Nuclear Medicine Research Articles

New Horizons in Nuclear Cardiology: Imaging of Peripheral Arterial Disease.

Lower extremity peripheral artery disease (PAD) is characterized by impairment of blood flow associated with arterial stenosis and frequently coexisting microvascular disease and is associated with high rates of morbidity and mortality. Current diagnostic modalities have limited accuracy in early diagnosis, risk stratification, preprocedural assessment, and evaluation of therapy and are focused on the detection of obstructive atherosclerotic disease. Early diagnosis and assessment of both large vessels and microcirculation may improve risk stratification and guide therapeutic interventions. SPECT and PET imaging have been shown to be accurate to detect changes in perfusion in preclinical models and clinical disease, and have the potential to overcome limitations of existing diagnostic modalities, while offering novel information about perfusion, metabolic, and molecular processes. This review provides a comprehensive reassessment of radiotracer-based imaging of PAD in preclinical and clinical studies, emphasizing the challenges that arise due to the complex physiology in the peripheral vasculature. We will also highlight the latest advancements, underscoring emerging artificial intelligence and big data analysis, as well as clinically relevant areas where the field could advance in the next decade.

Production and radiochemical separation of Tb-161 as a feasible beta therapeutic radioisotope from reactor irradiated Gd target

Terbium-161 (161Tb) is a promising therapeutic radionuclide that has gained significant attention in the field of nuclear medicine in recent years. 161Tb has several favorable characteristics that make it a valuable candidate for targeted radionuclide therapy. The production of No-carrier-added 161Tb was carried out by the neutron activation of natural gadolinium target in the Egyptian Second Research Reactor (ETRR-2) at a thermal neutron flux position of 1.8 × 1014 n cm-2 s-1. The radioactivities of 161Tb as well as coproduced Gd radioimpurities were computed theoretically by the MCNPX2.7.0 code and verified by actual measurements, where accepted discrepancies were obtained. The purification of 161Tb from irradiated Gd target was developed by Chelex-100 resin. The elution performance was studied using different eluents, and 0.1 M HNO3 was found to be the best medium to obtain a high separation efficiency of more than 92% in a short time. The eluted 161Tb was of high chemical, radiochemical, and radionuclidic purities, indicating its potential for effective application in radiopharmaceutical preparation.

Que peut nous apprendre l’étude du métabolisme cérébral en TEP au 18F-FDG du syndrome de Lance-Adams ?

Lance-Adams syndrome, also known as “chronic post-anoxic myoclonus”, is a rare syndrome characterised by intention and action myoclonus following cerebral anoxia, leading to major disability. The cortical or subcortical origin of the myoclonus is still debated. Answering this question would open up new avenues of translational research to gain a better understanding of the pathophysiology of this syndrome and better guide the therapeutic management of patients. In addition to a neurological examination, the initial diagnostic work-up includes a biological work-up, electrophysiological investigations and brain imaging to rule out diGerential diagnoses. Cerebral MRI is the reference imaging technique. In the literature, more than a third of patients have a normal MRI. MRI is used to rule out a vascular cause and to look for atrophy or neuronal damage. Few data are available in the literature on the role of nuclear medicine. To date, 13 cases have been published using 18F-FDG PET and 4 using cerebral perfusion scintigraphy. Abnormalities of cortical and/or subcortical perfusion or metabolism are reported in 65% of cases; they are limited to the neocortex in 23% and aGect the cerebellum in 12% of cases. In this article, we present three patients who underwent cerebral 18F-FDG PET scans for Lance-Adams syndrome with normal MRI. The results of these examinations are discussed and compared with the data found in the literature.

Perceptions of key informant neurologists before implementing anti-amyloid drugs in the Spanish departments of neurology.

A deep knowledge of the healthcare system and the organization of neurology departments is important for planning and optimizing changes to facilitate the successful implementation of anti-amyloid antibodies treatments. We aimed to assess the necessary changes prior to introducing these therapies in our setting. We conducted a key informant survey among heads of departments of neurology from 16 hospitals in Spain. The questionnaire comprised questions about changes in the organization and functioning of the departments of neurology with the introduction of anti-amyloid drugs, changes in diagnosis and patient care, use of diagnostic techniques, patients, families and public information, resources allocation, and research. Sixteen key informants completed the survey. They strongly agreed that the introduction of anti-amyloid drugs will impact the functioning of neurology services, especially in hospitals with dementia units. Consensus was reached regarding referring all Alzheimer's disease patients eligible for therapy to dementia units. There was also agreement on the need to expand the neurology services, day hospital units, extend visit durations, and hire more professionals, especially neurologists, neuropsychologists, and nuclear medicine physicians. Furthermore, consensus was achieved on increasing the use of MRI, amyloid PET, cerebrospinal fluid biomarkers, APOE genotyping, and the necessity of advancing blood biomarkers and tau tracers. Our study highlights the need for extensive changes within Spanish neurological departments to effectively integrate anti-amyloid antibodies. Implementing these changes is essential for the timely and equitable adoption of novel therapies.

Prognostic Role of Pleural Fluid SUVpeak Value obtained from 18F-FDG PET/CT in patients with Malignant Pleural Effusion

PurposeAssessing the prognosis of patients with malignant pleural effusion (MPE) is cruical to manage the treatment. We aimed to investigate the role of pleural fluid SUVpeak value in predicting mortality. MethodsIn our single center, prospective cohort study, we enrolled 158 patients with MPE. PET/CT was independently evaluated by two nuclear medicine physicians. To identify independent predictors of 90-day mortality, we conducted both univariate and multivariate Cox regression analyses. Furthermore, we assessed the discriminatory ability of these predictors compared to the LENT score using the DeLong statistic. ResultsIn our study, we enrolled 158 patients with a mean age of 66.29±12.6 years, of whom 100 (63.3%) were male. The majority of patients (84.9%) had primary lung cancer, while 24 (15.1%) had metastases from extrapulmonary malignancies. Among the followed-up patients, 51 (32%) died within 90 days, with a median survival of 30 (17-61) days. LENT score (HR: 1.52, 95% CI: 1.14-2.03), pleural fluid albumin value (HR: 0.92, 95% CI: 0.87-0.97), pleural fluid SUVpeak value (HR: 1.39, 95% CI: 1.15-1.69), and pleural effusion size (HR: 1.01, 95% CI: 1.001-1.02) were found to be significant predictors. Furthermore, in assessing the predictive performance for 90-day mortality, ROC curve of a combination of the independent predictors was significantly higher than that of LENT score alone. ConclusionOur study revealed that the metabolic characteristics of pleural fluid might predict 90-day mortality in patients with MPE. We established that the incorporation of pleural fluid SUVpeak value into the LENT score has the potential to enhance its discriminative ability.

Análisis de ganglios coincidentes con SentiMag® y técnica estándar en la BSGC del cáncer de mama

IntroductionIn breast cancer surgery, there are techniques for sentinel lymph node biopsy (SLNB) that do not require nuclear medicine, such as SentiMag®, which uses ferromagnetic particles. The main purpose of this analysis is to study the degree of concordance in SLNB between SentiMag® and the standard method (Tc99 radiotracer). The secondary objective is to identify factors that impact in sentinel node detection rate and matching detection rate between both probes. MethodsObservational and retrospective study performed from January to December 2021 focused on patients undergoing breast surgery and SLNB who were injected with both tracers, the ferromagnetic SentiMag® and Tc99 radiotracer. Once the diagnostic accuracy tests were performed, a further evaluation of the detection rate for each probe and the concordance between probes were accomplished. After those results, a deeper analysis of differences in detection rates for each probe and concordance between probes were assessed for various factors: neoadjuvant therapy, BMI, mitotic index, and triple-negative immunohistochemical profile. ResultsThe clinical study had a sample size of 70 patients. The overall false-negative rate (FNR) was 4.3%. The detection rate was the same for each technique (85.7%). A total of 106 nodes were biopsied, with a concordance rate of 70.75%. Significant differences were found in concordant nodes according to neoadjuvant therapy (p-value 0.012). For the Ki-67 factor (<20 or ≥20), significant differences were found in detected nodes (p-value 0.031 gamma probe; p-value 0.124 SentiMag®). ConclusionsThe detection rates of SentiMag® and the gamma probe are equivalent. The application of the dual technique minimizes the FNR. A high mitotic index affects the detection rate of the gamma probe, and neoadjuvant therapy negatively impacts the concordance rate.

The 1st World Congress of Nuclear Medicine and Biology held in Japan: a historical review with personal reminiscences.

The 1st World Congress of Nuclear Medicine and Biologywas held from September 30 to October 4 1974 in Japan. This was an epoch-making event in the history of Nuclear Medicine in Japan as well as in the World. The huge success of the meeting contributed a lot to the rapid and remarkable progress of nuclear medicine thereafter. The author served as a secretary of the local organizing committee for the Congress. The author would like to record the event summarizing the publications made by the local organization committee. The author would like to share with nuclear medicine professionals of younger generations the unforgettable experiences which he has kept in memory for the past half a century. The author believes this historical review will help to pave the future way of nuclear medicine by recalling how the World Federation and Congress was started with the great efforts of the excellent minds of predecessors.

Phase II study of uPAR-PET/CT for staging of primary breast cancer in comparison with ultrasound and fine needle biopsies

Accurate initial staging of patients with breast cancer is essential for planning optimal treatment strategies. However, currently, no imaging modality is able to detect lymph node metastases preoperatively with sufficient reliability; therefore, the N status depends on the sentinel node procedure for ~ 70% of patients. In a prospective clinical trial of breast cancer patients, we compared head-to-head uPAR-PET/CT with current standard-of-care, ultrasound (US) and fine needle biopsy (FNB) as staging methods. Forty-nine patients (48 women and 1 man) with biopsy-proven early breast cancer underwent uPAR-PET/CT prior to surgery. All image data were analyzed by two separate teams, each consisting of a highly experienced certified specialist in nuclear medicine and a highly experienced certified specialist in radiology for visualization of primary tumor lesions and detection of lymph node and distant metastases. Histopathological assessment and verification of malignancy in the excised tissues (primary tumors and lymph nodes) were considered standard-of-truth. On a per patient basis, uPAR PET/CT demonstrated a sensitivity of 94% [CI: 83–99%] for detecting the primary tumor (both teams). For the detection of axillary lymph nodes the pooled sensitivity of uPAR PET/CT was 33.3% [CI: 16.5–54.0%], specificity 87.0% [CI: 66.4–97.2%] and accuracy 58.0% [CI: 43.2–71.8%]. In comparison, the standard-of-care preoperative clinical staging algorithm with US and FNB had a sensitivity of 41% [CI: 22–61%] and specificity of 100% [CI: 85–100%] for axillary lymph node metastases. We conclude that the results do not support the use of uPAR PET/CT for staging in breast cancer patients. However, the finding that 94% of primary tumors were uPAR-PET positive may be encouraging for pursuing uPAR theranostics in localized disease. Additionally, other potential applications, such as using uPAR-PET as a prognostic imaging biomarker of tumor aggressiveness, remain to be investigated.

Nuclear imaging of PD-L1 expression promotes the synergistic antitumor efficacy of targeted radionuclide therapy and immune checkpoint blockade.

In order to maximize synergistic effect of targeted radionuclide therapy (TRT) and immune checkpoint blockade (ICB) as well as reduce the toxicity, we pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy. As a novel targeted radiotherapeutic agent, 177Lu-AB-3PRGD2 targeting integrin αvβ3 was developed to achieve sustained antitumor effect by introducing an albumin binder (AB) into the structure of 3PRGD2. The 177Lu-AB-3PRGD2 TRT as well as different types of combination therapies of 177Lu-AB-3PRGD2 TRT and anti-PD-L1 ICB were performed in animal models. The changes of PD-L1 expression in tumors after TRT were evaluated in vitro and in vivo by PD-L1-specific SPECT/CT imaging of 99mTc-MY1523. 177Lu-AB-3PRGD2 showed improved tumor uptake and prolonged tumor retention, leading to significantly enhanced tumor growth suppression. Moreover, 177Lu-AB-3PRGD2 TRT remodeled the tumor immune microenvironment by upregulating PD-L1 expression and increasing tumor-infiltrating CD8+ T cells, facilitating immunotherapy. We found that the anti-PD-L1 treatment was more effective during the upregulation of tumor PD-L1 expression, and the time window could be determined by 99mTc-MY1523 SPECT/CT. We developed a novel and long-acting radiotherapeutic agent 177Lu-AB-3PRGD2, and pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy, optimizing the therapeutic efficacy and reducing the cost and potential toxicity risks. This strategy could also be adapted for clinical practice, combining conventional radiotherapy or chemotherapy with ICB to enhance therapeutic efficacy.

Clinical, Pathologic, and Imaging Variables Associated with Prostate Cancer Detection by PSMA PET/CT and Multiparametric MRI.

Multiparametric MRI (mpMRI) and prostate-specific membrane antigen (PSMA) PET/CT are complementary imaging modalities used in the presurgical evaluation of patients with prostate cancer (PCa). The purpose of this study was to characterize clinically significant PCa (csPCa) detected and not detected by PSMA PET/CT and mpMRI, focusing on tumors detected solely by PSMA PET/CT and overlooked by mpMRI. Methods: We conducted a single-center, retrospective analysis of patients who underwent both PSMA PET/CT and mpMRI within 3 mo of each other and before radical prostatectomy. Two nuclear medicine physicians and 2 radiologists, in a masked manner, independently contoured PCa lesions on PSMA PET/CT and mpMRI, respectively. A consensus read was done with a third reader for each modality, and a majority rule was applied (2:1). After centralized imaging, a pathologic review was done by a genitourinary pathologist. We assessed agreement between imaging modalities and correlation with pathology. Logistic regression models explored associations between clinicopathologic variables and tumor detection on imaging. Results: In total, 132 csPCa tumors from 100 patients were identified on surgical pathology. PSMA PET/CT showed higher lesion-level (87% vs. 80%) and patient-level (98% vs. 94%) sensitivity than mpMRI. Tumors detected on both imaging modalities were larger and had higher grade groups than those not detected by one or both imaging modalities. On multivariable analysis, csPCa tumors undetected by mpMRI but detected by PSMA PET/CT were smaller than those detected by both modalities. Most tumors showing aggressive pathologic features, such as the large cribriform pattern (94.7%) and the intraductal carcinoma (96%), were correctly detected by both imaging modalities. Limitations included selection bias in a surgical cohort. Conclusion: PSMA PET/CT tends to detect smaller csPCa not detected by mpMRI. Larger tumors on pathology with higher grade groups are more likely to be correctly detected by both imaging modalities. These findings provide insights for refining presurgical evaluation strategies in PCa.

Potential of PSMA for breast cancer in nuclear medicine: digital quantitative immunohistochemical analysis and implications for a theranostic approach

BackgroundFurther research is still needed to fully understand the potential of prostate-specific membrane antigen (PSMA) in breast cancer (BC) and to develop and optimize targeted therapies and imaging modalities. The objective of this study was to present a comprehensive analysis of immunohistochemistry data on PSMA staining in BC and to discuss its potential value in a theranostic approach.MethodsFifty-eight male and female patients were randomly selected from a retrospective database of patients who underwent surgery for breast cancer between January 2012 and December 2017 and for whom a specimen is available in our tumour library. Immunodetection of PSMA and CD31 was performed on serial slides. The digitized slides were reviewed and analysed by an experienced pathologist. Additionally, the corresponding TIFF images were processed to calculate the percentage of positive neovessels.ResultsEighteen patients (31.6%) had no expression, 29 (50.9%) had PSMA neovascular expression scored as “1”, and 10 (17.5%) had neovascular expression scored as “2”. Digital immunohistochemistry analysis for this last specific group of patients showed a median proportion of positive neovessels equal to 5% (range: 3–19). A multivariable logistic regression demonstrated that the odds of PSMA positivity were 4.55 times higher in non-luminal tumours and decreased by a factor of 0.12 in lobular subtypes. There was no association between sex or the presence of a germline BRCA1/2 mutation and PSMA expression in tumours.ConclusionsOur study highlights generally low neovascular expression of PSMA in specific histopathological subtypes of breast cancer, which will likely hamper the development of an adequate theranostic strategy.Trial registrationThe procedure has been retrospectively registered to the French National Institute for Health Data (N° F20220615153900).

Improvement of myocardial lipolysis in iodine-123-beta-methyl-P-iodophenyl-pentadecanoic acid scintigraphy in patients with idiopathic triglyceride deposit cardiomyovasculopathy treated with Tricaprin

Abstract Background Triglyceride deposit cardiomyovasculopathy (TGCV) is a rare intractable cardiovascular disorder (Orphanet ORPHAcode: 565612) in which defective intracellular lipolysis results in heart failure and coronary artery disease. Myocardial scintigraphy with iodine-123-β-methyl-P-iodophenyl-pentadecanoic acid (BMIPP) is useful for evaluating myocardial TG metabolism and its washout rate (WR) reflects myocardial lipolysis. A decreased WR (&amp;lt;10%) of BMIPP is one of the diagnostic criteria for TGCV. CNT-01, the active ingredient of which is tricaprin, a medium-chain triglyceride, has the potential to facilitate myocardial lipolysis in a mouse model. However, the effects of CNT-01 (tricaprin) on BMIPP scintigraphy in patients with TGCV remain unclear. Purpose To evaluate the effects of CNT-01 on BMIPP-WR in patients with TGCV. Methods An investigator-initiated, randomized, double-blind exploratory trial (Phase IIa) was conducted. Ten patients with idiopathic TGCV in our hospital were enrolled and orally administered 1.5 g/day of CNT-01 or placebo for 8 weeks. The endpoint was the delta WR on BMIPP scintigraphy. All the participants underwent BMIPP scintigraphy after overnight fasting. Following the protocol recommended by the Japanese Society of Nuclear Cardiology, 111 MBq of BMIPP was intravenously injected at rest after fasting for ≥ 12 h. Early and delayed images were obtained after 20 and 180–210 min, respectively. BMIPP scintigraphy at baseline and 8-week was performed using the same SPECT apparatus. WR is defined as the ratio of the difference between the counts in the early image and time-decay-corrected delayed image divided by the former. We used a recently proposed algorithm for calculating the WR based on the total count and analyzed the WRs (Ann Nucl Cardiol. 2023;9(1):19-25). Results A total of 5 patients were assigned to placebo and 5 patients were assigned to CNT-01. During the protocol, delta BMIPP-WRs were -6.18 ± 4.43 and 5.44 ± 2.57 % (95% confidence intervals, -12.33 to -0.03 and 1.88 to 9.00) in the placebo and CNT-01 groups, respectively. The baseline-adjusted difference in delta BMIPP-WR between the two groups was significant (p=0.005) (Picture). No significant changes were observed in clinical parameters. Conclusion This study demonstrated that CNT-01 improved myocardial lipolysis in patients with TGCV as measured by BMIPP scintigraphy.

Usefulness of visual classification for cardiac pathophysiology using count-washout rate map in iodine-123-beta-methyl-P-iodophenyl-pentadecanoic acid scintigraphy

Abstract Background Myocardial washout rate (WR) analysis of radiopharmaceuticals is utilized in nuclear cardiology to evaluate the clinical pathophysiology of the heart. WR is defined as the ratio of the difference between the counts in the early image and time-decay-corrected delayed image divided by the former. The myocardial WR of iodine-123-β-methyl iodophenyl-pentadecanoic acid (BMIPP) is an indicator of myocardial lipolysis, and a decreased WR (&amp;lt;10%) of BMIPP is one of the diagnostic criteria for triglyceride deposit cardiomyovasculopathy (TGCV). However, decreased BMIPP uptake in the early images, as in old myocardial infarction (OMI), would also cause a markedly decreased WR. Since the distinction between these clinical conditions cannot be made based on WR alone, simultaneous evaluation of the counts in the early image and WR is needed to properly understand the cardiac pathophysiology. Purpose To differentiate between TGCV and non-TGCV with OMI, both of which show decreased BMIPP WR, a new Count-WR Map (CWRM) method was evaluated. The purpose is to visually and easily distinguish between the two conditions using CWRM. Methods We introduced a CWRM consisting of two axes: counting in the early image, and WR. The count window was set to a maximum of the mean plus two standard deviations and a minimum of 50 counts, and the WR window was set to a maximum of 30 % and a minimum of -20%. CWRM was visually evaluated as normal, TGCV, non-TGCV with OMI, or TGCV with OMI. Results In normal cases, sufficient counts were observed in the early images, and WR did not decrease; CWRM showed light blue. In TGCV, sufficient counts were observed in the early image, but WRs markedly decreased; CWRM showed even orange. In non-TGCV with OMI, regions with decreased and preserved counts coexisted; CWRM showed light blue in the normal and black in the OMI region. In TGCV with OMI, CWRM showed orange in the TGCV myocardium and black in the OMI region (figure). Conclusions CWRM is useful for visually and easily differentiating TGCV from non-TGCV with OMI. CWRM can be applied to other cardiovascular diseases with count and WR variations for visual classification.

Nuclear medicine based multimodal molecular imaging facilitates precision medicine for gastrointestinal tumors

Nuclear medicine based multimodal molecular imaging facilitates precision medicine for gastrointestinal tumors

The production study of Auger emitters in platinum group metal for radiotherapy

Targeted radioisotope therapy (TRT) is a type of internal radiotherapy that combines radiation therapy and targeted therapy to eliminate cancer cells without damaging healthy tissue. Radionuclides attached to targeting molecules travel to cancer cells and emit radiation in the form of beta-ray emitting nuclides and alpha nuclides. A third type of nuclide called Auger emitter can be used in a treatment called Auger therapy. Dr Tomoyuki Ohya, Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Sciences (iQMS), National Institutes for Quantum Science and Technology (QST), Japan, is interested in Auger therapy as a radiotherapy that only affects the tissues that require treatment. Challenges associated with this treatment are the short range of Auger electrons, meaning that they must be precisely targeted in order to be effective. With a view to overcoming this, Ohya is focusing on Pd-103 and Rh-103m as optimal nuclides for Auger therapy. He is working to develop a technology to facilitate high-quality, large-scale manufacturing that can be applied to the clinical use of Auger therapy, enhancing its efficiency and rendering its use on a wide scale possible. In one project, Ohya investigated the potential of developing an efficient and reliable method for producing Rh-103m. Due to its short half-life it needs to be produced by a generator for clinical use. As the anion-exchange resins used in previously developed generators are no longer commercially available, Ohya and the team prepared and tested generators using commercially available anion-exchange resins.

Occupational burnout in nuclear medicine technologists working in Australia and New Zealand - results of a multi-national survey.

Occupational burnout can be associated with negative feelings about the workplace and feeling that a person's efforts are of little consequence. Within a healthcare setting, occupational burnout can be attributed to a high workload or a non-supportive work environment. Higher levels of burnout are associated with increased absenteeism and turnover, increased medical errors and decreased patient care. The aim of this study was to investigate the levels of occupational burnout within nuclear medicine technologists (NMTs) working in Australia and New Zealand. An online questionnaire was distributed via QuestionPro. The questionnaire consisted of four sections, including the Professional Quality of Life Scale (ProQOL) Version 5 (2009) measuring compassion satisfaction, burnout and secondary traumatic stress in the workplace. For this study, only the burnout component of this scale is reported. There were 162 survey responses. Of the 18 New Zealand participants, 10 (56%) reported moderate levels of burnout. Of the 144 Australian participants, 114 (79%) reported moderate levels of burnout. No NMTs reported high levels of burnout. All states of Australia were represented in the survey, with Queensland, Western Australia and Victoria having the highest number of participants reporting moderate levels of burnout. This study revealed that more than half of New Zealand participants and three quarters of Australian participants reported moderate levels of burnout. It is imperative to address the wellbeing needs of NMTs working in Australia and New Zealand at an individual and organisational level to support NMTs to be more engaged in their work and help organisations retain staff.

Bone scintigraphy based on deep learning model and modified growth optimizer

Bone scintigraphy is recognized as an efficient diagnostic method for whole-body screening for bone metastases. At the moment, whole-body bone scan image analysis is primarily dependent on manual reading by nuclear medicine doctors. However, manual analysis needs substantial experience and is both stressful and time-consuming. To address the aforementioned issues, this work proposed a machine-learning technique that uses phases to detect Bone scintigraphy. The first phase in the proposed model is the feature extraction and it was conducted based on integrating the Mobile Vision Transformer (MobileViT) model in our framework to capture highly complex representations from raw medical imagery using two primary components including ViT and lightweight CNN featuring a limited number of parameters. In addition, the second phase is named feature selection, and it is dependent on the Arithmetic Optimization Algorithm (AOA) being used to improve the Growth Optimizer (GO). We evaluate the performance of the proposed FS model, named GOAOA using a set of 18 UCI datasets. Additionally, the applicability of Bone scintigraphy for real-world application is evaluated using 2800 bone scan images (1400 normal and 1400 abnormal). The results and statistical analysis revealed that the proposed GOAOA algorithm as an FS technique outperforms the other FS algorithms employed in this study.

Gender and Ethnicity Bias of Text-to-Image Generative Artificial Intelligence in Medical Imaging, Part 2: Analysis of DALL-E 3.

Disparity among gender and ethnicity remains an issue across medicine and health science. Only 26%-35% of trainee radiologists are female, despite more than 50% of medical students' being female. Similar gender disparities are evident across the medical imaging professions. Generative artificial intelligence text-to-image production could reinforce or amplify gender biases. Methods: In March 2024, DALL-E 3 was utilized via GPT-4 to generate a series of individual and group images of medical imaging professionals: radiologist, nuclear medicine physician, radiographer, nuclear medicine technologist, medical physicist, radiopharmacist, and medical imaging nurse. Multiple iterations of images were generated using a variety of prompts. Collectively, 120 images were produced for evaluation of 524 characters. All images were independently analyzed by 3 expert reviewers from medical imaging professions for apparent gender and skin tone. Results: Collectively (individual and group images), 57.4% (n = 301) of medical imaging professionals were depicted as male, 42.4% (n = 222) as female, and 91.2% (n = 478) as having a light skin tone. The male gender representation was 65% for radiologists, 62% for nuclear medicine physicians, 52% for radiographers, 56% for nuclear medicine technologists, 62% for medical physicists, 53% for radiopharmacists, and 26% for medical imaging nurses. For all professions, this overrepresents men compared with women. There was no representation of persons with a disability. Conclusion: This evaluation reveals a significant overrepresentation of the male gender associated with generative artificial intelligence text-to-image production using DALL-E 3 across the medical imaging professions. Generated images have a disproportionately high representation of white men, which is not representative of the diversity of the medical imaging professions.

TRU-IMP: techniques for reliable use of images in medical physics; a graphical user interface to analyze and compare segmentations in nuclear medicine.

Background. In the context of pharmacokinetic analyses, the segmentation method one uses has a large impact on the results obtained, thus the importance of transparency.Innovation. This paper introduces a graphical user interface (GUI), TRU-IMP, that analyzes time-activity curves and segmentations in dynamic nuclear medicine. This GUI fills a gap in the current technological tools available for the analysis of quantitative dynamic nuclear medicine image acquisitions. The GUI includes various techniques of segmentations, with possibilities to compute related uncertainties.Results. The GUI was tested on image acquisitions made on a dynamic nuclear medicine phantom. This allows the comparison of segmentations via their time-activity curves and the extracted pharmacokinetic parameters.Implications. The flexibility and user-friendliness allowed by the proposed interface make the analyses both easy to perform and adjustable to any specific case. This GUI permits researchers to better show and understand the reproducibility, precision, and accuracy of their work in quantitative dynamic nuclear medicine.Availability and Implementation. Source code freely available on GitHub:https://github.com/ArGilfea/TRU-IMPand location of the interface available from there. The GUI is fully compatible with iOS and Windows operating systems (not tested on Linux). A phantom acquisition is also available to test the GUI easily.

Gender and Ethnicity Bias of Text-to-Image Generative Artificial Intelligence in Medical Imaging, Part 1: Preliminary Evaluation.

Generative artificial intelligence (AI) text-to-image production could reinforce or amplify gender and ethnicity biases. Several text-to-image generative AI tools are used for producing images that represent the medical imaging professions. White male stereotyping and masculine cultures can dissuade women and ethnically divergent people from being drawn into a profession. Methods: In March 2024, DALL-E 3, Firefly 2, Stable Diffusion 2.1, and Midjourney 5.2 were utilized to generate a series of individual and group images of medical imaging professionals: radiologist, nuclear medicine physician, radiographer, and nuclear medicine technologist. Multiple iterations of images were generated using a variety of prompts. Collectively, 184 images were produced for evaluation of 391 characters. All images were independently analyzed by 3 reviewers for apparent gender and skin tone. Results: Collectively (individual and group characters) (n = 391), 60.6% were male and 87.7% were of a light skin tone. DALL-E 3 (65.6%), Midjourney 5.2 (76.7%), and Stable Diffusion 2.1 (56.2%) had a statistically higher representation of men than Firefly 2 (42.9%) (P < 0.0001). With Firefly 2, 70.3% of characters had light skin tones, which was statistically lower (P < 0.0001) than for Stable Diffusion 2.1 (84.8%), Midjourney 5.2 (100%), and DALL-E 3 (94.8%). Overall, image quality metrics were average or better in 87.2% for DALL-E 3 and 86.2% for Midjourney 5.2, whereas 50.9% were inadequate or poor for Firefly 2 and 86.0% for Stable Diffusion 2.1. Conclusion: Generative AI text-to-image generation using DALL-E 3 via GPT-4 has the best overall quality compared with Firefly 2, Midjourney 5.2, and Stable Diffusion 2.1. Nonetheless, DALL-E 3 includes inherent biases associated with gender and ethnicity that demand more critical evaluation.