title: Experimental determination of calibration settings of a commercially available radionuclide calibrator for various clinical measurement geometries and radionuclides.
abstract: Following the approach of the National Primary Laboratory of the UK (NPL) for the calibration of radionuclide calibrators, but using a commercially available instrument with no data available in the literature, the radionuclide calibrator response was investigated as a function of different measurement geometries at the "Regina Elena" National Cancer Institute (IRE) in Rome. Working with Italian National Metrology Institute for ionising radiation quantities (ENEA-INMRI), specific calibration factors with traceability to national primary standards were determined for different types of glass vials, solid capsules and plastic syringes, investigating three radionuclides with different energy spectra (Tc-99m, In-111, I-131). For each kind of syringe, calibration correction factors for different filling volumes were calculated. For Tc-99m and I-131 the difference between measured and true activity was in the range 2-7%, depending on measurement geometry. For In-111 a large percentage deviation from the true activity value was found in each geometry considered, reaching 35%. The magnitude of this difference is particularly dependent on the energies of the emitted photons.
authors.affiliation: Laboratorio di Fisica Medica e Sistemi Esperti, Regina Elena National Cancer Institute, via E. Chianesi, 53 - 00144 Rome, Italy. alessia.ceccatelli@tiscali.it
authors.forename: A
authors.initials: A
authors.lastname: Ceccatelli
authors.forename: M
authors.initials: M
authors.lastname: Benassi
authors.forename: M
authors.initials: M
authors.lastname: D'Andrea
authors.forename: P
authors.initials: P
authors.lastname: De Felice
authors.forename: A
authors.initials: A
authors.lastname: Fazio
authors.forename: S
authors.initials: S
authors.lastname: Nocentini
authors.forename: L
authors.initials: L
authors.lastname: Strigari
mesh_terms: D002138:Calibration; D005062:European Union; D017408:Guidelines as Topic; D011829:Radiation Dosage; D011868:Radioisotopes / Q000032:analysis* / Q000592:standards*; D011874:Radiometry / Q000295:instrumentation* / Q000592:standards*; D019275:Radiopharmaceuticals / Q000032:analysis* / Q000592:standards*; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals