Journal of nuclear medicine technology最新文献

Sensitive detection of small metastatic lesions, which is highly dependent on lesion visualization, is crucial for staging lung cancer. We investigated the potential benefit of HYPER Iterative for improving the visualization of small metastatic lesions of lung cancer on early ¹⁸F-labeled fibroblast activation protein inhibitor (FAPI) PET/CT. Methods: A total of 19 patients with lung cancer underwent a 60-min [¹⁸F]F-FAPI-42 dynamic total-body uEXPLORER PET/CT scan. PET images with a 5-min acquisition time were extracted at 10, 30 min, and 60 min after tracer injection. Ordered-subset expectation maximization (OSEM) and HYPER Iterative were used for image reconstruction. SUV_max, tumor-to-liver ratio, tumor-to-blood ratio, and tumor-to-adjacent-nontumor ratio were calculated and compared between the 2 reconstruction methods and at 10, 30, and 60 min after injection. Results: All HYPER and OSEM PET images were of high quality, with HYPER PET images showing superior clarity. Small positive lesions (maximum diameter, ≤1 cm) were depicted clearer on HYPER PET than on OSEM PET images at all time points, particularly at 10 min after injection, where 16.4% of lesions were poorly visualized on OSEM PET but clearly depicted on HYPER PET images. The tumor-to-liver ratio, tumor-to-blood ratio, and tumor-to-nontumor ratio at 10, 30, and 60 min after injection scan on HYPER PET images were significantly higher than those on OSEM images at corresponding time points (P ≥ 0.05 for all comparisons). SUV_max was more than 2-fold greater in large positive lesions (maximum diameter, >1.0 cm) than in small positive lesions (maximum diameter, ≤1 cm) on both OSEM and HYPER PET images at 10, 30, and 60 min after injection (P < 0.05 for all comparisons). The visualization of large positive lesions was not significantly affected by reconstruction methods or scan times. Conclusion: HYPER Iterative reconstruction enhanced the visualization of small metastatic lesions in lung cancer when compared with conventional OSEM, enabling effective early imaging using [¹⁸F]F-FAPI-42 uEXPLORER total-body PET/CT at 10 min after tracer injection.

We evaluated occupational radiation exposure associated with ¹⁸F-FDG injection using a traditional manual approach versus an automated injection system. Methods: Wrist and whole-body radiation exposure of nuclear medicine personnel using a manual injection method versus an automated injection system for ¹⁸F-FDG administration were assessed using electronic personal dosimeters. Radiation exposure while configuring both systems was also evaluated. The dose administered met the requirements of the "as low as reasonably achievable" principle. Radiation exposure during initial setup and dose administration, residual activity, dose accuracy, presence of contamination, and frequency of extravasation were compared between methods. Results: Compared with the traditional manual method, use of the automated injection system resulted in significantly lower mean radiation exposure to medical physicists' wrists (P < 0.01). Radiation exposure was 79.41% lower at the wrist while using the automated injection system. Differences in whole-body radiation exposure were not significant between injection methods (P < 0.56). The overall radiation dose per injection at the wrist and in the whole body and mean residual activity after injection were noticeably lower with the automated system (P < 0.01), with mean residual activity decreasing by 73.58%. Conclusion: The overall radiation exposure for nuclear medicine personnel was significantly decreased when administering ¹⁸F-FDG via an automated injection system.

The horse racing industry, like any sport, must contend with the effects of injuries on an athlete's performance and longevity. Catastrophic fractures linked to preexisting bone fatigue can be prevented with the use of imaging technology, such as the nuclear medicine bone scan. The accessibility and affordability of imaging for racehorses remain obstacles. The conventional role of bone scintigraphy has evolved with the advent of advanced techniques, including MRI, CT, and PET. Concurrently, SPECT has expanded the role of scintigraphy in the racehorse. This article explores the conventional and contemporary role of bone scintigraphy in the racehorse. Some applications are transferrable to other athletic horses (e.g., equestrian) and stock horses. Nuclear medicine planar and SPECT imaging provide valuable insights into underlying causes of pain or lameness and represent an opportunity to prevent catastrophic injuries. The increasing demand for scintigraphy among racehorses also affords an opportunity for role diversity or alternative career pathways for nuclear medicine scientists and technologists.

We sought to assess the diagnostic value of ⁶⁸Ga-fibroblast activation protein inhibitor (FAPI)-46 PET/CT for obtaining information on organ involvement in the process of inflammation and fibrosis in patients with juvenile systemic sclerosis (jSSc). Methods: In this retrospective study, 4 children with a diagnosis of jSSc underwent ⁶⁸Ga-FAPI-46 PET/CT imaging, 3 immediately after the diagnosis and before implementing immunmodulatory drugs and 1 a few years after active disease. Results: In this case series, ⁶⁸Ga-FAPI-46 PET/CT detected all clinically known organ manifestations of jSSc. Additionally, this diagnostic tool provided previously unknown information about cardiac and muscular involvement in jSSc. Conclusion: ⁶⁸Ga-FAPI-46 PET/CT provides valuable information to better assess disease activity and detect organ involvement. Further studies using ⁶⁸Ga-FAPI-46 PET/CT in patients with jSSc are encouraged.

While the establishment and operation of an equine nuclear medicine department share several principles with those of human nuclear medicine departments, they require an additional skill set to ensure safe and effective operation. This article explores the practical aspects of equine nuclear medicine facility location and design and details important considerations for safe and practical operation. Key considerations associated with the differences in physical and radiation safety and imaging approaches are explored. Specific adaptations of γ-camera gantries to allow either planar imaging or SPECT in a standing horse are described. The skill set and insights of nuclear medicine scientists and technologists are crucial for the safe and effective establishment of an equine nuclear medicine facility.

In systemic radiopharmaceutical therapy, a direct dosimetric correlation between the tumor absorbed dose and overall survival, that is, Grays to months, has never been explicitly defined. This dosimetric analysis expounds this relationship in the context of metastatic castration-resistant prostate cancer treated with ¹⁷⁷Lu prostate-specific membrane antigen (¹⁷⁷Lu-PSMA). Methods: The average tumor absorbed dose per unit of administered activity from the first to sixth treatments was extrapolated from population data. This was used to calculate the cumulative tumor absorbed doses above the response threshold for 2 empiric randomized ¹⁷⁷Lu-PSMA clinical trials (VISION and TheraP). This was correlated to the difference in overall survival between these 2 trials to derive the tumor absorbed dose-survival relationship. This result was used to calculate the overall survival for a hypothetical optimized first strike in the context of personalized predictive dosimetry. Results: The tumor absorbed dose-survival relationship is calculated to be approximately 1 mo of overall survival per 1 Gy above the response threshold. An optimized first strike can double the overall survival compared with empiric regimens, delivers a higher cumulative tumor absorbed dose in fewer treatments, and avoids futile whole-body irradiation. Overall survival is proportional to the area bounded by the tumor absorbed dose curve and the response threshold absorbed dose curve. This suggests that, in addition to an optimized first strike, overall survival may also be improved by the concurrent administration of other systemic agents that modify tumor radiobiology to lower the response threshold, such as radiosensitization. Conclusion: Dosimetric evidence advocates for personalized prescription based on predictive dosimetry to optimize overall survival by exploiting radiobiologic synergy between the first strike and tumor radiosensitization.