Publications by authors named "Tim E Phelps"

Objective: To assess impact of image quality on prostate cancer extraprostatic extension (EPE) detection on MRI using a deep learning-based AI algorithm.

Materials And Methods: This retrospective, single institution study included patients who were imaged with mpMRI and subsequently underwent radical prostatectomy from June 2007 to August 2022. One genitourinary radiologist prospectively evaluated each patient using the NCI EPE grading system.

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Background Multiparametric MRI (mpMRI) improves prostate cancer (PCa) detection compared with systematic biopsy, but its interpretation is prone to interreader variation, which results in performance inconsistency. Artificial intelligence (AI) models can assist in mpMRI interpretation, but large training data sets and extensive model testing are required. Purpose To evaluate a biparametric MRI AI algorithm for intraprostatic lesion detection and segmentation and to compare its performance with radiologist readings and biopsy results.

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Pheochromocytomas and paragangliomas (PPGLs) are rare catecholamine-producing tumors that express somatostatin receptors (SSTR) that can be treated with lutetium-177 DOTATATE (Lu-177-TRT); however, treatment can be associated with life-threatening cardiovascular events. A patient case with management strategies for high-risk PPGL patients receiving Lu-177-TRT is described. The 78-year-old patient with metastatic paraganglioma was enrolled and treated under NCT03206060.

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Rationale And Objectives: Efficiently detecting and characterizing metastatic bone lesions on staging CT is crucial for prostate cancer (PCa) care. However, it demands significant expert time and additional imaging such as PET/CT. We aimed to develop an ensemble of two automated deep learning AI models for 1) bone lesion detection and segmentation and 2) benign vs.

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Background: Image quality evaluation of prostate MRI is important for successful implementation of MRI into localized prostate cancer diagnosis.

Purpose: To examine the impact of image quality on prostate cancer detection using an in-house previously developed artificial intelligence (AI) algorithm.

Study Type: Retrospective.

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Article Synopsis
  • MRI/ultrasound fusion-guided targeted biopsy (TBx) is essential for effective management of prostate cancer by helping with precise risk stratification.
  • This study compared the performance of two versions of the PI-RADS scoring system (v2.0 and v2.1) in predicting changes in cancer severity after TBx and subsequent radical prostatectomy (RP).
  • Results showed no significant differences in upgrade or downgrade rates between the two versions, indicating that both versions are equivalent in assessing clinically significant prostate cancer.
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  • The study aimed to assess a biparametric MRI-based AI model for detecting local prostate cancer recurrence in post-radiotherapy patients.
  • Of 62 patients analyzed, the AI model identified 40 lesions, but its detection performance was lower than that of radiologists, with sensitivity rates of 76.1% compared to 91.3%.
  • The AI showed better results in patients treated with external beam radiation therapy, but further validation is needed before it can be used clinically.
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Currently most clinical models for predicting biochemical recurrence (BCR) of prostate cancer (PCa) after radical prostatectomy (RP) incorporate staging information from RP specimens, creating a gap in preoperative risk assessment. The purpose of our study was to compare the utility of presurgical staging information from MRI and postsurgical staging information from RP pathology in predicting BCR in patients with PCa. This retrospective study included 604 patients (median age, 60 years) with PCa who underwent prostate MRI before RP from June 2007 to December 2018.

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Osteosarcoma (OS) is an aggressive pediatric cancer with unmet therapeutic needs. Glutaminase 1 (GLS1) inhibition, alone and in combination with metformin, disrupts the bioenergetic demands of tumor progression and metastasis, showing promise for clinical translation. Three positron emission tomography (PET) clinical imaging agents, [F]fluoro-2-deoxy-2-D-glucose ([F]FDG), 3'-[F]fluoro-3'-deoxythymidine ([F]FLT), and (2S, 4R)-4-[F]fluoroglutamine ([F]GLN), were evaluated in the MG63.

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Background Data regarding the prospective performance of Prostate Imaging Reporting and Data System (PI-RADS) version 2.1 alone and in combination with quantitative MRI features for prostate cancer detection is limited. Purpose To assess lesion-based clinically significant prostate cancer (csPCa) rates in different PI-RADS version 2.

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Article Synopsis
  • The study assesses how effective reduced-core biopsy techniques are for detecting clinically significant prostate cancer (csPCa) in patients with specific mpMRI-visible lesions.
  • The research involved 212 patients undergoing both targeted biopsy (TBx) and systematic biopsy (SBx) to compare detection rates of various biopsy strategies.
  • Findings reveal that while reduced-core schemes showed decent detection rates, they underestimated csPCa by at least 8%, indicating that the combined TBx + SBx method is more effective in identifying the disease.
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Indeterminate bone lesions (IBLs) on prostate-specific membrane antigen (PSMA) PET/CT are common. This study aimed to define variables that predict whether such lesions are likely malignant or benign using features on PSMA PET/CT. F-DCFPyL PET/CT imaging was performed on 243 consecutive patients with high-risk primary or biochemically recurrent prostate cancer.

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Objective: To determine the rigor, generalizability, and reproducibility of published classification and detection artificial intelligence (AI) models for prostate cancer (PCa) on MRI using the Checklist for Artificial Intelligence in Medical Imaging (CLAIM) guidelines, a 42-item checklist that is considered a measure of best practice for presenting and reviewing medical imaging AI research.

Materials And Methods: This review searched English literature for studies proposing PCa AI detection and classification models on MRI. Each study was evaluated with the CLAIM checklist.

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High expression of prostate-specific membrane antigen (PSMA) in prostate cancers prompted the development of the PSMA-targeted PET-imaging agent [F]DCFPyL, which was recently approved by the FDA. Fluorine-18-labeled Lys-Urea-Glu-based oxime derivatives of [F]DCFPyL were prepared for the comparison of their in vitro and in vivo properties to potentially improve kidney clearance and tumor targeting. The oxime radiotracers were produced by condensation of an aminooxy functionalized PSMA-inhibitor Lys-Urea-Glu scaffold with fluorine-18-labeled aldehydes.

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Rhodium-105 (0.567 MeV β, 319 keV γ, 35.4 h half-life) was produced by neutron irradiation of enriched Ru (>99%) over multiple decades.

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[Th]Th-3,2-HOPO-MSLN-mAb, a mesothelin (MSLN)-targeted thorium-227 therapeutic conjugate, is currently in phase I clinical trial; however, direct PET imaging using this conjugate is technically challenging. Thus, using the same MSLN antibody, we synthesized 3,2-HOPO and deferoxamine (DFO)-based zirconium-89 antibody conjugates, [Zr]Zr-3,2-HOPO-MSLN-mAb and [Zr]Zr-DFO-MSLN-mAb, respectively, and compared them and . [Zr]Zr-3,2-HOPO-MSLN-mAb and [Zr]Zr-DFO-MSLN-mAb were evaluated to determine binding affinity and immunoreactivity in HT29-MSLN and PDX (NCI-Meso16, NCI-Meso21) cells.

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Article Synopsis
  • Patients with osteoblastic bone metastases may benefit from radium-223 therapy, and sodium fluoride-18 imaging can help identify bone lesions and predict ra-223 uptake.
  • This study analyzes the distribution of F-NaF and RaCl in human osteosarcoma mouse tumors to understand their correlation better.
  • Results show that F and Ra accumulate similarly in the tumors and particularly in microcalcified areas, suggesting that F-NaF may be a useful predictor of RaCl accumulation in these regions.
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The C-X-C motif chemokine receptor 4 (CXCR4) is a seven-transmembrane G protein-coupled receptor that is overexpressed in numerous diseases, particularly in various cancers and is a powerful chemokine, attracting cells to the bone marrow niche. Therefore, CXCR4 is an attractive target for imaging and therapeutic purposes. The goal of this study is to develop an efficient, reproducible, and straightforward method to prepare a fluorine-18 labeled CXCR4 ligand.

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The chemistry and radiochemistry of high specific activity radioisotopes of arsenic, rhenium and rhodium are reviewed with emphasis on University of Missouri activities over the past several decades, and includes recent results. The nuclear facilities at the University of Missouri (10 MW research reactor and 16.5 MeV GE PETtrace cyclotron) allow research and development into novel theranostic radionuclides.

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Introduction: Rhenium-186g (t = 3.72 d) is a β emitting isotope suitable for theranostic applications. Current production methods rely on reactor production by way of the reaction Re(n,γ)Re, which results in low specific activities limiting its use for cancer therapy.

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Here we report the formation of the first examples of dicopper(III) bis(μ-oxo) complexes ligated by the primary amines, propylenediamine, and N,N,-dimethyl propylenediamine. Stabilization of these new compounds is effected at -125 °C by "core capture"- introduction of exogenous ligand to a preformed dicopper(III) bis(μ-oxo) complex supported by the peralkylated tetramethyl propylenediamine. Primary amine ligation in these compounds matches the single primary amine coordination of the putative active site of particulate methane monooxygenase (pMMO) and polysaccharide monooxygenase.

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