Frontiers in nuclear medicine (Lausanne, Switzerland)最新文献

{"title":"Mixture prior distributions and Bayesian models for robust radionuclide image processing.","authors":"Muyang Zhang, Robert G Aykroyd, Charalampos Tsoumpas","doi":"10.3389/fnume.2024.1380518","DOIUrl":"10.3389/fnume.2024.1380518","url":null,"abstract":"<p><p>The diagnosis of medical conditions and subsequent treatment often involves radionuclide imaging techniques. To refine localisation accuracy and improve diagnostic confidence, compared with the use of a single scanning technique, a combination of two (or more) techniques can be used but with a higher risk of misalignment. For this to be reliable and accurate, recorded data undergo processing to suppress noise and enhance resolution. A step in image processing techniques for such inverse problems is the inclusion of smoothing. Standard approaches, however, are usually limited to applying identical models globally. In this study, we propose a novel Laplace and Gaussian mixture prior distribution that incorporates different smoothing strategies with the automatic model-based estimation of mixture component weightings creating a locally adaptive model. A fully Bayesian approach is presented using multi-level hierarchical modelling and Markov chain Monte Carlo (MCMC) estimation methods to sample from the posterior distribution and hence perform estimation. The proposed methods are assessed using simulated <math><mi>γ</mi> <msup><mtext>-eye</mtext> <mrow><mtext>TM</mtext></mrow> </msup> </math> camera images and demonstrate greater noise reduction than existing methods but without compromising resolution. As well as image estimates, the MCMC methods also provide posterior variance estimates and hence uncertainty quantification takes into consideration any potential sources of variability. The use of mixture prior models, part Laplace random field and part Gaussian random field, within a Bayesian modelling approach is not limited to medical imaging applications but provides a more general framework for analysing other spatial inverse problems. Locally adaptive prior distributions provide a more realistic model, which leads to robust results and hence more reliable decision-making, especially in nuclear medicine. They can become a standard part of the toolkit of everyone working in image processing applications.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"4 ","pages":"1380518"},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11440870/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Case Report: Application of ¹⁸F-FDG PET/CT in identifying plasmacytoma in monoclonal gammopathy associated peripheral neuropathy.","authors":"Jiequn Weng, Jie Lin, Chong Sun","doi":"10.3389/fnume.2024.1446780","DOIUrl":"10.3389/fnume.2024.1446780","url":null,"abstract":"<p><p>Peripheral neuropathy is a prevalent complication in plasma cell disorders, posing significant diagnostic and therapeutic challenges. This study presents three cases initially diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP). Despite initial symptom regression post-immunomodulatory treatment, the patients exhibited progressive neurological deficits. Advanced laboratory evaluation confirmed monoclonal protein presence, yet traditional diagnostic methods, including bone marrow biopsy and flow cytometry, yielded normal results. Utilizing ¹⁸F-FDG PET/CT, we identified multiple hypermetabolic vertebral lesions, which upon biopsy, confirmed the diagnosis of plasmacytoma. Our findings underscore the utility of PET/CT as a reliable diagnostic tool for monoclonal gammopathy associated neuropathy, advocating for its consideration in cases with equivocal diagnosis. When the diagnosis is in doubt, biopsy of a lesion may facilitate early and accurate diagnosis, potentially influencing treatment strategies and patient outcomes.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"4 ","pages":"1446780"},"PeriodicalIF":0.0,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11440967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Case report: positive pitfalls of PSMA PET/CT: diagnostic challenges in degenerative bone lesions including MODIC type 1.","authors":"Hicham Moukaddam, Ghida El Saheb, Nadine Omran, Nour El Ghawi, Alain Abi Ghanem, Mohamad Haidar","doi":"10.3389/fnume.2024.1451848","DOIUrl":"10.3389/fnume.2024.1451848","url":null,"abstract":"<p><p>Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is an imaging technique that has demonstrated high sensitivity and specificity in detecting prostate cancer and its metastasis, especially in the bones. This case describes a 60-year-old man who presented for increased prostate-specific antigen (PSA) level and underwent [⁶⁸Ga]gallium-PSMA-11 PET/CT imaging for better disease assessment. ⁶⁸Ga-PSMA-11 PET/CT revealed numerous radiotracer-positive lesions in both prostate lobes with associated sclerotic lesions on L4 and L5, but only L5 showed increased radiotracer avidity raising the possibility of metastasis. Magnetic Resonance Imaging (MRI) raises the possibility of aggressive MODIC type 1 lesion vs. infectious/inflammatory process. A biopsy of the radiotracer avid area was performed and showed no evidence of metastasis. The final diagnosis was aggressive MODIC type 1, in keeping with the false positive result of ⁶⁸Ga-PSMA-11 PET/CT. This example demonstrates the possible limitations of ⁶⁸Ga-PSMA-11 PET/CT, particularly in detecting bone metastases, and emphasizes the need for cautious interpretation and additional study to improve its diagnostic accuracy. Understanding and resolving these limitations is critical for increasing the accuracy of PSMA PET/CT in prostate cancer management.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"4 ","pages":"1451848"},"PeriodicalIF":0.0,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11440935/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PARALLELPROJ-an open-source framework for fast calculation of projections in tomography.","authors":"Georg Schramm, Kris Thielemans","doi":"10.3389/fnume.2023.1324562","DOIUrl":"10.3389/fnume.2023.1324562","url":null,"abstract":"<p><p>In this article, we introduce parallelproj, a novel open-source framework designed for efficient parallel computation of projections in tomography leveraging either multiple CPU cores or GPUs. This framework efficiently implements forward and back projection functions for both sinogram and listmode data, utilizing Joseph's method, which is further extended to encompass time-of-flight (TOF) PET projections. Our evaluation involves a series of tests focusing on PET image reconstruction using data sourced from a state-of-the-art clinical PET/CT system. We thoroughly benchmark the performance of the projectors in non-TOF and TOF, sinogram, and listmode employing multi CPU-cores, hybrid CPU/GPU, and exclusive GPU mode. Moreover, we also investigate the timing of non-TOF sinogram projections calculated in STIR (Software for Tomographic Image Reconstruction) which recently integrated parallelproj as one of its projection backends. Our results indicate that the exclusive GPU mode provides acceleration factors between 25 and 68 relative to the multi-CPU-core mode. Furthermore, we demonstrate that OSEM listmode reconstruction of state-of-the-art real-world PET data sets is achievable within a few seconds using a single consumer GPU.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"3 ","pages":"1324562"},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11440996/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A fast Monte Carlo cell-by-cell simulation for radiobiological effects in targeted radionuclide therapy using pre-calculated single-particle track standard DNA damage data.","authors":"A Lim, M Andriotty, T Yusufaly, G Agasthya, B Lee, C Wang","doi":"10.3389/fnume.2023.1284558","DOIUrl":"10.3389/fnume.2023.1284558","url":null,"abstract":"<p><strong>Introduction: </strong>We developed a new method that drastically speeds up radiobiological Monte Carlo radiation-track-structure (MC-RTS) calculations on a cell-by-cell basis.</p><p><strong>Methods: </strong>The technique is based on random sampling and superposition of single-particle track (SPT) standard DNA damage (SDD) files from a \"pre-calculated\" data library, constructed using the RTS code TOPAS-nBio, with \"time stamps\" manually added to incorporate dose-rate effects. This time-stamped SDD file can then be input into MEDRAS, a mechanistic kinetic model that calculates various radiation-induced biological endpoints, such as DNA double-strand breaks (DSBs), misrepairs and chromosomal aberrations, and cell death. As a benchmark validation of the approach, we calculated the predicted energy-dependent DSB yield and the ratio of direct-to-total DNA damage, both of which agreed with published <i>in vitro</i> experimental data. We subsequently applied the method to perform a superfast cell-by-cell simulation of an experimental <i>in vitro</i> system consisting of neuroendocrine tumor cells uniformly incubated with ¹⁷⁷Lu.</p><p><strong>Results and discussion: </strong>The results for residual DSBs, both at 24 and 48 h post-irradiation, are in line with the published literature values. Our work serves as a proof-of-concept demonstration of the feasibility of a cost-effective \"<i>in silico</i> clonogenic cell survival assay\" for the computational design and development of radiopharmaceuticals and novel radiotherapy treatments more generally.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"3 ","pages":"1284558"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460290/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142395674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Case Report: Post-traumatic splenosis and potential pitfall for PSMA-PET.","authors":"Marina Nearchou, Elizabeth Georgiou, Alexis Vrachimis, Konstantinos Ferentinos, Iosif Strouthos","doi":"10.3389/fnume.2023.1319952","DOIUrl":"10.3389/fnume.2023.1319952","url":null,"abstract":"<p><strong>Background: </strong>18F-prostate specific membrane antigen (PSMA) PET is fast becoming the gold-standard in prostate cancer, both in staging of intermediate-/high-risk patients and in re-staging patients with biochemical failure. Several pitfalls of 18F-PSMA PET have been reported, and we report, to our best of knowledge, for the first time, a case which could have been falsely diagnosed as peritoneal spread.</p><p><strong>Case presentation: </strong>A 67-year-old patient with high-risk prostate cancer underwent staging with 18F-PSMA-1007 PET/CT (PSMA-PET/CT). PSMA-PET/CT revealed a histologically confirmed prostatic malignancy in the peripheral left zone. Unexpectedly, additional multiple highly PSMA-expressing intraabdominal formations were discovered. Based on apparent anatomic asplenia and a history of traumatic splenic rapture during childhood, a suspicion of post-traumatic splenosis was raised. For further non-invasive evaluation, a C-99 sulphur colloid scintigraphy with SPECT was conducted, confirming the presence of multiple functional ectopic splenic tissues. This is, to our best of knowledge, the first case utilising 18F-PSMA-1007-PET/CT and 99mTc-sulphur colloid SPECT to detect intraabdominal splenosis, highlighting the high potential of nuclear medicine in such trivial cases.</p>","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"3 ","pages":"1319952"},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11440873/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First use of 18F-FDG PET in TEMPI syndrome: can it be used for treatment assessment? A case report","authors":"Henri Pasquesoone, Aurélien Callaud, Thibaut Carsuzaa, Thomas Chalopin, Maria-Joao Santiago-Ribeiro","doi":"10.3389/fnume.2023.1273967","DOIUrl":"https://doi.org/10.3389/fnume.2023.1273967","url":null,"abstract":"TEMPI syndrome (TEMPI) compounds telangiectasias and polycythemia with elevated erythropoietin levels, monoclonal gammopathy, perirenal fluid collections, and intrapulmonary shunt. Although the pathophysiology of this syndrome remains unclarified, prior research has been established that it is a plasma cell neoplasm, often containing less than 10% bone marrow plasma cells. 18 F-FDG PET serves as a valuable instrument for initial staging and treatment monitoring in multiple myeloma management. Thus, 18 F-FDG PET can be legitimately applied for TEMPI assessment. Here, we present the first 18 F-FDG PET images for the initial evaluation and treatment monitoring of TEMPI in a 51-year-old woman, who exhibited polycythemia (EPO:5,448 mIU/ml) without JAK2 mutation, telangiectasias, monoclonal IgG lambda gammopathy (13.9) g/L and 7% dysmorphic plasma cells (CD38 + CD138+), occasionally clustered, in favor of tumoral plasmacytomas. The first PET scan exhibited hypermetabolic diffuse bone marrow, potentially related to polycythemia, accompanied by non-lytic bone hypermetabolic lesions in the femoral and humeral diaphysis, and ametabolic peri-renal fluid collections, brown fat, and pleural talcoma. Post-treatment 18 F-FDG PET (Daratumumab Bortezomib Thalidomide Dexamethasone) revealed a completely reduced signal of bone lesions, suggesting a complete response, which was substantiated both clinically and biologically, with the concurrent disappearance of telangiectasia and the monoclonal component, and the normalization of the EPO level. In future, additional data will be required to confirm the added value of 18 F-FDG PET with TEMPI. Nevertheless, 18 F-FDG PET can be a preferred tool for the extension workup and therapeutic evaluation of TEMPI syndrome.","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134906255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emerging theragnostic radionuclide applications for hepatocellular carcinoma","authors":"N. E. Nyakale, C. Aldous, A. A. Gutta, X. Khuzwayo, L. Harry, M. M. Sathekge","doi":"10.3389/fnume.2023.1210982","DOIUrl":"https://doi.org/10.3389/fnume.2023.1210982","url":null,"abstract":"Hepatocellular carcinoma (HCC) is a major global health problem. Theragnostic is a term that refers to the integration of diagnostic and therapeutic modalities into a single system for personalized medicine. Theragnostic in HCC involves the use of imaging techniques to diagnose the cancer and assess its characteristics, such as size, location, and extent of spread. Theragnostic involves the use of molecular and genetic tests to identify specific biomarkers that can help guide treatment decisions and post treatment assess the dosimetry and localization of the treatment, thus assisting to guide future treatment. This can be done through either positron emission tomography (PET) scanning or single photon emission tomography (SPECT) using radiolabelled tracers that target specific molecules expressed by HCC cells or radioembolization. This technique can help identify the location and extent of the cancer, as well as provide information on the tumour's metabolic activity and blood supply. In summary, theragnostic is an emerging field that holds promise for improving the diagnosis and treatment of HCC. By combining diagnostic and therapeutic modalities into a single system, theragnostic can help guide personalized treatment decisions and improve patient outcomes.","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135218429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiopharmaceutical administration practices—Are they best practice?","authors":"Stephen Harris, James R. Crowley, Nancy Warden","doi":"10.3389/fnume.2023.1244660","DOIUrl":"https://doi.org/10.3389/fnume.2023.1244660","url":null,"abstract":"Background The nuclear medicine community has stated that they are using best practices to gain venous access and administer radiopharmaceuticals, and therefore do not contribute to extravasations. We tested this hypothesis qualitatively and quantitatively by evaluating four different perspectives of current radiopharmaceutical administration practices: (1) clinical observations of nuclear medicine technologists on the job, (2) quality improvement (QI) projects, (3) a high-level survey of current practices in 10 acute care hospitals, (4) intravenous (IV) access site data for 29,343 procedures. These four areas were compared to the gold standard of pharmaceutical administration techniques. Results From clinical observations of radiopharmaceutical administrations in adult populations, technologists extensively used 24-gauge peripheral intravenous catheters (PIVCs) and butterfly needles. They also performed direct puncture (straight stick). Technologists predominantly chose veins in areas of flexion (hand, wrist, and antecubital fossa), rather than forearm vessels for IV access placement; in many circumstances, antecubital fossa vessels are chosen first, often without prior assessment for other suitable vessels. For selecting the injection vein, technologists sometimes used infrared vein finders but primarily performed blind sticks. Review of QI projects suggested that smaller gauge needles were contributing factors to extravasations. Additionally, the review of surveys from 10 hospitals revealed an absence of formalized protocols, training, knowledge, and skills necessary to ensure the safety/patency of IV devices prior to the administration of radiopharmaceuticals. Finally, findings from a review of IV access data for 29,343 procedures supported the observations described above. Conclusions We expect that nuclear medicine technologists have the best intentions when providing patient care, but many do not follow venous access best practices; they lack formal protocols, have not received the latest comprehensive training, and do not use the best placement tools and monitoring equipment. Thus, the presumption that most nuclear medicine technologists use best practices may not be accurate. In order to improve radiopharmaceutical administration and patient care, the nuclear medicine community should update technical standards to address the most recent peripheral IV access and administration best practices, provide technologists with vascular visualization tools and the proper training, develop and require annual vascular access competency, and provide active monitoring with center and patient-specific data to create ongoing feedback.","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135854885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mini review of first-in-human integrin αvβ6 PET tracers","authors":"Richard H. Kimura, Andrei Iagaru, H. Henry Guo","doi":"10.3389/fnume.2023.1271208","DOIUrl":"https://doi.org/10.3389/fnume.2023.1271208","url":null,"abstract":"This mini review of clinically-evaluated integrin αvβ6 PET-tracers reveals distinct differences in human-biodistribution patterns between linear peptides, including disulfide-stabilized formats, compared to head-to-tail cyclized peptides. All PET tracers mentioned in this mini review were able to delineate disease from normal tissues, but some αvβ6 PET tracers are better than others for particular clinical applications. Each αvβ6 PET tracer was validated for its ability to bind integrin αvβ6 with high affinity. However, all the head-to-tail cyclized peptide PET-tracers reviewed here did not accumulate in the GI-tract, in striking contrast to the linear and disulfide-bonded counterparts currently undergoing clinical evaluation in cancer, IPF and long COVID. Multiple independent investigators have reported the presence of β6 mRNA as well as αvβ6 protein in the GI-tract. Currently, there remains further need for biochemical, clinical, and structural data to satisfactorily explain the state-of-the-art in human αvβ6-imaging.","PeriodicalId":73095,"journal":{"name":"Frontiers in nuclear medicine (Lausanne, Switzerland)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135095187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}