To our knowledge, clinically meaningful restoration of radioiodine avidity in established radioiodine-refractory differentiated thyroid cancer has not been reported after multikinase inhibitor therapy, despite successful redifferentiation reported with selective kinase inhibitors targeting BRAF, RAS, RET or NTRK. We report a 53-year-old woman with invasive follicular variant papillary thyroid carcinoma and synchronous cervical lymph node, pulmonary and bone metastases who underwent six cycles of radioiodine therapy within 3 years after total thyroidectomy. Initially radioiodine-avid metastases gradually lost radioiodine avidity, as suggested by serial post-radioiodine therapy whole-body scans. Lenvatinib was initiated after 3 years of active surveillance. Restored radioiodine uptake was observed on rhTSH-assisted diagnostic whole-body scan after 9 months of lenvatinib treatment, allowing subsequent salvage radioiodine therapy. Subsequent post-radioiodine therapy whole-body scans showed increased uptake intensity and additional radioiodine-avid bone metastases, with a marked decrease in suppressed thyroglobulin. Reassessment of radioiodine avidity after prolonged multikinase inhibitor treatment warrants clinical consideration to determine the feasibility of salvage radioiodine therapy.
Insulinomas are rare pancreatic neuroendocrine tumours, causing recurrent episodes of hypoglycaemia. Accurate localisation is essential for surgical management, yet imaging remains challenging. This case series presents unusual findings of paediatric insulinomas on [18F]-dihydroxyphenylalanine ([18F]FDOPA) positron emission tomography-computed tomography (PET-CT) imaging. We retrospectively reviewed medical notes and investigations of histologically proven paediatric insulinoma cases (n=4) presenting to Royal Manchester Children’s Hospital between 2008 and 2024. All patients underwent [18F]FDOPA PET-CT as part of their diagnostic workup. Imaging findings were analysed, with particular attention to tracer uptake patterns. Contrary to the increased tracer uptake typically seen in neuroendocrine tumours, three of the four insulinomas demonstrated focal photopenia at the site of the tumour on [18F]FDOPA PET-CT. Only one case showed increased uptake, suggesting a predominance of reduced, rather than enhanced, tracer activity in paediatric insulinomas Photopenia on [18F]FDOPA PET-CT may be a more frequent finding than increased uptake in paediatric insulinomas. Recognizing this atypical pattern is important for accurate tumour localisation before surgical management. Further studies are needed to validate these findings and find a mechanistic explanation.
PSMA PET/CT using 18F‑DCFPyL and 68Ga‑labelled tracers is central to prostate cancer staging, but 68Ga‑PSMA may show reduced sensitivity and quantitative accuracy, partly due to respiratory motion and lower spatial resolution. Device-based motion‑correction methods have limitations. Data‑driven gating (DDG) offers a hardware‑free alternative, though its impact on PSMA PET, especially 68Ga‑PSMA has not been systematically evaluated. To evaluate the quantitative and qualitative performance of the DDG motion-correction method in 68Ga-PSMA and 18F-DCFPyL-PSMA PET/CT, focusing on metastatic lymph node, lung, and bone lesions, and to assess its robustness across tracers. This retrospective study included patients with biopsy‑proven prostate cancer who underwent 68Ga‑PSMA or 18F‑DCFPyL PSMA PET/CT for primary staging or biochemical recurrence and had metastatic disease. Motion correction was applied using the OncoFreeze AI™ data‑driven gating (OFAI‑DDG) method. Metastatic lesions were segmented semi‑automatically, and SUV metrics, image noise, and contrast‑to‑noise ratio were quantified by anatomical site in both OFAI-DDG and static images. Qualitative image quality was independently scored by two experienced readers. Statistical analyses included non‑parametric tests, Bland-Altman agreement, regression analyses, tracer comparison, and inter‑reader reliability assessment. After exclusions, 23 68Ga‑PSMA and 40 18F‑PSMA patients were analyzed, yielding 133 and 192 metastatic lesions, respectively. OFAI‑DDG reconstruction significantly increased SUVmean and SUVmax compared with static imaging for both tracers across bone, lymph node, and lung lesions (p < 0.0001), with the largest gains in lung lesions. CNR improved for most lesion types, and image noise was significantly reduced. Qualitative analysis showed better image quality, sharpness, and noise with OFAI‑DDG, with high inter‑reader agreement. OFAI‑DDG performance was robust across tracers and largely independent of lesion location. This study demonstrates that OFAI‑DDG significantly improves PSMA PET/CT image quality and quantitative accuracy compared with standard static imaging. The improvements were observed for both 68Ga‑PSMA and 18F‑PSMA tracers, indicating tracer‑independent robustness. The OFAI‑DDG simplified the workflow and reduced time used for patient set-up, while enhancing lesion visualization and quantitative reliability without altering lesion detection, supporting its clinical value for metastatic prostate cancer imaging.
Recent advances in nuclear medicine are reshaping the evaluation of cardiac amyloidosis, as highlighted by the recent collection published in EJNMMI (collection link: https://link.springer.com/collections/igfdhcddjg). This commentary summarizes key insights from these studies, emphasizing the evolving shift from conventional diagnostic imaging toward a more integrated and comprehensive approach. Emerging developments include novel amyloid PET tracers, improved diagnostic accuracy with SPECT/CT, multimodality imaging strategies, and enhanced assessment of systemic disease burden extending beyond the left ventricle. There is also growing interest in longitudinal monitoring, pre-symptomatic detection, and the role of artificial intelligence. Together, these advances position nuclear medicine as an essential tool for disease characterization, risk stratification, and treatment assessment.
