J C Sanders1, T Kuwert, J Hornegger, P Ritt. 1. Pattern Recognition Lab, Department of Computer Science, University of Erlangen-Nuremberg, Martensstr. 3, 91058, Erlangen, Germany, James.Sanders@uk-erlangen.de.
Abstract
PURPOSE: The purpose of this study is to extend an established SPECT/CT quantitation protocol to (177)Lu and validate it in vivo using urine samples, thus providing a basis for 3D dosimetry of (177)Lu radiotherapy and improvement over current planar methods which improperly account for anatomical variations, attenuation, and overlapping organs. PROCEDURES: In our quantitation protocol, counts in images reconstructed using an ordered subset-expectation maximization algorithm are converted to kilobecquerels per milliliter using a calibration factor derived from a phantom experiment. While varying reconstruction parameters, we tracked the ratio of image to true activity concentration (recovery coefficient, RC) in hot spheres and a noise measure in a homogeneous region. The optimal parameter set was selected as the point where recovery in the largest three spheres (16, 8, and 4 ml) stagnated, while the noise continued to increase. Urine samples were collected following 12 SPECT/CT acquisitions of patients undergoing [(177)Lu]DOTATATE therapy, and activity concentrations were measured in a well counter. Data was reconstructed using parameters chosen in the phantom experiment, and estimated activity concentration from the images was compared to the urine values to derive RCs. RESULTS: In phantom data, our chosen parameter set yielded RCs in 16, 8, and 4 ml spheres of 80.0, 74.1, and 64.5 %, respectively. For patients, the mean bladder RC was 96.1 ± 13.2% (range, 80.6-122.4 %), with a 95 % confidence interval between 88.6 and 103.6 %. The mean error of SPECT/CT concentrations was 10.1 ± 8.3% (range, -19.4-22.4 %). CONCLUSIONS: Our results show that quantitative (177)Lu SPECT/CT in vivo is feasible but could benefit from improved reconstruction methods. Quantifying bladder activity is analogous to determining the amount of activity in the kidneys, an important task in dosimetry, and our results provide a useful benchmark for future efforts.
PURPOSE: The purpose of this study is to extend an established SPECT/CT quantitation protocol to (177)Lu and validate it in vivo using urine samples, thus providing a basis for 3D dosimetry of (177)Lu radiotherapy and improvement over current planar methods which improperly account for anatomical variations, attenuation, and overlapping organs. PROCEDURES: In our quantitation protocol, counts in images reconstructed using an ordered subset-expectation maximization algorithm are converted to kilobecquerels per milliliter using a calibration factor derived from a phantom experiment. While varying reconstruction parameters, we tracked the ratio of image to true activity concentration (recovery coefficient, RC) in hot spheres and a noise measure in a homogeneous region. The optimal parameter set was selected as the point where recovery in the largest three spheres (16, 8, and 4 ml) stagnated, while the noise continued to increase. Urine samples were collected following 12 SPECT/CT acquisitions of patients undergoing [(177)Lu]DOTATATE therapy, and activity concentrations were measured in a well counter. Data was reconstructed using parameters chosen in the phantom experiment, and estimated activity concentration from the images was compared to the urine values to derive RCs. RESULTS: In phantom data, our chosen parameter set yielded RCs in 16, 8, and 4 ml spheres of 80.0, 74.1, and 64.5 %, respectively. For patients, the mean bladder RC was 96.1 ± 13.2% (range, 80.6-122.4 %), with a 95 % confidence interval between 88.6 and 103.6 %. The mean error of SPECT/CT concentrations was 10.1 ± 8.3% (range, -19.4-22.4 %). CONCLUSIONS: Our results show that quantitative (177)Lu SPECT/CT in vivo is feasible but could benefit from improved reconstruction methods. Quantifying bladder activity is analogous to determining the amount of activity in the kidneys, an important task in dosimetry, and our results provide a useful benchmark for future efforts.
Authors: M De Jong; W H Bakker; W A Breeman; B F Bernard; L J Hofland; T J Visser; A Srinivasan; M Schmidt; M Béhé; H R Mäcke; E P Krenning Journal: Int J Cancer Date: 1998-01-30 Impact factor: 7.396
Authors: D J Kwekkeboom; W H Bakker; P P Kooij; M W Konijnenberg; A Srinivasan; J L Erion; M A Schmidt; J L Bugaj; M de Jong; E P Krenning Journal: Eur J Nucl Med Date: 2001-09
Authors: Marion De Jong; Roelf Valkema; Francois Jamar; Larry K Kvols; Dik J Kwekkeboom; Wout A P Breeman; Willem H Bakker; Chuck Smith; Stanislas Pauwels; Eric P Krenning Journal: Semin Nucl Med Date: 2002-04 Impact factor: 4.446
Authors: Jean-Mathieu Beauregard; Michael S Hofman; Jucilene M Pereira; Peter Eu; Rodney J Hicks Journal: Cancer Imaging Date: 2011-06-15 Impact factor: 3.909
Authors: Andreas Delker; Wolfgang Peter Fendler; Clemens Kratochwil; Anika Brunegraf; Astrid Gosewisch; Franz Josef Gildehaus; Stefan Tritschler; Christian Georg Stief; Klaus Kopka; Uwe Haberkorn; Peter Bartenstein; Guido Böning Journal: Eur J Nucl Med Mol Imaging Date: 2015-08-29 Impact factor: 9.236
Authors: Brian E Zimmerman; Darko Grošev; Irène Buvat; Marco A Coca Pérez; Eric C Frey; Alan Green; Anchali Krisanachinda; Michael Lassmann; Michael Ljungberg; Lorena Pozzo; Kamila Afroj Quadir; Mariella A Terán Gretter; Johann Van Staden; Gian Luca Poli Journal: Z Med Phys Date: 2016-04-19 Impact factor: 4.820
Authors: Andreas Delker; Harun Ilhan; Christian Zach; Julia Brosch; Franz Josef Gildehaus; Sebastian Lehner; Peter Bartenstein; Guido Böning Journal: Mol Imaging Biol Date: 2015-10 Impact factor: 3.488
Authors: Emilio Mezzenga; Vincenzo D'Errico; Marco D'Arienzo; Lidia Strigari; Koutla Panagiota; Federica Matteucci; Stefano Severi; Giovanni Paganelli; Andrew Fenwick; David Bianchini; Francesco Marcocci; Anna Sarnelli Journal: PLoS One Date: 2017-08-14 Impact factor: 3.240
Authors: Carlos F Uribe; Pedro L Esquinas; Jesse Tanguay; Marjorie Gonzalez; Emilie Gaudin; Jean-Mathieu Beauregard; Anna Celler Journal: EJNMMI Phys Date: 2017-01-07
Authors: Gwennaëlle Marin; Bruno Vanderlinden; Ioannis Karfis; Thomas Guiot; Zena Wimana; Patrick Flamen; Stefaan Vandenberghe Journal: EJNMMI Phys Date: 2017-01-26
Authors: Wei Zhao; Pedro L Esquinas; Xinchi Hou; Carlos F Uribe; Marjorie Gonzalez; Jean-Mathieu Beauregard; Yuni K Dewaraja; Anna Celler Journal: EJNMMI Phys Date: 2018-05-02