

Dosimetry Codes of Practice and Guidelines for Radiation Measurements

One of the subprogramme’s core responsibilities is to operate the central laboratory in the SSDL Network. In order to maintain the calibration service at the appropriate level and to enable dosimetry standards to be disseminated properly by SSDLs, it is essential that research and development in radiation dosimetry techniques be performed and encouraged. This project embodies these research and development activities. Through collaboration with international organizations such as ICRU and IOMP (International Organization of Medical Physicists), the Agency is able to influence their work in the area of dosimetry and to benefit from early access to on-going projects. The beneficiaries of this project are the SSDLs and the communities that they serve.

Medical Physics Developments for Quality Assurance and Clinical Applications of Ionizing Radiation

Quality assurance exercises and dosimetry auditing programmes are used to verify that radiation dosimetry standards are properly disseminated to the end users. Development of new dosimetry auditing procedures takes place within this project. However, even though knowledge of dosimetry is fundamental to the effective use of nuclear applications in human health, the need for collaboration between physicians and medical physicists broadens the mandate of the subprogramme beyond dosimetry. In radiotherapy, patients expect their treatments to be effective and the morbidity associated with the procedures to be acceptably low, thereby intrinsically coupling the outcome and the dose. In the case of diagnostic procedures, the information content of an image (image quality) must be optimized taking into account the dose absorbed by the patient, illustrating again the coupling of outcome and dose. This linkage of medical outcome and dose expands the mandate of medical physics to include other scientific and technical aspects of nuclear technology that affect the health of patients globally. The beneficiaries of this project are patients undergoing diagnosis and treatment.