Seminars in nuclear medicine最新文献

Diuretic renography remains central to evaluating suspected urinary tract obstruction in children, yet interpretation varies across centers. Modern pediatric practice benefits from standardized acquisition and analysis, including harmonized hydration, furosemide timing, and drainage parameters such as half-time (T½), normalized residual activity (NORA), and parenchymal transit time (PTT). Diuretic renography in children, including its indications, practical patient preparation and acquisition protocols, and interpretive framework linked to clinical decision points are discussed. Key protocol choices (F-15, F-0, F + 20/30), bladder management, minimization of sedation, and motion control are also reviewed, and pitfalls described at the end. Consistent technique-adequate hydration, standardized furosemide dosing, dynamic acquisition with post-void/post-upright positioning/delayed images, and quantitative assessment-improves reproducibility and reduces equivocal studies. NORA complements T½ by accounting for kidney size and residual activity; PTT helps separate obstructive from non-obstructive delay and may predict outcomes after pyeloplasty. Special populations (infants, neurogenic bladder, post-operative states) require tailored protocols and cautious interpretation of quantitative parameters. A practical, physiology-based approach to pediatric diuretic renography reduces variability and aligns imaging with urologic management. Standardized technique and transparent reporting of drainage metrics (T½, NORA, PTT) should be performed widely to optimize care and facilitate multi-center research.

Prostate cancer remains a major global health burden, and the integration of PSMA-targeted PET imaging and radioligand therapy has transformed diagnostic and therapeutic strategies for advanced disease. Traditional response assessment tools-such as PSA kinetics, CT, bone scans, and composite criteria like PCWG3 or RECIST-are limited by PSA flare phenomena, inability to evaluate bone-only disease, and lack of sensitivity for early metastatic changes. To address these limitations, the Response Evaluation Criteria in PSMA PET/CT (RECIP 1.0) was developed as the first evidence-based framework leveraging PSMA PET imaging for treatment response evaluation. RECIP 1.0 incorporates changes in PSMA-positive total tumour volume and the appearance of new lesions, enabling stratification into complete response, partial response, stable disease, or progressive disease. It has demonstrated strong prognostic value for overall and progression-free survival and supports standardized reporting essential for clinical trials. A visual RECIP method further enhances feasibility in routine practice, showing excellent concordance with quantitative software-based segmentation. Although challenges remain, particularly the labor-intensive nature of tumour segmentation and variability across imaging protocols emerging AI-based automated tools are poised to streamline RECIP implementation. As PSMA-based theranostics continue to expand, RECIP 1.0 offers a robust and clinically meaningful framework for response assessment.

Breast cancer remains one of the most heterogeneous malignancies, with marked variability in biology, therapeutic sensitivity, and clinical outcomes. As treatment strategies evolve toward individualized approaches, early and accurate assessment of response has become critical for optimizing outcomes and minimizing toxicity. Recent Findings: ¹⁸F-FDG PET/CT provides a biologically grounded, non-invasive measure of tumour metabolism, heterogeneity, and early treatment adaptation. Baseline metrics such as SUVmax, metabolic tumour volume (MTV), and total lesion glycolysis (TLG)-reflect proliferative drive and aggressiveness, while early changes (ΔSUV, ΔMTV/TLG after 1-2 cycles) predict pathological complete response (pCR) with high negative predictive value. PET-derived nomograms integrating clinical, molecular, and metabolic data outperform clinicopathologic models alone. Radiomic and artificial-intelligence (AI) analyses further refine prediction by quantifying spatial heterogeneity and enabling subtype-specific modelling. Joint EANM/SNMMI guidelines and NCCN recommendations increasingly endorse ¹⁸F-FDG PET/CT for staging and response monitoring in high-risk or locally advanced disease. ¹⁸F-FDG PET/CT has transitioned from staging to precision-response prediction, particularly in HER2-positive and triple-negative breast cancer. Integration into AI driven nomograms supports adaptive, patient-tailored decisions that minimize toxicity and cost while maximizing benefit. Prospective multicentre validation aligned with EANM/SNMMI/NCCN guidance will consolidate PET's role in adaptive oncology.

Artificial intelligence (AI) is increasingly permeating nuclear cardiology and offers the possibility to enhance diagnostic accuracy, prognostic stratification, and operational efficiency. AI is demonstrating applicability across the imaging workflow-from individualized patient selection and adaptive image reconstruction to denoising of low-dose datasets, automated attenuation and motion correction, calcium scoring, and the integration of imaging with clinical and functional variables for enhanced diagnosis and comprehensive risk assessment. But the translational trajectory of AI in nuclear cardiology is challenged by the lag in fundamental AI knowledge among researchers and clinicians, the quality of the target data regarding heterogeneity in acquisition protocols, scanner platforms, and patient populations, and by infrastructural disparities that constrain the generation of large, representative datasets needed for training and validation, particularly in low-resource settings. Additionally, necessary regulatory and legal frameworks remain in early stages of harmonization. This white paper, developed by an International Atomic Energy Agency (IAEA) working group, provides a succinct overview of the technical basis, areas of deployment, clinical value and unmet challenges of AI in nuclear cardiology. It makes punctual suggestions to aid maturation in this area while maintaining a sober interaction with the overwhelming nature of the field. These include promoting standardized acquisition and reporting practices, establishing globally representative reference datasets, promoting imaging multimodality frameworks and developing AI-proficient clinical and technical personnel. Under these conditions, AI may meaningfully enhance the diagnostic and prognostic value of nuclear cardiology while supporting equitable implementation and preserving clinical accountability.

The concept of death by neurologic criteria (DNC), a medicolegal construct also known as "brain death", is over 50 years old. Ancillary examinations have a well-defined role in this diagnosis, principally when the clinical examination cannot be completely or safely performed. Radionuclide studies, which provide a combination of ease of performance and high accuracy, remain amongst the most recommended ancillary studies in current clinical guidelines. There are in fact 2 discrete categories of radionuclide studies, using hydrophilic or lipophilic radiopharmaceuticals (RPs), which have overlapping but discrete features, described in this review. Lipophilic RPs that provide both flow and parenchymal imaging are superior to hydrophilic RPs that provide only flow imaging. Various signs have been described in regard to interpretation of the radionuclide study and serve to encapsulate findings in a concise and clearly understood manner. The trident and empty skull signs, relevant to flow and parenchymal phases of radionuclide examinations, respectively, remain the key elements of interpretation and are both necessary and sufficient to make the diagnosis of DNC. The hot nose sign and the sagittal sinus sign are not sufficiently specific for this diagnosis, and do not have a place in the interpretation of DNC examinations. Because it operates in the medicolegal realm and requires rapid and definitive reporting, the nuclear medicine physician must be particularly familiar with methods and interpretation of scintigraphy as an ancillary examination in determination of death by neurologic criteria.

PSMA-PET has become a pivotal imaging method for staging and restaging of prostate cancer. Risk stratification of the disease is a crucial for the patients to receive most appropriate treatment, and for the clinicians to follow the patients more precisely. PSMA-PET provides non-invasive biomarkers for the risk assessment of prostate cancer, offering prediction of clinical outcomes. PROMISE criteria have been developed as comprehensive and integrated framework demonstrating association with overall survival. In this review, we aim to provide a brief update of the prognostic value of PSMA-PET for risk assessment in prostate cancer.

Metastatic prostate cancer heterogeneity is a multifactorial spatiotemporally dynamic process that leads to disease progression, emergence of treatment resistance and eventual treatment failure. Understanding of the root causes of tumor heterogeneity is the key to develop strategies for more effective therapies. The intra-patient (inter-tumor), and inter-patient heterogeneity demands combinatorial treatment strategies anchored to patient-specific disease biology that can successfully tackle the complexity of the disease in the hopes of overcoming the biological barriers to cancer control. The aim of this article is to briefly review the elements of metastatic prostate cancer heterogeneity and propose approaches to tackle the ensuing therapeutic challenges to achieve durable clinical efficacy in the context of radiopharmaceutical therapy.

Radium-223 (²²³Ra), an alpha-emitting radiopharmaceutical targets bone and prolongs overall survival (OS) while reducing skeletal-related events (SREs) in metastatic castration-resistant prostate cancer patients (mCRPC). However, assessing ²²³Ra therapeutic response is difficult due to its distinct mechanism of action on bone remodeling and tumor microenvironment. Therefore, a multimodal approach to evaluate response is required, beyond conventional serum tumor biomarkers such as PSA and ALP. This review integrates current and emerging strategies for evaluating ²²³Ra response. We discuss classic serum biomarkers, highlighting their prognostic and monitoring roles. We also examine emerging liquid biopsy tools, such as circulating tumor cells, circulating tumor DNA, bone metabolism markers and exosomes that may reflect the metabolic changes induced by ²²³Ra. We also explore the clinical response patterns and limitations of imaging biomarkers that play a central role in response assessment such as ¹⁸F-fluoride PET/CT, whole-body diffusion-weighted MRI and PSMA PET/CT. We cover RECIST-based assessments and innovative technologies, including radiomics and artificial intelligence, that integrate clinical, molecular, and imaging data to enhance outcome prediction, automate lesion analysis, and reveal patterns related to treatment response, supporting personalized care. In conclusion, a multimodal approach that combines biological and imaging markers with modern analytical methods enhances ²²³Ra therapy response evaluation, leading to improved clinical outcomes in mCRPC.