Ida Skarping

Background: In routine practice, radiopharmaceuticals are administered via a newly placed peripheral intravenous catheter (PIVC). However, many patients referred for nuclear medicine imaging already have a semipermanent venous access device in place, such as a central venous catheter, peripherally inserted central catheter, or subcutaneous implantable venous port. Evidence regarding residual radiopharmaceutical activity within preexisting devices—and its potential consequences for SPECT/PET image quality, diagnostic interpretation, and radiation safety—remains limited. This study aimed to quantify device-related residual radiopharmaceutical activity across commonly used access types and to assess any associated clinical impact during image review. Results: In this observational cohort study at Skåne University Hospital, Sweden, 167 patient administrations during SPECT or PET imaging between June 2023 and January 2026 were included (40% aged < 18 years). Residual activity was evaluated using ROI/VOI based quantification at the venous access site on reconstructed or planar images. Measurements were performed in an activity meter using PIVCs that had been removed from patients prior to imaging. In an experimental setting, representative venous access devices were flushed under controlled conditions to determine residual activity fraction. Residual activity was expressed both as absolute activity (MBq) and as the percentage of the administered activity. Across 214 measurements including 13 radiopharmaceuticals, residual activity was generally low: only 3.3% of the measurements (7/214) exceeded 5% of the administered activity. The highest absolute residual activity was 31 MBq ([ ^99m Tc]pertechnetate, PIVC), and the highest proportional residual activity was 17.3% ([ ^99m Tc]Tc-MAA, Midline). On clinical image review, no instance of device related residual activity was associated with impaired interpretation or reduced diagnostic confidence. Conclusions: In this real-world cohort, residual radiopharmaceutical activity within preexisting venous access devices was generally low and showed no discernible impact on visual clinical SPECT or PET interpretation. Prospective studies including a broader range of tracers, access devices, and quantitative endpoints are needed to more fully characterize the clinical implications of residual activity.

Background: Heterogeneous treatment response, characterized by simultaneous regression of some lesions and progression of others within the same patient, is increasingly recognized in metastatic breast cancer (mBC) and may reflect biological heterogeneity. However, this response pattern is not captured by current response assessment frameworks. We aimed to determine the prevalence of heterogeneous treatment response on FDG-PET and mixed response on CT during mBC systemic therapy. Methods: This retrospective study included 51 female patients with mBC, treated between November 2017 and November 2025, each undergoing ≥ 2 FDG-PET/CT scans. Response was assessed according to RECIST 1.1 (CT) and PERCIST (FDG-PET), with using study‑specific definitions for heterogeneous/mixed response informed by literature. Results: Heterogeneous metabolic response was observed in 30% of all follow‑up FDG‑PET examinations (40/132). These examinations accounted for 60% (40/67) of the scans classified as progressive metabolic disease (PMD) according to PERCIST. Among CT-examinations, 65 of 141 (46%) follow-up examinations had measurable disease; none of these scans (0/65, 0%) fulfilled the mixed response criteria. Conclusion: In this real-world cohort of mBC undergoing systemic therapy, FDG-PET identified heterogeneous treatment response in a substantial proportion of patients; however, under current PERCIST criteria, these cases were uniformly classified as PMD. In contrast, using RECIST-inspired criteria, CT did not classify any patient as mixed response. These findings suggest that existing frameworks may not fully capture intra-patient response heterogeneity. As heterogeneous response is not an established PERCIST response category, further work is needed to determine how such patterns should be defined and incorporated into future response assessment frameworks. Clinical trial number: Not applicable.

Background: The integration of clinical decision support tools in medical practice is challenging and must be carefully undertaken, especially in cancer management. Noninvasive Lymph Node Status (NILS) is a web-based tool designed to estimate the probability of benign axillary lymph nodes in female patients with breast cancer scheduled for primary surgery. The aim was to identify barriers to NILS adoption in a clinical setting and assess whether intended users can operate the tool without significant errors or difficulties. Additionally, the study aimed to evaluate the appropriateness of result interpretation for decisions to abstain from sentinel lymph node biopsy (SNLB) and measure overall user satisfaction with the tool. Methods: This mixed-methods multicenter on-site qualitative human factor validation study was conducted in a simulated clinical environment, replicating both real-world physical and digital conditions. Based on the identified target user population for the NILS model, twenty physicians comprised the cohort. The study used simulated clinical cases, the System Usability Scale (SUS), and the After-Scenario Questionnaire (ASQ) to evaluate usability and satisfaction. An oral interview was conducted after the evaluations. The study followed a structured protocol, with distinct roles assigned to the test participants, leader, and observer. Results: Twenty physicians from four hospitals, with a median of 9.5 years of specialist practice, participated. Most participants were surgeons (75%, N = 15), while the remaining 25% ( N = 5) were oncologists. Usability scores were high, with a mean SUS score of 89.5 (“excellent”) and a mean ASQ score of 6.3 (Likert scale 1–7). Several interface challenges were identified, including difficulty in locating the reset and information buttons, the ability to enter values outside valid ranges (age and tumor size), and the risk of unintentionally modifying the entered values while scrolling. Conclusions: This study identified the key usability factors, barriers, and facilitators affecting the NILS model implementation. Physicians found the NILS interface easy to use and valued the presented risk estimates of benign axillary lymph node status in their decisions to perform or abstain from SLNB. Study-informed interface redesigns have been implemented. Iterative usability work in clinical settings is crucial for successful implementation. Trial registration: ISRCTN99301435.

Persistent circulating tumor DNA (ctDNA) during neoadjuvant treatment (NAT) of early breast cancer (EBC) indicates high-risk disease. Similarly, detection of ctDNA post-resection indicates molecular residual disease (MRD) and impending relapse. For ctDNA to be integrated into EBC management, accessible and scalable diagnostics are required. Here we apply an ultrasensitive, personalized tumor-informed approach to ctDNA evaluation predicated on analyses of structural variants (SVs) using a novel digital PCR (dPCR) multiplex SV technology. 136 patients eligible for NAT (29.4% TNBC, 44.9% HR+ /HER2− and 24.3% HER2+), enrolled between December 2014 and March 2019, were analyzed from the prospective SCAN-B study (NCT02306096, substudy NeoCircle). ctDNA detection at baseline was 89.7%; end-NAT ctDNA-positivity (21.4%) and NAT ctDNA-non-response (13.1%) were significant predictors of disease recurrence and death, and both superior to pathologic complete response. Detection of ctDNA post-operatively or during adjuvant monitoring was significantly associated with distant recurrence (median lead-time 13.8 months, range 0–47.7 months). These findings validate SVs as an MRD analyte and provide evidence for clinical use of this approach in EBC.

Post COVID-19 condition remains a complex and challenging issue, with diverse manifestations, despite accumulating research and clinical experience. Dyspnea is one of the most common symptoms reported in post COVID-19 condition. Cardiopulmonary exercise testing (CPET) offers a cohesive assessment of dyspnea and exercise limitations. The Nijmegen questionnaire is a form for assessment of dysfunctional breathing. The aim was to explore relationships between self-reported post COVID-19 respiratory symptoms, assessed by Nijmegen questionnaire, and the results of a 6-minute walk test (6MWT) and CPET, in patients with mild primary infection of COVID-19, managed within primary healthcare. A total of 15 participants with long-term dyspnea after a mild COVID-19 infection were prospectively included at primary healthcare facilities between July 2021 and April 2022. At inclusion, all subjects performed a 6MWT and answered the Nijmegen questionnaire. All subjects underwent CPET within 4 months of study inclusion. We estimated correlations between Nijmegen score (both total score and a subset of the questionnaire focusing on respiratory symptoms), and the 6MWT and CPET derived variables, respectively. Nijmegen scores (both total and particularly a respiratory subset) were inversely correlated to 6MWT walking distance, but not to spirometric parameters. Subjects with more self-reported symptoms had higher end-tidal O₂ and lower end-tidal CO₂, indicating mild hyperventilation. Nijmegen scores also correlated with CPET variables reflecting breathing pattern. Nijmegen score was associated with CPET variables and walking distance at 6MWT. Post COVID-19 condition could be associated with mild hyperventilation, also in subjects without overt dysfunctional breathing pattern.

Background: Prediction models for sentinel lymph node (SLN) status could potentially substitute surgical axillary staging in patients with early breast cancer. Several imaging modalities have been used with various feature extraction and selection approaches. This systematic review and meta-analysis aimed to evaluate prediction models for SLN status based on breast imaging in patients with early breast cancer to summarize the current evidence and to identify areas requiring additional research. Methods: The systematic literature search strategy was based on the Population, Intervention, Comparison, and Outcome (PICO) framework: P: female patients with clinically node-negative invasive breast cancer scheduled to undergo primary surgery; I: breast imaging; C: upfront sentinel lymph node biopsy; and O: prediction model performance regarding SLN status. The search was conducted in the PubMed, Embase, Web of Science, Cochrane, and Cumulative Index to Nursing and Allied Health Literature databases in March 2024. The screening of records, data collection, and bias assessments were performed independently by two reviewers. The risk of bias was assessed via the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool and the Prediction Model Study Risk of Bias Assessment Tool. A meta-analysis was performed using the random-effects model to assess performance and heterogeneity overall and in subgroups. Results: The literature search resulted in the inclusion of 32 articles with 11,464 patients in total. Five imaging categories were included: ultrasound ( n = 8), magnetic resonance imaging (MRI) ( n = 17), mammography ( n = 1), positron emission tomography computed tomography ( n = 1), and multiple modalities ( n = 5). Four studies, assessed as having a high risk of bias, were excluded from the meta-analysis. The meta-analysis revealed heterogeneity in overall performance, except for MRI-based studies, with a pooled area under the curve of 0.85 (95% confidence interval 0.82–0.87). Meta-regression indicated that MRI and model calibration assessment upon validation contributed to heterogeneity. Conclusions: This systematic review and meta-analysis revealed that prediction models using breast imaging—particularly MRI—could serve as a noninvasive alternative to surgical axillary staging in patients with early breast cancer. The results illustrate the heterogeneity between studies and the need for additional high-quality studies. Systematic review registration: PROSPERO CRD42022301852, available at https://www.crd.york.ac.uk/PROSPERO