Domenico Finocchiaro1, Salvatore Berenato2, Elisa Grassi3, Valentina Bertolini4, Gastone Castellani5, Nico Lanconelli5, Annibale Versari6, Emiliano Spezi7, Mauro Iori4, Federica Fioroni4. 1. Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy; Department of Physics, University of Bologna, Italy. 2. School of Engineering, Cardiff University, Cardiff, UK. 3. Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy. Electronic address: elisa.grassi@ausl.re.it. 4. Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy. 5. Department of Physics, University of Bologna, Italy. 6. Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Nuclear Medicine Unit, Reggio Emilia, Italy. 7. School of Engineering, Cardiff University, Cardiff, UK; Department of Medical Physics, Velindre Cancer Centre, Cardiff, UK.
Abstract
BACKGROUND: At present activity quantification is one of the most critical step in dosimetry calculation, and Partial Volume Effect (PVE) one of the most important source of error. In recent years models based upon phantoms that incorporate hot spheres have been used to establish recovery models. In this context the goal of this study was to point out the most critical issues related to PVE and to establish a model closer to a biological imaging environment. METHODS: Two different phantoms, filled with a 177Lu solution, were used to obtain the PVE Recovery Coefficients (RCs): a phantom with spherical inserts and a phantom with organ-shaped inserts. Two additional phantoms with inserts of various geometrical shapes and an anthropomorphic phantom were acquired to compare the real activities to predicted values after PVE correction. RESULTS: The RCs versus volume of the inserts produced two different curves, one for the spheres and one for the organs. After PVE correction, accuracy on activity quantification averaged over all inserts of three test phantoms passed from -26% to 1.3% (from 26% to 10% for absolute values). CONCLUSION: RCs is a simple method for PVE correction easily applicable in clinical routine. The use of two different models for organs and lesions has permitted to closely mimic the situation in a living subject. A marked improvement in the quantification of activity was observed when PVE correction was adopted, even if further investigations should be performed for more accurate models of PVE corrections.
BACKGROUND: At present activity quantification is one of the most critical step in dosimetry calculation, and Partial Volume Effect (PVE) one of the most important source of error. In recent years models based upon phantoms that incorporate hot spheres have been used to establish recovery models. In this context the goal of this study was to point out the most critical issues related to PVE and to establish a model closer to a biological imaging environment. METHODS: Two different phantoms, filled with a 177Lu solution, were used to obtain the PVE Recovery Coefficients (RCs): a phantom with spherical inserts and a phantom with organ-shaped inserts. Two additional phantoms with inserts of various geometrical shapes and an anthropomorphic phantom were acquired to compare the real activities to predicted values after PVE correction. RESULTS: The RCs versus volume of the inserts produced two different curves, one for the spheres and one for the organs. After PVE correction, accuracy on activity quantification averaged over all inserts of three test phantoms passed from -26% to 1.3% (from 26% to 10% for absolute values). CONCLUSION: RCs is a simple method for PVE correction easily applicable in clinical routine. The use of two different models for organs and lesions has permitted to closely mimic the situation in a living subject. A marked improvement in the quantification of activity was observed when PVE correction was adopted, even if further investigations should be performed for more accurate models of PVE corrections.
Authors: Katarina Sjögreen Gleisner; Nicolas Chouin; Pablo Minguez Gabina; Francesco Cicone; Silvano Gnesin; Caroline Stokke; Mark Konijnenberg; Marta Cremonesi; Frederik A Verburg; Peter Bernhardt; Uta Eberlein; Jonathan Gear Journal: Eur J Nucl Med Mol Imaging Date: 2022-03-14 Impact factor: 10.057
Authors: Daphne M V Huizing; Michiel Sinaasappel; Marien C Dekker; Marcel P M Stokkel; Berlinda J de Wit-van der Veen Journal: J Appl Clin Med Phys Date: 2020-08-13 Impact factor: 2.102