**3.3 Implementation and recognition of the Quality Management System – Approval of CMC files**

An international agreement for the practical use of the results obtained by the National Metrology Institutes (NMI) in assurance of the traceability chain and recognition of the measurements and certificates was concluded through the document: *"Joint statement by the CIPM and ILAC on the roles and responsibilities of national metrology institutes and national recognized accreditation bodies*". At the level of EURAMET, the implementation of the Quality

Role of the Radionuclide Metrology in Nuclear Medicine 155

of activity for gamma-ray, but also for strong beta-ray emitters, when the ionization current is produced by the bremsstrahlung radiations. Usually, the calibration factor is expressed in terms of absolute or relative efficiency, or in ionization current per activity unit, *pA MBq*-1. The calibration must be performed for several geometries of the recipients containing radioactive solution, or gelatin capsules in the case of iodine radioisotopes, as the calibration factor depends on the geometrical dimensions. For example, the IFIN-HH, RML well type ionization chamber is of the type CENTRONIC IG12/20A, filled with argon at a pressure of 2MPa (20Atm); its construction was first described in (Grigorescu et al. 2003). Recently, the old electrometric system was replaced with an electrometer Keithley E6517A. The validation of the calibration factors was done by several comparisons: (i) with the measurements performed at PTB-Braunschweig-Germany with PTB standard solutions; (ii) with the IFIN-HH, RML results obtained in international comparisons; (iii) respectively with the value of the KCRV (Sahagia et al. 2010). The calibration factors are determined for the radionuclides: 241Am, 57Co, 99mTc, 186Re, 188Re, 153Sm, 177Lu, 75Se, 169Yb, 131I, 133Ba, 51Cr, 192Ir, 134Cs, 137Cs, 54Mn, 65Zn, 60Co, 152Eu and for three geometries: (i) Solid sources; (ii) 131I gelatin capsules; (iii) Solutions of volumes: 2 mL (PTB), 3.6 mL (SIR-BIPM), 5 mL (P6 used for radiopharmaceuticals). From the above list one may notice that the calibration is assured for the majority of medical radionuclides. The determined calibration factors allow the measurement and certification of the radiopharmaceutical solutions or capsules to be used for: (a) the calibration of the radionuclide calibrators, including those belonging to the radiopharmaceutical unit from IFIN-HH, (b) to be distributed to the interested laboratories, or (c) to be used for organization of national comparisons. The chamber operation is in compliance with the QMS rules, established in agreement with the requirements of the EN ISO/IEC 17025:2005 and TRS 454 document. The

In the field of nuclear medicine, spectrometric systems are used for the measurement of the radionuclide impurity level in radiopharmaceuticals (RPMs); in order to perform an adequate check of the requirements imposed to the RPMs, the system must have a high resolution, to allow the identification of the main radionuclide and impurities, and to be sensitive enough (to have a low background) in order to detect impurities content of the

IFIN-HH, RML disposes of a system containing a high resolution HPGe detector: relative efficiency 29%; energy interval 35 *keV* – 3 *MeV*; resolution: 0.85 *keV* (122 *keV*) and 1.74 *keV*  (1.332 *MeV*) and a computer driven, software GAMMA VISION, V 6.01 spectrometric analyser. The specialized program GESPECOR (Sima & Arnold. 2002), for geometry, matrix and coincidence summation corrections is implemented. An efficient shield, consisting from: 10 cm old lead; 1 *mm* tin; 2 *mm* electrolytic cooper, assures a maximum integral background rate on the whole energy interval of 1.4 *s*-1. The system is calibrated in terms of energy and efficiency with standard sources, in various geometries from point sources up to volume recipients, prepared from standard solution absolutely standardized, by the coincidence method. Various distances, from zero, up to 44.3 *cm* from the detector surface are used in measurements, depending on the activity interval. The calibration of the system was also validated by the participation at international NPL-UK or IAEA exercises for the measurement of various volume samples, containing mixtures of radionuclides (Luca et al. 2010). The system is taken as reference for the dedicated HPGe spectrometer used in the radiopharmacy unit.

calibration uncertainty is in all cased less than 2.0%.

order of <0.1%, such as it is required for 99Mo content in 99mTc.

**4.2 High resolution spectrometric system** 

Management System (QMS) is monitored by the EURAMET, Technical Committee – Quality, TC-Q.

At the level of CIPM - MRA, the statement is practically applied by the use of the Annex C of the CIPM-MRA, Calibration and Measurement Capability files – CMCs. The approval and publication of CMCs for a NMI is the result of two types of evaluation components for the international recognition: (i) Approval of the international equivalence for primary and of the traceability for secondary standards; (ii) Implementation of the QMS and recognition by the MRO's, TC-Q.

