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Dreher N, Hahner S, Fuß CT, Schlötelburg W, Hartrampf PE, Serfling SE, Schirbel A, Samnick S, Higuchi T, Weich A, Lapa C, Rosenwald A, Buck AK, Kircher S, Werner RA. CXCR4-directed PET/CT with [ 68 Ga]Ga-pentixafor in solid tumors-a comprehensive analysis of imaging findings and comparison with histopathology. Eur J Nucl Med Mol Imaging 2024; 51:1383-1394. [PMID: 38082196 PMCID: PMC10957681 DOI: 10.1007/s00259-023-06547-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/26/2023] [Indexed: 03/22/2024]
Abstract
BACKGROUND C-X-C motif chemokine receptor 4 (CXCR4) is overexpressed in various solid cancers and can be targeted by CXCR4-directed molecular imaging. We aimed to characterize the in-vivo CXCR4 expression in patients affected with solid tumors, along with a comparison to ex-vivo findings. METHODS A total 142 patients with 23 different histologically proven solid tumors were imaged with CXCR4-directed PET/CT using [68 Ga]Ga-pentixafor (total number of scans, 152). A semi-quantitative analysis of the CXCR4-positive tumor burden including maximum standardized uptake values (SUVmax) and target-to-background ratios (TBR) using blood pool was conducted. In addition, we performed histopathological staining to determine the immuno-reactive score (IRS) from patients' tumor tissue and investigated possible correlations with SUVmax (by providing Spearman's rho ρ). Based on imaging, we also assessed the eligibility for CXCR4-targeted radioligand therapy or non-radioactive CXCR4 inhibitory treatment (defined as more than five CXCR4-avid target lesions [TL] with SUVmax above 10). RESULTS One hundred three of 152 (67.8%) scans showed discernible uptake above blood pool (TBR > 1) in 462 lesions (52 primary tumors and 410 metastases). Median TBR was 4.4 (1.05-24.98), thereby indicating high image contrast. The highest SUVmax was observed in ovarian cancer, followed by small cell lung cancer, desmoplastic small round cell tumor, and adrenocortical carcinoma. When comparing radiotracer accumulation between primary tumors and metastases for the entire cohort, comparable SUVmax was recorded (P > 0.999), except for pulmonal findings (P = 0.013), indicative for uniform CXCR4 expression among TL. For higher IRS, a weak, but statistically significant correlation with increased SUVmax was observed (ρ = 0.328; P = 0.018). In 42/103 (40.8%) scans, more than five TL were recorded, with 12/42 (28.6%) exhibiting SUVmax above 10, suggesting eligibility for CXCR4-targeted treatment in this subcohort. CONCLUSIONS In a whole-body tumor read-out, a substantial portion of prevalent solid tumors demonstrated increased and uniform [68 Ga]Ga-pentixafor uptake, along with high image contrast. We also observed a respective link between in- and ex-vivo CXCR4 expression, suggesting high specificity of the PET agent. Last, a fraction of patients with [68 Ga]Ga-pentixafor-positive tumor burden were rendered potentially suitable for CXCR4-directed therapy.
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Affiliation(s)
- Niklas Dreher
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.
| | - Stefanie Hahner
- Department of Internal Medicine I, Endocrinology, University Hospital Würzburg, Würzburg, Germany
| | - Carmina T Fuß
- Department of Internal Medicine I, Endocrinology, University Hospital Würzburg, Würzburg, Germany
| | - Wiebke Schlötelburg
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Philipp E Hartrampf
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Sebastian E Serfling
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Andreas Schirbel
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Samuel Samnick
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Alexander Weich
- Department of Internal Medicine II, Gastroenterology, University Hospital Würzburg, Würzburg, Germany
| | - Constantin Lapa
- Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | | | - Andreas K Buck
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Stefan Kircher
- Institute of Pathology, University of Würzburg, Würzburg, Germany
| | - Rudolf A Werner
- Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Division of Nuclear Medicine, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
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Gühne F, Schilder T, Seifert P, Kühnel C, Freesmeyer M. Dependence of Renal Uptake on Kidney Function in [ 68Ga]Ga-PSMA-11 PET/CT Imaging. Diagnostics (Basel) 2024; 14:696. [PMID: 38611608 PMCID: PMC11012145 DOI: 10.3390/diagnostics14070696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/21/2024] [Accepted: 03/24/2024] [Indexed: 04/14/2024] Open
Abstract
(1) Background: PSMA ligand PET/CT is increasingly important for diagnostics of prostate cancer and other tumor diseases. In particular, the radiopharmaceutical [68Ga]Ga-PSMA-11 is widely used. Besides its tumor-specific binding, the uptake within the kidneys is dominant and seems to visualize the renal cortex specifically. Kidney diseases may alter the uptake of radiopharmaceuticals. Therefore, the correlation between renal uptake in PET/CT imaging and renal function should be investigated. (2) Methods: A group of 103 male patients were retrospectively evaluated for eGFR according to the CKD-EPI equation, tracer uptake intensity (SUVmax, SUVpeak, SUVmean), the molecular volume of the renal cortex, morphological kidney size, and total renal uptake. Manual and three different computer-assisted contouring methods (thresholds at 50% of SUVmax, 30% of SUVmax, and absolute SUV of 20) were used for measurements. Correlations between parameters were calculated using linear regression models. (3) Results: Renal SUVmax, SUVpeak, and SUVmean do not correlate with eGFR for manual or computer-assisted measurements. In contrast, molecular cortex volume shows a moderate correlation with eGFR (R2 = 0.231, p < 0.001), superior to morphological kidney size. A contouring threshold of 30% of SUVmax outperformed the other settings for renal cortex volume and total renal uptake. (4) Conclusions: Renal uptake of [68Ga]Ga-PSMA-11 cannot predict eGFR, but the functional renal cortex can be quantified by PET/CT imaging.
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Affiliation(s)
| | | | | | | | - Martin Freesmeyer
- Clinic of Nuclear Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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3
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Duell J, Buck AK, Hartrampf PE, Schlötelburg W, Schneid S, Weich A, Dreher N, Lapa C, Kircher M, Higuchi T, Samnick S, Serfling SE, Raderer M, Rasche L, Einsele H, Topp MS, Kosmala A, Werner RA. Chemokine Receptor PET/CT Provides Relevant Staging and Management Changes in Marginal Zone Lymphoma. J Nucl Med 2023; 64:1889-1894. [PMID: 37797975 DOI: 10.2967/jnumed.123.266074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/07/2023] [Indexed: 10/07/2023] Open
Abstract
Because of gastral and extranodal manifestations, guideline-compatible diagnostic work-up of marginal zone lymphoma is challenging. We aimed to determine the diagnostic performance of C-X-C motif chemokine receptor 4 (CXCR4)-directed PET/CT compared with routine diagnostics, along with PET/CT-based retrospective changes in therapeutic management. The predictive potential of the PET signal was also investigated, and the number of patients eligible for CXCR4-directed radioligand therapy in a theranostic setting was determined. Methods: For this study, 100 marginal zone lymphoma patients underwent CXCR4-directed PET/CT. We compared staging results and treatment decisions from molecular imaging with respective results from guideline-compatible work-up (CT, esophagogastroduodenoscopy, and bone marrow-derived biopsy). Prognostic performance of the in vivo CXCR4 PET signal for progression-free survival (PFS) was evaluated (using log-rank test and Kaplan-Meier curves). Results: Relative to CT, CXCR4-directed imaging led to Ann Arbor (AA) staging changes for 27 of 100 patients (27.0%). Among those, clinically relevant upstaging from AA I or AA II to AA III or AA IV was observed for 23 patients (85.2%), along with respective changes in therapeutic management (escalation, 6/23 [26.1%]; deescalation, 17/23 [73.9%]). CXCR4 PET/CT yielded diagnostic accuracy of 94.0% relative to esophagogastroduodenoscopy and 76.8% relative to bone marrow-derived biopsy. An increased CXCR4 PET signal was linked to shorter PFS (707 d vs. median PFS not reached; hazard ratio, 3.18; 95% CI, 1.37-7.35; P = 0.01). CXCR4-directed radioligand therapy would have been feasible for 18 of 100 patients (18.0%). Conclusion: Relative to CT, CXCR4-directed PET/CT led to AA changes for 27 of 100 patients. Chemokine receptor PET/CT may improve current diagnostic algorithms and influence management relative to CT alone, potentially obviating some biopsies.
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Affiliation(s)
- Johannes Duell
- Medical Department II, University Hospital Würzburg, Würzburg, Germany
| | - Andreas K Buck
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Philipp E Hartrampf
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Wiebke Schlötelburg
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Simone Schneid
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Alexander Weich
- Medical Department II, University Hospital Würzburg, Würzburg, Germany
| | - Niklas Dreher
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Constantin Lapa
- Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Malte Kircher
- Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Samuel Samnick
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | | | - Markus Raderer
- Department of Internal Medicine I, Medical University Vienna, Vienna, Austria
| | - Leo Rasche
- Medical Department II, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, Würzburg, Germany; and
| | - Hermann Einsele
- Medical Department II, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, Würzburg, Germany; and
| | - Max S Topp
- Medical Department II, University Hospital Würzburg, Würzburg, Germany
- Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, Würzburg, Germany; and
| | - Aleksander Kosmala
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany;
| | - Rudolf A Werner
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
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Feuerecker B, Gafita A, Langbein T, Tauber R, Seidl C, Bruchertseifer F, Gschwendt JE, Weber WA, D’Alessandria C, Morgenstern A, Eiber M. Comparative Analysis of Morphological and Functional Effects of 225Ac- and 177Lu-PSMA Radioligand Therapies (RLTs) on Salivary Glands. Int J Mol Sci 2023; 24:16845. [PMID: 38069166 PMCID: PMC10706561 DOI: 10.3390/ijms242316845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/24/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
Most Prostate Specific Membrane Antigens (PSMAs) targeting small molecules accumulate in the salivary glands (SGs), raising concerns about SG toxicity, especially after repeated therapies or therapy with 225Ac-labeled ligands. SG toxicity is assessed clinically by the severity of patient-reported xerostomia, but this parameter can be challenging to objectively quantify. Therefore, we explored the feasibility of using SG volume as a biomarker for toxicity. In 21 patients with late-stage metastatic resistant prostate cancer (mCRPC), the PSMA volume and ligand uptake of SG were analyzed retrospectively before and after two cycles of 177Lu-PSMA (LuPSMA; cohort A) and before and after one cycle of 225Ac-PSMA-617 (AcPSMA, cohort B). Mean Volume-SG in cohort A was 59 ± 13 vs. 54 ± 16 mL (-10%, p = 0.4), and in cohort B, it was 50 ± 13 vs. 40 ± 11 mL (-20%, p = 0.007), respectively. A statistically significant decrease in the activity concentration in the SG was only observed in group B (SUVmean: 9.2 ± 2.8 vs. 5.3 ± 1.8, p < 0.0001; vs. A: SUVmean: 11.2 ± 3.3 vs. 11.1 ± 3.5, p = 0.8). SG volume and PSMA-ligand uptake are promising markers to monitor the SG toxicity after a PSMA RLT.
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Affiliation(s)
- Benedikt Feuerecker
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
- Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partnersite München, 69124 Heidelberg, Germany
- Department of Radiology, University Hospital, LMU Munich, 81377 München, Germany
- Department of Radiology, School of Medicine, Technical University of Munich, 81675 München, Germany
| | - Andrei Gafita
- Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Thomas Langbein
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
| | - Robert Tauber
- Department of Urology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Christof Seidl
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
| | | | - Jürgen E. Gschwendt
- Department of Urology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Wolfgang A. Weber
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
- Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partnersite München, 69124 Heidelberg, Germany
| | - Calogero D’Alessandria
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
| | - Alfred Morgenstern
- European Commission, Joint Research Centre (JRC), 76344 Karlsruhe, Germany
| | - Matthias Eiber
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 81675 München, Germany
- Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partnersite München, 69124 Heidelberg, Germany
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Groener D, Wichert J, Adams M, Mader N, Klimek K, Nguyen Ngoc C, Baumgarten J, Happel C, Mandel P, Chun FKH, Tselis N, Grünwald F, Sabet A. Impact of [ 177Lu]Lu-PSMA-617 Radioligand Therapy on Reference Organ Uptake Assessed by [ 68Ga]Ga-PSMA-11-PET/CT. Cancers (Basel) 2023; 15:3878. [PMID: 37568694 PMCID: PMC10417367 DOI: 10.3390/cancers15153878] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
This study aims to assess the change in uptake to reference organs, including the liver, parotid and salivary glands after radioligand therapy (RLT) with [177Lu]Lu-PSMA-617 in relation to pretreatment imaging metrics. Eighty-five patients with mCRPC underwent [68Ga]Ga-PSMA-11 PET/CT imaging prior to (pre RLT PET) and after (post RLT PET) a median of 3 (IQR 2-6) RLT cycles with [177Lu]Lu-PSMA-617. PSMA-positive tumor burden was stratified into 4 groups based on modified PROMISE criteria (oligofocal, multifocal, disseminated, diffuse). Uptake (SUVmean, SUVmax) in liver tissue, parotid and submandibular glands was measured. A control group was established with 54 patients who had received two separate PET acquisitions following the same protocol (PET1, PET2) within 12 months for localized or oligofocal prostate cancer without RLT in the interim. Baseline uptake values (SUVmean, SUVmax) in parotid (10.8 ± 3.2, 16.8 ± 5.4) and submandibular glands (11.3 ± 2.8, 18.1 ± 4.7) are 2-fold compared to liver uptake (4.9 ± 1.4, 7.7 ± 2.0), with no significant change between PET 1 and PET 2 in the control group. In the RLT group, increasing tumor burden class is significantly associated with decreasing uptake in the liver (p = 0.013), parotid (p < 0.001) and submandibular glands (p < 0.001); this tumor sink effect by respective tumor burden is widely maintained after RLT (p = 0.011, p < 0.001, p < 0.001). RLT has a significant impact on salivary gland uptake with decreasing values per patient in all groups of disease burden change (up to -30.4% in submandibular glands, p < 0.001), while liver tissue shows rising values in patients with declining tumor burden throughout RLT (+18.6%, p = 0.020). Uptake in liver tissue and salivary glands on [68Ga]Ga-PSMA-11 PET/CT imaging is inversely related to tumor burden prior to and following RLT with [177Lu]Lu-PSMA-617. Per patient, salivary gland uptake is further reduced throughout RLT independently from tumor burden, while changes in liver uptake remain burden-dependent. Liver and salivary gland uptake-derived metrics and segmentation thresholds may thus be of limited value when used as reference for response assessment to RLT.
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Affiliation(s)
- Daniel Groener
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Jennifer Wichert
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Magdalena Adams
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Nicolai Mader
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Konrad Klimek
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Christina Nguyen Ngoc
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Justus Baumgarten
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Christian Happel
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Philipp Mandel
- Department of Urology, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (P.M.); (F.K.H.C.)
| | - Felix K. H. Chun
- Department of Urology, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (P.M.); (F.K.H.C.)
| | - Nikolaos Tselis
- Department of Radiation Oncology, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany;
| | - Frank Grünwald
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
| | - Amir Sabet
- Department of Nuclear Medicine, University Hospital Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany; (D.G.); (J.W.); (M.A.); (N.M.); (K.K.); (C.N.N.); (J.B.); (C.H.)
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Kosmala A, Seifert S, Schneid S, Dreher N, Higuchi T, Weich A, Serfling SE, Hartrampf PE, Einsele H, Buck AK, Topp MS, Duell J, Werner RA. Lymphoma-Sink Effect in Marginal Zone Lymphoma Based on CXCR4-Targeted Molecular Imaging. Mol Imaging Biol 2023:10.1007/s11307-023-01830-9. [PMID: 37286923 DOI: 10.1007/s11307-023-01830-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023]
Abstract
PURPOSE Recent studies investigating a tumor-sink effect in solid tumors reported on decreasing uptake in normal organs in patients with higher tumor burden. This phenomenon, however, has not been evaluated yet for theranostic radiotracers applied to hematological neoplasms. As such, we aimed to determine a potential "lymphoma-sink effect" in patients with marginal zone lymphoma (MZL) imaged with C-X-C motif chemokine receptor (CXCR) 4-directed PET/CTs. PROCEDURES We retrospectively analyzed 73 patients with MZL who underwent CXCR4-directed [68Ga]Ga-PentixaFor PET/CT. Normal unaffected organ uptake (heart, liver, spleen, bone marrow, kidneys) was quantified using volumes of interests (VOIs) and mean standardized uptake values (SUVmean) were derived. MZL manifestations were also segmented to determine the maximum and peak standardized uptake values SUV (SUVmax/peak) and volumetric parameters, including lymphoma volume (LV), and fractional lymphoma activity (FLA, defined as LV*SUVmean of lymphoma burden). This approach resulted in 666 VOIs to capture the entire MZL manifestation load. We used Spearman's rank correlations to determine associations between organ uptake and CXCR4-expressing lymphoma lesions. RESULTS We recorded the following median SUVmean in normal organs: heart, 1.82 (range, 0.78-4.11); liver, 1.35 (range, 0.72-2.99); bone marrow, 2.36 (range, 1.12-4.83); kidneys, 3.04 (range, 2.01-6.37); spleen, 5.79 (range, 2.07-10.5). No relevant associations between organ radiotracer uptake and MZL manifestation were observed, neither for SUVmax (ρ ≤ 0.21, P ≥ 0.07), SUVpeak (ρ ≤ 0.20, P ≥ 0.09), LV (ρ ≤ 0.13, P ≥ 0.27), nor FLA (ρ ≤ 0.15, P ≥ 0.33). CONCLUSIONS Investigating a lymphoma-sink effect in patients with hematological neoplasms, we observed no relevant associations between lymphoma burden and uptake in normal organs. Those observations may have therapeutic implications, e.g., for "cold" SDF1-pathway disrupting or "hot," CXCR4-directed radiolabeled drugs, as with higher lymphoma load, normal organ uptake seems to remain stable.
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Affiliation(s)
- Aleksander Kosmala
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Simone Seifert
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Simone Schneid
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Niklas Dreher
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Alexander Weich
- Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
| | - Sebastian E Serfling
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Philipp E Hartrampf
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Hermann Einsele
- Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
| | - Andreas K Buck
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Max S Topp
- Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
| | - Johannes Duell
- Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
| | - Rudolf A Werner
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany.
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Sciences, Baltimore, MD, USA.
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7
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Burgard C, Rosar F, Marlowe RJ, Bartholomä M, Dewes S, Schaefer-Schuler A, Linxweiler J, Khreish F, Ezziddin S. Tumor Sink Effect with Prostate-Specific Membrane Antigen-Targeted Theranostics in Patients with Metastatic Castration-Resistant Prostate Cancer: Intra-Individual Evaluations. Cancers (Basel) 2023; 15:cancers15092592. [PMID: 37174058 PMCID: PMC10177482 DOI: 10.3390/cancers15092592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/25/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
"Tumor sink effects", decreased physiological uptake of radiopharmaceuticals due to sequestration by a tumor, may impact radioligand therapy (RLT) toxicity and dosing. We investigated these effects with prostate-specific membrane antigen (PSMA)-targeted radiopharmaceuticals in the healthy organs-at-risk (the parotid glands, kidneys, liver, and spleen) of 33 patients with metastatic castration-resistant prostate cancer (mCRPC). We retrospectively performed three intra-individual comparisons. First, we correlated changes from baseline to post-RLT (after two 177-lutetium (177Lu)-PSMA-617 cycles) in total lesional PSMA (∆TLP) and organ mean standardized uptake values (∆SUVmean). Second, in 25 RLT responders, we compared the organ SUVmean post-RLT versus that at baseline. Lastly, we correlated the baseline TLP and organ SUVmean. Data were acquired via 68-gallium-PSMA-11 positron emission tomography before the first and after the second 177Lu-PSMA-617 cycle. In the parotid glands and spleen, ∆TLP and ∆SUVmean showed a significant inverse correlation (r = -0.40, p = 0.023 and r = -0.36, p = 0.042, respectively). Additionally, in those tissues, the median organ SUVmean rose significantly from baseline after the response to RLT (p ≤ 0.022), and the baseline TLP and SUVmean were significantly negatively correlated (r = -0.44, p = 0.01 and r = -0.42, p = 0.016, respectively). These observations suggest tumor sink effects with PSMA-targeted radiopharmaceuticals in the salivary glands and spleen of patients with mCRPC.
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Affiliation(s)
- Caroline Burgard
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
| | - Florian Rosar
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
| | | | - Mark Bartholomä
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
| | - Sebastian Dewes
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
| | | | - Johannes Linxweiler
- Department of Urology, Saarland University-Medical Center, 66421 Homburg, Germany
| | - Fadi Khreish
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
| | - Samer Ezziddin
- Department of Nuclear Medicine, Saarland University-Medical Center, 66421 Homburg, Germany
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8
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Rowe SP, Salavati A, Werner RA, Pienta KJ, Gorin MA, Pomper MG, Solnes LB. 18F-Labeled Radiotracers for Prostate-specific Membrane Antigen. PET Clin 2022; 17:585-593. [DOI: 10.1016/j.cpet.2022.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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9
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Lau YC, Chen S, Ho CL, Cai J. Reliability of gradient-based segmentation for measuring metabolic parameters influenced by uptake time on 18F-PSMA-1007 PET/CT for prostate cancer. Front Oncol 2022; 12:897700. [PMID: 36249043 PMCID: PMC9559596 DOI: 10.3389/fonc.2022.897700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
PurposeTo determine an optimal setting for functional contouring and quantification of prostate cancer lesions with minimal variation by evaluating metabolic parameters on 18F-PSMA-1007 PET/CT measured by threshold-based and gradient-based methods under the influence of varying uptake time.Methods and materialsDual time point PET/CT was chosen to mimic varying uptake time in clinical setting. Positive lesions of patients who presented with newly diagnosed disease or biochemical recurrence after total prostatectomy were reviewed retrospectively. Gradient-based and threshold-based tools at 40%, 50% and 60% of lesion SUVmax (MIM 6.9) were used to create contours on PET. Contouring was considered completed if the target lesion, with its hottest voxel, was delineated from background tissues and nearby lesions under criteria specific to their operations. The changes in functional tumour volume (FTV) and metabolic tumour burden (MTB, defined as the product of SUVmean and FTV) were analysed. Lesion uptake patterns (increase/decrease/stable) were determined by the percentage change in tumour SUVmax at ±10% limit.ResultsA total of 275 lesions (135 intra-prostatic lesions, 65 lymph nodes, 45 bone lesions and 30 soft tissue lesions in pelvic region) in 68 patients were included. Mean uptake time of early and delayed imaging were 94 and 144 minutes respectively. Threshold-based method using 40% to 60% delineated only 85 (31%), 110 (40%) and 137 (50%) of lesions which all were contoured by gradient-based method. Although the overall percentage change using threshold at 50% was the smallest among other threshold levels in FTV measurement, it was still larger than gradient-based method (median: 50%=-7.6% vs gradient=0%). The overall percentage increase in MTB of gradient-based method (median: 6.3%) was compatible with the increase in tumour SUVmax. Only a small proportion of intra-prostatic lesions (<2%), LN (<4%), bone lesions (0%) and soft tissue lesions (<4%) demonstrated decrease uptake patterns.ConclusionsWith a high completion rate, gradient-based method is reliable for prostate cancer lesion contouring on 18F-PSMA-1007 PET/CT. Under the influence of varying uptake time, it has smaller variation than threshold-based method for measuring volumetric parameters. Therefore, gradient-based method is recommended for tumour delineation and quantification on 18F-PSMA-1007 PET/CT.
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Affiliation(s)
- Yu Ching Lau
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China
- Department of Nuclear Medicine and Positron Emission Tomography, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong SAR, China
| | - Sirong Chen
- Department of Nuclear Medicine and Positron Emission Tomography, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong SAR, China
| | - Chi Lai Ho
- Department of Nuclear Medicine and Positron Emission Tomography, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong SAR, China
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China
- *Correspondence: Jing Cai,
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van der Sar ECA, Kühr AJS, Ebbers SC, Henderson AM, de Keizer B, Lam MGEH, Braat AJAT. Baseline Imaging Derived Predictive Factors of Response Following [ 177Lu]Lu-PSMA-617 Therapy in Salvage Metastatic Castration-Resistant Prostate Cancer: A Lesion- and Patient-Based Analysis. Biomedicines 2022; 10:biomedicines10071575. [PMID: 35884878 PMCID: PMC9313142 DOI: 10.3390/biomedicines10071575] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/24/2022] Open
Abstract
Earlier studies have mostly identified pre-therapeutic clinical and laboratory parameters for the prediction of treatment response to [177Lu]Lu-PSMA-617 in metastatic castration resistant prostate cancer patients (mCRPC). The current study investigated whether imaging-derived factors on baseline [68Ga]Ga-PSMA-11 PET/CT can potentially predict the response after two cycles of [177Lu]Lu-PSMA-617 treatment, in a lesion- and patient-based analysis in men with mCRPC. Included patients had histologically proven mCRPC and a [68Ga]Ga-PSMA-11 PET/CT before and after two cycles of [177Lu]Lu-PSMA-617 treatment. The imaging-based response was evaluated on lesion-level (standardized uptake value (SUV) reduction) and patient-level (total lesion PSMA (TL-PSMA) reduction). In the lesion-level analysis, a clear relationship was found between SUVpeak/max and the imaging-based response to [68Ga]Ga-PSMA-11 PET/CT (most avid lesion SUVpeak/max ≥ 30% reduction) (p < 0.001), with no significant difference in cut-off values between different sites of metastases (i.e., lymph node, bone or visceral metastasis). In patient-level analysis, baseline PSA and SUVpeak values of most avid metastasis were significantly associated with imaging-based response (TL-PSMA ≥ 30% reduction) (p = 0.019 and p = 0.015). In pre-treatment with [68Ga]Ga-PSMA-11 PET/CT, a clear accumulation-response relationship in lesion-level was found for SUVpeak/max in men with mCRPC receiving two cycles of [177Lu]Lu-PSMA-617 treatment. The SUVpeak of the most avid lesion was the only image-derived factor predictive of the imaging-based response at the patient-level.
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Affiliation(s)
- Esmée C. A. van der Sar
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
- Correspondence:
| | - Adinda J. S. Kühr
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
| | - Sander C. Ebbers
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
| | | | - Bart de Keizer
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
| | - Marnix G. E. H. Lam
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
| | - Arthur J. A. T. Braat
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (A.J.S.K.); (S.C.E.); (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
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11
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Rowe SP, Buck A, Bundschuh RA, Lapa C, Serfling SE, Derlin T, Higuchi T, Gorin MA, Pomper MG, Werner RA. [18F]DCFPyL PET/CT for Imaging of Prostate Cancer. Nuklearmedizin 2022; 61:240-246. [PMID: 35030637 DOI: 10.1055/a-1659-0010] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Prostate-specific membrane antigen (PSMA)-directed positron emission tomography (PET) has gained increasing interest for imaging of men affected by prostate cancer (PC). In recent years, 68Ga-labeled PSMA compounds have been widely utilized, although there is a trend towards increased utilization of 18F-labeled agents. Among others, [18F]DCFPyL (piflufolastat F 18, PYLARIFY) has been tested in multiple major trials, such as OSPREY and CONDOR, which provided robust evidence on the clinical utility of this compound for staging, restaging, and change in management. Recent explorative prospective trials have also utilized [18F]DCFPyL PET/CT for response assessment, e.g., in patients under abiraterone or enzalutamide, rendering this 18F-labeled PSMA radiotracer as an attractive biomarker for image-guided strategies in men with PC. After recent approval by the U.S. Food and Drug Administration, one may expect more widespread use, not only in the U.S., but also in Europe in the long term. In the present review, we will provide an overview of the current clinical utility of [18F]DCFPyL in various clinical settings for men with PC.
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Affiliation(s)
- Steven P Rowe
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, United States.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, United States.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Andreas Buck
- Nuclear Medicine, Würzburg University Medical Center Clinic for Nuclear Medicine, Würzburg, Germany
| | - Ralph A Bundschuh
- Department of Nuclear Medicine, University Hospital Bonn, Bonn, Germany
| | | | - Sebastian E Serfling
- Nuclear Medicine, Würzburg University Medical Center Clinic for Nuclear Medicine, Würzburg, Germany
| | - Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Takahiro Higuchi
- Nuclear Medicine, Würzburg University Medical Center Clinic for Nuclear Medicine, Würzburg, Germany.,Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Michael A Gorin
- Urology Associates and UPMC Western Maryland, Cumberland, United States.,Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Martin G Pomper
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, United States.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, United States.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Rudolf A Werner
- Nuclear Medicine, Würzburg University Medical Center Clinic for Nuclear Medicine, Würzburg, Germany
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12
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Kosmala A, Serfling SE, Dreher N, Lindner T, Schirbel A, Lapa C, Higuchi T, Buck AK, Weich A, Werner RA. Associations between Normal Organs and Tumor Burden in Patients Imaged with Fibroblast Activation Protein Inhibitor-Directed Positron Emission Tomography. Cancers (Basel) 2022; 14:cancers14112609. [PMID: 35681588 PMCID: PMC9179441 DOI: 10.3390/cancers14112609] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 05/21/2022] [Accepted: 05/22/2022] [Indexed: 12/04/2022] Open
Abstract
Simple Summary Several radiolabeled fibroblast activation protein targeted inhibitors (FAPI) have been developed for molecular imaging and therapy. A potential correlation of radiotracer uptake in normal organs and extent of tumor burden may have consequences for a theranostic approach using ligands structurally associated with [68Ga]Ga-FAPI, as one may anticipate decreased doses to normal organs in patients with extensive tumor load. In the present proof-of-concept study investigating patients with solid tumors, we aimed to quantitatively determine the normal organ biodistribution of [68Ga]Ga-FAPI-04, depending on the extent of tumor. Except for a trend towards significance in the myocardium, we did not observe any relevant associations between PET-based tumor burden and normal organs. Those preliminary findings may trigger future studies to determine possible implications for theranostic approaches and FAP-directed drugs, as one may expect an unchanged dose for normal organs even in patients with higher tumor load. Abstract (1) Background: We aimed to quantitatively investigate [68Ga]Ga-FAPI-04 uptake in normal organs and to assess a relationship with the extent of FAPI-avid tumor burden. (2) Methods: In this single-center retrospective analysis, thirty-four patients with solid cancers underwent a total of 40 [68Ga]Ga-FAPI-04 PET/CT scans. Mean standardized uptake values (SUVmean) for normal organs were established by placing volumes of interest (VOIs) in the heart, liver, spleen, pancreas, kidneys, and bone marrow. Total tumor burden was determined by manual segmentation of tumor lesions with increased uptake. For tumor burden, quantitative assessment included maximum SUV (SUVmax), tumor volume (TV), and fractional tumor activity (FTA = TV × SUVmean). Associations between uptake in normal organs and tumor burden were investigated by applying Spearman’s rank correlation coefficient. (3) Results: Median SUVmean values were 2.15 in the pancreas (range, 1.05–9.91), 1.42 in the right (range, 0.57–3.06) and 1.41 in the left kidney (range, 0.73–2.97), 1.2 in the heart (range, 0.46–2.59), 0.86 in the spleen (range, 0.55–1.58), 0.65 in the liver (range, 0.31–2.11), and 0.57 in the bone marrow (range, 0.26–0.94). We observed a trend towards significance for uptake in the myocardium and tumor-derived SUVmax (ρ = 0.29, p = 0.07) and TV (ρ = −0.30, p = 0.06). No significant correlation was achieved for any of the other organs: SUVmax (ρ ≤ 0.1, p ≥ 0.42), TV (ρ ≤ 0.11, p ≥ 0.43), and FTA (ρ ≤ 0.14, p ≥ 0.38). In a sub-analysis exclusively investigating patients with high tumor burden, significant correlations of myocardial uptake with tumor SUVmax (ρ = 0.44; p = 0.03) and tumor-derived FTA with liver uptake (ρ = 0.47; p = 0.02) were recorded. (4) Conclusions: In this proof-of-concept study, quantification of [68Ga]Ga-FAPI-04 PET showed no significant correlation between normal organs and tumor burden, except for a trend in the myocardium. Those preliminary findings may trigger future studies to determine possible implications for treatment with radioactive FAP-targeted drugs, as higher tumor load or uptake may not lead to decreased doses in the majority of normal organs.
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Affiliation(s)
- Aleksander Kosmala
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
- Correspondence: (A.K.); (C.L.); Tel.: +49-821-400-3050 (C.L.)
| | - Sebastian E. Serfling
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
| | - Niklas Dreher
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
| | - Thomas Lindner
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
| | - Andreas Schirbel
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
| | - Constantin Lapa
- Nuclear Medicine, Faculty of Medicine, University of Augsburg, 86156 Augsburg, Germany
- Correspondence: (A.K.); (C.L.); Tel.: +49-821-400-3050 (C.L.)
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Andreas K. Buck
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
| | - Alexander Weich
- Gastroenterology, Department of Internal Medicine II, University Hospital Würzburg, 97080 Würzburg, Germany;
| | - Rudolf A. Werner
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany; (S.E.S.); (N.D.); (T.L.); (A.S.); (T.H.); (A.K.B.); (R.A.W.)
- The Russell H Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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13
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Voter AF, Werner RA, Pienta KJ, Gorin MA, Pomper MG, Solnes LB, Rowe SP. Piflufolastat F-18 ( 18F-DCFPyL) for PSMA PET imaging in prostate cancer. Expert Rev Anticancer Ther 2022; 22:681-694. [DOI: 10.1080/14737140.2022.2081155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Andrew F. Voter
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Transitional Year Residency Program, Aurora St. Luke’s Medical Center, Advocate Aurora Health, Milwaukee, WI, USA
| | - Rudolf A. Werner
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Kenneth J. Pienta
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael A. Gorin
- Urology Associates and UPMC Western Maryland, Cumberland, MD, USA
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lilja B. Solnes
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steven P. Rowe
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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14
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Serfling SE, Lapa C, Dreher N, Hartrampf PE, Rowe SP, Higuchi T, Schirbel A, Weich A, Hahner S, Fassnacht M, Buck AK, Werner RA. Impact of Tumor Burden on Normal Organ Distribution in Patients Imaged with CXCR4-Targeted [68Ga]Ga-PentixaFor PET/CT. Mol Imaging Biol 2022; 24:659-665. [PMID: 35312939 PMCID: PMC9296404 DOI: 10.1007/s11307-022-01717-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 12/16/2022]
Abstract
Abstract
Background
CXCR4-directed positron emission tomography/computed tomography (PET/CT) has been used as a diagnostic tool in patients with solid tumors. We aimed to determine a potential correlation between tumor burden and radiotracer accumulation in normal organs.
Methods
Ninety patients with histologically proven solid cancers underwent CXCR4-targeted [68Ga]Ga-PentixaFor PET/CT. Volumes of interest (VOIs) were placed in normal organs (heart, liver, spleen, bone marrow, and kidneys) and tumor lesions. Mean standardized uptake values (SUVmean) for normal organs were determined. For CXCR4-positive tumor burden, maximum SUV (SUVmax), tumor volume (TV), and fractional tumor activity (FTA, defined as SUVmean x TV), were calculated. We used a Spearman's rank correlation coefficient (ρ) to derive correlative indices between normal organ uptake and tumor burden.
Results
Median SUVmean in unaffected organs was 5.2 for the spleen (range, 2.44 – 10.55), 3.27 for the kidneys (range, 1.52 – 17.4), followed by bone marrow (1.76, range, 0.84 – 3.98), heart (1.66, range, 0.88 – 2.89), and liver (1.28, range, 0.73 – 2.45). No significant correlation between SUVmax in tumor lesions (ρ ≤ 0.189, P ≥ 0.07), TV (ρ ≥ -0.204, P ≥ 0.06) or FTA (ρ ≥ -0.142, P ≥ 0.18) with the investigated organs was found.
Conclusions
In patients with solid tumors imaged with [68Ga]Ga-PentixaFor PET/CT, no relevant tumor sink effect was noted. This observation may be of relevance for therapies with radioactive and non-radioactive CXCR4-directed drugs, as with increasing tumor burden, the dose to normal organs may remain unchanged.
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High SUVs Have More Robust Repeatability in Patients with Metastatic Prostate Cancer: Results from a Prospective Test-Retest Cohort Imaged with 18F-DCFPyL. Mol Imaging 2022; 2022:7056983. [PMID: 35283693 PMCID: PMC8896803 DOI: 10.1155/2022/7056983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/11/2022] [Accepted: 02/02/2022] [Indexed: 12/27/2022] Open
Abstract
Objectives In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with 18F-DCFPyL. Methods In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two 18F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUVmax) and mean (SUVmean) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA − TV × SUVmean)). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. Results In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUVmax (1.5–80.5) and SUVmean (1.4–24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation (R2 ≥ 0.99), with high repeatability for SUVmean and SUVmax (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs (P < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV ≥ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong (R2 ≥ 0.98). Moreover, LN-based SUVmean also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, P < 0.0001). This was also noted for SUVmax (wCOV, LN 8.8% vs. bone 12.0%, P < 0.03). On a compartment-based level, wCOVs for volumetric features were ≥22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, P =0.63; TL-PSMA, P =0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUVmax of the most intense lesion per patient (R2, 0.99; wCOV, 11.2%). Conclusion In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability.
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Gafita A, Wang H, Robertson A, Armstrong WR, Zaum R, Weber M, Yagubbayli F, Kratochwil C, Grogan TR, Nguyen K, Navarro F, Esfandiari R, Rauscher I, Menze B, Elashoff D, Delpassand ES, Herrmann K, Czernin J, Hofman MS, Calais J, Fendler WP, Eiber M. Tumor Sink Effect in 68Ga-PSMA-11 PET: Myth or Reality? J Nucl Med 2022; 63:226-232. [PMID: 34049987 PMCID: PMC8805781 DOI: 10.2967/jnumed.121.261906] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/04/2021] [Indexed: 01/19/2023] Open
Abstract
We aimed to systematically determine the impact of tumor burden on 68Ga-prostate-specific membrane antigen-11 (68Ga-PSMA) PET biodistribution by the use of quantitative measurements. Methods: This international multicenter, retrospective analysis included 406 men with prostate cancer who underwent 68Ga-PSMA PET/CT. Of these, 356 had positive findings and were stratified by quintiles into a very low (quintile 1, ≤25 cm3), low (quintile 2, 25-189 cm3), moderate (quintile 3, 189-532 cm3), high (quintile 4, 532-1,355 cm3), or very high (quintile 5, ≥1,355 cm3) total PSMA-positive tumor volume (PSMA-VOL). PSMA-VOL was obtained by semiautomatic segmentation of total tumor lesions using qPSMA software. Fifty prostate cancer patients with no PSMA-positive lesions (negative scan) served as a control group. Normal organs, which included salivary glands, liver, spleen, and kidneys, were semiautomatically segmented using 68Ga-PSMA PET images, and SUVmean was obtained. Correlations between the SUVmean of normal organs and PSMA-VOL as continuous and categoric variables by quintiles were evaluated. Results: The median PSMA-VOL was 302 cm3 (interquartile range [IQR], 47-1,076 cm3). The median SUVmean of salivary glands, kidneys, liver, and spleen was 10.0 (IQR, 7.7-11.8), 26.0 (IQR, 20.0-33.4), 3.7 (IQR, 3.0-4.7), and 5.3 (IQR, 4.0-7.2), respectively. PSMA-VOL showed a moderate negative correlation with the SUVmean of the salivary glands (r = -0.44, P < 0.001), kidneys (r = -0.34, P < 0.001), and liver (r = -0.30, P < 0.001) and a weak negative correlation with the spleen SUVmean (r = -0.16, P = 0.002). Patients with a very high PSMA-VOL (quintile 5, ≥1,355 cm3) had a significantly lower PSMA uptake in the salivary glands, kidneys, liver, and spleen than did the control group, with an average difference of -38.1%, -40.0%, -43.2%, and -34.9%, respectively (P < 0.001). Conclusion: Tumor sequestration affects 68Ga-PSMA biodistribution in normal organs. Patients with a very high tumor load showed a significantly lower uptake of 68Ga-PSMA in normal organs, confirming a tumor sink effect. As similar effects might occur with PSMA-targeted radioligand therapy, these patients might benefit from increased therapeutic activity without exceeding the radiation dose limit for organs at risk.
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Affiliation(s)
- Andrei Gafita
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California;
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Hui Wang
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Andrew Robertson
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Wesley R Armstrong
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California
| | - Raphael Zaum
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium-University Hospital Essen, Essen, Germany
| | - Farid Yagubbayli
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Clemens Kratochwil
- Department of Nuclear Medicine, Heidelberg University Hospital, Heidelberg, Germany
| | - Tristan R Grogan
- Department of Medicine Statistics Core, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Kathleen Nguyen
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California
| | - Fernando Navarro
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
- Department of Informatics, Technical University Munich, Munich, Germany
| | | | - Isabel Rauscher
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Bjoern Menze
- Department of Informatics, Technical University Munich, Munich, Germany
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland; and
| | - David Elashoff
- Department of Medicine Statistics Core, David Geffen School of Medicine, UCLA, Los Angeles, California
| | | | - Ken Herrmann
- Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium-University Hospital Essen, Essen, Germany
| | - Johannes Czernin
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California
| | - Michael S Hofman
- Prostate Cancer Theranostics and Imaging Centre of Excellence, Molecular Imaging and Therapeutic Nuclear Medicine, Peter MacCallum Cancer Centre, and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Jeremie Calais
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California
| | - Wolfgang P Fendler
- Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium-University Hospital Essen, Essen, Germany
| | - Matthias Eiber
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
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Fedrigo R, Kadrmas DJ, Edem PE, Fougner L, Klyuzhin IS, Petric MP, Bénard F, Rahmim A, Uribe C. Quantitative evaluation of PSMA PET imaging using a realistic anthropomorphic phantom and shell-less radioactive epoxy lesions. EJNMMI Phys 2022; 9:2. [PMID: 35032234 PMCID: PMC8761183 DOI: 10.1186/s40658-021-00429-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/20/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Positron emission tomography (PET) with prostate specific membrane antigen (PSMA) have shown superior performance in detecting metastatic prostate cancers. Relative to [18F]fluorodeoxyglucose ([18F]FDG) PET images, PSMA PET images tend to visualize significantly higher-contrast focal lesions. We aim to evaluate segmentation and reconstruction algorithms in this emerging context. Specifically, Bayesian or maximum a posteriori (MAP) image reconstruction, compared to standard ordered subsets expectation maximization (OSEM) reconstruction, has received significant interest for its potential to reach convergence with minimal noise amplifications. However, few phantom studies have evaluated the quantitative accuracy of such reconstructions for high contrast, small lesions (sub-10 mm) that are typically observed in PSMA images. In this study, we cast 3 mm-16-mm spheres using epoxy resin infused with a long half-life positron emitter (sodium-22; 22Na) to simulate prostate cancer metastasis. The anthropomorphic Probe-IQ phantom, which features a liver, bladder, lungs, and ureters, was used to model relevant anatomy. Dynamic PET acquisitions were acquired and images were reconstructed with OSEM (varying subsets and iterations) and BSREM (varying β parameters), and the effects on lesion quantitation were evaluated. RESULTS The 22Na lesions were scanned against an aqueous solution containing fluorine-18 (18F) as the background. Regions-of-interest were drawn with MIM Software using 40% fixed threshold (40% FT) and a gradient segmentation algorithm (MIM's PET Edge+). Recovery coefficients (RCs) (max, mean, peak, and newly defined "apex"), metabolic tumour volume (MTV), and total tumour uptake (TTU) were calculated for each sphere. SUVpeak and SUVapex had the most consistent RCs for different lesion-to-background ratios and reconstruction parameters. The gradient-based segmentation algorithm was more accurate than 40% FT for determining MTV and TTU, particularly for lesions [Formula: see text] 6 mm in diameter (R2 = 0.979-0.996 vs. R2 = 0.115-0.527, respectively). CONCLUSION An anthropomorphic phantom was used to evaluate quantitation for PSMA PET imaging of metastatic prostate cancer lesions. BSREM with β = 200-400 and OSEM with 2-5 iterations resulted in the most accurate and robust measurements of SUVmean, MTV, and TTU for imaging conditions in 18F-PSMA PET/CT images. SUVapex, a hybrid metric of SUVmax and SUVpeak, was proposed for robust, accurate, and segmentation-free quantitation of lesions for PSMA PET.
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Affiliation(s)
- Roberto Fedrigo
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
| | - Dan J Kadrmas
- Department of Radiology and Imaging Sciences, University of Utah, 201 Presidents' Cir, Salt Lake City, UT, 84112, USA
| | - Patricia E Edem
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - Lauren Fougner
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - Ivan S Klyuzhin
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
| | - M Peter Petric
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - François Bénard
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
- Department of Molecular Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
- Department of Radiology, University of British Columbia, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
| | - Carlos Uribe
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada.
- Department of Radiology, University of British Columbia, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada.
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18
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Prive BM, Peters S, Uijen MJM, Janssen MJR, van Gemert WAM, Kreissl MC, Ezziddin S, Konijnenberg MW, Nagarajah J. Letter to the Editor RE: Tumor sink effect in 68Ga-PSMA-11 PET: Myth or Reality? J Nucl Med 2022; 63:1124-1125. [PMID: 35027370 DOI: 10.2967/jnumed.122.263802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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19
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Jadvar H, Calais J, Fanti S, Feng F, Greene KL, Gulley JL, Hofman M, Koontz BF, Lin DW, Morris MJ, Rowe SP, Royce TJ, Salami S, Savir-Baruch B, Srinivas S, Hope TA. Appropriate Use Criteria for Prostate-Specific Membrane Antigen PET Imaging. J Nucl Med 2022; 63:59-68. [PMID: 34593595 PMCID: PMC8717184 DOI: 10.2967/jnumed.121.263262] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 09/21/2021] [Indexed: 11/16/2022] Open
Affiliation(s)
- Hossein Jadvar
- Department of Radiology, University of Southern California, Los Angeles, California
| | - Jeremie Calais
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | | | - Felix Feng
- Department of Radiation Oncology, University of California, San Francisco, California
| | - Kirsten L. Greene
- Department of Urology, University of Virginia, Charlottesville, Virginia
| | | | - Michael Hofman
- Molecular Imaging and Therapeutic Nuclear Medicine, Peter MacCallum Cancer Center, Melbourne, Victoria, Australia and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria Australia
| | - Bridget F. Koontz
- Department of Radiation Oncology, Duke University, Durham, North Carolina
| | - Daniel W. Lin
- Department of Urology, University of Washington, Seattle, Washington
| | - Michael J. Morris
- Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Steve P. Rowe
- Department of Radiological Sciences, Johns Hopkins University, Baltimore, Maryland
| | - Trevor J. Royce
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina
| | - Simpa Salami
- Department of Urology, University of Michigan, Ann Arbor, Michigan
| | | | - Sandy Srinivas
- Department of Medicine (Oncology), Stanford University, California; and
| | - Thomas A. Hope
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
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20
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Bodar YJL, Koene BPF, Jansen BHE, Cysouw MCF, Meijer D, Hendrikse NH, Vis AN, Boellaard R, Oprea-Lager DE. SUVs Are Adequate Measures of Lesional 18F-DCFPyL Uptake in Patients with Low Prostate Cancer Disease Burden. J Nucl Med 2021; 62:1264-1269. [PMID: 33509971 DOI: 10.2967/jnumed.120.260232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/03/2021] [Indexed: 01/03/2023] Open
Abstract
In prostate cancer (PCa) patients, the tumor-to-blood ratio (TBR) has been validated as the preferred simplified method for lesional 18F-DCFPyL (a radiolabeled prostate-specific membrane antigen ligand) uptake quantification on PET. In contrast to SUVs, the TBR accounts for variability in arterial input functions caused by differences in total tumor burden between patients (the sink effect). However, TBR depends strongly on tracer uptake interval and has worse repeatability and is less applicable in clinical practice than SUVs. We investigated whether SUV could provide adequate quantification of 18F-DCFPyL uptake on PET/CT in a patient cohort with low PCa burden. Methods: In total, 116 patients with PCa undergoing 18F-DCFPyL PET/CT imaging were retrospectively included. All 18F-DCFPyL-avid lesions suspected of being PCa were semiautomatically delineated. SUVpeak was plotted against TBR for the most intense lesion of each patient. The correlation of SUVpeak and TBR was evaluated using linear regression and was stratified for patients undergoing PET/CT for primary staging, patients undergoing restaging at biochemical recurrence, and patients with metastatic castration-resistant PCa. Moreover, the correlation was evaluated as a function of tracer uptake time, prostate-specific antigen level, and PET-positive tumor volume. Results: In total, 436 lesions were delineated (median, 1 per patient; range, 1-66). SUVpeak correlated well with TBR in patients with PCa and a total tumor volume of less than 200 cm3 (R2 = 0.931). The correlation between SUV and TBR was not affected by disease setting, prostate-specific antigen level, or tumor volume. SUVpeak depended less on tracer uptake time than did TBR. Conclusion: For 18F-DCFPyL PET/CT, SUVpeak correlates strongly with TBR. Therefore, it is a valuable simplified, semiquantitative measurement in patients with low-volume PCa (<200 cm3). SUVpeak can therefore be applied in 18F-DCFPyL PET assessment as an imaging biomarker to characterize tumors and to monitor treatment outcomes.
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Affiliation(s)
- Yves J L Bodar
- Department of Urology, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands;
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Prostate Cancer Network, Noord Holland, The Netherlands; and
| | - Berend P F Koene
- Department of Urology, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
| | - Bernard H E Jansen
- Department of Urology, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Prostate Cancer Network, Noord Holland, The Netherlands; and
| | - Matthijs C F Cysouw
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
| | - Dennie Meijer
- Department of Urology, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Prostate Cancer Network, Noord Holland, The Netherlands; and
| | - N Harry Hendrikse
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Department of Clinical Pharmacology and Pharmacy, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
| | - André N Vis
- Department of Urology, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
- Prostate Cancer Network, Noord Holland, The Netherlands; and
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
| | - Daniela E Oprea-Lager
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, VU University, Amsterdam, The Netherlands
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Abstract
Piflufolastat F 18 (PYLARIFY®) is an 18F-labelled diagnostic imaging agent that has been developed by Progenics Pharmaceuticals Inc., a Lantheus company, for positron emission tomography (PET) that targets prostate-specific membrane antigen (PSMA). Piflufolastat F 18 was approved in the USA on 27 May 2021 for PET of PSMA positive lesions in men with prostate cancer with suspected metastasis who are candidates for initial definitive therapy or with suspected recurrence based on elevated serum prostate specific antigen (PSA) level. This article summarizes the milestones in the development of piflufolastat F 18 leading to this approval as a radioactive diagnostic agent in prostate cancer.
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Affiliation(s)
- Susan J Keam
- Springer Nature, Private Bag 65901, Mairangi Bay, Auckland, 0754, New Zealand.
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22
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van der Sar ECA, de Keizer B, Lam MGEH, Braat AJAT. Competition ('Steal' Phenomenon) between [ 68Ga]Ga-PSMA-11 Uptake in Prostate Tumor Tissue Versus Healthy Tissue. Pharmaceutics 2021; 13:699. [PMID: 34064990 PMCID: PMC8151729 DOI: 10.3390/pharmaceutics13050699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/30/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022] Open
Abstract
We aimed to clarify whether a steal 'phenomenon' exists by investigating if uptake of 'prostate specific membrane antigen' (PSMA) in prostate tumor tissue correlates with the uptake in healthy tissue. Patients with prostate cancer referred for a [68Ga]Ga-PSMA-11 PET/CT were identified retrospectively. Semi-automated quantitative image analysis was performed; fractional healthy tissue [68Ga]Ga-PSMA-11 uptake volume (HT-PSMA (SUV*cm3)) in the lacrimal, submandibular, and parotid glands, and kidneys, and the fractional total lesion [68Ga]Ga-PSMA-11 uptake volume (TL-PSMA (SUV*cm3)) of prostate cancer were used. Ninety-two patients, age 78 ± 8 years, were analyzed. Median TL-PSMA was 703.37 SUV*cm3 (IQR 119.56-2778.20), median HT-PSMA of the lacrimal, submandibular, and parotid glands, and kidneys was: 13.69 (IQR 7.29-19.06), 194.75 (IQR 133.67-276.53), 552.54 (IQR 379.98-737.16), and 8092.75 SUV*cm3 (IQR 5793.02-11,385.86), respectively. A significant (p-value ≤ 0.001) but weak-moderate correlation was found between the TL-PSMA and HT-PSMA of the parotid- and submandibular glands, and kidneys (correlation coefficient of -0.447, -0.345, and -0.394, respectively). No correlation was found between TL-PSMA and HT-PSMA of the lacrimal glands. The existence of a 'steal' phenomenon cannot be confirmed in this study. Healthy tissue uptake of [68Ga]Ga-PSMA-11 is only partially influenced by TL-PSMA. Thus, modification of therapeutic PSMA activity should not be adjusted based on TL-PSMA alone.
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Affiliation(s)
- Esmée C. A. van der Sar
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (B.d.K.); (M.G.E.H.L.); (A.J.A.T.B.)
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23
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Tuncel M, Telli T, Tuncalı MÇ, Karabulut E. Predictive factors of tumor sink effect: Insights from 177Lu-Prostate-specific membrane antigen therapy. Ann Nucl Med 2021; 35:529-539. [PMID: 33586096 DOI: 10.1007/s12149-021-01593-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 01/28/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Tumor sink effect (TSE) has been defined as; decreased uptake in healthy tissue with increased tumor sequestration of the radiopharmaceuticals. It enables us to give high tumoral radiation doses while resulting in lower absorbed radiation to critical organs. However, the factors which influence this effect are yet to be defined. In this study, we have investigated the predictive factors of the tumor sink effect in a group of patients who received 177Lu-Prostate-specific membrane antigen (PSMA) therapy due to progressive metastatic castration-resistant prostate cancer (mCRPC). METHODS We have retrospectively analyzed the pre-therapy 68Ga-PSMA positron-emission tomography (PET)-computed tomography (CT) and post-therapy planar whole-body scans of 65 patients who received at least two cycles of 7.4 GBq of 177Lu-PSMA therapy. All patients with mCRPC were referred to our department after multiple treatment lines. Age, previous therapies, International Society of Urological Pathology (ISUP) score, and pre-therapy serum tumor marker levels were recorded. Post 177Lu-PSMA therapy images were analyzed for TSE. 68Ga-PSMA PET-CT images were used for the calculation of SUVmax in malignant and healthy tissues as well as metabolic tumor volume (MTV) and total lesion PSMA index (TLPI). RESULTS Based on the post-therapy scans, TSE was seen in 17/65 (26.2%) patients. In univariate analysis, patients with TSE had higher pre-therapy PSA, PSA velocity, and ALP (p < 0.0001). In relation to PET parameters, patients with TSE had higher 68Ga-PSMA MTV, 68Ga-PSMA TLPI and lower pretherapy renal SUVmax (p < 0.0001)), pretherapy liver SUVmax (p:0.012), pretherapy parotid gland SUVmax (p:0.032), and pretherapy parotid gland SUVmean (p:0.038). In the multivariant analysis, 68Ga-PSMA TLPI, pre-therapy PSA, and PSA velocity were found to be statistically significant. When analyzed according to Youden index, pretherapy PSA level of 133 ng/ml (sensitivity 0.765 and 0.875), PSA velocity of 246 ng/ml/year (sensitivity 0.765 and 0.833), and 68Ga-PSMA TLPI of 2969 g (sensitivity 0.765 and 0.875) was found to be the best cut-off points to predict TSE. CONCLUSION The tumor sink effect was seen in 26.2% of patients. 68Ga- PSMA TLPI, pre-therapy PSA, and PSA velocity was found to be the predictors of TSE. Accurate prediction of TSE may lead to increased tumoral doses while sparing healthy organs. Clinical trials that consider this effect as a part of a dose algorithm may further increase therapeutic efficacy.
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Affiliation(s)
- Murat Tuncel
- Faculty of Medicine, Department of Nuclear Medicine, Hacettepe University, Sıhhiye, 06100, Ankara, Turkey.
| | - Tuğçe Telli
- Faculty of Medicine, Department of Nuclear Medicine, Hacettepe University, Sıhhiye, 06100, Ankara, Turkey
| | - Meltem Çağlar Tuncalı
- Faculty of Medicine, Department of Nuclear Medicine, Hacettepe University, Sıhhiye, 06100, Ankara, Turkey
| | - Erdem Karabulut
- Faculty of Medicine, Department of Biostatistics, Hacettepe University, Sıhhiye, 06100, Ankara, Turkey
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Prospective Evaluation of 18F-DCFPyL PET/CT in Detection of High-Risk Localized Prostate Cancer: Comparison With mpMRI. AJR Am J Roentgenol 2020; 215:652-659. [PMID: 32755168 DOI: 10.2214/ajr.19.22042] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. The purpose of this study was to assess the utility of PET with (2S)-2-[[(1S)-1-carboxy-5-[(6-(18F)fluoranylpyridine-3-carbonyl)amino]pentyl]carbamoylamino]pentanedioic acid (18F-DCFPyL), a prostate-specific membrane antigen (PSMA)-targeted radiotracer, in the detection of high-risk localized prostate cancer as compared with multiparametric MRI (mpMRI). SUBJECTS AND METHODS. This HIPAA-compliant prospective study included 26 consecutive patients with localized high-risk prostate cancer (median age, 69.5 years [range, 53-81 years]; median prostate-specific antigen [PSA] level, 18.88 ng/mL [range, 1.03-20.00 ng/mL]) imaged with 18F-DCFPyL PET/CT and mpMRI. Images from PET/CT and mpMRI were evaluated separately, and suspicious areas underwent targeted biopsy. Lesion-based sensitivity and tumor detection rate were compared for PSMA PET and mpMRI. Standardized uptake value (SUV) and PSMA PET parameters were correlated with histopathology score, and uptake in tumor was compared with that in nonmalignant tissue. On a patient level, SUV and PSMA tumor volume were correlated with PSA density. RESULTS. Forty-four tumors (one in Gleason grade [GG] group 1, 12 in GG group 2, seven in GG group 3, nine in GG group 4, and 15 in GG group 5) were identified at histopathology. Sensitivity and tumor detection rate of 18F-DCFPyL PET/CT and mpMRI were similar (PET/CT, 90.9% and 80%; mpMRI, 86.4% and 88.4%; p = 0.58/0.17). Total lesion PSMA and PSMA tumor volume showed a relationship with GG (τ = 0.27 and p = 0.08, τ = 0.30 and p = 0.06, respectively). Maximum SUV in tumor was significantly higher than that in nonmalignant tissue (p < 0.05). Tumor burden density moderately correlated with PSA density (r = 0.47, p = 0.01). Five true-positive tumors identified on 18F-DCFPyL PET/CT were not identified on mpMRI. CONCLUSION. In patients with high-risk prostate cancer, 18F-DCFPyL PET/CT is highly sensitive in detecting intraprostatic tumors and can detect tumors missed on mpMRI. Measured uptake is significantly higher in tumor tissue, and PSMA-derived tumor burden is associated with severity of disease.
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25
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Letter to the Editor re: Semiquantitative Parameters in PSMA-Targeted PET Imaging with [ 18F]DCFPyL: Impact of Tumor Burden on Normal Organ Uptake. Mol Imaging Biol 2020; 22:15-17. [PMID: 31624994 DOI: 10.1007/s11307-019-01438-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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26
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Werner RA, Derlin T, Lapa C, Sheikbahaei S, Higuchi T, Giesel FL, Behr S, Drzezga A, Kimura H, Buck AK, Bengel FM, Pomper MG, Gorin MA, Rowe SP. 18F-Labeled, PSMA-Targeted Radiotracers: Leveraging the Advantages of Radiofluorination for Prostate Cancer Molecular Imaging. Theranostics 2020; 10:1-16. [PMID: 31903102 PMCID: PMC6929634 DOI: 10.7150/thno.37894] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/11/2019] [Indexed: 12/22/2022] Open
Abstract
Prostate-specific membrane antigen (PSMA)-targeted PET imaging for prostate cancer with 68Ga-labeled compounds has rapidly become adopted as part of routine clinical care in many parts of the world. However, recent years have witnessed the start of a shift from 68Ga- to 18F-labeled PSMA-targeted compounds. The latter imaging agents have several key advantages, which may lay the groundwork for an even more widespread adoption into the clinic. First, facilitated delivery from distant suppliers expands the availability of PET radiopharmaceuticals in smaller hospitals operating a PET center but lacking the patient volume to justify an onsite 68Ge/68Ga generator. Thus, such an approach meets the increasing demand for PSMA-targeted PET imaging in areas with lower population density and may even lead to cost-savings compared to in-house production. Moreover, 18F-labeled radiotracers have a higher positron yield and lower positron energy, which in turn decreases image noise, improves contrast resolution, and maximizes the likelihood of detecting subtle lesions. In addition, the longer half-life of 110 min allows for improved delayed imaging protocols and flexibility in study design, which may further increase diagnostic accuracy. Moreover, such compounds can be distributed to sites which are not allowed to produce radiotracers on-site due to regulatory issues or to centers without access to a cyclotron. In light of these advantageous characteristics, 18F-labeled PSMA-targeted PET radiotracers may play an important role in both optimizing this transformative imaging modality and making it widely available. We have aimed to provide a concise overview of emerging 18F-labeled PSMA-targeted radiotracers undergoing active clinical development. Given the wide array of available radiotracers, comparative studies are needed to firmly establish the role of the available 18F-labeled compounds in the field of molecular PCa imaging, preferably in different clinical scenarios.
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Affiliation(s)
- Rudolf A. Werner
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Constantin Lapa
- Department of Nuclear Medicine, University Hospital Würzburg, Germany
| | - Sara Sheikbahaei
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital Würzburg, Germany
- Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Frederik L. Giesel
- Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg, Germany
| | - Spencer Behr
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital Cologne, Germany
| | - Hiroyuki Kimura
- Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Andreas K. Buck
- Department of Nuclear Medicine, University Hospital Würzburg, Germany
| | - Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael A. Gorin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steven P. Rowe
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Letter to the Editor re: "Semiquantitative Parameters in PSMA-Targeted PET Imaging with [ 18F]DCFPyL: Impact of Tumor Burden on Normal Organ Uptake". Mol Imaging Biol 2019; 22:19-21. [PMID: 31832870 DOI: 10.1007/s11307-019-01452-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Werner RA, Thackeray JT, Pomper MG, Bengel FM, Gorin MA, Derlin T, Rowe SP. Recent Updates on Molecular Imaging Reporting and Data Systems (MI-RADS) for Theranostic Radiotracers-Navigating Pitfalls of SSTR- and PSMA-Targeted PET/CT. J Clin Med 2019; 8:E1060. [PMID: 31331016 PMCID: PMC6678732 DOI: 10.3390/jcm8071060] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/05/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022] Open
Abstract
The theranostic concept represents a paradigmatic example of personalized treatment. It is based on the use of radiolabeled compounds which can be applied for both diagnostic molecular imaging and subsequent treatment, using different radionuclides for labelling. Clinically relevant examples include somatostatin receptor (SSTR)-targeted imaging and therapy for the treatment of neuroendocrine tumors (NET), as well as prostate-specific membrane antigen (PSMA)-targeted imaging and therapy for the treatment of prostate cancer (PC). As such, both classes of radiotracers can be used to triage patients for theranostic endoradiotherapy using positron emission tomography (PET). While interpreting PSMA- or SSTR-targeted PET/computed tomography scans, the reader has to navigate certain pitfalls, including (I.) varying normal biodistribution between different PSMA- and SSTR-targeting PET radiotracers, (II.) varying radiotracer uptake in numerous kinds of both benign and malignant lesions, and (III.) resulting false-positive and false-negative findings. Thus, two novel reporting and data system (RADS) classifications for PSMA- and SSTR-targeted PET imaging (PSMA- and SSTR-RADS) have been recently introduced under the umbrella term molecular imaging reporting and data systems (MI-RADS). Notably, PSMA- and SSTR-RADS are structured in a reciprocal fashion, i.e., if the reader is familiar with one system, the other system can readily be applied. Learning objectives of the present case-based review are as follows: (I.) the theranostic concept for the treatment of NET and PC will be briefly introduced, (II.) the most common pitfalls on PSMA- and SSTR-targeted PET/CT will be identified, (III.) the novel framework system for theranostic radiotracers (MI-RADS) will be explained, applied to complex clinical cases and recent studies in the field will be highlighted. Finally, current treatment strategies based on MI-RADS will be proposed, which will demonstrate how such a generalizable framework system truly paves the way for clinically meaningful molecular imaging-guided treatment of either PC or NET. Thus, beyond an introduction of MI-RADS, the present review aims to provide an update of recently published studies which have further validated the concept of structured reporting systems in the field of theranostics.
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Affiliation(s)
- Rudolf A Werner
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine and Molecular Imaging, Baltimore, MD 21287, USA
| | - James T Thackeray
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Martin G Pomper
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine and Molecular Imaging, Baltimore, MD 21287, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Frank M Bengel
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Michael A Gorin
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine and Molecular Imaging, Baltimore, MD 21287, USA
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Steven P Rowe
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine and Molecular Imaging, Baltimore, MD 21287, USA.
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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