Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera
Abstract Background Dosimetry after radiopharmaceutical therapy with 177Lu (177Lu-RPT) relies on quantitative SPECT/CT imaging, for which suitable reconstruction protocols are required. In this study, we characterized for the first time the quantitative performance of a ring-shaped CZT-based camera...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-10-01
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| Series: | EJNMMI Physics |
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| Online Access: | https://doi.org/10.1186/s40658-023-00586-z |
| _version_ | 1797451391925485568 |
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| author | Rachele Danieli Martina Stella Julian Leube Johannes Tran-Gia Clementine Marin Carlos F. Uribe Bruno Vanderlinden Nick Reynaert Patrick Flamen Hugo Levillain |
| author_facet | Rachele Danieli Martina Stella Julian Leube Johannes Tran-Gia Clementine Marin Carlos F. Uribe Bruno Vanderlinden Nick Reynaert Patrick Flamen Hugo Levillain |
| author_sort | Rachele Danieli |
| collection | DOAJ |
| description | Abstract Background Dosimetry after radiopharmaceutical therapy with 177Lu (177Lu-RPT) relies on quantitative SPECT/CT imaging, for which suitable reconstruction protocols are required. In this study, we characterized for the first time the quantitative performance of a ring-shaped CZT-based camera using two different reconstruction algorithms: an ordered subset expectation maximization (OSEM) and a block sequential regularized expectation maximization (BSREM) combined with noise reduction regularization. This study lays the foundations for the definition of a reconstruction protocol enabling accurate dosimetry for patients treated with 177Lu-RPT. Methods A series of 177Lu-filled phantoms were acquired on a StarGuide™ (GE HealthCare), with energy and scatter windows centred at 208 (± 6%) keV and 185 (± 5%) keV, respectively. Images were reconstructed with the manufacturer implementations of OSEM (GE-OSEM) and BSREM (Q.Clear) algorithms, and various combinations of iterations and subsets. Additionally, the manufacturer-recommended Q.Clear-based reconstruction protocol was evaluated. Quantification accuracy, measured as the difference between the SPECT-based and the radionuclide calibrator-based activity, and noise were evaluated in a large cylinder. Recovery coefficients (RCs) and spatial resolution were assessed in a NEMA IEC phantom with sphere inserts. The reconstruction protocols considered suitable for clinical applications were tested on a cohort of patients treated with [177Lu]Lu-PSMA-I&T. Results The accuracy of the activity from the cylinder, although affected by septal penetration, was < 10% for all reconstructions. Both algorithms featured improved spatial resolution and higher RCs with increasing updates at the cost of noise build-up, but Q.Clear outperformed GE-OSEM in reducing noise accumulation. When the reconstruction parameters were carefully selected, similar values for noise (~0.15), spatial resolution (~1 cm) and RCs were found, irrespective of the reconstruction algorithm. Analogue results were found in patients. Conclusions Accurate activity quantification is possible when imaging 177Lu with StarGuide™. However, the impact of septal penetration requires further investigations. GE-OSEM is a valid alternative to the recommended Q.Clear reconstruction algorithm, featuring comparable performances assessed on phantoms and patients. |
| first_indexed | 2024-03-09T14:54:00Z |
| format | Article |
| id | doaj.art-2e831c6aa83d4f408a68f7fb761662c7 |
| institution | Directory Open Access Journal |
| issn | 2197-7364 |
| language | English |
| last_indexed | 2024-03-09T14:54:00Z |
| publishDate | 2023-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | EJNMMI Physics |
| spelling | doaj.art-2e831c6aa83d4f408a68f7fb761662c72023-11-26T14:16:56ZengSpringerOpenEJNMMI Physics2197-73642023-10-0110111810.1186/s40658-023-00586-zQuantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based cameraRachele Danieli0Martina Stella1Julian Leube2Johannes Tran-Gia3Clementine Marin4Carlos F. Uribe5Bruno Vanderlinden6Nick Reynaert7Patrick Flamen8Hugo Levillain9Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB)Department of Nuclear Medicine, University Hospital WürzburgDepartment of Nuclear Medicine, University Hospital WürzburgDepartment of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Functional Imaging, BC CancerDepartment of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Department of Nuclear Medicine, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB)Abstract Background Dosimetry after radiopharmaceutical therapy with 177Lu (177Lu-RPT) relies on quantitative SPECT/CT imaging, for which suitable reconstruction protocols are required. In this study, we characterized for the first time the quantitative performance of a ring-shaped CZT-based camera using two different reconstruction algorithms: an ordered subset expectation maximization (OSEM) and a block sequential regularized expectation maximization (BSREM) combined with noise reduction regularization. This study lays the foundations for the definition of a reconstruction protocol enabling accurate dosimetry for patients treated with 177Lu-RPT. Methods A series of 177Lu-filled phantoms were acquired on a StarGuide™ (GE HealthCare), with energy and scatter windows centred at 208 (± 6%) keV and 185 (± 5%) keV, respectively. Images were reconstructed with the manufacturer implementations of OSEM (GE-OSEM) and BSREM (Q.Clear) algorithms, and various combinations of iterations and subsets. Additionally, the manufacturer-recommended Q.Clear-based reconstruction protocol was evaluated. Quantification accuracy, measured as the difference between the SPECT-based and the radionuclide calibrator-based activity, and noise were evaluated in a large cylinder. Recovery coefficients (RCs) and spatial resolution were assessed in a NEMA IEC phantom with sphere inserts. The reconstruction protocols considered suitable for clinical applications were tested on a cohort of patients treated with [177Lu]Lu-PSMA-I&T. Results The accuracy of the activity from the cylinder, although affected by septal penetration, was < 10% for all reconstructions. Both algorithms featured improved spatial resolution and higher RCs with increasing updates at the cost of noise build-up, but Q.Clear outperformed GE-OSEM in reducing noise accumulation. When the reconstruction parameters were carefully selected, similar values for noise (~0.15), spatial resolution (~1 cm) and RCs were found, irrespective of the reconstruction algorithm. Analogue results were found in patients. Conclusions Accurate activity quantification is possible when imaging 177Lu with StarGuide™. However, the impact of septal penetration requires further investigations. GE-OSEM is a valid alternative to the recommended Q.Clear reconstruction algorithm, featuring comparable performances assessed on phantoms and patients.https://doi.org/10.1186/s40658-023-00586-zSPECT/CTCalibrationImage reconstructionBlock sequential regularized expectation maximization (BSREM)Quantitative Lu-177 SPECTDosimetry |
| spellingShingle | Rachele Danieli Martina Stella Julian Leube Johannes Tran-Gia Clementine Marin Carlos F. Uribe Bruno Vanderlinden Nick Reynaert Patrick Flamen Hugo Levillain Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera EJNMMI Physics SPECT/CT Calibration Image reconstruction Block sequential regularized expectation maximization (BSREM) Quantitative Lu-177 SPECT Dosimetry |
| title | Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera |
| title_full | Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera |
| title_fullStr | Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera |
| title_full_unstemmed | Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera |
| title_short | Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera |
| title_sort | quantitative 177lu spect ct imaging for personalized dosimetry using a ring shaped czt based camera |
| topic | SPECT/CT Calibration Image reconstruction Block sequential regularized expectation maximization (BSREM) Quantitative Lu-177 SPECT Dosimetry |
| url | https://doi.org/10.1186/s40658-023-00586-z |
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