Abstract

Accurate dose measurements are vital in the medical use of radiation, as well as to assure the safety of patients, radiation workers and members of the public in a wide range of medical and industrial applications. To achieve this goal, the IAEA and the WHO have established in 1976 an international network of Secondary Standard Dosimetry Laboratories (SSDL) seconded by Primary Standard Dosimetry Laboratories (PSDL) such as NIST, PTB, NPL,and many collaborating organizations (BIPM, ICRU, IEC, OIML and IOMP). The main role of these SSDLs is to provide accurate calibration of radiation measuring instruments, used in medicine, industry and research laboratories, traceable to PSDLs through the international measurement chain. 

The SSDL of King Faisal Specialist Hospital and Research Centre, was accepted as a member of the IAEA/WHO network in 1988. Currently, its calibration and measurement capabilities include the calibration of Radiation protection measuring instruments (ionization chambers, Survey-meters and personal dosimeters) using Six ¹³⁷Cs from 0.04 Ci to 390 Ci gamma sources and nine X-ray energies from 40 kV to 250 kV, Contamination monitors and radioactivity measuring instruments using reference sources (⁹⁹Tc, ³⁶Cl and ⁹⁰Sr), Neutron detectors using Neutron beams generated by linear accelerators operated at 15 MV and shortly using 2 Ci Am-Be neutron source and Reference irradiation in terms of air kerma and ambient and personal dose equivalent using gamma and x-rays beams.

As the only service in the region, the KFSHRC SSDL provides also calibration of diagnostic radiology detectors used in general radiography (RQR), Computerized tomography (CT) and Mammography (RQM) with 40 kV to 150 kV x-ray beam qualities, Cylindrical and plane parallel ionization chambers used in radiotherapy in terms of absorbed dose to water using ⁶⁰Co and High dose rate Brachytherapy well type chambers in terms of air Kerma Strength using ¹⁹²Ir.

The calibration certificates provided by the SSDL are recognized by the NRCC and are val.id for one year. The presentation describes the international measurement chain and details the practical calibration performed at the KFSHRC’s SSDL.