Pretargeting decouples biologic recognition from radionuclide delivery by administering a primary carrier (P)─such as an antibody, engineered scaffold, nanoparticle, or cell product─bearing capture handles, followed after a delay by a fast-clearing secondary agent (S) retained at target sites through a defined recognition pair (e.g., IEDDA, SPAAC, hybridization, or bsAb-hapten binding). This split-dose architecture suppresses blood-pool background, shortens time-to-readout, and can reduce normal-tissue absorbed dose relative to directly labeled biologics. Across platforms, the P-S dosing interval is the key coordinating variable: it must align (i) high tumor surface-accessible capture-site availability with (ii) sufficiently low circulating P to avoid off-target capture, while matching (iii) S clearance and (iv) radionuclide half-life and workflow constraints. If mistimed, S is consumed in blood and organs, inflating marrow or renal exposure and lowering tumor yield; if optimized, the interval converts biochemical specificity into measurable contrast and therapeutic index. This review focuses on oncology-oriented applications, which currently provide the strongest evidence base for interval optimization in pretargeted radionuclide imaging and therapy. We propose an interval-first design framework: map P blood and tumor kinetics, quantify time-dependent accessible-site dynamics, and perform interval-aware simulations of image quality and dosimetry. We also highlight when clearing or masking agents can expand the actionable window, enabling same-day PET with short-lived nuclides, and propose a minimum reporting checklist to improve reproducibility and cross-study comparison.

Chimeric antigen receptor (CAR) T-cell therapy carries a rare but critical risk of secondary CAR+ T-Cell Lymphoma (CAR-TCL), highlighting the urgent need for precise diagnostic tools. Current noninvasive imaging methods struggle to differentiate CAR-TCL from inflammatory sequelae, while biopsy presents several clinical challenges. In this study, we developed a novel positron emission tomography (PET) imaging probe, [68Ga]Ga-BCMA-NOTA, by repurposing the extracellular domain of B-cell maturation antigen (BCMA-ECD) as a specific molecular recognizer for the BCMA-CAR single-chain variable fragment (scFv). Leveraging the high-affinity antigen-antibody interaction, the recombinant BCMA probe was produced with high purity (>98%) and demonstrated nanomolar affinity for the BCMA CAR scFv (KD = 5.17 nM). The probe was synthesized with excellent radiochemical purity (>95%) and a good radiochemical yield (>50%). In preclinical xenograft models, [68Ga]Ga-BCMA-NOTA PET/MR imaging demonstrated high and specific uptake in BCMA CAR-positive tumors (2.56 ± 0.61%ID/g), compared to negligible uptake in BCMA CAR-negative tumors (0.21 ± 0.05%ID/g), with a tumor-to-muscle (T/M) ratio of 16.0 ± 3.8. The uptake was blockable, confirming the probe's target specificity in vivo. Importantly, in a head-to-head comparison, [68Ga]Ga-BCMA-NOTA provided significantly superior imaging contrast and a stronger correlation with tumor burden (R2 = 0.93) compared to [18F]FDG (R2 = 0.76). This BCMA CAR scFv-specific probe offers a powerful new tool for the precise noninvasive visualization of BCMA CAR-positive malignancies, with significant clinical translational potential for ensuring the long-term safety and monitoring of CAR-T therapies.

Exportin 1 (XPO1), a nuclear export protein frequently overexpressed in multiple myeloma (MM), represents a validated therapeutic target. However, noninvasive imaging approaches capable of assessing XPO1 engagement and pharmacodynamic modulation during therapy remain limited. Here, we present the radiosynthesis and preclinical evaluation of [18F]selinexor, an XPO1-targeted positron emission tomography (PET) radiotracer derived from the clinically used drug selinexor via an 18F/19F isotope exchange method. This labeling approach preserves the parent drug's molecular structure and pharmacological characteristics, enabling in vivo tracking of selinexor. [18F]Selinexor was synthesized with a radiochemical yield of 23.9 ± 4.1% and molar activity of 0.41 ± 0.08 GBq/μmol. The tracer exhibited favorable stability, XPO1-specific binding, and tumor retention. PET imaging and pharmacokinetic analysis demonstrated rapid systemic distribution followed by slow elimination, closely consistent with known pharmacokinetics of selinexor. Predominant hepatobiliary clearance and prolonged blood retention supported optimal tumor uptake at delayed imaging time points, with tracer uptake peaking at 3 h post-injection in MM.1S (2.92 ± 0.30% ID/g) and NCI-H929 (2.50 ± 0.18% ID/g) xenografts. Uptake was markedly reduced upon blocking, confirming the tracer's in vivo specificity. During therapeutic intervention, repeated selinexor administration effectively suppressed tumor growth and was accompanied by a progressive reduction in tumor uptake from 3.03 ± 0.25% ID/g (day 0) to 0.93 ± 0.13% ID/g (day 15). Notably, this reduction in uptake occurred independently of changes in tumor volume and correlated with decreased XPO1 expression by immunohistochemistry. Conversely, doxorubicin reduced tumor size without affecting uptake, indicating preserved XPO1-associated signal. Together, these findings demonstrate that [18F]selinexor PET functions as a noninvasive imaging tool for evaluating the in vivo pharmacokinetics and pharmacodynamic behavior of selinexor, and capturing treatment-induced alterations in XPO1 engagement, although further structural optimization will be required prior to potential translation.

Selinexor, an FDA-approved XPO1 inhibitor for relapsed or refractory multiple myeloma (MM), has been explored as a precursor for isotopologically 18F-labeling to enable PET imaging of XPO1 expression in MM. However, low tumor-to-muscle (T/M) ratio and poor imaging contrast were observed due to high tracer's lipophilicity. In the present study, selinexor was conjugated to a NOTA chelator via an amide-linked two-carbon (ethylene) spacer to generate the target compound NOTA-selinexor. Subsequent radiolabeling with 68Ga successfully yielded [68Ga]Ga-NOTA-selinexor in over 95% radiochemical yield (RCY) and approximately 96% radiochemical purity (RCP), as well as a molar activity of 12.08 ± 1.37 GBq/μmol. Molecular docking analysis confirmed that the unlabeled precursor retained binding affinity toward XPO1. Furthermore, the radiotracer possessed a hydrophilic profile (log D7.4 = -0.91 ± 0.07) and demonstrated favorable stability under physiological conditions. In vivo PET imaging in MM xenograft models demonstrated that [68Ga]Ga-NOTA-selinexor achieved superior imaging contrast and a significantly higher T/M ratio (∼4.4) compared to previously reported [18F]selinexor (∼2.1). Taken together, these findings suggest that [68Ga]Ga-NOTA-selinexor serves as a valuable PET tracer for noninvasively evaluating XPO1 expression in vivo, highlighting its potential for both precise diagnosis and treatment assessment in MM.

CAR T cell therapies targeting CD19 and B cell maturation antigen (BCMA) induce profound responses in B cell malignancies, yet relapse highlight the need for non-invasive, quantitative tools to track cell kinetics. Here we develop an engineering-free, antigen-based PET/MR strategy to track tandem scFv BCMA/CD19 CAR-T product using a 68 Ga-labelled minimal BCMA ectodomain probe (BED). [ 68 Ga]Ga-NOTA-BED retains nanomolar affinity and high specificity for BCMA-scFv-containing cells, detects as few as ~ 2×10 4 cells without compromising effector functions. In mouse models, the probe enables quantitative discrimination of CAR-positive clusters, revealing a linear relationship between PET signal and cell number. Longitudinal PET/MR in lymphoma and myeloma xenografts visualizes heterogeneous CAR T expansion and trafficking patterns that align with distinct response phenotypes under varying antigen burden. This antigen-derived, human-sequence probe provides a repeatable, low-burden framework for kinetic phenotyping of dual-target CAR T therapies without additional cell engineering, and is positioned for clinical translation (NCT:07280793) as an imaging companion to guide patient-specific monitoring and trial design.

Lung cancer continues to be the leading cause of cancer-related deaths worldwide, primarily due to persistent challenges in early detection and the limited effectiveness of precision medicine. Although low-dose computed tomography (CT) has been widely implemented for lung cancer screening and has contributed to a measurable reduction in disease-specific mortality, its diagnostic accuracy is limited by its inability to reliably distinguish benign from malignant pulmonary nodules. Furthermore, the clinical standard for metabolic imaging18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)is significantly constrained by a high incidence of false-positive findings in patients with inflammatory conditions and frequent false-negative results in tumors exhibiting low glycolytic activity. To overcome these critical limitations, highly specific PET radiotracers have been developed to target immune checkpoints, cell surface receptors, and distinct features of the tumor microenvironment. These molecularly targeted probes offer improved biological specificity, enabling more precise visualization of tumor pathophysiology and supporting applications in early diagnosis, real-time treatment monitoring, and prognostic stratification. This review summarizes recent advances in targeted PET imaging and critically evaluates the potential of integrating these approaches with multimodal imaging, liquid biopsy, and artificial intelligence (AI)-driven radiomics to enhance diagnostic accuracy and inform therapeutic decision-making. By synthesizing key developments from both preclinical studies and clinical trials, we highlight the translational significance and future directions of target-specific PET tracers. Despite existing challenges related to tracer development, regulatory approval, and methodological standardization, the integration of next-generation whole-body PET systems with advanced artificial intelligence algorithms holds considerable promise for establishing molecular-targeted PET as a cornerstone of precision oncology in lung cancer management.

Biologically active molecules, such as carbohydrates, peptides, and proteins, are attractive candidates for positron emission tomography (PET) imaging because of their strong target affinity and biocompatibility. Among available radionuclides, fluorine-18 (18F) is widely used in clinical practice because of its moderate half-life and high-quality imaging properties. However, traditional 18F-labeling methods often require a laborious procedure and harsh conditions, which may compromise the structural integrity and biological functions. Developing mild and efficient 18F-labeling strategies is therefore critical for advancing biomolecular PET tracers. In this study, we developed a novel clickable 18F-labeled synthon, 1-ethynyl-3-([18F]trifluoromethyl)-5-(trifluoromethyl)benzene ([18F]1), prepared via an 18F/19F isotope exchange reaction (RCY = 17.2 ± 3.9%). [18F]1 exhibited excellent performance in copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) conjugation, enabling rapid and chemoselective labeling of azide-modified glucose derivatives, Arg-Gly-Asp (RGD) and cyclic RGD (cRGD) peptides, and phospholipids under mild conditions. PET imaging in U87 MG, 4T1, and BT474 xenograft models showed favorable tumor uptake for both [18F]5a and [18F]5b, peaking at 30 min postinjection. Tumor accumulation for [18F]5a reached 3.11 ± 0.21, 2.40 ± 0.17, and 1.95 ± 0.09% ID/g in U87 MG, 4T1, and BT474 models, respectively, while [18F]5b achieved higher values of 5.19 ± 0.42, 4.90 ± 0.97, and 2.05 ± 0.11% ID/g at the same time point─consistent with the superior binding affinity of cRGD. Tumor-to-muscle ratios were favorable, with[18F]5b reaching 4.32 ± 0.39 in the 4T1 model. Blocking studies in U87 tumors confirmed high binding specificity, with uptake reduced to approximately 1% ID/g. This isotope exchange-based CuAAC labeling strategy streamlines PET tracer synthesis, preserves biomolecule integrity, and offers a versatile platform for molecular imaging and pretargeting applications.

A novel immune checkpoint, FGL1, is a potentially viable target for tumor immunotherapy. The development of FGL1-targeted PET probes could provide significant insights into the immune system's status and the evaluation of treatment efficacy. A ClusPro 2.0 server was used to analyze the interaction between FGL1 and LAG3, and the candidate peptides were identified by using the Rosetta peptide derivate protocol. Three candidate peptides targeting FGL1, named FGLP21, FGLP22, and FGLP23, with a simulated affinity of -9.56, -8.55, and -8.71 kcal/mol, respectively, were identified. The peptides were readily conjugated with p-NCS-benzyl-NODA-GA, and the resulting compounds were successfully labeled with 68Ga in approximately 70% yields and radiochemical purity greater than 95%. In vitro competitive cell-binding assay demonstrated that all probes bound to FGL1 with IC50 ranging from 100 nM to 160 nM. Among the probes, PET imaging revealed that 68Ga-NODA-FGLP21 exhibited the best tumor imaging performance in mice bearing FGL1 positive Huh7 tumor. At 60 min p.i., the tumor uptake of 68Ga-NODA-FGLP21 was significantly higher than those of 68Ga-NODA-FGLP22 and 68Ga-NODA-FGLP23, respectively (2.51 ± 0.11% ID/g vs 1.00 ± 0.16% ID/g and 1.49 ± 0.05% ID/g). Simultaneously, the tumor-to-muscle uptake ratios of the former were also higher than those of the latter, respectively (19.40 ± 2.30 vs 9.65 ± 0.62 and 12.45 ± 0.72). In the presence of unlabeled FGLP21, the uptake of 68Ga-NODA-FGLP21 in Huh7 xenograft decreased to 0.81 ± 0.09% ID/g at 60 min p.i., which is similar to that observed in the FGL1 negative U87 MG tumor (0.46 ± 0.03% ID/g). The results were consistent with the immunohistochemical analysis and ex vivo autoradiography. No significant radioactivity was accumulated in normal organs, except for kidneys. In summary, a preclinical study confirmed that the tracer 68Ga-NODA-FGLP21 has the potential to specifically detect FGL1 expression in tumors with good contrast to the background.

Poly(ADP-ribose) polymerase (PARP) imaging shows great potential as a valuable tool for tumor detection, therapeutic monitoring, and patient stratification in clinical oncology. Nonetheless, current PARP-targeted radiotracers face limitations, including suboptimal tumor uptake and insufficient retention within tumor tissue. Fuzuloparib, a PARP inhibitor featuring a trifluoromethyl moiety, offers improved metabolic stability, enhanced lipophilicity, and increased binding affinity. In this work, we developed an 18F-labeled isotopologue of Fuzuloparib, termed [18F]Fuzuloparib, and systematically evaluated its biological performance evaluated its biological performance using MDA-MB-453 cells, which exhibit high PARP-1 expression, through a combination of cell-based and animal experiments. [18F]Fuzuloparib showed high tumor accumulation (peak 9.06 ± 0.31 %ID/g at 2 h) and sustained intratumoral retention (7.12 ± 0.31 %ID/g at 6 h), underscoring its potential as a promising PET imaging agent. These preclinical findings highlight the potential of [18F]Fuzuloparib as a robust non-invasive imaging agent for identifying PARP-overexpressing malignancies, with implications for optimizing PARP inhibitor therapy and forecasting therapeutic response.

Transforming immunologically "cold" tumors into "hot" lesions amenable to immunotherapy remains a central challenge. Here, we introduce fluorobenzylation as a sequence-dependent amplifier of peptide immunogenicity that enhances membrane interaction and stability. Among peptide panels, the fluorobenzylated lead FPP5 (but not scrambled controls) significantly increased ICD hallmarks (CRT, ATP, and HMGB1) relative to the native peptide and matched the doxorubicin benchmark in vitro. To enable delivery, FPP5 was assembled with FPRGD and FPPEG into composition-defined nanoparticles that are ∼150 nm and serum-stable, and exhibit a low CAC (∼10 μg mL-1), supporting dilution-triggered intracellular disassembly and release of bioactive FPP5 after uptake. FPP5 showed enhanced penetration in 3D spheroids, and FPNPs further improved intratumoral transport via multivalency and integrin engagement. 18F-labeled FPNPs enabled PET tracking, confirming efficient tumor accumulation consistent with long-circulating nanocarrier behavior. In a breast cancer model, FPNPs potentiated ICD, increased calreticulin exposure and CD8+ T-cell infiltration, and synergized with anti-PD-L1 to elicit robust antitumor immunity. Collectively, these data delineate a coherent mechanism-sequence-dependent fluorobenzylation, nanoparticle delivery, intracellular release, ICD and immune activation-and establish a programmable platform to convert cold tumors and enhance combination immunotherapy.

Low-dose CT (LDCT) screening effectively reduces lung adenocarcinoma (LUAD) mortality. However, accurately evaluating the malignant potential of indeterminate lung nodules remains a challenge. Carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6), a potential biomarker for distinguishing benign pulmonary nodules from LUAD, may be leveraged for noninvasive positron emission tomography (PET) imaging to aid LUAD diagnosis. This study utilized mRNA, protein, and survival datasets of LUAD patients, along with an animal model of malignant pulmonary nodules, to investigate CEACAM6 expression specificity and its correlation with LUAD. Targeting ligands for CEACAM6 were designed using the Rosetta platform, labeled with [68Ga]Ga, and screened through high-throughput PET imaging to identify the optimal tracer. CEACAM6 was found to be specifically overexpressed in LUAD and was significantly associated with poor prognosis and disease progression. In vivo, [68Ga]Ga-NODA-P3 demonstrated high specificity for delineating CEACAM6-positive A549 xenografts, a LUAD model, via PET imaging, achieving a highest target-to-background ratio of 7.68 ± 0.44. Region of interest (ROI) analysis showed significantly higher tracer uptake in A549 xenografts compared to CEACAM6-negative Huh7 xenografts (a hepatocellular carcinoma model) at 30 min post-injection (1.81 ± 0.10

Nitric oxide (NO) modulates several cancer-related physiological processes and has advanced the development of green methods for cancer treatment and integrated platforms for combination or synergistic therapies. Although a nanoengineering strategy has been proposed to overcome deficiencies of NO gas or small NO donor molecules, such as short half-life, lipophilicity, non-selectivity, and poor stability, it remains challenging to prepare NO nanomedicines with simple composition, multiple functions and enhanced therapeutic efficacy. Herein, we build a liquid metal nanodroplet (LMND)-based NO nanogenerator (LMND@HSG) that is stabilized by a bioreducible guanylated hyperbranched poly(amido amine) (HSG) ligand. Mechanically, the tumor microenvironment specifically triggers a cascade process of glutathione elimination, reactive oxygen species (ROS) generation, and NO release. According to actual demand, the ROS and NO concentrations could be readily controlled by tuning the LMND and HSG feed amounts. Along with the intrinsic anticancer property of LMND (ROS-mediated apoptosis and anti-angiogenesis), LMND@HSG administration could further enhance tumor growth suppression compared with LMND and HSG alone. From this study, leveraging LMND for NO gas therapy provides more possibilities for the prospect of LMND-based anticancer nanomedicines.

Mitochondria are indispensable for the normal physiological activities and metabolism of living organisms. The proper function of mitochondria in the brain is crucial for maintaining the normal brain function with high energy demands. There are growing evidences that mitochondrial dysfunction plays a critical role in multiple of neurodegenerative diseases (NDDs), including Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, and Huntington's disease. In this review, the research progress and future development trajectory of mitochondrial function in NDDs will be comprehensively summarized, which focusing on mitochondrial physiological function, the mechanisms underlying mitochondrial dysfunction in diverse NDDs, research approaches for exploring mitochondrial function, various strategies for targeted mitochondrial therapy, and the challenges and opportunities encountered in the evaluation of mitochondrial-targeted therapeutic drugs. The feasibility of in vivo mitochondrial imaging and the future perspectives of AI for mitochondria-targeted drug screening are deliberated, which will facilitate the advancement of the comprehension of mitochondrial functional mechanisms in NDDs and the development of future clinical therapeutic drugs. This review shall furnish several insights regarding novel research methodologies and drug developments for researchers engaged in the investigation of mitochondrial dysfunction in NDDs.

Poly(ADP-ribose) polymerase (PARP) is an important therapeutic target in cancer treatment, and dynamic assessment of its expression level is essential for achieving precision therapy. Although 18F-labeled PARP-targeted radiotracers have demonstrated remarkable tumor-imaging capabilities in preclinical studies, their high lipophilicity leads to increased non-specific uptake in abdominal organs, which has severely hindered their clinical translation. Furthermore, while PET imaging provides superior resolution and sensitivity, its infrastructure and operational demands may limit widespread accessibility in certain regions. Therefore, the development of SPECT-based PARP radiotracers could offer a complementary approach, potentially expanding access to PARP imaging in a broader range of clinical settings. To provide a more affordable and accessible alternative to PET probes, hydrazinonicotinamide (HYNIC)-olaparib was radiolabeled with technetium-99m (99mTc) and evaluated both in vitro and in vivo using the MDA-MB-453 breast cancer model. [99mTc][Tc-HYNIC/EDDA]-olaparib exhibits a high radiochemical yield (> 90

Spatiotemporal control of injectable biomaterials is emerging as a powerful strategy to enhance precision theranostics. We report here an injectable, two-step pretargeting system that leverages M1 macrophage-derived exosomes metabolically engineered to display azide groups (M1-Exos-N3) and DBCO-functionalized radiopharmaceuticals labeled with 68Ga or 177Lu. Following intratumoral accumulation of M1-Exos-N3, a temporally controlled intravenous injection of 68Ga-DOTA-PEG5-C4-DBCO achieves in vivo strain-promoted azide-alkyne cycloaddition (SPAAC) for PET visualization of breast tumors. Subsequent administration of 177Lu-DOTA-PEG5-C4-DBCO at the optimized time point enables site-specific radionuclide therapy. Confocal microscopy and flow cytometry confirm efficient exosome binding to 4T1 cells, and NIRF imaging pinpoints the optimal 24 h window for probe delivery. PET imaging delineates tumor lesions, and targeted 177Lu treatment yields significant tumor suppression with minimal off-target toxicity. This spatiotemporally orchestrated, injectable exosome-based platform exemplifies advanced spatial and temporal control in biomaterial design, offering a versatile approach for precision diagnosis and therapy in oncology.

Effective drug accumulation at tumor sites remains a critical challenge in cancer therapy due to poor targeting and off-target effects. This study leverages bioorthogonal chemistry to develop a novel liposome-based drug delivery system designed to enhance tumor-specific accumulation and achieve controlled drug release for improved therapeutic outcomes. DBCO- and azide-modified liposomes were engineered to optimize encapsulation efficiency, stability, and sustained drug release. Their performance was evaluated through in vitro cellular assays to assess uptake and toxicity, alongside in vivo biodistribution and efficacy studies in tumor-bearing models. The bioorthogonal liposomes demonstrated significantly enhanced tumor accumulation compared to free doxorubicin and conventional liposomes, achieving a tumor inhibition rate of 60%. In vitro experiments confirmed improved cellular uptake and retention without additional toxicity, while in vivo results highlighted superior therapeutic efficacy and reduced systemic toxicity, as evidenced by increased tumor apoptosis, suppressed proliferation, and minimal body weight loss. This study underscores the potential of bioorthogonal liposomes as a precise drug delivery platform, offering enhanced tumor targeting, better efficacy, and lower toxicity. These findings pave the way for next-generation targeted cancer therapies, with future efforts aimed at refining liposome design for clinical translation.

Poly (ADP-ribose) polymerase 1 (PARP-1) imaging shows great promise in clinical oncology, offering a non-invasive way to quantify tumor PARP-1 expression, select patients for PARP inhibitor therapy, and monitor treatment response in real-time. However, current PARP-1-targeted radiotracers are highly lipophilic, leading to low tumor uptake, high off-target accumulation, and poor imaging contrast, which restrict their diagnostic utility and accuracy. To overcome these limitations, we developed a series of [18F]AlF-labeled dimeric positron emission tomography (PET) probes based on the olaparib pharmacophore, leveraging a multivalency strategy with PEGylation. Among the candidates, [18F]AlF-NOTA-L3 (log P = -2.33 ± 0.50, KD = 75.2 nM) emerged as the most promising, exhibiting high tumor uptake values of 5.77 ± 0.48, 4.21 ± 0.33, and 3.12 ± 0.19 %ID/g at 10, 30, and 60 min post-injection, respectively, with corresponding tumor-to-muscle ratios of 2.75 ± 0.26, 10.75 ± 2.16, and 10.84 ± 3.24, which were markedly superior to the monomeric probe [18F]AlF-NOTA-L0. Taken together, [18F]AlF-NOTA-L3 exhibits reduced lipophilicity, enhanced binding affinity, and superior tumor-to-background contrast, demonstrating significant potential to advance the accuracy for PARP-1 PET imaging for clinical translation.