Journal of Nuclear Medicine

Cancer of unknown primary (CUP) represents a heterogeneous group of metastatic tumors for which standardized diagnostic work-up fails to identify the primary site. We aimed to describe the Peter MacCallum Cancer Centre experience with 18 F-FDG PET/CT in extracervical CUP with respect to detection of a primary site and its impact on management. A secondary aim was to compare overall survival (OS) in patients with and without a detected primary site. Methods: CUP patients treated between 2014 and 2020 were identified from medical oncology clinics and 18 F-FDG PET/CT records...

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Understanding which patients with human epidermal growth factor receptor 2 (HER2)-negative or -low metastatic breast cancer (MBC) benefit from HER2-targeted strategies is urgently needed. We assessed the whole-body heterogeneity of HER2 expression on 89 Zr-trastuzumab PET (HER2 PET) and the diagnostic performance of HER2 PET in a large series of patients, including HER2-negative and -low MBC. Methods: In the IMPACT-MBC study, patients with newly diagnosed and nonrapidly progressive MBC of all subtypes were included...

Unspecific bone uptake (UBU) related to [18 F]PSMA-1007 PET/CT imaging represents a clinical challenge. We aimed to assess whether a combination of clinical, biochemical, and imaging parameters could predict skeletal metastases in patients with [18 F]PSMA-1007 bone focal uptake, aiding in result interpretation. Methods: We retrospectively analyzed [18 F]PSMA-1007 PET/CT performed in hormone-sensitive prostate cancer (PCa) patients at 3 tertiary-level cancer centers. A fourth center was involved in performing an external validation...

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C-X-C motif chemokine receptor 4 (CXCR4)-directed imaging has gained clinical interest in aiding clinical diagnostics in primary aldosteronism (PA). We retrospectively evaluated the feasibility of CXCR4-directed scintigraphy using the novel CXCR-4 ligand [99m Tc]Tc-pentixatec in patients with PA. Methods: Six patients (mean age ± SD, 49 ± 15 y) underwent CXCR4-directed scintigraphy (including planar imaging and SPECT/CT) 30, 120, and 240 min after injection of 435 ± 50 MBq of [99m Tc]Tc-pentixatec...

Preclinical data have shown that 161 Tb-labeled peptides targeting the somatostatin receptor are therapeutically more effective for peptide receptor radionuclide therapy than are their 177 Lu-labeled counterparts. To further substantiate this enhanced therapeutic effect, we performed cellular dosimetry to quantify the absorbed dose to the cell nucleus and compared dose-response curves to evaluate differences in relative biological effectiveness in vitro. Methods: CA20948 cell survival was assessed after treatment with [161 Tb]Tb- and [177 Lu]Lu-DOTATATE (agonist) and with [161 Tb]Tb- and [177 Lu]Lu-DOTA-LM3 (antagonist) via a clonogenic assay...

Quantification of 18 F-FDG PET images is useful for accurate diagnosis and evaluation of various brain diseases, including brain tumors, epilepsy, dementia, and Parkinson disease. However, accurate quantification of 18 F-FDG PET images requires matched 3-dimensional T1 MRI scans of the same individuals to provide detailed information on brain anatomy. In this paper, we propose a transfer learning approach to adapt a pretrained deep neural network model from amyloid PET to spatially normalize 18 F-FDG PET images without the need for 3-dimensional MRI...

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The tumor marker cancer antigen 15-3 (CA 15-3) is that most commonly used to monitor metastatic breast cancer during active therapy and surveillance for disease recurrence after treatment. The association of CA 15-3 and 18 F-FDG PET/CT findings can be considered complementary, since any significant rise may indicate the presence of disease and imaging is able to map the tumor sites. Although current guidelines do not recommend the routine performance of CA 15-3 in asymptomatic patients being followed up after definitive breast cancer treatment, most oncologists perform serial assessment of the tumor markers as part of routine follow-up of patients...

This analysis aimed to identify clinical factors associated with positivity on repeat 68 Ga-PSMA-11 PET/CT after a negative scan in patients with recurrent prostate cancer (PCa) under observation. Methods: This single-center, retrospective analysis included patients who underwent at least 2 68 Ga-PSMA-11 PET/CT scans (PET1 and PET2) at UCLA between October 2016 and June 2021 for recurrent PCa with negative PET1 and no PCa-related treatments between the 2 scans. Using Prostate Cancer Molecular Imaging Standardized Evaluation criteria to define negative and positive scans, the final cohort was divided into PET2-negative (PET2-Neg) and PET2-positive (PET2-Pos)...

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No abstract text is available yet for this article.

Radiolabeled small-molecule DOTA-haptens can be combined with antitumor/anti-DOTA bispecific antibodies (BsAbs) for pretargeted radioimmunotherapy (PRIT). For optimized delivery of the theranostic γ- and β-emitting isotope 177 Lu with DOTA-based PRIT (DOTA-PRIT), bivalent Gemini (DOTA-Bn-thiourea-PEG4-thiourea-Bn-DOTA, aka (3,6,9,12-tetraoxatetradecane-1,14-diyl)bis(DOTA-benzyl thiourea)) was developed. Methods: Gemini was synthesized by linking 2 S -2-(4-isothiocyanatobenzyl)-DOTA molecules together via a 1,14-diamino-PEG4 linker...

Here we describe an anti-prostate-specific membrane antigen (PSMA) minibody (IAB2MA) conjugated to an octadentate, macrocyclic chelator based on four 1-hydroxypyridin-2-one coordinating units (Lumi804 [L804]) labeled with 89 Zr (PET imaging) and 177 Lu (radiopharmaceutical therapy), with the goal of developing safer and more efficacious treatment options for prostate cancer. Methods: L804 was compared with the current gold standard chelators, DOTA and deferoxamine (DFO), conjugated to IAB2MA for radiolabeling with 177 Lu and 89 Zr in cell binding, preclinical biodistribution, imaging, dosimetry, and efficacy studies in the PSMA-positive PC3-PIP tumor-bearing mouse model of prostate cancer...

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Diffuse intrinsic pontine glioma (DIPG) is a rare childhood malignancy with poor prognosis. There are no effective treatment options other than external beam therapy. We conducted a pilot, first-in-human study using 124 I-omburtamab imaging and theranostics as a therapeutic approach using a localized convection-enhanced delivery (CED) technique for administering radiolabeled antibody. We report the detailed pharmacokinetics and dosimetry results of intratumoral delivery of 124 I-omburtamab. Methods: Forty-five DIPG patients who received 9...

In oncologic PET, the SUV and standardized uptake ratio (SUR) of a viable tumor generally increase during the postinjection period. In contrast, the net influx rate ( Ki ), which is derived from dynamic PET data, should remain relatively constant. Uptake-time-corrected SUV (cSUV) and SUR (cSUR) have been proposed as uptake-time-independent, static alternatives to Ki Our primary aim was to quantify the intrascan repeatability of Ki , SUV, cSUV, SUR, and cSUR among malignant lesions on PET/CT. An exploratory aim was to assess the ability of cSUR to estimate Ki Methods: This prospective, single-center study enrolled adults undergoing standard-of-care oncologic PET/CT...

Recurrence of meningiomas after surgery and radiotherapy deserves specific attention because of the lack of active third-line therapies. Somatostatin receptors are usually overexpressed on the cell membrane of meningiomas, and this has led the way to a radionuclide theranostic approach. Diagnoses with 68 Ga-DOTA-octreotide and peptide receptor radionuclide therapy (PRRT) with 90 Y/177 Lu-DOTA-octreotide are currently possible options within experimental protocols or as compassionate use in small patient groups...

In up to two thirds of prostate-specific membrane antigen (PSMA) PET scans, unspecific bone uptake has been described. The aim of this study was to estimate the diagnostic accuracy of [68 Ga]Ga-PSMA-11 PET/CT for bone metastases and the occurrence of equivocal lesions. Methods: We analyzed retrospectively 118 patients who underwent a [68 Ga]Ga-PSMA-11 PET/CT for initial staging or recurrence evaluation. Lesions were interpreted according to the PSMA reporting and data system (PSMA-RADS) and the prostate cancer molecular imaging standardized evaluation (PROMISE) criteria...