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Grand RoundsWeekly Evidence Brief

Nuclear Medicine

Edition

30-Second Takeaway

  • Non-FDG PET tracers and PET/MR are reshaping bladder cancer staging and response assessment.
  • β3-amino acid linker engineering yields a PSMA theranostic with higher tumor uptake and lower salivary–renal dose burden.
  • PRRT remains central for advanced well-differentiated GEP-NETs, but optimal sequencing with other modalities is individualized.
  • [18F]FAPI PET/CT with a quantitative activity score stratifies IgG4-related disease activity with high sensitivity.
  • Nuclear medicine tools now detect early autonomic and cardiac involvement in hereditary ATTR before overt symptoms.

Week ending March 7, 2026

Emerging PET theranostics and targeted imaging across oncology, inflammation, and cardiology

PET in bladder cancer: non-FDG tracers, PET/MR, and radiomics move toward precision staging

SEMINARS IN NUCLEAR MEDICINEMar 4, 2026

This review outlines current and emerging roles of PET in bladder cancer management across staging, restaging, and response assessment. It highlights FDG’s limitations from urinary excretion, complicating primary tumor and pelvic node evaluation. Emerging non-FDG tracers targeting receptors, fibroblast activation, or Nectin‑4 may improve lesion conspicuity and biological characterization. The article discusses PET/MRI, quantitative metrics, radiomics, and AI to enhance risk stratification and guide individualized treatment decisions.

β3-amino acid–linked PSMA-HK9 improves theranostic profile over current PSMA ligands

JOURNAL OF MEDICINAL CHEMISTRYMar 2, 2026

This study introduces PSMA-HK9, a redesigned [18F]PSMA‑1007 scaffold incorporating a β3‑amino acid linker and DOTA chelator. In preclinical models, [68Ga]Ga‑PSMA‑HK9 showed higher tumor uptake with markedly reduced kidney and salivary gland accumulation versus a [68Ga]-labeled PSMA‑1007 analog. First-in-human [68Ga]Ga‑PSMA‑HK9 PET suggested higher tumor uptake compared with [68Ga]Ga‑PSMA‑617, indicating potential imaging advantages. Therapeutically, [177Lu]Lu‑PSMA‑HK9 achieved superior tumor inhibition and efficient internalization versus [177Lu]Lu‑PSMA‑617, with acceptable safety in early evaluation.

PRRT for well-differentiated GEP-NETs: efficacy established, sequencing remains nuanced

ENDOCRINE-RELATED CANCERMar 2, 2026

This review synthesizes evidence for peptide receptor radionuclide therapy in advanced well-differentiated GEP‑NETs expressing somatostatin receptors. It confirms PRRT as an effective option, especially for inoperable or progressive disease after other systemic or locoregional therapies. The article discusses integration with surgery, liver-directed therapy, chemotherapy, and targeted agents, emphasizing individualized sequencing. Patient-specific factors such as tumor type, receptor expression, burden, and comorbidities drive timing decisions in a multidisciplinary framework.

[18F]FAPI PET/CT with FPAS-IgG4 quantifies organ involvement and activity in IgG4-related disease

RMD OPENMar 5, 2026

This retrospective study evaluated [18F]FAPI PET/CT in 85 IgG4‑related disease patients and 10 controls, defining organ-specific uptake thresholds. Using these thresholds, [18F]FAPI PET/CT achieved sensitivity 86.2%, specificity 83.3%, and accuracy 85.9% for detecting IgG4‑RD involvement. The authors developed an [18F]FAPI PET/CT Activity Score (FPAS‑IgG4), which was significantly higher in active versus inactive disease. An FPAS‑IgG4 cutoff >2 distinguished active from inactive disease with 93.2% sensitivity and 73.1% specificity, strongly associating with active IgG4‑RD.

References

Numbered in order of appearance. Click any reference to view details.

Additional Reads

Optional additional studies from this edition.

Edition context

Clinical signal

  • Targeted PET tracers and antibody theranostics are rapidly expanding beyond SSTR and PSMA to fibroblast activation, CAIX, and SORT1.
  • Standardized quantitative metrics and scoring systems are increasingly crucial for interpreting inflammatory and oncologic PET studies.
  • Radiotheranostic pairs enable imaging-based patient selection, individualized dosimetry, and tighter integration with systemic oncology care.