Journal of nuclear medicine technology最新文献

This study aims to determine whether the calculation of the differential renal function (DRF) for renal scintigraphy using volumetric assessment is equivalent to conventional planar assessment using the geometric mean. Methods: A retrospective study was conducted with 108 patients referred for cortical renal scintigraphy. Forty-five patients were injected with ^99mTc-dimercaptosuccinic acid (DMSA), and 63 patients were injected with ^99mTc-glucoheptonate and furosemide, depending on which radiotracer was available at the time of the examination. DRF was measured using automatic 3-dimensional volume-of-interest delineation software on SPECT and 2-dimensional manual regions of interest on planar images, with geometric mean calculated for all patients. Images were reviewed by 2 independent masked observers. To assess intrarater reliability, a random sample of 20 images (10 with ^99mTc-DMSA and 10 with ^99mTc-glucoheptonate) was reprocessed by the same observers to after a minimum 2-wk interval to minimize recall bias. Values obtained by planar and SPECT methods were compared using a paired Student t test. Reproducibility was assessed through intraobserver and interobserver analyses using the intraclass correlation coefficient. Results: There was a significant difference in DRF values obtained by planar and SPECT methods with both ^99mTc-glucoheptonate and ^99mTc-DMSA (P < 0.05), with maximum absolute differences of 40.0% and 13.0%, respectively. High intrarater and interrater intraclass correlation coefficients were obtained for both methods and radiotracers (>0.9), indicating excellent reliability. Conclusion: The SPECT quantification method for the evaluation of DRF is reliable because of high intraobserver and interobserver agreement. Furthermore, it differs significantly from the planar quantification method, with more pronounced differences observed with ^99mTc-glucoheptonate compared with ^99mTc-DMSA.

The diagnosis and staging of primary gastric carcinoma, particularly linitis plastica morphology, is challenging. Fibroblast activation protein, abundantly expressed in cancer-associated fibroblasts and absent in normal gastrointestinal mucosa, enables high tumor-to-background contrast. We report 2 cases of signet ring cell gastric adenocarcinoma with linitis plastica morphology, demonstrating minimal uptake on [¹⁸F]FDG PET/CT but intense uptake on [⁶⁸Ga]Ga-FAPI-04 PET/CT. These findings highlight the superior diagnostic performance of fibroblast activation protein inhibitor imaging in this challenging subset of gastric cancers.

Isolated cubital nodal metastasis is an extremely rare site of recurrence in posttreatment cases of breast carcinoma. A 37-y-old woman with breast carcinoma had a disease-free interval of 2 y. Follow-up ¹⁸F-FDG PET/CT showed a ¹⁸F-FDG-avid lesion in the proximal part of the right forearm, and PET/CT-guided fine-needle aspiration revealed metastatic carcinoma. With proven disease recurrence, the patient was scheduled for chemotherapy.

Isolated skeletal lymphoma is a rare subtype of lymphoma, and isolated mandibular involvement is extremely uncommon. We describe a case of isolated mandibular lymphoma detected on ¹⁸F-FDG PET/CT, presenting as an ¹⁸F-FDG-avid lytic expansile lesion in the left hemimandible, with no other pathologic findings in the body.

The increase in life expectancy has raised the incidence of neurologic diseases among the elderly, resulting in greater demand for nuclear neurology examinations and a need to adapt procedures to meet these specific needs. This study aimed to assess the adaptation of nuclear neurology procedures performed in Portugal and, through questionnaires directed at nuclear medicine technologists (NMTs), identify the most common adaptations. Methods: An online questionnaire was distributed to NMTs in clinical practice, excluding those in commercial, production, or research settings. The questionnaire investigated NMTs' adaptations in patient preparation, positioning, and image acquisition for the elderly population. Results: Responses from 17 NMTs were collected and revealed that nuclear neurology procedures are infrequent (41.2%), with Parkinson disease dementia and Lewy body dementia being the most common clinical indications (23.5% each). Cerebral perfusion scintigraphy and dopaminergic transporter or receptor assessments were the most frequently performed examinations (17.6% each). Adaptations were not routinely applied, but when needed, dialogue and family involvement (76.5%) were used. Positioning challenges were noted by 64.7%, with 29.4% using immobilization accessories. PET/CT scans were preferred by 41.2% for their speed and diagnostic quality. Conclusion: Clear communication, family participation, and the use of immobilization aids key to maintaining image quality and patient comfort in elderly populations. Adapting imaging protocols and prioritizing faster modalities may improve diagnostic outcomes and patient care.

We report the cases of 3 patients with biopsy-proven light-chain cardiac amyloidosis (AL-CA) presenting with varying clinical manifestations and abnormal findings on Tc-based bone-avid scintigraphy, illustrating the diagnostic challenges of distinguishing AL-CA from transthyretin-related CA. All patients demonstrated typical electrocardiographic and echocardiographic features of CA, including low voltage and apical-sparing strain pattern. Despite abnormal scintigraphy suggestive of transthyretin-related CA, concurrent abnormal light-chain assays raised diagnostic uncertainty. Endomyocardial biopsy with mass spectrometry confirmed AL-CA in all cases. These cases emphasize the heterogeneous presentation of CA and the essential role of light-chain assays, regardless of the presence of myocardial uptake pattern on scintigraphy.

¹⁸F-FDG, widely used in PET imaging, produces high-energy 511-keV annihilation photons that pose radiation exposure risks in radiopharmaceutical preparation and handling areas, or hot labs. Understanding how environmental factors influence background radiation in hot labs is essential for maintaining a safe workflow and ensuring accurate instrument readings. This study aims to evaluate the impact of shielding and distance on background radiation levels detected by a well counter in the presence of ¹⁸F-FDG vials. Eight ¹⁸F-FDG vials were measured in a specific sequence under 7 conditions. First, a background measurement was taken with no vial present. This was followed by measurements with the vials placed at distances of 1, 2, and 3 m from the detector, each tested both with and without the standard tungsten shielding. Count rates (counts per minute [cpm]) were recorded and analyzed for each condition. Unshielded ¹⁸F-FDG values (21,157 cpm at 1 m, 2,166.4 cpm at 2 m, and 1,582.9 cpm at 3 m) were significantly higher than those for shielded ¹⁸F-FDG at all distances (529.4, 243.5, and 229.4 cpm at 1, 2, and 3 m, respectively). Shielding reduced radiation exposure by up to 97.5% at 1 m. Shielded values at 3 m approached background levels (201.0 cpm), demonstrating the compounded effectiveness of distance and shielding. Both distance and shielding reduced radiation exposure from ¹⁸F-FDG sources, with the greatest shielding benefit observed at closer distances. These findings emphasize the importance of spatial and protective strategies in hot lab environments to safeguard technologists, maintain regulatory compliance, and ensure precise measurements from radiation detection instruments.

Global expansion of radiopharmaceutical therapy (RPT) and the rising need for patient-centered approaches present opportunities for innovation in the United States and New Zealand. The first part of this paper outlines in detail the Society of Nuclear Medicine and Molecular Imaging's Radiopharmaceutical Therapy Center of Excellence designation, including its tiers, criteria, and practical blueprint for establishing RPT centers. The New Zealand center is presented as a practical framework for building a center that adheres to the country's rules and regulations. In the United States, the Society of Nuclear Medicine and Molecular Imaging established a Center of Excellence designation that is awarded to centers performing RPT with the highest standards of care. The Center of Excellence program sets the framework for successfully establishing RPT centers, aiding expansion nationwide. Expansion is especially necessary in underserved and rural communities that lack access to nuclear medicine services and RPT. Although many common challenges exist that make it more difficult to expand RPT services, potential solutions can be used to overcome these challenges and successfully establish well-rounded RPT programs. Establishing RPT centers that are engrained with the Center of Excellence values is highly beneficial to patients, referring providers, and payers. With highly skilled Centers of Excellence, RPT is no longer the future of medicine; it is the present of precision health care. In New Zealand, Hawke's Bay on the North Island's east coast lacked PET/CT and radiopharmaceutical services. In 2022, the decision was made to design and construct a molecular imaging and therapy center. Embedded in this design was emphasis on patient journey, radiation safety, cultural sensitivity, future readiness, sustainability, and ensuring continuous service delivery. Like the United States, New Zealand faced a shortage of nuclear medicine technologists. Compounding this challenge was that New Zealand had only 1 radiopharmacist at the time. As a result, nuclear medicine technologists had to upskill rapidly, especially in radiopharmaceutical synthesis, to meet the demands of the service. After extensive collaboration among the physicist, planning team, and nuclear medicine staff, a consensus was reached on a design that successfully integrated all key expectations. Despite challenges, there are centers in the United States and New Zealand that have succeeded in performing RPT with the highest level of expertise in training, personnel, equipment, radiation safety, and patient management and are at the forefront of innovation with regard to RPT.

Major pharmaceutical companies are investing heavily in nuclear medicine theranostics, including mass-market television and print campaigns that highlight the precision tools we provide to physicians. The number of clinical trials has reached unprecedented levels, and the current demands and expected growth are straining the system. The complexity of what is needed is increasing, including the expertise and resources required. Companies and outside organizations see huge potential in theranostics but also note challenges to reaching its full potential. The Society of Nuclear Medicine and Molecular Imaging (SNMMI) has been at the forefront of advancing the field of theranostics through initiatives and programs that have accelerated both clinical practice and research including the creation of Centers of Excellence, establishment of a dedicated Therapy Clinical Trials Network, development of accreditation in partnership with the Intersocietal Accreditation Commission, and the planning and hosting of the annual Therapeutics Conference, recently renamed the Theranostics Conference. These efforts reflect SNMMI's vision to meet the growing demand for theranostics while also tackling challenges such as workforce development, supply shortages, and facility infrastructure-all with a focus on keeping care patient-centered. To broaden its perspective on the challenges and to develop practical solutions with broad support, the SNMMI took a bold step and invited participants from outside of the society to join the discussion. The SNMMI held a stakeholder summit on May 1-3, 2025, where more than 100 stakeholders came together to develop a path forward to ensure that the enormous potential for theranostics for patients could be realized. Herein is a synopsis of that summit.

Theranostics refers to the combination of therapy and diagnostics in a single clinical entity or approach. Theranostics is particularly adaptable to radiopharmaceutical therapy (RPT) based on the unique ability to scintigraphically image radiopharmaceuticals in vivo and thereby noninvasively measure their time-dependent activities in and among target lesions and normal organs. Theranostics with personalized RPT, based on the maximum tolerated dose to the therapy-limiting tissue or the prescribed dose to the target tissue, offers the important advantages of lower toxicity or greater efficacy compared with fixed-administered-activity RPT but requires rather time-consuming, technically challenging patient measurements and analyses. Importantly, however, the perceived obstacles to dosimetry-based RPT have been or are being largely overcome. Further, the currently available dose-response data, though still rather limited, indicate that patient-specific dosimetry may help optimize RPT by minimizing toxicity or maximizing efficacy. Additional dose-response data from prospective multicenter trials are still required to definitively establish the value of patient-specific dosimetry in RPT. Such trials will require standardization of calibration procedures, acquisition protocols, and reconstruction methods among participating institutions.