Development of radiation metrology methods and reference systems

Abstract

The main objectives of this proposal of the research group of the Calibration Laboratory of IPEN are to develop, improve and establish methods and reference systems to calibrate instruments used in radiation, therapy, diagnostic radiology and radioprotection levels, following national and international guides and standards. At the radiation therapy level, a reference system (special extrapolation chamber) and the calibration methodology of ophthalmic and dermatological applicators will be developed. The new International Atomic Energy Agency dosimetry protocol and the calibration methodology of instruments used in brachytherapy as well in radiotherapy will be implanted at the laboratory. Intercomparisons of reference systems will be realized in the quality assurance program. At the diagnostic radiology level, standard X ray fields and a reference system for the calibration of pencil type ionization chambers used in the dosimetry of computer tomography, beams will be established. As intercomparisons among mammography systems of diagnostic clinics of several cities at São Paulo state is planned, by using special ionization chambers and phantoms. Dose calibrators used at the nuclear medicine services will be calibrated and intercompared. Tandem systems of two parallel plate ionization chambers will be applied to the quality control programs of radiotheraphy and diagnostic radiology levels. At the radioprotection level, intermediate energy X ray beams will be established at the 300 kV system to allow the irradiation of multiple samples and the calibration of portable monitoring devices. A reference system for the determination of personal dose equivalent and the beam energy will be developed. A special set-up for neutron monitor calibrations will be established, that will provide support to several other activities as environmental, area and individual monitoring too. Finally, an extensive program of obtaining spectra data of all X ray beams of the laboratory is planned for their complete characterization and for the quality assurance program of the laboratory. (AU)