American journal of nuclear medicine and molecular imaging最新文献

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is a type of skin T-cell lymphoma with a favorable prognosis. Some patients may experience recurrence, but systemic involvement is rare. Some studies suggest that systemic progression is associated with poor prognosis. The value of ¹⁸F-FDG PET/CT in diagnosing lymphoma has been recognized, but there is often controversy over the application value of ¹⁸F-FDG PET/CT in pcALCL. We present a rare case of pcALCL involving multiple systemic lesions, monitored and evaluated using ¹⁸F-FDG PET/CT to assist in clinical treatment decisions. Through this case, we consider that ¹⁸F-FDG PET/CT has significant value in diagnosing pcALCL. However, more clinical cases are needed to confirm whether high FDG uptake is associated with the invasiveness of pcALCL and the impact of high FDG uptake and Ki-67 expression on the progression and prognosis of pcALCL.

A 61-year-old male presented with hematemesis and melena. Biopsy and immunohistochemistry confirmed mucosa-associated lymphoid tissue (MALT) lymphoma in the posterior wall of the gastric antrum, prompting further evaluation with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT). In addition to elevated uptake in the gastric antrum, ¹⁸F-FDG PET/CT showed diffuse uptake in multiple bone marrow, initially suspected to indicate bone marrow involvement by lymphoma. Further examination identified it as primary myelofibrosis (PMF). Following concurrent therapies, ¹⁸F-FDG PET/CT demonstrated negative uptake in gastric antrum, indicating complete remission of the lymphoma, while the elevated bone marrow uptake suggested progression of PMF. The coexistence of MALT lymphoma and PMF is very rare. This case highlights the image characteristics and potential diagnostic and therapeutic monitoring value of ¹⁸F-FDG PET/CT in patients with concurrent MALT lymphoma and PMF.

Colony-stimulating factor 1 receptor (CSF1R) is almost exclusively expressed on microglia in the human brain and thus, has promise as a biomarker for imaging microglia density as a proxy for neuroinflammation. [¹¹C]CPPC is a radiotracer with selective affinity to CSF1R, and has been evaluated for in-human microglia PET imaging. The flourine-18 labeled CPPC derivative, 5-cyano-N-(4-(4-(2-[¹⁸F]fluoroethyl)piperazin-1-yl)-2-(piperidin-1-yl)phenyl)furan-2-carboxamide ([¹⁸F]FCPPC), was previously synthesized, however, with a low radiochemical yield using manual radiosynthesis. In this work, we report a fully automated radiosynthesis of [¹⁸F]FCPPC on a Synthra RNplus research module. In a total synthesis time of 50 min, [¹⁸F]FCPPC was obtained in decay corrected radiochemical yields of 26.8 ± 0.1% (n = 3) with >99% radiochemical purities. Quality control testing showed that [¹⁸F]FCPPC met all release criteria. In sum, we report the first fully automated radiosynthesis of [¹⁸F]FCPPC, a promising radiopharmaceutical for imaging microglia in humans.

This review assesses the primary neuroimaging techniques used to evaluate Parkinson's disease (PD) - a neurological condition characterized by gradual dopamine-producing nerve cell degeneration. The neuroimaging techniques explored include positron emission tomography (PET), single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI). These modalities offer varying degrees of insights into PD pathophysiology, diagnostic accuracy, specificity by way of exclusion of other Parkinsonian syndromes, and monitoring of disease progression. Neuroimaging is thus crucial for diagnosing and managing PD, with integrated multimodal approaches and novel techniques further enhancing early detection and treatment evaluation.

Observational studies suggest a link between osteoarthritis (OA) and frailty, but the shared genetic architecture and causal relationships remain unclear. We analyzed X-ray and ¹⁸F-FDG PET/CT images in frail and non-frail individuals and conducted genetic correlation analyses using Linkage Disequilibrium Score Regression (LDSC) based on recent Genome-Wide Association Studies (GWAS) for OA and frailty. We identified pleiotropic single-nucleotide polymorphisms (SNPs) through Cross-Phenotype Association (CPASSOC) and Colocalization (COLOC) analyses and investigated genetic overlaps using Multi-marker Analysis of GenoMic Annotation (MAGMA). Transcriptome-wide association studies (TWAS) were conducted to analyze pleiotropic gene expression, and Mendelian Randomization (MR) was used to assess causal relationships between OA and frailty. Frail individuals showed more severe OA on X-ray (67% vs. 31%, P ≤ 0.01) and higher SUVmax on ¹⁸F-FDG PET/CT (4.1 vs. 3.6, P < 0.05) compared to non-frail individuals. Genetic correlation between frailty and OA was significant (rg = 0.532, P = 4.230E-88). Cross-trait analyses identified 42 genomic loci and 138 genes shared between the conditions. COLOC analysis revealed 2 pleiotropic loci, while TWAS identified 27 significant shared genetic expressions in whole blood and musculoskeletal tissue. Bidirectional MR indicated that OA increases the risk of frailty (IVW: beta: 0.13, P = 1.52E-08) and vice versa (IVW: beta: 0.73, P = 1.66E-04). Frail individuals exhibit more severe imaging features of OA. The shared genetic basis between OA and frailty suggests an intrinsic link, providing new insights into the relationship between these conditions.

Metabotropic glutamate receptor 7 (mGlu₇) is a G protein-coupled receptor that is preferentially found in the active zone of neurotransmitter release in the central nervous system (CNS). mGlu₇ plays a vital role in memory, learning, and neuronal development, rendering it a potential target for treating epilepsy, depression, and anxiety. The development of noninvasive imaging ligands targeting mGlu₇ could help elucidate the functional significance of mGlu₇ and accelerate drug discovery for neurological and psychiatric disorders. In this report, a novel carbon-11 labeled positron emission tomography (PET) tracer designated [¹¹C]18 (codenamed MG7-2109) was synthesized via ¹¹C-methylation in 23% decay-corrected radiochemical yield (RCY). In vitro serum stability, serum protein binding, in vitro autoradiography and ex vivo biodistribution studies of [¹¹C]18 were conducted. Preliminary PET imaging results revealed a homogeneous distribution of [¹¹C]18 and rapid clearance in rodent brains. This study provides valuable insights into the development of mGlu₇-targeted PET tracer based on an isoxazolo(5,4-c)pyridine scaffold.

Electrochemical separation technology has brought a renaissance in the field of nuclear medicine towards obtaining clinical-grade radiometals for preparation of a wide variety of radiopharmaceuticals. This article is a comprehensive summary of the electrochemical processes developed for the separation of radiometals that could be used for diagnostic or therapeutic applications in nuclear medicine. For using electrochemistry as a tool for the separation of radiometals, intricate knowledge is essential to understand the basic parameters of electrochemical separation processes which include applied potential, selection of electrolyte, choice of the electrode, the temperature of the electrolyte, pH of the electrolyte and time of electrolysis. The advantages of the electrochemical separation approach over the other conventional methodologies such as solvent extraction, column chromatography, sublimation, etc., have also been discussed. The latest research and development from our laboratory on electrochemical methodologies developed for separation of ⁹⁰Y from ⁹⁰Sr, ¹⁸⁸Re from ¹⁸⁸W, ^99mTc from ⁹⁹Mo, ⁴⁷Sc from ⁴⁶Ca, ⁴⁵Ca from ⁴⁶Sc,¹⁵³Sm from ¹⁵⁴Eu, ¹⁶⁹Er from ¹⁶⁹Yb, ¹⁷⁷Lu from Yb and ^132/135La from Ba have been described. In all the cases, the final product is obtained either in a 'no-carrier-added' (NCA) form or free from inextricable impurities and thus found suitable for formulation of radiopharmaceuticals.

Inflammatory bowel disease (IBD), which encompasses ulcerative colitis (UC) and Crohn's disease (CD), is a chronic inflammatory condition of the gastrointestinal (GI) tract that presents complex diagnostic and management challenges. Early detection and treatment of IBD is paramount, as IBD can present with serious complications, including bowel perforation, arthritis, and colorectal cancer. Most forms of diagnosis and therapeutic management, like ileocolonoscopy and upper endoscopy are highly invasive and require extensive preparation at great discomfort to patients. 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) imaging can be a potential solution to the current limitations in imaging for IBD. This review explores the utility and limitations of various imaging modalities used to detect and manage IBD including ileocolonoscopy, magnetic resonance enterography (MRE), gastrointestinal ultrasound (IUS), and 18F-FDG-PET/computed tomography (18F-FDG-PET/CT) and magnetic resonance imaging (18F-FDG-PET/MR). This review has an emphasis on PET imaging and highlights its benefits in detection, management, and monitoring therapeutic response of UC and CD.

Microglia, a type of immune cells of the central nervous system, play a critical role in the pathophysiology of neurodegenerative disorders including Alzheimer's disease (AD). Recently, efforts for drug discovery have focused on modifying the function of microglia to halt AD progression. One such effort targets a multifaceted kinase called receptor-interacting protein kinase 1 (RIPK1) that controls inflammation and cell death. Pharmaceutical inhibition of RIPK1 in microglia prevents their homeostatic status from transforming to disease-associated status. Thus, RIPK1 inhibitors can be a therapeutic agent for halting AD progression. Therefore, in vivo imaging of RIPK1 may be a useful biomarker of AD. Recently, a novel PET ligand, [¹¹C]TZ7774, targeting RIPK1 was developed showing its ability to enter the brain and an increased uptake in the spleen of acute inflammation model mice. However, they have not yet shown direct evidence of specific binding of [¹¹C]TZ7774 to RIPK1 in the brain. In this study, we replicated the synthesis of [¹¹C]TZ7774 and examined its specific binding in the rat and human brain. Our studies with this ligand failed to detect sufficient specific binding of [¹¹C]TZ7774 to RIPK1 in the brain neither by PET imaging with healthy and acute inflammation model rats, nor by autoradiography with healthy rat and human brain slices. Our results suggest that the RIPK1 ligand, [¹¹C]TZ7774, is unlikely to be useful in humans. Future studies are warranted to develop more optimal radioligands for PET imaging of RIPK1.

Background: High-affinity radiohybrid PSMA-targeting radiopharmaceutical ¹⁸F-flotufolastat (¹⁸F-rhPSMA-7.3) is newly approved for diagnostic imaging of prostate cancer. Here, we conduct a post hoc analysis of two phase 3 studies to quantify ¹⁸F-flotufolastat uptake in a range of normal organs.

Methods: All 718 evaluable ¹⁸F-flotufolastat scans from LIGHTHOUSE and SPOTLIGHT were re-evaluated. Additionally, patients' medical records were reviewed and any patients with high tumor burden (PSA>20 ng/mL), altered biodistribution (e.g., chronic kidney disease), major anatomical changes to normal organs (e.g., nephrectomy), or any other history of cancer were excluded. A medical physicist defined volumes of interest over specific organs for evaluation of SUV_mean and SUV_peak per PERCIST 1.0 criteria. Normally distributed data are reported as mean (SD) and non-normally distributed data as median (IQR). The co-efficient of variation (CoV; calculated as SD/mean for normally distributed data and IQR/median for non-normally distributed data) was used to quantify variability of SUV metrics.

Results: In total, scans from 546 patients (244 primary, 302 recurrent) were eligible for this analysis. All organs were considered to be normally distributed except for the bladder and spleen. In the liver, the mean SUV_mean was 6.7 (SD 1.7), CoV 26%, while the bladder median SUV_mean was 10.6 (IQR 11.9), CoV 112%. The mean SUV_peak in the liver was 8.2 (SD 2.1), CoV 26% and median SUV_peak in the bladder was 16.0 (IQR 18.5), CoV 116%.

Conclusions: Physiological ¹⁸F-flotufolastat uptake in normal organs was broadly consistent with other renally-cleared radiopharmaceuticals, which may have clinically significant implications when considering patient selection for radioligand therapy. Additionally, the bladder median SUV_peak for ¹⁸F-flotufolastat was lower than that previously reported for ⁶⁸Ga-PSMA-11 and ¹⁸F-DCFPyL.