scholarly journals PSMA PET Imaging in Glioblastoma: A Preclinical Evaluation and Theranostic Outlook

2021 ◽  
Vol 11 ◽  
Author(s):  
Maximilian A. Kirchner ◽  
Adrien Holzgreve ◽  
Matthias Brendel ◽  
Michael Orth ◽  
Viktoria C. Ruf ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Ex Vivo ◽  
Time Frame ◽  
Normal Brain ◽  
Radioligand Therapy ◽  
Time Activity ◽  
Preclinical Evaluation ◽  
Standardized Uptake Values ◽  
Psma Pet ◽  
Post Implantation

BackgroundProstate specific membrane antigen (PSMA) PET imaging has recently gained attention in glioblastoma (GBM) patients as a potential theranostic target for PSMA radioligand therapy. However, PSMA PET has not yet been established in a murine GBM model. Our goal was to investigate the potential of PSMA PET imaging in the syngeneic GL261 GBM model and to give an outlook regarding the potential of PMSA radioligand therapy in this model.MethodsWe performed an 18F-PSMA-1007 PET study in the orthotopic GL261 model (n=14 GBM, n=7 sham-operated mice) with imaging at day 4, 8, 11, 15, 18 and 22 post implantation. Time-activity-curves (TAC) were extracted from dynamic PET scans (0-120 min p. i.) in a subset of mice (n=4 GBM, n=3 sham-operated mice) to identify the optimal time frame for image analysis, and standardized-uptake-values (SUV) as well as tumor-to-background ratios (TBR) using contralateral normal brain as background were calculated in all mice. Additionally, computed tomography (CT), ex vivo and in vitro18F-PSMA-1007 autoradiographies (ARG) were performed.ResultsTAC analysis of GBM mice revealed a plateau of TBR values after 40 min p. i. Therefore, a 30 min time frame between 40-70 min p. i. was chosen for PET quantification. At day 15 and later, GBM mice showed a discernible PSMA PET signal on the inoculation site, with highest TBRmean in GBM mice at day 18 (7.3 ± 1.3 vs. 1.6 ± 0.3 in shams; p=0.024). Ex vivo ARG confirmed high tracer signal in GBM compared to healthy background (TBRmean 26.9 ± 10.5 vs. 1.6 ± 0.7 in shams at day 18/22 post implantation; p=0.002). However, absolute uptake values in the GL261 tumor remained low (e.g., SUVmean 0.21 ± 0.04 g/ml at day 18) resulting in low ratios compared to dose-relevant organs (e.g., mean tumor-to-kidney ratio 1.5E-2 ± 0.5E-2).ConclusionsAlthough 18F-PSMA-1007 PET imaging of GL261 tumor-bearing mice is feasible and resulted in high TBRs, absolute tumoral uptake values remained low and hint to limited applicability of the GL261 model for PSMA-directed therapy studies. Further investigations are warranted to identify suitable models for preclinical evaluation of PSMA-targeted theranostic approaches in GBM.

scholarly journals Dynamic 18F-FDOPA-PET/MRI for the preoperative evaluation of gliomas: correlation with stereotactic histopathology

2020 ◽  
Vol 7 (6) ◽  
pp. 656-667
Author(s):  
Maria R Ponisio ◽  
Jonathan E McConathy ◽  
Sonika M Dahiya ◽  
Michelle M Miller-Thomas ◽  
Keith M Rich ◽  
...  
Keyword(s):  
Patient Management ◽  
Preoperative Evaluation ◽  
Tracer Uptake ◽  
Low Grade ◽  
Normal Brain ◽  
Dynamic Pet ◽  
Ki 67 ◽  
Time Activity ◽  
Standardized Uptake Values ◽  
Significant Difference

Abstract Background MRI alone has limited accuracy for delineating tumor margins and poorly predicts the aggressiveness of gliomas, especially when tumors do not enhance. This study evaluated simultaneous 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (FDOPA)-PET/MRI to define tumor volumes compared to MRI alone more accurately, assessed its role in patient management, and correlated PET findings with histopathology. Methods Ten patients with known or suspected gliomas underwent standard of care surgical resection and/or stereotactic biopsy. FDOPA-PET/MRI was performed prior to surgery, allowing for precise co-registration of PET, MR, and biopsies. The biopsy sites were modeled as 5-mm spheres, and the local FDOPA uptake at each site was determined. Correlations were performed between measures of tumor histopathology, and static and dynamic PET values: standardized uptake values (SUVs), tumor to brain ratios, metabolic tumor volumes, and tracer kinetics at volumes of interest (VOIs) and biopsy sites. Results Tumor FDOPA-PET uptake was visualized in 8 patients. In 2 patients, tracer uptake was similar to normal brain reference with no histological findings of malignancy. Eight biopsy sites confirmed for glioma had FDOPA uptake without T1 contrast enhancement. The PET parameters were highly correlated only with the cell proliferation marker, Ki-67 (SUVmax: r = 0.985, P = .002). In this study, no statistically significant difference between high-grade and low-grade tumors was demonstrated. The dynamic PET analysis of VOIs and biopsy sites showed decreasing time-activity curves patterns. FDOPA-PET imaging directly influenced patient management. Conclusions Simultaneous FDOPA-PET/MRI allowed for more accurate visualization and delineation of gliomas, enabling more appropriate patient management and simplified validation of PET findings with histopathology.

Preclinical evaluation of F-18-PSMA PET in glioblastoma as a potential theranostic approach

2020 ◽  
Author(s):  
M Kirchner ◽  
A Holzgreve ◽  
M Brendel ◽  
V Ruf ◽  
D Pötter ◽  
...  
Keyword(s):  
Preclinical Evaluation ◽  
Psma Pet

scholarly journals Fluorinated PET imaging probes targeting fibroblast activation protein: radiolabeling and preclinical evaluation

2021 ◽  
Vol 96-97 ◽  
pp. S40-S41
Author(s):  
Filipe Elvas ◽  
Muhammet Tanc ◽  
Yentl Van Rymenant ◽  
Lucas Beroske ◽  
Stef De Lombaerde ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Fibroblast Activation Protein ◽  
Preclinical Evaluation ◽  
Fibroblast Activation ◽  
Imaging Probes

PET imaging of neural activity, β-amyloid, and tau in normal brain aging

2021 ◽  
Author(s):  
Kai Zhang ◽  
Hiroshi Mizuma ◽  
Xiaohui Zhang ◽  
Kayo Takahashi ◽  
Chentao Jin ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Neural Activity ◽  
Brain Aging ◽  
Normal Brain ◽  
Β Amyloid

scholarly journals Correlation of an Index-Lesion-Based SPECT Dosimetry Method with Mean Tumor Dose and Clinical Outcome after 177Lu-PSMA-617 Radioligand Therapy

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 428
Author(s):  
Friederike Völter ◽  
Lena Mittlmeier ◽  
Astrid Gosewisch ◽  
Julia Brosch-Lenz ◽  
Franz Josef Gildehaus ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Single Photon ◽  
Photon Emission ◽  
Whole Body ◽  
Biochemical Response ◽  
Emission Computed Tomography ◽  
Radioligand Therapy ◽  
Index Lesion ◽  
Recist 1.1 ◽  
Psma Pet

Background: Dosimetry can tailor prostate-specific membrane-antigen-targeted radioligand therapy (PSMA-RLT) for metastatic castration-resistant prostate cancer (mCRPC). However, whole-body tumor dosimetry is challenging in patients with a high tumor burden. We evaluate a simplified index-lesion-based single-photon emission computed tomography (SPECT) dosimetry method in correlation with clinical outcome. Methods: 30 mCRPC patients were included (median 71 years). The dosimetry was performed for the first cycle using quantitative 177Lu-SPECT. The response was evaluated using RECIST 1.1 and PERCIST criteria, as well as changes in PSMA-positive tumor volume (PSMA-TV) in post-therapy PSMA-PET and biochemical response according to PSA changes after two RLT cycles. Results: Mean tumor doses as well as index-lesion doses were significantly higher in PERCIST responders compared to non-responders (10.2 ± 12.0 Gy/GBq vs. 4.0 ± 2.9 Gy/GBq, p = 0.03 and 13.7 ± 14.2 Gy/GBq vs. 5.9 ± 4.4 Gy/GBq, p = 0.04, respectively). No significant differences in mean tumor and index lesion doses were observed between responders and non-responders according to RECIST 1.1, PSMA-TV, and biochemical response criteria. Conclusion: Compared to mean tumor doses on a patient level, single index-lesion-based SPECT dosimetry correlates equally well with the response to PSMA-RLT according to PERCIST criteria and may represent a fast and feasible dosimetry approach for clinical routine.

scholarly journals Synthesis and preclinical evaluation of [methylpiperazine-11C]brigatinib as a PET imaging agent for mutated EGFR and ALK positive tumors

2021 ◽  
Vol 96-97 ◽  
pp. S51-S52
Author(s):  
Antonia Högnäsbacka ◽  
Esther Kooijman ◽  
Robert Schuit ◽  
Maxime Schreurs ◽  
Mariska Verlaan ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Imaging Agent ◽  
Preclinical Evaluation ◽  
Alk Positive

scholarly journals Pattern of failure in prostate cancer previously treated with radical prostatectomy and post-operative radiotherapy: a secondary analysis of two prospective studies using novel molecular imaging techniques

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Lindsay S. Rowe ◽  
Stephanie Harmon ◽  
Adam Horn ◽  
Uma Shankavaram ◽  
Soumyajit Roy ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radical Prostatectomy ◽  
Pet Imaging ◽  
Biochemical Recurrence ◽  
Imaging Techniques ◽  
Specific Antigen ◽  
Definitive Treatment ◽  
Pattern Of Failure ◽  
Link Type ◽  
Psma Pet

Abstract Background Prostate Membrane Specific Antigen (PSMA) positron emission tomography (PET) and multiparametric MRI (mpMRI) have shown high accuracy in identifying recurrent lesions after definitive treatment in prostate cancer (PCa). In this study, we aimed to outline patterns of failure in a group of post-prostatectomy patients who received adjuvant or salvage radiation therapy (PORT) and subsequently experienced biochemical recurrence, using 18F-PSMA PET/CT and mpMRI. Methods PCa patients with biochemical failure post-prostatectomy, and no evident site of recurrence on conventional imaging, were enrolled on two prospective trials of first and second generation 18F-PSMA PET agents (18F-DCFBC and 18F-DCFPyL) in combination with MRI between October 2014 and December 2018. The primary aim of our study is to characterize these lesions with respect to their location relative to previous PORT field and received dose. Results A total of 34 participants underwent 18F-PSMA PET imaging for biochemical recurrence after radical prostatectomy and PORT, with 32/34 found to have 18F-PSMA avid lesions. On 18F-PSMA, 17/32 patients (53.1%) had metastatic disease, 8/32 (25.0%) patients had locoregional recurrences, and 7/32 (21.9%) had local failure in the prostate fossa. On further exploration, we noted 6/7 (86%) of prostate fossa recurrences were in-field and were encompassed by 100% isodose lines, receiving 64.8–72 Gy. One patient had marginal failure encompassed by the 49 Gy isodose. Conclusions 18F-PSMA PET imaging demonstrates promise in identifying occult PCa recurrence after PORT. Although distant recurrence was the predominant pattern of failure, in-field recurrence was noted in approximately 1/5th of patients. This should be considered in tailoring radiotherapy practice after prostatectomy. Trial registrationwww.clinicaltrials.gov, NCT02190279 and NCT03181867. Registered July 12, 2014, https://clinicaltrials.gov/ct2/show/NCT02190279 and June 8 2017, https://clinicaltrials.gov/ct2/show/NCT03181867.

scholarly journals Imaging and Methotrexate Response Monitoring of Systemic Inflammation in Arthritic Rats Employing the Macrophage PET Tracer [18F]Fluoro-PEG-Folate

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Durga M. S. H. Chandrupatla ◽  
Gerrit Jansen ◽  
Elise Mantel ◽  
Philip S. Low ◽  
Takami Matsuyama ◽  
...  
Keyword(s):  
Systemic Inflammation ◽  
Pet Imaging ◽  
Ex Vivo ◽  
Folate Receptor ◽  
Tracer Uptake ◽  
Response Monitoring ◽  
Distribution Analysis ◽  
Pet Tracer ◽  
Systemic Inflammatory Disease ◽  
Before And After

Background. In rheumatoid arthritis, articular inflammation is a hallmark of disease, while the involvement of extra-articular tissues is less well defined. Here, we examined the feasibility of PET imaging with the macrophage tracer [18F]fluoro-PEG-folate, targeting folate receptorβ(FRβ), to monitor systemic inflammatory disease in liver and spleen of arthritic rats before and after methotrexate (MTX) treatment.Methods. [18F]Fluoro-PEG-folate PET scans (60 min) were acquired in saline- and MTX-treated (1 mg/kg, 4x) arthritic rats, followed by tissue resection and radiotracer distribution analysis. Liver and spleen tissues were stained for ED1/ED2-macrophage markers and FRβexpression.Results. [18F]Fluoro-PEG-folate PET and ex vivo tissue distribution studies revealed a significant (p<0.01) 2-fold lower tracer uptake in both liver and spleen of MTX-treated arthritic rats. Consistently, ED1- and ED2-positive macrophages were significantly (p<0.01) decreased in liver (4-fold) and spleen (3-fold) of MTX-treated compared with saline-treated rats. Additionally, FRβ-positive macrophages were also significantly reduced in liver (5-fold,p<0.005) and spleen (3-fold,p<0.01) of MTX- versus saline-treated rats.Conclusions. MTX treatment reduced activated macrophages in liver and spleen, as markers for systemic inflammation in these organs. Macrophage PET imaging with [18F]fluoro-PEG-folate holds promise for detection of systemic inflammation in RA as well as therapy (MTX) response monitoring.

scholarly journals Investigating CXCR4 expression of tumor cells and the vascular compartment: A multimodal approach

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260186
Author(s):  
Marta Braga ◽  
Chee Hau Leow ◽  
Javier Hernandez Gil ◽  
Jin H. Teh ◽  
Laurence Carroll ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Microvessel Density ◽  
Ex Vivo ◽  
Cost Effective ◽  
Cxcr4 Expression ◽  
Attractive Alternative ◽  
Tumor Models ◽  
Chemokine Receptor 4 ◽  
And Control ◽  
Vascular Compartment

The C-X-C chemokine receptor 4 (CXCR4) is G protein-coupled receptor that upon binding to its cognate ligand, can lead to tumor progression. Several CXCR4-targeted therapies are currently under investigation, and with it comes the need for imaging agents capable of accurate depiction of CXCR4 for therapeutic stratification and monitoring. PET agents enjoy the most success, but more cost-effective and radiation-free approaches such as ultrasound (US) imaging could represent an attractive alternative. In this work, we developed a targeted microbubble (MB) for imaging of vascular CXCR4 expression in cancer. A CXCR4-targeted MB was developed through incorporation of the T140 peptide into the MB shell. Binding properties of the T140-MB and control, non-targeted MB (NT-MB) were evaluated in MDA-MB-231 cells where CXCR4 expression was knocked-down (via shRNA) through optical imaging, and in the lymphoma tumor models U2932 and SuDHL8 (high and low CXCR4 expression, respectively) by US imaging. PET imaging of [18F]MCFB, a tumor-penetrating CXCR4-targeted small molecule, was used to provide whole-tumor CXCR4 readouts. CXCR4 expression and microvessel density were performed by immunohistochemistry analysis and western blot. T140-MB were formed with similar properties to NT-MB and accumulated sensitively and specifically in cells according to their CXCR4 expression. In NOD SCID mice, T140-MB persisted longer in tumors than NT-MB, indicative of target interaction, but showed no difference between U2932 and SuDHL8. In contrast, PET imaging with [18F]MCFB showed a marked difference in tumor uptake at 40–60 min post-injection between the two tumor models (p<0.05). Ex vivo analysis revealed that the large differences in CXCR4 expression between the two models are not reflected in the vascular compartment, where the MB are restricted; in fact, microvessel density and CXCR4 expression in the vasculature was comparable between U2932 and SuDHL8 tumors. In conclusion, we successfully developed a T140-MB that can be used for imaging CXCR4 expression in the tumor vasculature.

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