Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Our purpose was to determine the relationship between serum prostate-specific antigen (PSA) level categories (<5, 5-10, 10-20, and >20 ng/mL) and the incidence of bone metastases detected by total-body 68Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT and to assess if expanding the 68Ga-PSMA-11 PET/CT imaging field to include the vertex and lower extremities (total-body acquisition) affects bone metastasis detection rates and patient management. Methods: This was a retrospective analysis of 388 prostate cancer patients enrolled in 5 prospective studies (NCT02940262, NCT03368547, NCT03042312, NCT04050215, and NCT03515577). All underwent 68Ga-PSMA-11 PET/CT scans acquired from vertex to toes for primary staging (n = 93/388, 24%), biochemical recurrence (BCR) localization (n = 225/388, 58%), or restaging metastatic disease (M1) before or during systemic therapy (n = 70/388, 18%) between September 2017 and May 2018. ⋯ Conclusion: Bone metastases as assessed with 68Ga-PSMA-11 PET/CT are prevalent even in patients with low serum PSA levels. Therefore, current guidelines for bone assessments in prostate cancer patients should be revisited because 68Ga-PSMA-11 PET/CT may provide additional information for accurate bone staging at low serum PSA levels. Including the total body (from vertex to toes) in 68Ga-PSMA-11 PET/CT imaging revealed additional bone lesions in 6% of patients, but without significantly affecting patient management.
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The world's first 194-cm-long total-body PET/CT scanner (uEXPLORER) has been built by the EXPLORER Consortium to offer a transformative platform for human molecular imaging in clinical research and health care. Its total-body coverage and ultra-high sensitivity provide opportunities for more accurate tracer kinetic analysis in studies of physiology, biochemistry, and pharmacology. The objective of this study was to demonstrate the capability of total-body parametric imaging and to quantify the improvement in image quality and kinetic parameter estimation by direct and kernel reconstruction of the uEXPLORER data. ⋯ Conclusion: This study demonstrated the capability of total-body parametric imaging using the uEXPLORER. Furthermore, the results showed the benefits of kernel-regularized reconstruction and direct parametric reconstruction. Both can achieve superior image quality for tracer kinetic studies compared with the conventional indirect OSEM for total-body imaging.
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Comparative Study Clinical Trial
Prospective Comparison of PET Imaging with PSMA-Targeted 18F-DCFPyL Versus Na18F for Bone Lesion Detection in Patients with Metastatic Prostate Cancer.
Bone metastases in prostate cancer (PCa) have important prognostic significance, and imaging modalities used for PCa staging should have high sensitivity for detecting such lesions. Prostate-specific membrane antigen (PSMA)-targeted PET radiotracers are promising new agents for imaging PCa. We undertook a head-to-head comparison of PSMA-targeted 2-(3-{1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) PET to Na18F PET to determine which modality was more sensitive for the detection of lesions suggestive of bone metastases in a group of patients with metastatic PCa. ⋯ Conclusion: PET/CT imaging using 18F-DCFPyL and Na18F PET had nearly identical sensitivities for the detection of bone lesions in patients with metastatic PCa. As would be expected, PSMA-targeted PET provides more information on soft-tissue disease. There may be little additional value to imaging PCa patients with Na18F after a PSMA-targeted PET scan has already been performed.
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Biochemically recurrent prostate cancer (BCR) is the main indication to perform prostate-specific membrane antigen PET/CT. However, localizing BCR with prostate-specific membrane antigen PET/CT remains challenging in patients with low prostate-specific antigen (PSA) values. Here, we studied the impact of advanced PET image reconstruction methods on BCR localization and interobserver agreement with 18F-DCFPyL PET/CT scans in patients with BCR and low PSA values. ⋯ Conclusion: Applying advanced image reconstruction for 18F-DCFPyL PET/CT scans did not increase BCR localization in patients with BCR and low PSA values (reader consensus). Yet, the increased number of positive individual readings may imply that further development of image reconstruction methods holds potential to improve BCR localization. No improved interobserver agreement was observed with advanced reconstruction compared with standard 4-mm reconstruction.
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By contributing to noninvasive molecular imaging and radioguided surgery, nuclear medicine has been instrumental in the realization of precision medicine. During the last decade, it has also become apparent that nuclear medicine (e.g., in the form of bimodal/hybrid tracers) can help to empower fluorescence-guided surgery. More specifically, when using hybrid tracers, lesions can be noninvasively identified and localized with a high sensitivity and precision (guided by the radioisotope) and ultimately resected under real-time optical guidance (fluorescent dye). This topical review discusses early clinical successes, preclinical directions, and key aspects that could have an impact on the future of this field.