Search Results (1,280)

Objectives: Respiratory motion degrades the quantitative accuracy and test–retest (TRT) reliability of fluorine-18 fluorodeoxyglucose ([¹⁸F] FDG) positron emission tomography (PET)/computed tomography (CT) in lung cancer. This study investigated whether a deep-learning-based respiratory motion correction (RMC) method improves the TRT reliability and image quality of [¹⁸F] FDG PET tumor quantification compared with non-motion-corrected (NMC) reconstructions. Methods: Thirty-one patients with primary lung cancer underwent three PET acquisitions: whole body free breathing (Scan1), thoracic free breathing (Scan2), and thoracic controlled breathing (ScanCB). Each dataset was reconstructed with and without RMC. Visual assessments of liver motion artifacts, lesion clarity, and PET-CT co-registration were scored. Lung tumors were segmented to derive standardized uptake value max (SUVmax), SUVmean, metabolic tumor volume (MTV), PET-derived lesion length (PLL), and total lesion glycolysis (TLG). Visual image scores and TRT reliability of tumor quantification were compared using Kruskal–Wallis one-way analysis of variance and intraclass correlation coefficients (ICCs). Results: RMC reconstructions achieved higher visual scores of lesion clarity and PET-CT co-registration across all lung lobes and significantly reduced liver motion artifacts compared with NMC reconstructions. Differences in SUVmax, SUVmean, PLL, MTV, and TLG between Scan2 and ScanCB were significantly smaller with RMC than with NMC. ICCs for SUVmax, SUVmean, MTV, and TLG were higher between scans with RMC than NMC reconstructions, indicating improved TRT reliability. Conclusions: The deep-learning-based RMC method improved the image quality and TRT reproducibility of [¹⁸F] FDG PET/CT quantification in lung cancer, supporting its potential for routine adoption in therapy-response assessments. Full article

Actinium-225 (²²⁵Ac) has emerged as a pivotal alpha-emitter in modern radiopharmaceutical therapy, offering potent cytotoxicity with the potential for precise tumour targeting. Accurate, patient-specific image-based dosimetry for ²²⁵Ac is essential to optimize therapeutic efficacy while minimizing radiation-induced toxicity. Establishing a robust dosimetry workflow is particularly challenging due to the complex decay chain, low administered activity, limited count statistics, and the indirect measurement of daughter gamma emissions. Clinical single-photon emission computed tomography/computed tomography protocols with harmonized acquisition parameters, combined with robust volume-of-interest segmentation, artificial intelligence (AI)-driven image processing, and voxel-level analysis, enable reliable time-activity curve generation and absorbed-dose calculation, while reduced mixed-model approaches improve workflow efficiency, reproducibility, and patient-centred implementation. Cadmium zinc telluride-based gamma cameras further enhance quantitative accuracy, enabling rapid whole-body imaging and precise activity measurement, supporting patient-friendly dosimetry. Complementing these advances, the cerium-134/lanthanum-134 positron emission tomography in vivo generator provides a unique theranostic platform to noninvasively monitor ²²⁵Ac progeny redistribution, evaluate alpha-decay recoil, and study tracer internalization, particularly for internalizing vectors. Together, these technological and methodological innovations establish a mechanistically informed framework for individualized ²²⁵Ac dosimetry in targeted alpha therapy, supporting optimized treatment planning and precise response assessment. Continued standardization and validation of imaging, reconstruction, and dosimetry workflows will be critical to translate these approaches into reproducible, patient-specific clinical care. Full article

This study establishes a murine model of corticosteroid-associated osteonecrosis of the femoral head (ONFH) using a sustained-release prednisolone pellet and evaluates mitochondrial stress using ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and changes in key histologic markers of bone over a 6-week period. Sixteen 12-week-old Balb/C mice were divided into two groups: a prednisolone group (PRED) and a control group (SHAM). The PRED group received a subcutaneous 60-day sustained-release pellet containing 2.5 mg of prednisolone, while the SHAM group received placebo pellets. PET/CT imaging was performed at 1, 3, and 6 weeks. Bone mineral density (BMD) measurements, and histomorphological analyses for the number of empty lacunae, osteoblasts, osteoclasts, and NADPH oxidase (NOX) 2, a marker for oxidative stress, were conducted at 4 or 6 weeks. PET/CT imaging demonstrated increased uptake in the femoral head at 3 weeks in the PRED group. This was accompanied by increased numbers of empty lacunae and osteoclasts, increased oxidative stress, and decreased alkaline phosphatase staining at 4 weeks in the PRED group. We have successfully established and validated a small murine model of ONFH. The findings of this preclinical study suggest a critical timeline for potential interventions to mitigate the early adverse effects of continuous corticosteroid exposure on bone. Full article

The “Neuroimaging and Pathology Biomarkers in Parkinson’s Disease” course held on 12–13 September 2025 in Milan, Italy, convened an international faculty to review state-of-the-art biomarkers spanning neurotransmitter dysfunction, protein pathology and clinical translation. Here, we synthesize the four themed sessions and highlights convergent messages for diagnosis, stratification and trial design. The first session focused on neuroimaging markers of neurotransmitter dysfunction, highlighting how positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) provided complementary insights into dopaminergic, noradrenergic, cholinergic and serotonergic dysfunction. The second session addressed in vivo imaging of protein pathology, presenting recent advances in PET ligands targeting α-synuclein, progress in four-repeat tau imaging for progressive supranuclear palsy and corticobasal syndromes, and the prognostic relevance of amyloid imaging in the context of mixed pathologies. Imaging of neuroinflammation captures inflammatory processes in vivo and helps study pathophysiological effects. The third session bridged pathology and disease mechanisms, covering the biology of α-synuclein and emerging therapeutic strategies, the clinical potential of seed amplification assays and skin biopsy, the impact of co-pathologies on disease expression, and the “brain-first” versus “body-first” model of pathological spread. Finally, the fourth session addressed disease progression and clinical translation, focusing on imaging predictors of phenoconversion from prodromal to clinically overt stages of synucleinopathies, concepts of neural reserve and compensation, imaging correlates of cognitive impairment, and MRI approaches for atypical parkinsonism. Biomarker-informed pharmacological, infusion-based, and surgical strategies, including network-guided and adaptive deep brain stimulation, were discussed as examples of how multimodal biomarkers may inform personalized management. Across all sessions, the need for harmonization, longitudinal validation, and pathology-confirmed outcome measures was consistently emphasized as essential for advancing biomarker qualification in multicentre research and clinical practice. Full article

Background: Sarcoidosis is a multisystem inflammatory disorder characterized by non-caseating granulomas, most commonly affecting the lungs and intrathoracic lymph nodes. Angiotensin-converting enzyme (ACE) levels and calcium abnormalities are recognized biomarkers, while ^18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is increasingly used to assess disease activity. However, neither provides sufficient diagnostic accuracy alone. Therefore, this study aimed to investigate the relationship between FDG-PET/CT metabolic findings and serum ACE and calcium (Ca²⁺) levels as surrogate indicators of inflammatory metabolic intensity in sarcoidosis. Methods: In this retrospective single-center study, 127 patients with pulmonary sarcoidosis who underwent PET/CT at diagnosis were evaluated. Demographic and clinical data, ACE, and Ca²⁺ levels were recorded. FDG uptake in mediastinal, pulmonary, and extrapulmonary sites was analyzed, and correlations with biomarkers were assessed. Results: The cohort included 89 females (70.1%) and 38 males (29.9%), mean age 51.3 ± 11.9 years. FDG uptake was most frequent in mediastinal lymph nodes (84.3%) and lung parenchyma (40.9%). ACE levels correlated weakly with total SUVmax (r = 0.214, p = 0.019). Calcium levels correlated with extrapulmonary SUVmax (r = 0.327, p = 0.001) and were higher in patients with extrapulmonary involvement (p = 0.045). No associations were found between symptom presence and biomarkers or SUVmax values. Conclusions: FDG-PET/CT metabolic parameters, particularly total and extrapulmonary SUVmax, demonstrated modest yet statistically significant associations with ACE and calcium levels. These findings suggest that a combined biomarker-imaging approach may provide complementary information regarding inflammatory metabolic intensity and systemic involvement; however, the results should be interpreted as exploratory and require validation in prospective studies. Full article

A 74-year-old man with type 2 diabetes presented with fever, urinary retention, and urinary difficulties. Initial abdominal Computed Tomography (CT) suggested acute pyelonephritis, but a low-density area in the prostate was overlooked. Following the confirmation of methicillin-resistant Staphylococcus aureus (MRSA) in blood and urine cultures, comprehensive screening for metastatic abscesses was necessitated. Diffusion-weighted whole-body imaging with background suppression (DWIBS) was utilized and clearly identified a prostatic abscess (PA), nephritis, urethritis, and subcutaneous cysts. These findings also raised suspicion of pyogenic vertebral osteomyelitis. Crucially, the PA, urethritis, subcutaneous cysts, and potentially the vertebral osteomyelitis were either overlooked or not detected by initial CT imaging. DWIBS allows for simultaneous whole-body screening and serves as a useful adjunctive tool for identifying minute abscesses, which may assist in detecting inflammatory foci that are sometimes overlooked by conventional imaging. Unlike CT, DWIBS avoids radiation and contrast agents, and is significantly more cost-effective than positron emission tomography-CT (PET-CT). DWIBS can thus serve as a useful, non-invasive tool for the early detection and exclusion of abscesses in other organs when metastatic abscess formation is suspected or cultures are positive for microorganisms causing metastatic abscesses. Full article

Introduction: Radiotracer-based nuclear imaging, including positron emission tomography (PET) and single-photon emission computed tomography (SPECT), can complement conventional cross-sectional imaging in renal cell carcinoma (RCC) by providing biological characterisation of tumour metabolism, angiogenesis, hypoxia, and the tumour microenvironment. While computed tomography (CT) and magnetic resonance imaging (MRI) remain the diagnostic standard, accumulating evidence suggests that selected nuclear imaging techniques may offer incremental value in specific clinical scenarios. Methods: A narrative literature review was performed using PubMed, Embase, and Web of Science to identify preclinical, retrospective, and prospective studies evaluating PET and SPECT radiotracers in localised and metastatic RCC. Priority was given to meta-analyses, multicentre prospective trials, and studies with histopathological correlation. Results: [¹⁸F]fluorodeoxyglucose (FDG) PET/CT demonstrates limited sensitivity for primary renal tumours (pooled sensitivity of approximately 60%) but performs substantially better in metastatic and recurrent disease (pooled sensitivity and specificity of approximately 85–90%), where uptake correlates with tumour grade, progression-free survival, and overall survival. [^99mTc]sestamibi SPECT/CT differentiates oncocytoma and hybrid oncocytic/chromophobe tumours from malignant RCC with pooled sensitivity and specificity of around 85–90%, supporting its role in evaluating indeterminate renal masses rather than staging. Prostate-specific membrane antigen (PSMA) PET/CT shows high detection rates in clear-cell RCC, particularly in metastatic disease, with reported sensitivities of approximately 85–90% and management changes in up to 40–50% of selected cohorts. Carbonic anhydrase IX (CAIX)-targeted PET/CT enables the biologically specific visualisation of clear-cell RCC, achieving sensitivities and specificities in the range of 85–90% in prospective phase II and III trials for primary tumour characterisation. Fibroblast activation protein inhibitor (FAPI) PET/CT demonstrates high tumour-to-background uptake in early RCC studies, but evidence remains preliminary, with small cohorts and recognised non-specific uptake in benign inflammatory and fibrotic conditions. Conclusions: Radiotracer-based nuclear imaging provides complementary, biology-driven insights in RCC that extend beyond anatomical assessment. While most modalities remain adjunctive or investigational and are not recommended for routine use, selective application in carefully chosen clinical scenarios may enhance tumour characterisation, prognostication, and personalised treatment planning. Full article

Background: Oligometastatic bladder cancer (OMBC) is increasingly recognised as an intermediate state between localised and widespread metastatic disease, although its definition and optimal management remain uncertain. Patients with OMBC have a generally more favourable prognosis compared to patients with metastatic disease. However, its definition, diagnostic criteria, and optimal management remain poorly standardised. Methods: This narrative review summarises current evidence on the definitions, diagnostic approaches, and treatment strategies for OMBC, with an emphasis on emerging biological and molecular insights that may refine disease classification and guide therapy. Results: Existing definitions of OMBC rely on lesion count and anatomical distribution, overlooking molecular and clinicopathological heterogeneity that influences prognosis and treatment response. Advances in Positron Emission Tomography (PET)/Computed Tomography (CT) and magnetic resonance imaging (MRI) have improved detection of small-volume disease, while liquid biopsy and circulating tumour DNA show promise for assessing micrometastatic burden. Therapeutic approaches, including metastasis-directed and consolidative therapies, are under investigation. Nonetheless, most data are derived from small, retrospective series, and evidence from prospective studies remains limited. Conclusions: Prospective, biomarker-integrated, and randomised trials are essential to refine definitions, optimise patient selection for therapy, and define the role of precision-based multimodal therapy in OMBC management. Full article

Ovarian cancer continues to be the most lethal gynaecological malignancy, principally due to its late-stage diagnosis, extensive peritoneal dissemination, chemoresistance, and limitations of current imaging and therapeutic strategies. By optimising pharmacokinetics, refining tumour-selective drug delivery, and supporting high-resolution, multimodal imaging, nanomedicine offers a versatile platform to address these limitations. In this review, current progress across lipid-based, polymeric, inorganic, hybrid, and biomimetic nanocarriers is synthesised, emphasising how tailored physiochemical properties, surface functionalisation, and stimuli-responsive designs can improve tumour localisation, surmount stromal and ascetic barriers, and enable controlled drug release. Concurrently, significant advancement in imaging nanoprobes, including magnetic resonance imaging (MRI), positron emission tomography (PET)/single-photon emission computed tomography (SPECT), optical, near-infrared imaging (NIR), ultrasound, and photoacoustic systems, has evolved early lesion detection, intraoperative guidance, and quantitative monitoring of treatment. Diagnosis and therapy are further integrated within single platforms by emerging theranostic constructs, encouraging real-time visualisation of drug distribution and treatment response. Additionally, immune-nanomedicine, intraperitoneal depot systems, and nucleic acid-centred nanotherapies offer promising strategies to address immune suppression and molecular resistance in advanced ovarian cancer. In spite of noteworthy achievements, clinical translation is limited by complex manufacturing requirements, challenges with safety and stability, and restricted patient stratification. To unlock the full clinical potential of nanotechnology in ovarian cancer management, constant innovation in scalable design, regulatory standardisation, and integration of precision biomarkers will be necessary. Full article

Background: Adjuvant anti-PD-1 therapy improves recurrence-free survival (RFS) in high-risk melanoma, but many patients experience adverse events. 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography with computed tomography [¹⁸F]FDG-PET/CT has been proposed to identify biomarkers that may predict outcome of treatment. Objectives: The aim of this register-based study was to investigate the prognostic value of immune-related adverse events (irAEs), spleen-to-liver ratio (SLR), and bone marrow-to-liver ratio (BLR), detected by [¹⁸F]FDG-PET/CT. Methods: This retrospective, register-based cohort study included 122 patients with radically resected stage III–IV melanoma treated with adjuvant anti-PD-1. Patient data were extracted from a Danish register, and measurements for SLR and BLR were made using an AI model. Cox regression models were made on irAEs and BLR to assess associations with RFS and overall survival (OS). Results: Over half of the patients experienced recurrence, and one quarter died during follow-up of 4 ¾ years. Seventy-four percent exhibited at least one PET-detected irAE. This study found no association between irAEs and OS. Regarding RFS, our findings suggest an increased risk of recurrence for the presence of irAEs within the first 1.5 years of follow-up (HR: 2.93, CI: 1.10–7.84, p = 0.032). BLR and SLR were not associated with RFS or OS in multivariable models. Conclusions: This study did not confirm the findings of a positive association between irAEs and survival found in previous studies. PET-detected irAEs were common in the study population, but did not predict OS, while early-onset irAEs were linked to increased recurrence risk. Neither SLR nor BLR demonstrated prognostic value. Further research is needed to clarify the clinical utility of PET-derived biomarkers, especially in the adjuvant setting. Full article

Intravesical Bacillus Calmette–Guérin (iBCG) immunotherapy is the standard adjuvant treatment of non-muscle-invasive bladder cancer (NMIBC). Among the potential complications, cases of mycotic aneurysms and acute respiratory distress syndrome (ARDS) are rare but can be life-threatening. Because prior reports have not included whole-genome sequencing (WGS) of clinical Mycobacterium bovis BCG (M. bovis BCG) isolates to assess whether the infecting strain acquires mutations in vivo, we performed WGS in a severe disseminated iBCG-related infection. A 72-year-old man with bladder cancer underwent iBCG instillation. Twelve months after the final instillation, the patient developed an abdominal aortic aneurysm, which was detected and treated with endovascular aneurysm repair (EVAR). Two months later, the patient presented with fever, abdominal pain, and septic shock. Contrast-enhanced computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) showed rapid aneurysm enlargement. Ziehl–Neelsen staining and PCR of aortic material identified M. bovis BCG. Direct PCR on BAL fluid and urine was negative; however, BAL and urine culture subsequently grew M. bovis BCG, and PCR performed on the culture isolate confirmed M. bovis BCG. Despite combined antituberculosis triplet therapy (isoniazid, rifampicin, and ethambutol), the patient developed ARDS, which gradually improved after surgical management. WGS (with >96% genome coverage) showed the isolate was highly concordant with the vaccine strain and lacked additional virulence-associated mutations, including in esxM. This case illustrates that severe systemic iBCG-related complications can occur without detectable in vivo acquisition of virulence-enhancing mutations; however, interpretation is limited by the single-case design and the absence of host genetic susceptibility testing. Our findings underscore the need for prolonged vigilance regarding late-onset vascular and pulmonary complications after iBCG, and highlight the importance of early multidisciplinary management. Full article

Background: We aimed to evaluate ability of a novel scoring system that combines fluorodeoxyglucose-uptake parameters and systemic inflammatory response indicators to predict hepatocellular carcinoma (HCC) prognosis. Methods: Clinical data were collected from patients with HCC who underwent hepatectomy at our hospital in 2014–2022. The tumor-to-liver ratio (TLR) was adopted as a positron emission tomography/computed tomography (PET/CT) standardized uptake value (SUV)-related indicator and calculated as the ratio of the SUV_max of tumor tissue to the SUV_mean of normal liver tissue. The patients’ immune microenvironment reflected the NLR. Postoperative overall survival (OS)- and disease-free survival (DFS)-related independent prognostic factors were analyzed using Cox proportional hazards regression modeling. Results: Eighty-nine patients were included. TLR, NLR, and alpha-fetoprotein levels were independently associated with OS and DFS. The OS and DFS in the zero-point group were significantly longer than those in the one- and two-point groups. Time-dependent ROC curve analyses revealed area under the curve values of 0.830 and 0.752 for 5-year OS and DFS, respectively, for the scoring system, outperforming single evaluation indices. Conclusions: The proposed scoring system, which incorporates both TLR and NLR, simultaneously reflects metabolic tumor characteristics and the host’s immune microenvironment, enabling more accurate patients with early to intermediate-stage HCC undergoing hepatectomy classification and better prognostic evaluation. Full article

Breast cancer screening, while vital for reducing mortality, faces significant limitations in sensitivity and specificity, particularly in dense breasts. Current modalities primarily detect anatomical changes, often missing biologically aggressive tumors at their earliest stages. The altered metabolism of cancer cells establishes a characteristic inverted pH gradient that drives tumor invasion, metastasis, and treatment resistance. This makes tumor acidity a compelling, functional biomarker for early detection. This review synthesizes the emerging role of pH as a diagnostic biomarker and provides a critical evaluation of advanced imaging techniques for its non-invasive or minimal measurement. We detail the biological underpinnings of tumor acidosis, emphasizing its regulation through glycolytic reprogramming and dysregulated proton transport. Our analysis encompasses a broad spectrum of pH-sensitive imaging modalities, including magnetic resonance methods such as Chemical Exchange Saturation Transfer (CEST) MRI for extracellular pH mapping and multi-nuclear Magnetic Resonance Spectroscopy (MRS) using ¹H, ³¹P, and ¹⁹F nuclei to probe various cellular compartments. Furthermore, we examine hyperpolarized ¹³C MRI for real-time metabolic flux imaging, where metrics such as the lactate-to-pyruvate ratio demonstrate significant predictive value for treatment response. The review also assesses optical and photoacoustic imaging techniques, which offer high sensitivity but are often constrained to superficial tumors. Imaging tumor pH provides a powerful functional window into the earliest metabolic shifts in breast cancer, far preceding macroscopic anatomical changes. The ongoing development and evidence support the role of the pH-sensitive imaging techniques in diagnosis, lesion characterization, and therapy. Additionally, it holds promise for supplementing breast cancer screening by enabling earlier, more specific detection and personalized risk stratification, ultimately aiming to improve patient outcomes. Full article

Background: The aim of the present systematic review (SR) is to compile evidence regarding the use of radiomic-based machine learning (ML) models for predicting human papillomavirus (HPV) status in oropharyngeal squamous cell carcinoma (OPSCC) patients and to assess their reliability, methodological frameworks, and clinical applicability. The SR was conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD42025640065). Methods: Using the PICOS framework, the review question was defined as follows: “Can radiomic-based ML models accurately predict HPV status in OPSCC?” Electronic databases (Cochrane, Embase, IEEE Xplore, BVS, PubMed, Scopus, Web of Science) and gray literature (arXiv, Google Scholar and ProQuest) were searched. Retrospective cohort studies assessing radiomics for HPV prediction were included. Risk of bias (RoB) was evaluated using Prediction model Risk Of Bias ASsessment Tool (PROBAST), and data were synthesized based on imaging modality, architecture type/learning modalities, and the presence of external validation. Meta-analysis was performed for externally validated models using MetaBayesDTA and RStudio. Results: Twenty-four studies including 8627 patients were analyzed. Imaging modalities included computed tomography (CT), magnetic resonance imaging (MRI), contrast-enhanced computed tomography (CE-CT), and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET). Logistic regression, random forest, eXtreme Gradient Boosting (XGBoost), and convolutional neural networks (CNNs) were commonly used. Most datasets were imbalanced with a predominance of HPV+ cases. Only eight studies reported external validation results. AUROC values ranged between 0.59 and 0.87 in the internal validation and between 0.48 and 0.91 in the external validation results. RoB was high in most studies, mainly due to reliance on p16-only HPV testing, insufficient events, or inadequate handling of class imbalance. Deep Learning (DL) models achieved moderate performance with considerable heterogeneity (sensitivity: 0.61; specificity: 0.65). In contrast, traditional models provided higher, more consistent performance (sensitivity: 0.72; specificity: 0.77). Conclusions: Radiomic-based ML models show potential for HPV status prediction in OPSCC, but methodological heterogeneity and a high RoB limit current clinical applicability. Full article

Background/Objectives: Pulmonary fibrosis is a progressive and fatal lung disease with limited diagnostic and therapeutic options. Fibroblast activation protein (FAP) has emerged as a promising molecular imaging target for the non-invasive assessment of fibrotic activity. This study aimed to evaluate the diagnostic feasibility of [⁶⁸Ga]Ga-FAP inhibitor (FAPI) and [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography (PET) for imaging pulmonary fibrosis in a mouse model. Methods: A pulmonary fibrosis model was established by intratracheal administration of polyhexamethylene guanidine-phosphate (PHMG-p) to C57BL/6 mice. Fibrosis severity was quantified by the Ashcroft scoring system using hematoxylin and eosin and Masson’s trichrome staining and evaluated by computed tomography (CT) imaging at 7, 14, and 21 days after PHMG-p exposure. PET imaging was performed, and ex vivo biodistribution was assessed after injection of [⁶⁸Ga]Ga-FAPI-04 and [¹⁸F]FDG. Results: Histological analysis and Ashcroft scoring revealed greater fibrosis severity in the PHMG-p-treated group. Western blot analysis demonstrated upregulation of FAP expression after PHMG-p exposure. CT showed increased mean lung density, while [⁶⁸Ga]Ga-FAPI-04 PET revealed significantly elevated pulmonary uptake of [⁶⁸Ga]Ga-FAPI-04 in the PHMG-p-treated group compared with the controls. [¹⁸F]FDG PET imaging also showed higher uptake of [¹⁸F]FDG in the PHMG-p-treated group than in the controls. Ex vivo biodistribution confirmed greater [⁶⁸Ga]Ga-FAPI-04 accumulation in the lungs of PHMG-p-treated mice. Conclusions: [⁶⁸Ga]Ga-FAPI-04 PET serves as a sensitive imaging biomarker for evaluation of fibrotic activity in PHMG-p-induced pulmonary fibrosis and complements [¹⁸F]FDG PET for assessing disease progression and therapeutic response. Full article