HER2-positive tumors account for 20 to 25 percent of all breast cancer cases and are among the most aggressive forms of the disease, associated with poorer outcomes when not effectively treated. Neoadjuvant therapy is frequently administered before surgery with the goal of shrinking the tumor, sometimes to the point where surgeons find no residual invasive cancer at all—a result known as pathologic complete response, which carries important prognostic weight. The problem, according to the researchers behind the new study, is that the tools currently used to monitor treatment response each fall short in some way.

“Ultrasound offers cost-effective assessment of lymph nodes but is operator-dependent; mammography detects calcifications well but poorly measures tumor size; MRI, the standard neoadjuvant therapy monitoring modality, faces challenges in differentiating between fibrosis and tumors; and clinical examination, although rapid, lacks accuracy,” said Yunjiang Liu, MD, PhD, professor at the Fourth Hospital of Hebei Medical University and Hebei Provincial Tumor Hospital in Shijiazhuang, China. “This trade-off between accuracy and timeliness drives the need for novel approaches.”

That is where molecular imaging enters the picture. 68Ga-HER2 PET/CT uses a radioactive tracer engineered to bind specifically to HER2 receptors on the surface of cancer cells, allowing physicians to visualize HER2 expression throughout the entire body noninvasively. Unlike anatomical imaging, which measures the size of a tumor, molecular imaging measures biological activity—how much of the HER2 target is actually present and accessible. When treatment begins to work, HER2 expression and tumor metabolism can change before the tumor itself measurably shrinks, potentially offering an earlier window into therapeutic success or failure.

To test this concept rigorously, the research team conducted a prospective study of 44 patients with biopsy-confirmed HER2-positive breast cancer. Every patient received at least four cycles of neoadjuvant therapy, though the specific regimens varied from patient to patient, followed by surgery. The researchers performed 68Ga-HER2 PET/CT scans at three time points: at baseline before treatment began, after the second therapy cycle, and again before surgery. They then measured how tracer uptake in the primary breast tumors and in lymph nodes changed across these imaging sessions and analyzed whether those changes correlated with pathologic complete response when the surgical specimens were examined under the microscope.

The results were striking in one respect and sobering in another. The baseline scan, performed before any treatment, did not distinguish between patients who would go on to achieve a pathologic complete response and those who would not. But after only two cycles of therapy, a clear signal emerged. Patients whose primary tumor tracer uptake dropped by at least 61 percent after the second treatment cycle had an 85 percent rate of pathologic complete response at surgery. Among patients whose uptake fell by less than that threshold, the complete response rate was just 38 percent. In other words, a single early scan nearly doubled the predictive separation between responders and non-responders.

The imaging findings from a representative case illustrate the principle vividly. At baseline, one patient’s scan showed a soft-tissue lesion measuring approximately 2.3 by 2.2 centimeters in the upper outer quadrant of the left breast, with marked radiotracer uptake and a maximum standardized uptake value of 10.1—a measure of how intensely the tracer accumulated in the tumor. At the end of the second treatment cycle, the residual lesion measured approximately 2.2 by 1.0 centimeters, but crucially, no abnormal radiotracer accumulation remained. By the preoperative scan, the lesion had shrunk further to approximately 2.0 by 0.6 centimeters, again with no abnormal tracer uptake detected. The biological signal had vanished well before the anatomical lesion did.

“These findings provide preliminary prospective evidence that changes in HER2-targeted tracer uptake can predict treatment response at a very early stage,” said Xinming Zhao, MD, PhD, director of the Department of Nuclear Medicine at the Fourth Hospital of Hebei Medical University and Hebei Provincial Tumor Hospital. “For patients, the potential importance is that treatment response may be assessed much earlier. If future studies confirm our findings, imaging could provide earlier information to support discussions about alternative treatment strategies or surgical timing.”

The clinical implications could be substantial. If an early 68Ga-HER2 PET/CT scan shows that a patient’s tumor is not responding—tracer uptake remaining stubbornly high after two cycles—physicians could consider switching to an alternative treatment strategy sooner, or move directly to surgery rather than continuing a regimen that appears ineffective. Conversely, patients showing a dramatic drop in uptake could proceed with confidence that their current therapy is working. This kind of early, biologically grounded feedback addresses precisely the trade-off that Liu described: the existing modalities are either accurate but slow, or fast but imprecise.

The authors are careful to note the limitations of their work. The study was small, conducted at a single center, and included variation in neoadjuvant treatment regimens among patients. Moreover, the study was designed to evaluate diagnostic performance only—it did not test whether actually changing treatment based on PET/CT findings improves patient outcomes, which would require a different kind of trial. Those caveats mean the 61 percent uptake-reduction threshold and the response rates reported here should be considered preliminary rather than definitive. Still, as a prospective study with serial imaging and surgical confirmation, it provides some of the strongest evidence to date that HER2-targeted molecular imaging can serve as an early biomarker of treatment response. Larger, multicenter trials will be needed to validate the findings and determine whether early 68Ga-HER2 PET/CT can genuinely change the course of care for patients with this aggressive form of breast cancer.

Subject of Research: Using 68Ga-HER2 PET/CT molecular imaging to predict pathologic complete response in HER2-positive breast cancer during neoadjuvant therapy

Article Title: Molecular imaging demonstrates promise for predicting complete pathologic response in HER2-positive breast cancer

Article References: Molecular imaging demonstrates promise for predicting complete pathologic response in HER2-positive breast cancer. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: HER2-positive breast cancer, 68Ga-HER2 PET/CT, molecular imaging, neoadjuvant therapy, pathologic complete response, PET imaging, radiotracer, breast cancer treatment, nuclear medicine, treatment response prediction, oncology, The Journal of Nuclear Medicine

The clinical logic behind the probe rests on the growing importance of PARP inhibitors in oncology. Drugs such as olaparib, rucaparib, niraparib, and talazoparib have been approved by the FDA and the European Medicines Agency for multiple cancer types, including breast, ovarian, prostate, and small-cell lung cancers. PARP-1 is the most abundantly expressed member of the PARP family, accounting for more than 90 percent of the family’s DNA repair functions, and its activity is heightened in many tumors with dysregulated DNA damage repair pathways. Because tumor PARP-1 expression may predict sensitivity to PARP-targeted therapy, the researchers argue that a noninvasive way to measure that expression across the whole body could guide patient selection before treatment and quantify tumor response during and after therapy.

Today, assessing PARP protein levels relies on pathological biopsy, which the authors describe as the clinical gold standard. But biopsies have well-known drawbacks in this context. Tumors are heterogeneous, so a sample from a single lesion may not reflect gene expression patterns at other metastatic sites, and obtaining reliable tissue from organs such as the lungs or brain requires highly invasive procedures. Radiolabeled PARP inhibitor derivatives, imaged with positron emission tomography (PET) or single-photon emission computed tomography (SPECT), offer a systemic alternative. Existing compounds such as [18F]FTT and [18F]PARPi have already shown clinical value in multiple trials, but all known PARP-1 radiotracers accumulate strongly in the abdomen, particularly the liver, spleen, kidneys, and intestines, which can obscure lesions in exactly the organs where breast, ovarian, prostate, and pancreatic cancers commonly spread.

The innovation in this study lies in how the new tracer was designed. Rather than relying purely on experience-driven, trial-and-error optimization, the team built a multi-stage AI prioritization workflow. Starting from fuzuloparib, China’s first independently developed PARP inhibitor, approved in December 2020 and highly potent against tumor cells with an IC50 of 1.46 nanomolar, they used a SMILES-based conditional chemical language model, a recurrent neural network implemented in the Lib-INVENT framework, to generate candidate analogs. Two scaffold-constrained decoration runs, one attaching substituents directly to the triazole-containing ring system and one using a methylene-extended attachment point, produced a compact set of seven analogs bearing methyl, ethyl, propyl, amino, aminomethyl, trifluoromethyl, or phenyl groups.

Computational triage then narrowed the field. A synthetic complexity model, SCScore, trained on reaction data scored the candidates between 4.6 and 4.8, with compound 005, named NH2-FZPF, receiving the lowest value of 4.6, indicating the lowest predicted synthetic difficulty. Its derivatization-ready amine and the commercial availability of a key amine-containing building block made it the practical choice. Convolutional neural network-guided docking against the human PARP-1 crystal structure (PDB ID 5DS3) showed that the fuzuloparib-derived cores of the resulting gallium-complexed ligands occupied the same binding pocket as the parent drug, sharing interactions with key residues S904 and G863. A deep neural network trained on 7,546 ChEMBL targets using combined ECFP4 and MHFP6 fingerprints ranked PARP-1 as the top predicted target for fuzuloparib, NH2-FZPF, NOTA-FZPF, and DOTA-FZPF alike, with confidence scores between 0.98 and 1.00, suggesting that adding the chelator did not compromise selectivity. Explicit-solvent molecular dynamics simulations in GROMACS, run for 100 nanoseconds, confirmed that the protein backbone converged and the complexes remained stable, even though the bulky DOTA conjugate showed greater ligand-level fluctuations than the parent compound.

The two lead candidates, [68Ga]Ga-DOTA-FZPF and [68Ga]Ga-NOTA-FZPF, were then labeled with generator-produced gallium-68 and rigorously characterized. Radiochemical purities reached 99.35 plus or minus 0.56 percent and 98.48 plus or minus 1.22 percent, respectively, with molar activities of roughly 7 to 11 GBq per micromole. Both tracers proved highly hydrophilic, with log D7.4 values of -1.15 for the DOTA version and -2.23 for the NOTA version, and retained more than 95 percent integrity after 180 minutes in saline, mouse serum, and human serum, as well as after three hours of in vivo metabolism in mice. In cell experiments, both tracers were taken up significantly more by 22Rv1 prostate cancer and A2780 ovarian cancer cells, which express high levels of PARP-1, than by AsPC-1 pancreatic cancer cells with low PARP-1 expression, and co-incubation with a 500-fold excess of fuzuloparib blocked that uptake, confirming specificity.

Micro-PET/CT imaging in tumor-bearing mice delivered the decisive preclinical result. One hour after injection, [68Ga]Ga-DOTA-FZPF accumulated at 5.03 plus or minus 0.77 percent of the injected dose per gram in 22Rv1 tumors and 5.27 plus or minus 0.40 percent in A2780 tumors, significantly higher than the 1.90 plus or minus 0.10 percent seen in low-PARP-1 AsPC-1 tumors. Tumor-to-muscle ratios reached 14.80 plus or minus 8.80 in the 22Rv1 model, and blocking experiments cut tumor uptake dramatically, from 5.03 to 1.53 percent ID/g in 22Rv1 mice and from 5.27 to 1.83 percent ID/g in A2780 mice. Critically, the DOTA tracer outperformed its NOTA sibling on every front: higher tumor uptake, and far lower accumulation in the liver (2.43 versus 7.27 percent ID/g), spleen (0.57 versus 2.64), and kidney (3.37 versus 6.90) at 60 minutes. The NOTA compound was therefore excluded, and [68Ga]Ga-DOTA-FZPF advanced to clinical studies. The tracer also functioned as a pharmacodynamic readout: in mice treated with fuzuloparib, tumor uptake of the probe fell during therapy even though PARP-1 expression by immunohistochemistry remained similar, a pattern consistent with the unlabeled drug occupying the binding sites, exactly what a target-engagement imaging agent should show.

The first-in-human phase enrolled three breast cancer patients and one ovarian cancer patient in a small exploratory cohort approved by the Ethics Committee of Fudan University Shanghai Cancer Center. No adverse events or vital sign abnormalities were observed after injection, and the tracer cleared rapidly from blood, with a distribution half-life of less than two minutes in preclinical pharmacokinetics and predominantly renal excretion. In one patient with left breast cancer, the scan showed markedly higher uptake in the affected breast than in the contralateral normal breast, with a maximum standardized uptake value of 3.7 versus 1.8, and pathology confirmed high PARP-1 expression in the lesion. In a second patient with hepatic metastases after mastectomy, uptake in the liver lesion was close to the liver background, SUVmax 1.3 versus 1.1, and immunohistochemistry showed low PARP-1 expression. The authors note that, compared with clinical data for [18F]FTT and [18F]PARPi, their trial showed significantly reduced uptake in non-specific organs such as the liver, spleen, gastrointestinal tract, and bones, although tumor uptake itself was modest, possibly because of the small cohort, the relatively low PARP-1 expression at the enrolled lesions, and the pronounced hydrophilicity of the DOTA chelator, which may limit cell membrane penetration. The modest tumor-to-liver ratio of 1.38 plus or minus 0.28 may also constrain sensitivity for detecting hepatic metastases.

Despite those limitations, the study marks a genuine milestone. According to the authors, no prior clinical investigation of a gallium-68-labeled PARP-1-targeting radiotracer has been reported, and no AI-designed radiotracer has previously undergone clinical evaluation, making this a preliminary attempt at both. The work demonstrates that established computational tools, generative chemistry, CNN-based docking, synthetic complexity scoring, reverse target screening, and molecular dynamics, can be integrated with medicinal chemistry judgment into a reproducible closed loop that delivers experimentally verifiable imaging agents. The team frames the result as a case study that could be extended to radiotracers targeting other molecules, and the broader implications are striking: if AI pipelines can reliably compress the years of iterative medicinal chemistry normally required to tune a radiotracer’s affinity, synthesizability, and pharmacokinetics, the path from molecular target to clinic-ready imaging agent could shorten considerably. For now, [68Ga]Ga-DOTA-FZPF remains an early-stage candidate, and the authors themselves call for further optimization and larger clinical studies to validate PET imaging of PARP-1, but the bench-to-bedside journey it completed offers a template for how artificial intelligence may reshape radiopharmaceutical development.

Subject of Research: AI-assisted development and first-in-human evaluation of the PARP-1-targeted PET radiotracer [68Ga]Ga-DOTA-FZPF

Article Title: An artificial intelligence-assisted PARP-1-targeted PET imaging agent [ 68 Ga]Ga-DOTA-FZPF: From bench to clinic

Article References: Ji, M., Jiang, C., Xi, Y., Liu, S., He, S., Zhang, J., Xu, X., Yang, Z., Wang, X., & Song, S. (2026). An artificial intelligence-assisted PARP-1-targeted PET imaging agent [68Ga]Ga-DOTA-FZPF: From bench to clinic. Materials Today Bio, 41, Article 103728. https://doi.org/10.1016/j.mtbio.2026.103728

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103728

Keywords: PARP-1, PET imaging, radiotracer, artificial intelligence, gallium-68, fuzuloparib, molecular imaging, drug design, breast cancer, ovarian cancer, PARP inhibitors, radiopharmaceuticals

The tracer, named β-Me-2-[18F]FDG, is described in a study published in Nature Biomedical Engineering. It is derived from [18F]FDG, the glucose analogue that has anchored clinical PET for decades, but with a crucial chemical modification: a methyl group attached at the anomeric C-1 position through a β-glycosidic linkage. That small structural change transforms the molecule from a probe of host metabolism into a probe of bacterial metabolism. Human cells import glucose through GLUT and SGLT transporters, which depend on hydroxyl groups at the C-1 and C-2 positions of the sugar. By replacing the C-1 hydroxyl with a methyl group and lacking the C-2 hydroxyl entirely, β-Me-2-[18F]FDG is no longer recognized by mammalian transporters. Bacteria, however, possess an entirely different carbohydrate import machinery, the phosphoenolpyruvate-dependent phosphotransferase system, or PTS, which simultaneously transports and phosphorylates sugars using phosphoenolpyruvate as the phosphoryl donor. Because this system exists only in prokaryotes, it offers a metabolic doorway that is invisible to human tissue.

The discovery began with a remarkably simple synthetic strategy. Rather than building each candidate tracer from scratch, the researchers took clinical-grade [18F]FDG, dried it by azeotropic distillation, and subjected it to Fischer glycosidation with a series of alcohols under acidic conditions. In a single step, and with isolated radiochemical yields ranging from roughly 33 to 92 percent, they generated a library of nine 18F-labelled alkyl glucosides. Screening these compounds against Staphylococcus aureus in vitro revealed that the methyl glucoside, an anomeric mixture of α and β forms, accumulated in the bacteria far more readily than any of its longer-chain counterparts. Because glucosides do not undergo mutarotation under physiological conditions, the team could separate the two anomers by high-performance liquid chromatography and test them independently. The result was unambiguous: the β-anomer drove essentially all of the bacterial uptake, while the α-anomer was nearly inert.

Crucially, the active β-anomer can be manufactured without any new equipment. The researchers synthesized a β-methyl mannose triflate precursor and showed that it could be radiofluorinated and hydrolyzed using the same workflow, and even the same commercially available cassettes, used for routine [18F]FDG production. Manual synthesis delivered the tracer in 74.6 percent radiochemical yield with purity above 99 percent within 40 minutes, and an automated run on a GE FASTlab module produced it in 31.3 percent yield starting from 37 GBq of fluoride in about 34 minutes. In an era when most experimental PET tracers require bespoke radiochemistry, a compound that can be swapped into existing FDG infrastructure is a significant translational advantage. The team also demonstrated that direct glycosidation of clinical [18F]FDG could serve as an alternative route for imaging centers that receive FDG from commercial vendors but lack their own cyclotrons.

In laboratory assays, β-Me-2-[18F]FDG was taken up robustly and consistently by every clinical isolate of methicillin-resistant and methicillin-susceptible S. aureus tested, spanning the USA100 through USA800 pulsed-field types, as well as by methicillin-susceptible and vancomycin-intermediate Staphylococcus epidermidis. Streptococcus agalactiae and Streptococcus pyogenes also accumulated the tracer, though with somewhat more variability. By contrast, uptake in Escherichia coli, Mycobacterium smegmatis and mammalian cell lines was negligible. Heat-killed bacteria did not take up the compound, and uptake was blocked by excess non-radioactive competitor, confirming that accumulation requires live, metabolically active organisms. The tracer was also stable in both mouse and human serum for at least four hours at 37 degrees Celsius, a prerequisite for clinical use.

Genetic experiments pinpointed the transporter responsible. S. aureus encodes four glucose uptake systems: the PTS components GlcA, GlcB and GlcC, and a non-PTS transporter called GlcU. Using a panel of transposon mutants, the researchers showed that deletion of glcA, which encodes the glucose-specific PTS component EIICBAGlc1, dramatically reduced tracer uptake, whereas deletion of glcB, glcC, glcU or manA had no effect. HPLC analysis of bacterial lysates revealed that most intracellular radioactivity corresponded to a phosphorylated metabolite, consistent with the PTS mechanism of import-coupled phosphorylation, which traps the sugar inside the cell and prevents efflux. Notably, β-Me-2-[18F]FDG was not phosphorylated by mammalian hexokinase, reinforcing its selectivity for bacterial biochemistry. Protein sequence analysis showed that EIICBAGlc1 is highly conserved across Staphylococcus species, explaining why the tracer performed well against multiple staphylococcal pathogens.

In healthy mice, the tracer behaved exactly as a bacteria-specific agent should. Dynamic PET/CT imaging showed rapid distribution to lung, liver and kidneys followed by predominantly renal excretion into the bladder, with low retention in brain, heart and other background tissues. Pharmacokinetic modeling yielded a distribution half-life of 0.48 minutes and an elimination half-life of 44.34 minutes, and extrapolated human dosimetry estimated effective doses of 0.020 to 0.041 mSv/MBq depending on sex and the ICRP model applied, with the urinary bladder receiving the highest absorbed dose. Urine analysis confirmed high in vivo metabolic stability, with no detectable degradation to [18F]FDG, an advantage attributed to the stability of β-glycosidic linkages over their α counterparts.

The imaging performance in disease models was striking. In a murine myositis model, sites inoculated with live S. aureus showed a target-to-non-target ratio of 6.1, rising to 14.6 when imaging was delayed to four hours after injection, while sites inoculated with heat-killed bacteria and tissues of mice with lipopolysaccharide-induced sterile inflammation showed no significant uptake. Conventional [18F]FDG, by comparison, lit up brain, spinal cord and brown adipose tissue in inflamed animals, illustrating precisely the background problem the new tracer is designed to solve. In a wound infection model, signal at infected tissue was nearly seventeenfold higher than in uninfected tissue, and in a pulmonary model, infected lungs accumulated 11.3 percent of the injected dose per cubic centimeter versus 0.6 in uninfected lungs. In a rat model of vertebral discitis-osteomyelitis, tracer signal at the inoculated spinal level rose progressively over six days, reaching sixteenfold above baseline, and expanded to adjacent vertebrae in a pattern that mirrors multifocal spondylodiscitis in patients.

Perhaps the most clinically consequential experiments involved treatment monitoring and disseminated infection. In mice dually infected with oxacillin-susceptible and oxacillin-resistant S. aureus, serial PET scans before and after a three-day course of oxacillin showed a significant drop in signal at the susceptible site, from 5.1 to 2.9 percent injected dose per cubic centimeter, while the resistant site showed persistent uptake and visible spread of infection. Ex vivo bacterial counts correlated with the imaging findings. In a bacteremia model, the tracer revealed secondary foci of infection in the brain, heart, liver, shoulder joint and ilium by day three, sites that the gram-negative-targeting comparator tracer [18F]FDS failed to highlight. The researchers note that interpreting PET signals during bloodstream infection requires caution, since circulating bacteria and sepsis-altered tracer kinetics can confound quantification, but the pattern of focal uptake still mapped plausibly onto hematogenous dissemination.

The team, led by David M. Wilson and Sang Hee Lee at UCSF, is now preparing an investigational new drug application, including toxicity testing of the non-radioactive 19F standard, to support first-in-human studies. Because β-Me-2-[18F]FDG targets gram-positive organisms, it is envisioned as a clinical complement to [18F]FDS, which images gram-negative bacteria, allowing tracer selection based on the likely pathogen. If human trials confirm the preclinical profile, the tracer could enable physicians to distinguish infection from sterile inflammation, localize disseminated disease, and judge antibiotic success within days rather than weeks, potentially shortening therapy, sparing patients unnecessary drugs, and offering a new tool in the fight against resistant pathogens such as MRSA.

Subject of Research: Development of a bacteria-specific PET radiotracer targeting the glucose phosphotransferase system for imaging gram-positive infections

Article Title: Selective PET imaging of bacterial infection using a glycosylated 18F-fluorodeoxyglucose-derived tracer

Article References: Lee, S. H., Kim, J. M., López-Álvarez, M., Wadhwa, A., Bidkar, A. P., Ur Rahim, J., Blecha, J., Flavell, R. R., Ordonez, A. A., Seo, Y., Engel, J., Ohliger, M. A., & Wilson, D. M. (2026). Selective PET imaging of bacterial infection using a glycosylated 18F-fluorodeoxyglucose-derived tracer. Nature Biomedical Engineering. https://doi.org/10.1038/s41551-026-01798-1

Image Credits: AI Generated

DOI: 10.1038/s41551-026-01798-1

Keywords: PET imaging, bacterial infection, Staphylococcus aureus, radiotracer, phosphotransferase system, 18F-FDG, MRSA, antimicrobial resistance, molecular imaging, gram-positive bacteria, antibiotic response monitoring, infection diagnostics

Positron emission tomography depends on a simple but elegant physical principle. A biologically active molecule, in this case fluorodeoxyglucose labelled with the positron-emitting isotope fluorine-18, is injected into the bloodstream. As the radiotracer decays, each positron annihilates with a nearby electron, producing a pair of gamma photons that fly off in nearly opposite directions. Ring-shaped detectors surrounding the patient register these coincident photon pairs, and reconstruction algorithms convert millions of such events into a three-dimensional map of where the glucose analogue has accumulated. Because cells with high metabolic demand, such as tumour cells or inflamed tissue, consume more glucose, FDG PET has become a cornerstone of oncology, cardiology and neurology.

Conventional PET scanners, however, cover only a modest axial length of the body, typically around 15 to 30 centimetres, which means that either the field of view must be moved along the patient or the region of interest must be chosen in advance. LAFOV systems change that equation dramatically. With detector rings extending across much of the body, and with markedly higher sensitivity thanks to a larger solid angle of coverage, these scanners can capture whole-body distributions in a single position, at lower injected activities, in shorter acquisition times, and, crucially, with the temporal resolution needed for true dynamic imaging. It is precisely this combination of sensitivity and continuous coverage that made the Copenhagen team’s fetal study feasible.

Dynamic PET is a fundamentally different exercise from the static snapshots that dominate routine practice. Rather than acquiring a single image after the tracer has distributed, dynamic protocols record the tracer’s journey continuously from injection onward: the bolus arriving through the maternal circulation, the transit across the placenta, and the gradual accumulation and clearance within fetal tissues. From these time-activity curves, quantitative parameters such as uptake rates and glucose metabolism can in principle be derived, rather than merely inferred from a single late time point. In the fetus, where every organ is growing and maturing at a different pace, such kinetic information has long been a tantalising but largely inaccessible prize.

The obstacles to fetal PET are formidable, which is why published examples remain rare. The fetus is a small, moving target suspended in amniotic fluid inside a body that is itself undergoing physiological change. Maternal organs, the placenta and the myometrium all lie in the imaging path, and the fetal signal must be separated from this crowded background. Fetal position shifts and maternal breathing add motion that standard reconstruction pipelines were never designed to handle. Radiation exposure, while modest with modern protocols, must be justified with particular rigour, and the physical dimensions of the pregnant abdomen challenge the geometric assumptions of scanner design. For all these reasons, fetal PET has historically been confined to isolated case reports, usually performed when a clinical question could not be answered by ultrasound or MRI.

That is precisely the context in which the Rigshospitalet report sits. As an Image of the Month contribution, the article documents a single, carefully justified clinical scenario in which the diagnostic value of dynamic FDG PET/CT outweighed the considerations that normally preclude it. The authors obtained written informed consent that explicitly covered the extended scan duration required for research purposes, as well as separate consent for the publication of data and images, underscoring the ethical scaffolding that surrounds any imaging of a pregnant patient. The study received no external funding, and the authors declared that the work itself was free of commercial involvement, although three of the authors noted honoraria from Siemens Healthineers for unrelated academic presentations and, in one case, an ongoing research agreement with the company.

The technical achievement deserves unpacking for readers unfamiliar with the machinery involved. A LAFOV PET/CT scanner pairs the extended PET field of view with computed tomography for anatomical localisation and attenuation correction. The CT component maps how strongly different tissues absorb photons, allowing the reconstruction algorithm to correct for the fact that gamma rays leaving the deep pelvis must traverse more tissue than those leaving superficial structures. In a pregnant patient this correction is especially delicate, because the attenuation landscape changes with fetal and placental position. The high sensitivity of the long-axis design means the injected activity can be kept as low as reasonably achievable, in line with the ALARA principle that governs all radiation medicine, while still collecting enough coincidence events to reconstruct images of diagnostic and scientific quality.

What can dynamic fetal FDG imaging actually reveal? Glucose is the fundamental fuel of the developing brain, and patterns of cerebral FDG uptake reflect the metabolic maturation of neural tissue. The placenta, an organ with its own distinctive glucose handling, appears in the images as a structure whose tracer kinetics can be followed over time. Fetal liver, heart and other organs each leave their metabolic signature. In principle, dynamic acquisition allows clinicians and researchers to distinguish between altered perfusion, altered transport and altered intracellular metabolism, distinctions that static imaging cannot make. For fetal medicine, where conditions such as growth restriction, congenital tumours and metabolic disorders are currently assessed largely through indirect ultrasound markers and MRI morphology, a direct quantitative window onto fetal metabolism represents a genuinely new class of information.

The publication also illustrates a broader shift in the culture of nuclear medicine. As total-body and long-axis PET installations proliferate in academic centres, investigators are revisiting patient populations and physiological questions that were previously off-limits, from ultra-low-dose paediatric studies to kinetic imaging of diffuse disease. The Danish team’s work is a case study in how new hardware creates new scientific opportunities almost as a side effect of its clinical deployment: a scanner bought for oncology becomes, with careful ethics approval and protocol design, an instrument for observing human development. The authors’ data availability statement, which offers access to the datasets on reasonable request, reflects the growing expectation that such rare and valuable imaging records should be shared with the wider research community.

Caution is, of course, the appropriate frame for a single-case Image of the Month. One examination cannot establish reference values, define normal fetal uptake patterns or change clinical guidelines, and the authors themselves present the work as a documentation of feasibility rather than a new standard of care. Yet the historical pattern in medical imaging is that today’s carefully documented case report becomes tomorrow’s protocol. Ultrasound, fetal MRI and even fetal echocardiography all began with isolated demonstrations that the previously invisible could be seen. If LAFOV dynamic PET follows the same trajectory, the Copenhagen images may be remembered as an early, technically demanding first look at the fetal body in motion, organ by organ, molecule by molecule, at the level of its glucose metabolism, a view that no previous generation of imaging technology could provide.

Subject of Research: Dynamic long-axial field-of-view PET/CT imaging of fetal fluorodeoxyglucose uptake

Article Title: Dynamic LAFOV PET/CT imaging of [18F]FDG uptake in the human fetus

Article References: Madsen, K., Korsholm, K., Andersen, F. L., & Andersen, T. L. (2026). Dynamic LAFOV PET/CT imaging of [18F]FDG uptake in the human fetus. European Journal of Nuclear Medicine and Molecular Imaging. https://doi.org/10.1007/s00259-026-08192-8

Image Credits: AI Generated

DOI: 10.1007/s00259-026-08192-8

Keywords: PET/CT, LAFOV PET, FDG, fetal imaging, dynamic PET, molecular imaging, nuclear medicine, fetal metabolism, radiotracer, placenta, prenatal diagnostics, Copenhagen University Hospital

The numbers reported by the research team are striking. Among 49 patients with renal medullary carcinoma who underwent 18F-FDG PET/CT scans at MD Anderson between 2016 and 2025, the radiotracer detected lesions in 98 percent of cases, or 48 of the 49 patients. Even more consequential, in 65 percent of patients the tracer revealed additional cancer lesions that were not visualized on standard anatomical imaging such as computed tomography or magnetic resonance imaging. Those extra findings were not merely academic curiosities: in 21 percent of patients with active disease, the PET/CT results directly changed the clinical management plan, steering physicians away from treatments that would have been futile or harmful and toward strategies better matched to the true extent of disease.

Renal medullary carcinoma is a disease that demands precision from the very first scan. It predominantly affects adolescents and young adults, occurs more often in males, and is strongly associated with sickle cell trait and related hemoglobinopathies, conditions in which the oxygen-carrying environment of the renal medulla appears to create conditions favorable to tumor development. At the time of diagnosis, patients frequently already present with metastatic disease, and the median overall survival is approximately 14.5 months. Against that grim backdrop, every staging decision carries enormous weight. Surgery that might offer curative potential in localized disease becomes a source of suffering and delay when the cancer has in fact spread undetected, because high-morbidity operations postpone the systemic therapies that metastatic patients urgently need.

Simone Krebs, MD, MS, a nuclear medicine physician and scientist at MD Anderson and the study’s lead author, emphasized just how much rides on getting staging right in this disease. In renal medullary carcinoma, she noted, the value of accurate staging cannot be overstated, because upstaging a patient from localized to metastatic disease spares them from noncurative, high-morbidity surgeries that would only delay the initiation of essential systemic therapy. Identifying metastatic disease, she added, may also open opportunities for more effective therapies tailored to a patient’s actual disease burden. Her comments underscore a central tension in oncology: the difference between what imaging shows and what the cancer is actually doing can determine whether a patient receives the right treatment at the right time or loses precious months to the wrong one.

The biological basis for the study’s success lies in the way renal medullary carcinoma handles glucose. 18F-FDG is a glucose analog labeled with fluorine-18; it is taken up by cells through glucose transporters and then becomes metabolically trapped, allowing positron emission tomography to visualize tissues with high glycolytic activity. Many cancers are avid for FDG, but uptake varies considerably across kidney tumor subtypes, which has historically limited the tracer’s reputation in urologic oncology. Clear cell renal cell carcinoma, the most common kidney cancer, often shows variable FDG uptake, and some renal lesions are better characterized by other tracers or by dedicated CT protocols. Renal medullary carcinoma, however, demonstrates strong and consistent FDG uptake, distinguishing it from other kidney cancers and making it an unusually suitable target for FDG PET/CT imaging.

That metabolic avidity translated into practical diagnostic power even in patients who had already begun systemic treatment. The study found that 18F-FDG PET/CT remained highly effective after therapy had been initiated, an important point because treatment can alter tumor metabolism and degrade the performance of metabolic imaging in some cancers. In renal medullary carcinoma, the tracer continued to illuminate active disease, giving oncologists a reliable way to assess how patients were responding and whether residual lesions represented viable tumor. Quantitative PET/CT metrics were evaluated alongside visual interpretation, and the researchers systematically recorded every instance in which imaging findings altered treatment, providing a structured account of the scan’s real-world impact rather than anecdotal impressions.

The clinical consequences of the additional findings were often dramatic. In one illustrative case included in the published work, a patient demonstrated intense focal FDG uptake in nodal, hepatic, soft-tissue, and osseous metastases on maximum-intensity-projection imaging. Axial FDG PET and fused PET/CT images revealed focal intense uptake in the right iliac bone, a finding without a definite correlate on the dedicated CT image. That discrepancy, a metabolically active lesion invisible on anatomical imaging, led directly to changes in the patient’s clinical management. It is precisely this pattern, PET revealing disease that CT cannot confirm, that explains how the tracer upstaged so many patients and redirected so many treatment plans in the study cohort.

For patients, the implications of these findings are potentially life-altering. A young adult with renal medullary carcinoma who appears to have localized disease on a conventional CT scan might, in fact, harbor hepatic, nodal, or bone metastases that only PET/CT can reveal. Detecting those lesions before surgery could spare the patient a major operation that would never have been curative, while simultaneously accelerating access to systemic therapy, the treatment modality most likely to extend survival in metastatic disease. Conversely, for patients whose PET/CT confirms truly limited disease, the scan provides confidence that aggressive local treatment is justified. In both directions, the additional information changes decisions, and in a cancer with a median survival measured in months, better decisions translate directly into better use of the limited time available.

The study’s authors argue that the evidence now justifies a formal change in clinical practice. Their conclusion is that the findings may support the inclusion of 18F-FDG PET/CT in upcoming guidelines regarding renal medullary carcinoma, which would enable broader clinical use beyond specialized centers like MD Anderson. Guideline inclusion matters because renal medullary carcinoma is rare enough that many treating institutions will encounter only a handful of cases, and clinicians may default to conventional staging pathways unless professional society recommendations explicitly endorse metabolic imaging. Krebs and her colleagues contend that PET/CT provides clinically meaningful information beyond conventional imaging, helping doctors better assess the extent of disease and choose the most appropriate treatment strategy, and that on a larger scale the research supports wider adoption in routine patient care.

As molecular imaging continues to expand its role in oncology, the MD Anderson study offers a compelling case study in how an old, proven tool can find new purpose in an underserved disease. 18F-FDG has been a staple of nuclear medicine for decades, yet its value in kidney cancer has been considered limited and subtype-dependent. By rigorously documenting its performance specifically in renal medullary carcinoma, a population of predominantly young patients with few good options, the researchers have turned a routine radiotracer into a potential standard of care for one of oncology’s most aggressive diagnoses. With 98 percent detection, additional lesions found in nearly two-thirds of patients, and management changes in one in five, the case for FDG PET/CT in this disease is difficult to ignore, and the coming updates to clinical guidelines may soon make this powerful scan a routine part of the fight against renal medullary carcinoma.

Subject of Research: Use of 18F-FDG PET/CT imaging for staging and treatment planning in renal medullary carcinoma

Article Title: Proven radiotracer highly effective in detecting rare, aggressive kidney cancer

Article References: Proven radiotracer highly effective in detecting rare, aggressive kidney cancer. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: renal medullary carcinoma, 18F-FDG PET/CT, kidney cancer, molecular imaging, metastatic disease, staging, nuclear medicine, radiotracer, MD Anderson Cancer Center, treatment planning, non-clear cell renal cell carcinoma, Journal of Nuclear Medicine

The central concept behind the research is receptor saturation. Atezolizumab is a monoclonal antibody designed to bind PD-L1, a protein that many tumours deploy on their surfaces to suppress the immune cells that would otherwise attack them. By occupying PD-L1, atezolizumab blocks this molecular camouflage and releases the brakes on the immune system. But the drug can only work where it actually reaches the target in sufficient quantity. If a tumour expresses abundant PD-L1 but has poor blood supply, dense stromal barriers, or unfavourable pharmacokinetics, the antibody may fail to saturate the target even though the patient receives a full therapeutic dose. Conventional testing, which involves staining a biopsy sample for PD-L1 expression, captures only a snapshot of a tiny fragment of the tumour at a single moment in time and says nothing about whether the drug is engaging its target throughout the body.

PET imaging offers a fundamentally different perspective. In the approach examined by the researchers, atezolizumab is labelled with a radioactive tracer, typically the radionuclide zirconium-89, whose decay signature can be detected by the PET scanner. When the labelled antibody is injected into a patient, the scanner produces three-dimensional maps showing exactly where the drug accumulates. If a tumour lights up with signal before treatment, it indicates that PD-L1 is present and accessible to the antibody. If the signal diminishes or disappears after the patient begins therapy with unlabelled atezolizumab, it indicates that the therapeutic antibody has flooded the target sites, occupying them so thoroughly that the labelled tracer can no longer bind. This drop in tracer uptake is the imaging signature of target saturation, the pharmacodynamic state in which the drug is doing its intended molecular job at the tumour site.

The logic of this imaging paradigm rests on a simple competitive principle. Before treatment begins, when no therapeutic antibody is circulating, the radiolabelled atezolizumab analogue can bind freely to PD-L1 molecules on tumour cells, producing strong PET signal. Once a patient starts standard atezolizumab infusions, the circulating therapeutic antibody competes with the tracer for the same binding sites. As the drug concentration rises and saturates available PD-L1, tracer uptake falls. The degree of that fall provides a direct, whole-body measure of how completely the treatment is engaging its target in each tumour lesion. This is often described as an in vivo pharmacodynamic biopsy: instead of sampling one lesion surgically, clinicians can observe drug-target interactions across every detectable tumour deposit simultaneously, including metastases in locations that could never be biopsied safely.

The significance of this capability becomes clear when considering how immunotherapy is currently managed. Patients with non-small cell lung cancer, bladder cancer, and other PD-L1-positive malignancies typically receive atezolizumab or similar agents on fixed schedules, often for months, before standard imaging can reveal whether the tumours are shrinking. Response assessment by CT generally takes weeks to months to show meaningful change, because tumour shrinkage is a delayed downstream consequence of immune activation. Target saturation, by contrast, is an immediate upstream event. If imaging shows that the antibody has fully occupied PD-L1 within days of the first dose, and the tumour still fails to respond over the following months, the problem lies elsewhere: the tumour may have developed alternative immune-evasion mechanisms, the tumour microenvironment may lack infiltrating T cells, or downstream signalling may be blocked. Distinguishing pharmacokinetic failure, where the drug never reached the target, from biological resistance, where the drug engaged the target but the cancer resisted anyway, is exactly the information that saturation imaging is designed to provide.

Past work in this field has demonstrated the technical feasibility of the approach. Radiolabelled versions of atezolizumab and the related antibody pembrolizumab have been used in early-phase clinical trials, showing that PD-L1-specific PET signal can be detected in human tumours, that uptake varies widely between patients, and that heterogeneity exists even among different metastatic lesions within the same individual. These studies revealed something that biopsies had long obscured: a patient whose primary tumour shows strong PD-L1 staining may harbour liver metastases with negligible target expression, and those lesions may behave very differently under treatment. Quantitative measures derived from PET scans, such as standardised uptake values, have been correlated with clinical outcomes in preliminary analyses, hinting that baseline tracer uptake and early changes during therapy could serve as predictive biomarkers in their own right.

Dosing is another area where saturation imaging carries substantial implications. Current atezolizumab regimens were established through trials that sought doses safely exceeding the levels needed for receptor occupancy, but those occupancy estimates were largely derived from circulating drug levels and receptor occupancy measurements on peripheral blood cells, not from direct measurements inside tumours. Tumour penetration is governed by different physics: antibody extravasation through leaky but uneven vasculature, diffusion through the extracellular matrix, binding-site barriers created by dense target expression near blood vessels, and clearance rates that vary with tumour type and location. PET saturation imaging brings these hidden variables into view. A tumour that retains strong tracer uptake even after multiple treatment doses is telling clinicians that the target remains unsaturated, suggesting that dose escalation, altered scheduling, or combination strategies that improve drug delivery might be worth considering for that specific patient.

The study published in the British Journal of Cancer contributes to this evolving evidence base by evaluating PD-L1 PET/CT specifically as a tool to assess tumour saturation during atezolizumab treatment. The broader research programme of which it forms a part reflects a decisive shift in oncology drug development: away from one-size-fits-all dosing and toward imaging-verified pharmacodynamics. Regulatory science has begun to take note. Methods that demonstrate target engagement early in treatment could accelerate clinical trials by providing early surrogate indicators, reducing the sample sizes and follow-up durations needed to establish whether a drug regimen is mechanistically active. They could also support adaptive treatment strategies in routine care, in which imaging results after the first one or two doses inform whether the patient should continue, switch, or intensify therapy long before tumour volume changes would be visible.

Challenges remain before such imaging can enter routine practice. Radiolabelling antibodies with zirconium-89 requires cyclotron facilities, radiochemistry expertise, and regulatory compliance that currently limits availability to specialised centres. The half-life of zirconium-89, roughly 78 hours, suits the slow pharmacokinetics of antibodies, which circulate for days to weeks before reaching peak tumour uptake, but it also means patients must return for scans several days after injection and absorb a meaningful radiation dose. Cost, reimbursement, and the need for standardised scanning protocols and uptake thresholds all stand between promising trial results and clinical adoption. Questions also persist about how best to interpret partial saturation, how tracer signal in the liver and spleen, organs with high background antibody uptake, affects quantification of abdominal lesions, and how the immune response triggered by treatment itself alters target expression over time.

Nevertheless, the trajectory of the field is unmistakable. Molecular imaging of drug-target engagement is converging with immunotherapy at a moment when the limitations of current biomarkers have become painfully evident. PD-L1 immunohistochemistry, tumour mutational burden, and gene-expression signatures each capture only a fragment of the biology that determines whether a patient responds to checkpoint blockade. Saturation imaging promises something those tools cannot: a dynamic, whole-body, patient-specific readout of whether the drug is doing, at the molecular level, what it was designed to do. If validated in larger cohorts, the approach exemplified by this line of research could move immunotherapy closer to the ideal of precision medicine, where the first weeks of treatment generate actionable information rather than a waiting period measured in months. For the many patients whose tumours do not respond to atezolizumab and its peers, that shift could mean less time on ineffective therapy, faster transitions to alternatives, and a clearer mechanistic understanding of why immunotherapy succeeds or fails in each individual.

Subject of Research: PD-L1 PET/CT molecular imaging to assess tumour target saturation during atezolizumab immunotherapy

Article Title: Programmed death ligand 1 (PD-L1) PET/CT imaging to evaluate tumour saturation during atezolizumab treatment

Article References: Hooiveld-Noeken, J. S., van de Donk, P. P., Kist de Ruijter, L., Kok, I. C., van Winkel, C. A. J., Giesen, D., Lub-de Hooge, M. N., Brouwers, A. H., Oosting, S. F., Bensch, F., Smit, L. M., Schröder, C. P., Jalving, M., Elias, S. G., Gietema, J. A., Deurloo, R. J., Williams, S. P., Ungewickell, A., de Groot, D.-J. A., & de Vries, E. G. E. (2026). Programmed death ligand 1 (PD-L1) PET/CT imaging to evaluate tumour saturation during atezolizumab treatment. British Journal of Cancer. https://doi.org/10.1038/s41416-026-03595-8

Image Credits: AI Generated

DOI: 10.1038/s41416-026-03595-8

Keywords: PD-L1, PET/CT imaging, atezolizumab, immunotherapy, checkpoint inhibitors, target saturation, molecular imaging, radiotracer, tumour microenvironment, pharmacodynamics, precision oncology, British Journal of Cancer

The tracer at the center of the research is called [68Ga]Ga-FZ-NR-1, a gallium-68-labeled radioligand designed to bind specifically to Nectin-4, a cell adhesion molecule that has emerged as one of the most compelling targets in modern oncology. Nectin-4 sits on the surface of cells and is largely silenced in healthy adult tissue, but it is overexpressed in a wide range of malignancies, including triple-negative breast cancer, where it has been linked to proliferation, metastasis, and poor prognosis. Its clinical importance has been underscored by the success of enfortumab vedotin, a Nectin-4-directed antibody-drug conjugate approved for urothelial carcinoma, and by a growing pipeline of next-generation Nectin-4-targeted agents now being tested across solid tumors. If a tracer could map where Nectin-4 is expressed throughout a patient’s body, physicians would gain a non-invasive window into which tumors might respond to these drugs.

That is precisely what a team at Fudan University Shanghai Cancer Center set out to test. In a clinical translational study, the researchers enrolled 40 patients with recurrent or metastatic triple-negative breast cancer, each of whom underwent both [68Ga]Ga-FZ-NR-1 PET/CT and conventional FDG PET/CT within a single week. This head-to-head design allowed a direct comparison of the two tracers on the same patients, same lesions, and same time points, eliminating many of the confounders that plague cross-study comparisons. Diagnostic performance was assessed against a reference standard and compared statistically using the McNemar test, while survival outcomes were analyzed with Kaplan-Meier methods to determine whether imaging features could predict how long patients remained free of progression or alive.

The first striking finding concerned heterogeneity. When the researchers examined Nectin-4 expression across all lesions within a single patient, they found remarkable spatial variability: the median inter-lesion fold difference in uptake was 3.10, and the median coefficient of variation reached 31.70 percent. In practical terms, one metastatic deposit in a patient might light up intensely on the Nectin-4 scan while another lesion in the same body barely registered. This kind of whole-body mapping of molecular heterogeneity is something a single biopsy can never provide, and it carries real therapeutic consequences. Antibody-drug conjugates depend on target expression at every disease site; a tumor clone that has downregulated Nectin-4 could survive treatment and seed relapse, even when the primary lesion shows abundant target. The scan essentially renders this invisible biology visible.

On raw signal intensity, FDG still held an advantage. The study found that FDG achieved higher maximum standardized uptake values, or SUVmax, reflecting the intense glucose consumption typical of aggressive cancers. But raw uptake is not the whole story, because a tracer is only as useful as its contrast between tumor and surrounding tissue. Here the new agent excelled: [68Ga]Ga-FZ-NR-1 delivered a significantly higher tumor-to-background ratio across a variety of metastatic sites. Because Nectin-4 is minimally expressed in normal adult tissues, the tracer paints tumors in sharp relief against a quiet background, whereas FDG competes with the physiological glucose uptake of the brain, heart, bowel, and inflamed tissue. High contrast translates directly into clinical confidence, allowing radiologists to distinguish true lesions from ambiguous uptake with far less uncertainty.

The diagnostic numbers bore this out decisively. [68Ga]Ga-FZ-NR-1 PET/CT detected more lesions overall than FDG PET/CT and achieved a sensitivity of 98.13 percent compared with 93.46 percent for FDG, meaning it missed fewer true tumor deposits. The gap in specificity was even more dramatic: 68.63 percent for the Nectin-4 tracer versus just 27.45 percent for FDG. In other words, when the Nectin-4 scan showed uptake, it was far more likely to represent genuine malignancy rather than a benign mimic. For patients with recurrent disease, where scar tissue from prior surgery and radiation can confound interpretation, that difference in specificity could spare patients from unnecessary biopsies, inappropriate treatment changes, and the psychological toll of false alarms.

Beyond diagnosis, the study delivered something arguably more valuable: prognostic power. The researchers measured volumetric and heterogeneity parameters from the baseline Nectin-4 scans, including metabolic tumor volume at a 40 percent threshold (MTV40) and a heterogeneity index (HI). Patients with a high baseline mean MTV40 on the Nectin-4 scan had significantly shorter progression-free survival, with a P value of 0.009, while a high heterogeneity index predicted significantly shorter overall survival, with a P value of 0.008. These associations suggest that the sheer burden of Nectin-4-expressing disease and the unevenness of its expression are not merely visual curiosities but quantitative signals of aggressive biology. A single pretreatment scan could therefore help stratify patients into risk groups before a single dose of therapy is given.

The implications extend naturally into the era of Nectin-4-targeted therapeutics. Companion diagnostics have become essential as antibody-drug conjugates multiply, because these expensive and sometimes toxic drugs work best in patients whose tumors actually express the target. Immunohistochemistry on a biopsy sample offers only a local, single-site answer, and studies in urothelial carcinoma have shown that Nectin-4 expression can decrease during metastatic spread, contributing to resistance against enfortumab vedotin. A whole-body PET tracer like [68Ga]Ga-FZ-NR-1 offers a complementary, dynamic view: it can confirm target expression across every known lesion, quantify heterogeneity, and potentially identify patients most likely to benefit from Nectin-4-directed treatment. The authors describe their findings as hypothesis-generating, an appropriately cautious framing, but the direction of travel is clear.

Several caveats temper the enthusiasm. The study involved 40 patients at a single institution, and the survival analyses, while statistically significant, require validation in larger, multicenter cohorts before they can guide clinical decision-making. The comparison also reflects the specific tracer and imaging protocols used, and questions remain about optimal timing, dosimetry, and how Nectin-4 PET findings should be integrated with existing staging tools. Cost and availability of gallium-68 radiopharmaceutical production will also shape adoption, although generator-based production and the growing network of radiopharmacies are steadily lowering those barriers. None of these caveats, however, diminishes the central achievement of the study: demonstrating, in a rigorous head-to-head comparison, that a molecularly targeted tracer can outperform the workhorse of oncologic imaging in one of the hardest cancers to image and treat.

For patients with recurrent or metastatic triple-negative breast cancer, the study offers a glimpse of a more precise future. Instead of asking simply whether a tumor is metabolically active, clinicians could soon ask whether it expresses the specific molecule their next drug is designed to attack, and how uniformly that expression is distributed across the entire disease burden. The Fudan team’s work positions [68Ga]Ga-FZ-NR-1 as both a diagnostic upgrade and a prognostic instrument, a dual role that mirrors the theranostic philosophy transforming nuclear medicine. As Nectin-4-targeted antibody-drug conjugates advance through clinical trials in breast cancer and beyond, the ability to see the target before committing to therapy could become as routine as receptor testing is today. This study is an early but persuasive step toward that goal, and it signals that the next generation of cancer imaging will speak the molecular language of the tumor itself.

Subject of Research: Nectin-4-targeted [68Ga]Ga-FZ-NR-1 PET/CT imaging for diagnosis and prognosis in recurrent or metastatic triple-negative breast cancer

Article Title: Prognostic value and diagnostic performance of nectin-4-targeted [68Ga]Ga-FZ-NR-1 PET/CT versus [18F]FDG in recurrent or metastatic triple-negative breast cancer

Article References: Li, Y., Sun, Y., Sun, L., Wang, D., Pan, X., Xu, X., & Song, S. (2026). Prognostic value and diagnostic performance of nectin-4-targeted [68Ga]Ga-FZ-NR-1 PET/CT versus [18F]FDG in recurrent or metastatic triple-negative breast cancer. European Journal of Nuclear Medicine and Molecular Imaging. https://doi.org/10.1007/s00259-026-08177-7

Image Credits: AI Generated

DOI: 10.1007/s00259-026-08177-7

Keywords: Nectin-4, triple-negative breast cancer, PET/CT, [68Ga]Ga-FZ-NR-1, FDG PET, molecular imaging, antibody-drug conjugates, tumor heterogeneity, prognosis, radiotracer, nuclear medicine, survival prediction