Investigation of the response variability of ionization chambers for the standard transfer of SIR-Spheres

• Published in: Applied radiation and isotopes 2016-03, Vol.109, p.231-235
• Main Authors: Thiam, C., Bobin, C., Lourenço, V., Chisté, V., Amiot, M.-N., Mougeot, X., Lacour, D., Rigoulay, F., Ferreux, L.
• Format: Article
• Language: English
• Subjects: 90Y-labeled resin microspheres; Bioengineering; Computer Science; Ionization chamber calibration; Life Sciences; Medical Physics; Modeling and Simulation; Monte Carlo simulation; Nuclear Experiment; Nuclear medicine; Pharmaceutical sciences; Physics; Radionuclide metrology; SIR-Spheres® standardization
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2015.11.056

The present paper addresses the calibration of well-type ionization chambers (ICs) used at LNE-LNHB as standard transfer instruments to calibrate hospitals in the case of SIR-Spheres®90Y resin microspheres (Sirtex, Australia). Developed for interventional oncology, this radiopharmaceutical is directly injected in the liver for cancer treatment via a selective internal radiation therapy. The present work was carried out in the framework of the European project “Metrology for molecular radiotherapy” (MetroMRT). As commonly performed in radionuclide metrology for radiopharmaceuticals, the objective is to ensure the metrological traceability of SIR-Spheres® to hospitals. Preceding studies were focused on primary measurements of SIR-Spheres® based on the TDCR (Triple to Double Coincidence Ratio) method, applied after the dissolution of the 90Y-labeled resin microspheres. As 90Y is a high-energy β--emitter, the IC response strongly depends on the transport of electrons in the radioactive solution and surroundings (vial, chamber liners and materials). The variability of the IC-response due to the geometry dependence is investigated by means of measurements and Monte Carlo simulations in the case of a Vinten IC. The aim of the present study was also to propose a reliable uncertainty for ICs calibrations for the standard transfer of SIR-Spheres® to hospitals. •LNE-LNHB ionization chambers (ICs) have been calibrated with SIR-Spheres®.•The variability of ICs responses due to the Sirtex vial geometry was investigated.•Systematic underestimations of ICs responses for pure β--emitters were also addressed.•A strong correlation between ICs responses and empty-vials masses was observed.•A reliable uncertainty for the standard transfer of SIR-Spheres® is proposed.