Journal of nuclear medicine technology最新文献

Recently, it was proposed that follow-up imaging for patients treated with ¹⁷⁷Lu-labeled radiopharmaceuticals should be focused on posttherapy SPECT/CT, given the intrinsic γ-photon emitted by ¹⁷⁷Lu, suggesting that real-time imaging of radiopharmaceutical infusions using γ-camera technology may be feasible. In this pilot feasibility study, we used a portable γ-camera situated within our theranostics suite to visualize the infusion of ¹⁷⁷Lu-labeled radiopharmaceuticals in real time. Methods: Patients were consecutively enrolled between June 5, 2025, and July 17, 2025, with any patient receiving a ¹⁷⁷Lu-based radiopharmaceutical infusion at our theranostics center being eligible for inclusion. ¹⁷⁷Lu-based radiopharmaceuticals were administered via syringe method. A portable γ-camera was used for dynamic image acquisition. An open-energy window was used to obtain 120 frames at 30 s per frame for a total of 5 or 30 min (to include the entirety of either a ¹⁷⁷Lu-PSMA-617 or a ¹⁷⁷Lu-DOTATATE infusion, respectively) using a 128 × 128 matrix and a low-energy, high-resolution collimator. Results: Six patients were imaged, and the ¹⁷⁷Lu-labeled radiopharmaceutical was visibly confined to the venous system, with measurable time-activity curves, in all patients. No evidence of immediate complication was seen during the imaging of any of the infusions, and no findings suggest an event such as extravasation occurred. Conclusion: Dynamic, real-time imaging of infusions of ¹⁷⁷Lu-labeled radiopharmaceuticals with a γ-camera is feasible. Although further study is needed, this method may be useful for the early identification of complications from infusions, potentially allowing for the alleviation of toxicities and preservation of expensive radiopharmaceutical doses.

Lung perfusion scintigraphy is a cornerstone for evaluating pulmonary embolism but may reveal unexpected vascular anomalies. Persistent left superior vena cava, a congenital anomaly, can cause a right-to-left shunt when draining into the left atrium, bypassing pulmonary circulation. We report the incidental detection of persistent left superior vena cava during lung perfusion scintigraphy in a patient with post-COVID-19 hypoxia. Dual-site radiotracer injections and SPECT/CT confirmed the diagnosis, highlighting the need for adaptive imaging techniques to accurately interpret atypical findings in nuclear medicine.

Today's common practice of empiric activity prescription in radiopharmaceutical therapy is inconsistent with the modern philosophy of personalized medicine. We investigate the radiobiologic relationship between tumor mean absorbed dose (D _mean) and progression-free survival (PFS) in ¹⁷⁷Lu-PSMA I&T therapy guided by personalized predictive dosimetry in metastatic castration-resistant prostate cancer. Methods: We conducted a single-center retrospective study of the first 20 patients treated with ¹⁷⁷Lu-PSMA I&T at our institution. PFS was calculated from the day a patient was assessed by a nuclear medicine physician in the clinic until treatment cessation (due to progression or toxicity) or death. D _mean was estimated by predictive dosimetry. Correlation with PFS was performed on the following baseline characteristics: age, Gleason score, Eastern Cooperative Oncology Group performance status, estimated glomerular filtration rate, prostate-specific antigen (PSA) doubling time, injected activity per treatment, D _mean and D _mean per gigabecquerel. Results: Twenty patients naïve to ¹⁷⁷Lu-PSMA were treated over a 2-y period, totaling 65 infusions. The median PSA doubling time was 1.6 mo at baseline. The median follow-up time was 8.4 mo (interquartile range [IQR], 4.6-14.5 mo). Each patient received 3 ± 1 treatments (range, 1-5), with a mean injected activity of 7.74 ± 0.66 GBq per treatment. The mean injected activity for the first treatment was 7.85 ± 0.71 GBq. The median D _mean for the first treatment was 23 Gy (IQR, 15-36 Gy). The median PFS was 10.6 mo for a D _mean of 23 Gy or greater and was 3.1 mo for a D _mean of less than 23 Gy (hazard ratio, 0.39; 95% CI, 0.22-0.68; P < 0.01). There were statistically significant correlations between PFS, PSA doubling time, and D _mean (P < 0.05). However, there was no statistically significant correlation between the injected activity per treatment versus PFS or D _mean (P > 0.05). Conclusion: We found a strong direct correlation between D _mean and PFS in patients with metastatic castration-resistant prostate cancer treated with ¹⁷⁷Lu-PSMA in a real-world setting. We identified a D _mean of 23 Gy as a possible threshold for significantly better PFS in our cohort with median PSA doubling time of 1.6 mo. Our findings support radiobiologically sound prescription based on the radiation absorbed dose by personalized predictive dosimetry.

We report a case of follicular thyroid carcinoma presenting with a solitary skeletal metastasis in right iliac bone that remained structurally persistent after 2 high-dose ¹³¹I treatments. However, the lesion showed no uptake on [¹⁸F]FDG PET/CT, ¹³¹I scintigraphy, or [⁶⁸Ga]Ga-FAPI PET/CT, suggesting the absence of metabolic or receptor activity. This discordance between anatomic persistence and lack of molecular expression highlights the potential of molecular imaging to detect early treatment response, even when the lesion is structurally persistent. This case highlights the importance of integrating molecular imaging into treatment response evaluation to better assess disease activity and guide further management in differentiated thyroid carcinoma.

The use of amyloid PET to assess patient suitability of disease-modifying drugs for Alzheimer disease is increasing. This study aimed to synthesize amyloid PET images from ¹⁸F-FDG PET images using a generative artificial intelligence algorithm to reduce unnecessary amyloid PET scans. Methods: A 2-dimensional pix2pix algorithm was used. The algorithm was evaluated across 4 domains: image quality, voxel values, contrast between white and gray matter, and diagnostic performance for detecting the presence or absence of β-amyloid (Aβ) deposition. Pairs of ¹⁸F-FDG PET and amyloid PET images from 55 Aβ-negative and -positive cases were evaluated. A 6-fold cross-validation was conducted. Results: Synthetic images were visually consistent, producing plausible negative and positive patterns while preserving continuity in the sagittal plane. Voxel values of the synthetic images showed a significant linear relationship with the real images. The contrast correlated well with the real images, and the differences between the negative and positive cases were significant as well as those in the real images. The performance of the positive or negative 2-class classifier exceeded 85% for the synthetic images. Conclusion: The synthetic images successfully captured features of Aβ deposition, and evaluation with a 2-class classifier achieved an acceptable accuracy of 85%. These results suggest that amyloid images can potentially be generated from ¹⁸F-FDG PET images for use in clinical practice.

In this study, we aimed to quantify the impact of data-driven motion-correction reconstruction for PET imaging on still and motion-corrupted ¹⁸F-FDG PET brain scans of children and adolescents. Methods: In this prospective study, participants underwent a 9-min PET brain scan after clinically indicated whole-body ¹⁸F-FDG PET/CT between December 2022 and March 2023. Participants remained still during minutes 1-6 and performed scripted head movements during minutes 7-9. PET images were reconstructed from list-mode data into still (minutes 1-6) and mixed still/motion-corrupted (minutes 4-9) datasets, with and without motion correction. Three radiologists independently assessed image quality, gray and white matter differentiation, basal ganglia definition, and cortical uniformity. Quantitative parameters of the brain (SUV_max and SUV_mean) were obtained by a separate observer. Wilcoxon rank-sum and Kruskal-Wallis tests assessed differences between reconstructions and motion groups. Results: Sixteen participants (mean age, 13 ± 3 y; 8 males and 8 females) were included. Still images with motion correction scored higher than still images without motion correction for overall image quality (P = 0.013). Motion-corrupted images with motion correction outperformed still images without motion correction in gray and white matter contrast, basal ganglia delineation, and cortical uniformity (P < 0.018). Quantitatively, motion-corrected images did not significantly differ from still images without motion correction. Conclusion: Motion correction software improved the image quality of motion-corrupted ¹⁸F-FDG PET/CT brain scans. Corrected scans were qualitatively superior or did not differ from non-motion-corrected images, with no impact on quantitative measurements. Motion correction has the potential to allow awake, nonsedated pediatric patients to undergo PET scans.

In nuclear medicine, simulation-based instruction offers a safer alternative to traditional training, yet no studies have specifically applied virtual reality (VR) to clinical education and training within nuclear medicine departments. This study aimed to investigate whether a VR-based teaching module enhances students' perceived understanding of myocardial perfusion imaging (MPI) procedures and overall learning satisfaction. Methods: Between July and December 2023, we enrolled a group of 19 internship students, who were asked to complete a survey on their learning expectations regarding MPI. Survey analysis revealed that 73.7% of students were unfamiliar with the MPI procedure and 57.9% indicated that they required over 2 h of learning and hands-on practice to achieve proficiency. To address these needs, the research team produced a 10-min simulation video, covering learning objectives, training duration, evaluation criteria, patient education, procedural steps, and key safety considerations. Using the survey results, we designed a teaching video to capture realistic clinical scenes that involved MPIs. After students completed the simulation-based module, they viewed the teaching video and completed a satisfaction survey to evaluate the effectiveness of our teaching. Results: All students agreed that the video length was appropriate, the quiz questions facilitated understanding, and the interactive design supported understanding. Furthermore, 89.5% of students found the contents clear and easy to understand, with an overall mean satisfaction score of 8.95 (of 10 possible points). Conclusion: The VR teaching program for MPI was successful and serves as an effective preparatory resource for students completing nuclear medicine internships.

A man in his 60s was referred to our institution for evaluation of suspected chronic thromboembolic pulmonary disease in the context of progressive exertional dyspnea and a mismatched ventilation/perfusion defect on scintigraphy. The ventilation/perfusion scan revealed complete absence of perfusion to the left hemithorax with preserved ventilation. CT pulmonary angiography demonstrated unilateral pulmonary vein atresia, characterized by absent left pulmonary venous drainage, a hypoplastic pulmonary arterial tree on the affected side, and compensatory hyperinflation of the contralateral lung. This case highlights the distinctive scintigraphic pattern of unilateral pulmonary vein atresia, in which global absent perfusion in the affected hemithorax results from the reversal of pulmonary arterial flow due to elevated pulmonary venous pressures. Additionally, perfusion is further impaired by retrograde bronchial collateralization, compounding the hemodynamic compromise.

Relating planar lung scintigraphic image features to bronchopulmonary anatomy is a mental task requiring specialized medical experience. This study aimed to accurately normalize spatial data to overlay patient images onto a bronchopulmonary segment atlas (BSA), enhancing image interpretation for nonexperts and enabling quantification. Methods: This study evaluates the efficacy of 3 spatial normalization techniques: naïve registration, cost function masking, and perfusion defect removal with convolutional autoencoders. Autoencoders were trained for each of 6 projection angles using a large cohort of healthy patients (n = 660). Perfusion planar population templates for each projection, with its corresponding BSA, were constructed using a random subset sample of these patients (n = 149). Synthetic perfusion defects were applied on 60 projections from 10 patients with normal perfusion, allowing a comprehensive assessment of each spatial normalization technique's performance and effect on defect size in the template space. Results: The results reveal that autoencoder preprocessing significantly outperforms the naïve method and exhibits comparable or superior performance to cost function masking, particularly in preserving defect size and minimizing registration error to the population template within the defect. Visual comparisons further support the efficacy of autoencoder preprocessing in preserving anatomic features. Conclusion: Autoencoder preprocessing is a fully automatic and reliable method for reducing distortions during spatial normalization in perfusion scintigraphy, highlighting its potential for enhancing registration accuracy in clinical practice for BSA overlay and defect quantification.

Long-axial-field-of-view (LAFOV) PET/CT scanners (>1 m axial field of view) provide an order-of-magnitude improvement in system sensitivity compared with conventional PET/CT systems, allowing clinicians to optimize scan protocols in terms of acquisition time, injected activity, and image quality. However, implementing these optimizations requires workflow changes, which may affect the patient experience and the quality of care provided. This study aims to contextualize the workflow changes for patients while comparing their experiences after a transition from conventional to LAFOV PET/CT at a metropolitan hospital. Methods: Patient movement through a conventional PET/CT facility was observed for 1 working week. This was repeated 1 mo after transitioning to the LAFOV PET/CT system. The median times that patients spent in the uptake room, camera room, hallway, and toilet were compared. Additionally, a separate cohort of patients was invited to participate in a short survey regarding their experience during their PET/CT procedure. The same survey was provided to both cohorts. The questions used a 5-point Likert scale to assess patient concerns, physical discomforts, and perceptions of staff care. In total, 108 and 105 responses were collected for the conventional and LAFOV PET/CT cohorts, respectively. Results: Patients who were scanned using the LAFOV PET/CT system spent significantly less time in the camera room and the uptake room (after injection and when including time waiting before injection). There was a significant reduction in the number of participants who felt that the scan was too long, were concerned about the radiation involved, were anxious, or reported feeling uncomfortable after transitioning to a LAFOV PET/CT system. No significant differences were observed between the 2 cohorts regarding their perceptions of the level of staff preparation and care provided or physical discomforts experienced, including claustrophobia. Conclusion: Transitioning from a conventional to LAFOV PET/CT system reduced the time patients were required to remain stationary during the scan and resulted in decreased patient concerns. There was no evidence of a difference in the levels of physical discomfort, such as claustrophobia, experienced by the 2 cohorts despite the increased length of the gantry bore.