Refine
Has Fulltext
- yes (27)
Is part of the Bibliography
- yes (27) (remove)
Document Type
- Journal article (23)
- Preprint (4)
Language
- English (27) (remove)
Keywords
- Positronen-Emissions-Tomografie (8)
- prostate cancer (8)
- theranostics (7)
- PET (5)
- PSMA (5)
- PSMA-RADS (4)
- RADS (4)
- neuroendocrine tumor (4)
- prostate-specific membrane antigen (4)
- 18F-DCFPyL (3)
Institute
- Klinik und Poliklinik für Nuklearmedizin (27)
- Deutsches Zentrum für Herzinsuffizienz (DZHI) (4)
- Medizinische Klinik und Poliklinik II (4)
- Institut für diagnostische und interventionelle Radiologie (Institut für Röntgendiagnostik) (2)
- Pathologisches Institut (2)
- Urologische Klinik und Poliklinik (2)
- Comprehensive Cancer Center Mainfranken (1)
- Institut für Pharmazie und Lebensmittelchemie (1)
- Medizinische Klinik und Poliklinik I (1)
- Neurochirurgische Klinik und Poliklinik (1)
Sonstige beteiligte Institutionen
EU-Project number / Contract (GA) number
- 701983 (11)
In recent years, a paradigm shift from single-photon-emitting radionuclide radiotracers toward positron-emission tomography (PET) radiotracers has occurred in nuclear oncology. Although PET-based molecular imaging of the kidneys is still in its infancy, such a trend has emerged in the field of functional renal radionuclide imaging. Potentially allowing for precise and thorough evaluation of renal radiotracer urodynamics, PET radionuclide imaging has numerous advantages including precise anatomical co-registration with CT images and dynamic three-dimensional imaging capability. In addition, relative to scintigraphic approaches, PET can allow for significantly reduced scan time enabling high-throughput in a busy PET practice and further reduces radiation exposure, which may have a clinical impact in pediatric populations. In recent years, multiple renal PET radiotracers labeled with C-11, Ga-68, and F-18 have been utilized in clinical studies. Beyond providing a precise non-invasive read-out of renal function, such radiotracers may also be used to assess renal inflammation. This manuscript will provide an overview of renal molecular PET imaging and will highlight the transformation of conventional scintigraphy of the kidneys toward novel, high-resolution PET imaging for assessing renal function. In addition, future applications will be introduced, e.g. by transferring the concept of molecular image-guided diagnostics and therapy (theranostics) to the field of nephrology.
Prostate-specific membrane antigen (PSMA)-directed positron emission tomography/computed tomography (PET/CT) is increasingly utilized for staging of men with prostate cancer (PC). To increase interpretive certainty, the standardized PSMA reporting and data system (RADS) has been proposed. Using PSMA-RADS, we characterized lesions in 18 patients imaged with \(^{18}\)F-PSMA-1007 PET/CT for primary staging and determined the stability of semi-quantitative parameters. Six hundred twenty-three lesions were categorized according to PSMA-RADS and manually segmented. In this context, PSMA-RADS-3A (soft-tissue) or -3B (bone) lesions are defined as being indeterminate for the presence of PC. For PMSA-RADS-4 and -5 lesions; however, PC is highly likely or almost certainly present [with further distinction based on absence (PSMA-RADS-4) or presence (PSMA-RADS-5) of correlative findings on CT]. Standardized uptake values (SUV\(_{max}\), SUV\(_{peak}\), SUV\(_{mean}\)) were recorded, and volumetric parameters [PSMA-derived tumor volume (PSMA-TV); total lesion PSMA (TL-PSMA)] were determined using different maximum intensity thresholds (MIT) (40 vs. 45 vs. 50%). SUV\(_{max}\) was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories (p ≤ 0.0322). In particular, the clinically challenging PSMA-RADS-3A lesions showed significantly lower SUV\(_{max}\) and SUV\(_{peak}\) compared to the entire PSMA-RADS-4 or -5 cohort (p < 0.0001), while for PSMA-RADS-3B this only applies when compared to the entire PSMA-RADS-5 cohort (p < 0.0001), but not to the PSMA-RADS-4 cohort (SUV\(_{max}\), p = 0.07; SUV\(_{peak}\), p = 0.08). SUV\(_{mean}\) (p = 0.30) and TL-PSMA (p = 0.16) in PSMA-RADS-5 lesions were not influenced by changing the MIT, while PSMA-TV showed significant differences when comparing 40 vs. 50% MIT (p = 0.0066), which was driven by lymph nodes (p = 0.0239), but not bone lesions (p = 0.15). SUV\(_{max}\) was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories in \(^{18}\)F-PSMA-1007 PET/CT. As such, the latter parameter may assist the interpreting molecular imaging specialist in assigning the correct PSMA-RADS score to sites of disease, thereby increasing diagnostic certainty. In addition, changes of the MIT in PSMA-RADS-5 lesions had no significant impact on SUV\(_{mean}\) and TL-PSMA in contrast to PSMA-TV.
The use of prostate-specific membrane antigen targeted PET imaging for the evaluation of prostate cancer has increased significantly in the last couple of decades. When evaluating these imaging findings based on the PSMA reporting and data system version 1.0, which categorize lesions based on their likelihood of prostate cancer involvement, PSMA-RADS-3A lesions are commonly seen, which are indeterminate for the presence of disease. A total of 28 patients with 171 PSMA-RADS-3A lesions on \(^{18}\)F-DCFPyL PET/CT scans from June 2016 to May 2017 who had follow-up cross-sectional imaging over time were included in this study. The PSA levels of patients with PSMA-RADS-3A lesions were categorized into four groups, 0–0.2, 0.2–1, 1–2, and >2 ng/mL. The pre-operative Gleason score of these patients was categorized into two groups, Gleason score < 7 or ≥7. The median age for these patients was 72.5 years (range 59–81). The median PSA value for patients with positive lesions was significantly higher than those with negative lesions (5.8 ng/mL vs. 0.2 ng/mL, p < 0.0001). The lesion positivity rate was significantly higher in patients with PSA > 1 ng/mL (18.2% vs. 81.9%, p < 0.001). On ROC analysis, the highest classification accuracy was seen at PSA ≥ 0.6 ng/mL of 80.12% (95% CI = 73.69–86.16%), and the area under the curve was 71.32% (95% CI = 61.9–80.7%, p < 0.0001). A total of 96.4% (108/112) of patients with positive lesions and 86.4% (51/59) of patients with negative lesions had a PSMA-RADS-4/5 lymph node on the initial \(^{18}\)F-DCFPyL PET/CT scan (p = 0.02). In patients with a Gleason score ≥ 7, the presence of positive PSMA-RADS-3A lesions was higher, compared to negative PSMA-RADS-3A lesions (p = 0.049). Higher PSA levels in patients with PSMA-RADS-3A lesions can point towards the presence of true positivity. PSA levels may be considered in deciding whether to call an indeterminate lesion on PSMA PET.
Prostate-specific membrane antigen (PSMA)-targeted PET imaging for prostate cancer with \(^{68}\)Ga-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 \(^{68}\)Ga- to \(^{18}\)F-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 \(^{68}\)Ge/\(^{68}\)Ga 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, \(^{18}\)F-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, \(^{18}\)F-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 \(^{18}\)F-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 \(^{18}\)F-labeled compounds in the field of molecular PCa imaging, preferably in different clinical scenarios.
We have recently demonstrated CXCR4 overexpression in vestibular schwannomas (VS). This study investigated the feasibility of CXCR4-directed positron emission tomography/computed tomography (PET/CT) imaging of VS using the radiolabeled chemokine ligand [\(^{68}\)Ga]Pentixafor.
Methods: 4 patients with 6 primarily diagnosed or pre-treated/observed VS were enrolled. All subjects underwent [\(^{68}\)Ga]Pentixafor PET/CT prior to surgical resection. Images were analyzed visually and semi-quantitatively for CXCR4 expression including calculation of tumor-to-background ratios (TBR). Immunohistochemistry served as standard of reference in three patients.
Results: [\(^{68}\)Ga]Pentixafor PET/CT was visually positive in all cases. SUV\(_{mean}\) and SUV\(_{max}\) were 3.0 ± 0.3 and 3.8 ± 0.4 and TBR\(_{mean}\) and TBR\(_{max}\) were 4.0 ± 1.4 and 5.0 ± 1.7, respectively. Histological analysis confirmed CXCR4 expression in tumors.
Conclusion: Non-invasive imaging of CXCR4 expression using [\(^{68}\)Ga]Pentixafor PET/CT of VS is feasible and could prove useful for in vivo assessment of CXCR4 expression.