Quantitative proteomics revealed extensive microenvironmental changes after stem cell transplantation in ischemic stroke / 医学前沿

The local microenvironment is essential to stem cell-based therapy for ischemic stroke, and spatiotemporal changes of the microenvironment in the pathological process provide vital clues for understanding the therapeutic mechanisms. However, relevant studies on microenvironmental changes were mainly confined in the acute phase of stroke, and long-term changes remain unclear. This study aimed to investigate the microenvironmental changes in the subacute and chronic phases of ischemic stroke after stem cell transplantation. Herein, induced pluripotent stem cells (iPSCs) and neural stem cells (NSCs) were transplanted into the ischemic brain established by middle cerebral artery occlusion surgery. Positron emission tomography imaging and neurological tests were applied to evaluate the metabolic and neurofunctional alterations of rats transplanted with stem cells. Quantitative proteomics was employed to investigate the protein expression profiles in iPSCs-transplanted brain in the subacute and chronic phases of stroke. Compared with NSCs-transplanted rats, significantly increased glucose metabolism and neurofunctional scores were observed in iPSCs-transplanted rats. Subsequent proteomic data of iPSCs-transplanted rats identified a total of 39 differentially expressed proteins in the subacute and chronic phases, which are involved in various ischemic stroke-related biological processes, including neuronal survival, axonal remodeling, antioxidative stress, and mitochondrial function restoration. Taken together, our study indicated that iPSCs have a positive therapeutic effect in ischemic stroke and emphasized the wide-ranging microenvironmental changes in the subacute and chronic phases.

Radical prostatectomy on a 66-year-old patient with a positive 18F-PSMA uptake: Potential application for multiple negative prostate biopsy results

@#The decision to proceed with radical prostatectomy has to be supported with biopsy-proven prostate cancer. However, when a patient has persistently multiple negative prostate biopsies and a high PSA, a serious diagnostic and therapeutic dilemma arises. The PIRADS score generated by the multiparametric-MRI of the prostate provides a guide for a template biopsy using MRI-ultrasound fusion technology, with the hope of minimizing a false negative result. Fluorine-18 Prostate-Specific Membrane Antigen (18F-PSMA) PET CT scan, on the other hand, is used mainly for staging prostate cancer after biochemical recurrence. The use of 18F-PSMA PET CT in the primary clinical diagnosis of prostate cancer has never been reported.The authors performed radical prostatectomy on a 66-year-old HIV-positive male with suspicious lesion on 18F-PSMA, PIRADS 5 on mp-MRI, and a persistently elevated PSA >100 despite multiple negative biopsies. The final histopathological analysis confirmed the presence of adenocarcinoma of the prostate, Gleason 7 (3+4), with negative margins. There were no intraoperative complications, and the patient was discharged in good condition. On follow-up, he had a nadir PSA of 0.058 ng/ml, has partial incontinence, and decreased erectile function and was advised phosphodiesterase inhibitors. 18F-PSMA may be utilized in the decision process for patients who are highly suspected with malignancy but have no preoperatively biopsy-proven cancer after multiple negative biopsies.

Development of a highly-specific

As a serine hydrolase, monoacylglycerol lipase (MAGL) is principally responsible for the metabolism of 2-arachidonoylglycerol (2-AG) in the central nervous system (CNS), leading to the formation of arachidonic acid (AA). Dysfunction of MAGL has been associated with multiple CNS disorders and symptoms, including neuroinflammation, cognitive impairment, epileptogenesis, nociception and neurodegenerative diseases. Inhibition of MAGL provides a promising therapeutic direction for the treatment of these conditions, and a MAGL positron emission tomography (PET) probe would greatly facilitate preclinical and clinical development of MAGL inhibitors. Herein, we design and synthesize a small library of fluoropyridyl-containing MAGL inhibitor candidates. Pharmacological evaluation of these candidates by activity-based protein profiling identified

The relationship between SUVmax on preoperative 68Ga-PSMA PET-CT and the clinicopahtological characteristics in patients treated with radical prostatectomy / 中华泌尿外科杂志

Objective@#To investigate the relationship between SUVmax on preoperative 68Ga-PSMA PET-CT and the clinicopathological characteristics of patients treated with radical prostatectomy.@*Methods@#The clinicopahtological data of patients evaluated with 68Ga-PSMA PET-CT preoperatively and treated with radical prostatectomy between May 2016 and August 2019 were retrospectively reviewed. 31 patients with a mean age (63.1±4.9) and baseline PSA (72.71±173.15)ng/ml were enrolled. Their BMI mean (24.6±3.0)kg/m2. Baseline testosterone of 14 patients was (4.72±1.64)ng/ml.Based on the Gleason scores related ISUP classification, all patients were classified into grade one in 5 cases, grade 2in 7 cases, grade 3 in 4 cases, grade 4 in 10 cases and grade 5 in 5 cases. The clinical classification included 6 cases in T2a stage, 2 cases in T2b stage, 17 cases in T2c stage, 1 case in T3a stage, 4 cases in T3b stage and 1 case in T4 stage. SUVmax was accessed by two independent professional nuclear medicine physicians. SUVmax was 12.49±9.38. SPSS 16.0 software was used to do statistic analysis.@*Results@#The post-operative pathological results showed the surgical margin positive in 19 cases, negative in 12 cases, vascular positive in 5 cases, negative in 20 case, positive nerve invasion in 20 cases and negative in 11 cases. 2 patients were low risk, 7 patients were medium risk and 22 patients were high risk according to D′Amico classification. Based on the basis of PSA(≤10 or>10) and Gleason score(≤6 or>6), 6 patients were in group with low PSA and low Gleason score, 5 patients were low PSA and high Gleason score, 9 patients were high PSA and low Gleason score, 11 patients were high PSA and high Gleason score. SUVmax had a significant positive relationship with pathological ISUP(r=0.434, P=0.015) and SUVmax in patients with positive intravascular tumor emboli was significantly higher than those with negative intravascular tumor emboli(14.78±10.68 vs. 8.17±2.81, P=0.005). No significant correlation was found between SUVmax and baseline PSA, testosterone, pathologic T stage, surgical margin, nerve invasion, pelvic lymph node status as well as risk stratification. SUVmax could distinguish pathologic ISUP grade 5 with a maximum AUC 0.747 (P=0.033) and the sensitivity was 88.9%. The specificity was 77.3% when SUVmax≥11.34. SUVmax in patients with upgrading ISUP was significantly higher than that in patients with downgrading ISUP (16.01±5.40 vs. 4.98±2.11, P=0.007).@*Conclusions@#SUVmax measured on preoperative 68Ga-PSMA PET-CT may have a clinical significance in predicting unfavorable pathological factors for patients treated with radical prostatectomy.

The relationship between SUVmax on preoperative 68Ga-PSMA PET-CT and the clinicopahtological characteristics in patients treated with radical prostatectomy / 中华泌尿外科杂志

Objective To investigate the relationship between SUVmax on preoperative 68Ga-PSMA PET-CT and the clinicopathological characteristics of patients treated with radical prostatectomy.Methods The clinicopahtological data of patients evaluated with 68Ga-PSMA PET-CT preoperatively and treated with radical prostatectomy between May 2016 and August 2019 were retrospectively reviewed.31 patients with a mean age (63.1 ± 4.9) and baseline PSA (72.71 ± 173.15) ng/ml were enrolled.Their BMI mean (24.6 ± 3.0) kg/m2.Baseline testosterone of 14 patients was (4.72 ± 1.64) ng/ml.Based on the Gleason scores related ISUP classification,all patients were classified into grade one in 5 cases,grade 2in 7 cases,grade 3 in 4 cases,grade 4 in 10 cases and grade 5 in 5 cases.The clinical classification included 6 cases in T2a stage,2 cases in T2b stage,17 cases in T2c stage,1 case in T3a stage,4 cases in T3b stage and 1 case in T4 stage.SUVmax was accessed by two independent professional nuclear medicine physicians.SUVmax was 12.49 ± 9.38.SPSS 16.0 software was used to do statistic analysis.Results The post-operative pathological results showed the surgical margin positive in 19 cases,negative in 12 cases,vascular positive in 5 cases,negative in 20 case,positive nerve invasion in 20 cases and negative in 11 cases.2 patients were low risk,7 patients were medium risk and 22 patients were high risk according to D'Amico classification.Based on the basis of PSA(≤ 10 or ＞ 10) and Gleason score (≤6 or ＞ 6),6 patients were in group with low PSA and low Gleason score,5 patients were low PSA and high Gleason score,9 patients were high PSA and low Gleason score,11 patients were high PSA and high Gleason score.SUVmax had a significant positive relationship with pathological ISUP (r =0.434,P =0.015) and SUVmax in patients with positive intravascular tumor emboli was significantly higher than those with negative intravascular tumor emboli (14.78 ± 10.68 vs.8.17 ± 2.81,P =0.005).No significant correlation was found between SUVmax and baseline PSA,testosterone,pathologic T stage,surgical margin,nerve invasion,pelvic lymph node status as well as risk stratification.SUVmax could distinguish pathologic ISUP grade 5 with a maximum AUC 0.747 (P =0.033) and the sensitivity was 88.9％.The specificity was 77.3％ when SUVmax ≥ 11.34.SUVmax in patients with upgrading ISUP was significantly higher than that in patients with downgrading ISUP (16.01 ± 5.40 vs.4.98 ± 2.11,P =0.007).Conclusions SUVmax measured on preoperative 68 Ga-PSMA PET-CT may have a clinical significance in predicting unfavorable pathological factors for patients treated with radical prostatectomy.

PET imaging on neurofunctional changes after optogenetic stimulation in a rat model of panic disorder / 医学前沿

Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology. The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD. However, the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo. In this study, optogenetic stimulation to the dPAG was performed to induce panic-like behaviors, and in vivo positron emission tomography (PET) imaging with F-flurodeoxyglucose (F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation. Compared with the baseline, post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P < 0.001) in dPAG, the cuneiform nucleus, the cerebellar lobule, the cingulate cortex, the alveus of the hippocampus, the primary visual cortex, the septohypothalamic nucleus, and the retrosplenial granular cortex but significantly decreased (P < 0.001) in the basal ganglia, the frontal cortex, the forceps minor corpus callosum, the primary somatosensory cortex, the primary motor cortex, the secondary visual cortex, and the dorsal lateral geniculate nucleus. Taken together, these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.

Progress of the application of PET technology in acupuncture research / 中国针灸

To further investigate the application of positron emission tomography (PET) technology in acupuncture research field, with "PET" and "acupuncture" as keywords, the related literature published from 1997 to 2018 was searched in PubMed, CNKI and WANFANG database; then the literature was classified and analyzed. The results showed that in clinical and experimental studies, whether in physiological or pathological conditions, PET technology has verified the specificity of acupoints, bidirectional regulation of acupoints, and the clinical effect of -arrival from the level of brain functional activity. It has deeply revealed the central mechanism underlying that acupuncture has multi-target, multi-channel and multi-level overall effects. The purpose of this study is to provide objective scientific basis for acupuncture research, and then potentially guide the clinical practice.

Progress of Coordination and Utilization of Zirconium-89 for Positron Emission Tomography (PET) Studies / 대한핵의학회잡지

Radiometals have been commonly used in medical applications, and utilization of such metals continues to be an attractive research area. In particular, a variety of radiometals have been developed and implemented for molecular imaging. For such applications, ⁸⁹Zr has been one of the most interesting radiometals currently used for tumor targeting. Several chemical ligands were developed as ⁸⁹Zr chelators, and new coordinating methods have also been developed more recently. In addition, immunopositron emission tomography (PET) studies using ⁸⁹Zr-labeled monoclonal antibodies have been performed by several scientists. In this review, recent advances to the coordination of ⁸⁹Zr and the utilization of ⁸⁹Zr in PET studies are described.

Establishment and characterization of a patient-derived orthotopic xenograft ( PDOX) model of pancreatic cancer / 中国实验动物学报

Objective To establish and evaluate a patient-derived orthotopic xenograft ( PDOX ) model of pancreatic cancer. Methods Tissues of patient-derived pancreatic tumor were transplanted into nude mouse pancreas by surgery. The PDOX models were evaluated by the small animal near infrared fluorescence ( NIRF) optical imaging and PET/CT. The traceability of PDOX models was detected by STR technology, and the pathological changes were observed by H&E staining, immunohistochemistry, and serum level of CA19-9 was detected by ELISA. Results Apparent NIRF were observed to be accumulated in pancreatic site by optical imaging system. The location and size of the xenografts tumor were revealed by fluorescence intensity. The PET/CT images with 18F-FDG molecular probe confirmed the tumor's location and size. Ex vivo NIRF imaging of isolated organ further showed the tumor formation. The traceability of PDOX models was 99. 99% with human origin. H&E staining pathology and immunohistochemistry indicated the pancreatic cancer characteristics. The high serum level of ca19-9 confirmed the mice bearing tumor. Conclusions Pancreatic PDOX models are successfully established in this study, and it can be evaluated comprehensively by NIRF optical imaging and PET/CT, providing an appropriate platform for further research of pancreatic cancer.

Application of Quantitative Indexes of FDG PET to Treatment Response Evaluation in Indolent Lymphoma / 대한핵의학회잡지

PURPOSE: Although ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a standard imaging modality for response evaluation in FDG-avid lymphoma, there is a controversy using FDG PET in indolent lymphoma. The purpose of this study was to investigate the effectiveness of quantitative indexes on FDG PET in response evaluation of the indolent lymphoma.METHODS: Fifty-seven indolent lymphoma patients who completed chemotherapy were retrospectively enrolled. FDG PET/computed tomography (CT) scans were performed at baseline, interim, and end of treatment (EOT). Response was determined by Lugano classification, and progression-free survival (PFS) by follow-up data. Maximumstandardized uptake value (SUV(max)), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured in the single hottest lesion (target A) or five hottest lesions (target B). Their efficacies regarding response evaluation and PFS prediction were evaluated.RESULTS: On EOT PET, SUV(max), and MTVof both targets were well associated with visual analysis. Changes between initial and EOT PET were not significantly different between CR and non-CR groups. On interim PET, SUV(max), and %ΔSUV(max) in both targets were significantly different between CR and non-CR groups. For prediction of PFS, most tested indexes were significant on EOT and interim PET, with SUVmax being the most significant prognostic factor.CONCLUSION: Quantitative indexes of FDG PET are well associated with Lugano classification in indolent lymphoma. SUV(max) measured in the single hottest lesion can be effective in response evaluation and prognosis prediction on interim and EOT PET.

Specific molecular probes in early diagnosis and efficacy monitoring for Alzheimer’s disease: Research advances / 国际药学研究杂志

Alzheimer’s disease AD is the general type of senile dementia, posing a serious harm to the health of the elderly. Making an accurate and reliable diagnosis of AD at the earliest disease stages and evaluating the efficacy of drug in the course of drug treatment of AD is challenging and has become increasingly important. AD is characterized by early neuropathological senile plaque SP deposits and intracellular neurofibrillary tangles NFT in the brain. The studies of specific molecular probes targeted amyloid β Aβ and tau profein play an important role in the early diagnosis, classification of severity and efficacy monitoring of AD.Therefore, many research groups have focused on developing the high specific molecular probes of positron emission tomography PET imaging. In this article, we review the progress and clinical applications of the specific molecular probes of PET imaging in AD.

Molecular Neuroimaging in Posttraumatic Stress Disorder

Over the past decade, an increasing number of neuroimaging studies have provided insight into the neurobiological mechanisms of posttraumatic stress disorder (PSTD). In particular, molecular neuroimaging techniques have been employed in examining metabolic and neurochemical processes in PTSD. This article reviews molecular neuroimaging studies in PTSD and focuses on findings using three imaging modalities including positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance spectroscopy (MRS). Although there were some inconsistences in the findings, patients with PTSD showed altered cerebral metabolism and perfusion, receptor bindings, and metabolite profiles in the limbic regions, medial prefrontal cortex, and temporal cortex. Studies that have investigated brain correlates of treatment response are also reviewed. Lastly, the limitations of the molecular neuroimaging studies and potential future research directions are discussed.

Functional Imaging of Tinnitus / 한양의대학술지

Tinnitus is an auditory phantom characterized by the perception of sound without the presence of an external acoustical source. The peripheral auditory system is considered to contribute to the initiation of tinnitus but only explains the severity and distress level to a limited degree. The neuropsychological models of tinnitus have been developed to explain the pathophysiology of tinnitus as a malfunctioning feedforward/feedback signal in the central neural system including the auditory brainstem, limbic system, auditory cortices, and other anatomical features. Functional neuroimaging techniques have been introduced in recent decades and have provided non-invasive tools to assess the working human brain in vivo. Researchers have found these techniques valuable in examining the neural correlates of tinnitus and have been able to not only support the neuropsychological model but to expand it. Though neuroimaging studies on tinnitus only began in 1990s, they have been increasing exponentially in number. In this review, we investigate the current state of functional neuroimaging studies on tinnitus in humans. The characteristics of commonly used functional neuroimaging techniques including positron emission tomography (PET), functional magnetic resonance imaging (fMRI), electroencephalography (EEG) and magnetoencephalography (MEG) are also discussed. We briefly review recent studies on the tinnitus-brain relationship that have used those research tools.

Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block.

Tomografia por emissão de pósitrons com FDG-18F na avaliação de pacientes com artrite reumatoide - revisão sistemática / Positron emission tomography with 18F-FDG in the evaluation of patients with rheumatoid arthritis - a systematic review

Introdução A artrite reumatoide (AR) é uma doença caracterizada pela inflamação da membrana sinovial. Diversos autores têm investigado o papel da tomografia por emissão de pósitrons (PET) com flúor-18 (FDG-18F) na AR. Objetivos Revisão sistemática da literatura atual sobre o papel do PET com FDG-18F no diagnóstico, determinação da atividade da doença e avaliação da resposta ao tratamento em pacientes com AR. Métodos Foram realizadas buscas nas bases de dados Medline, Biblioteca Cochrane, Lilacs, Pubmed e Scopus nos idiomas português, inglês e espanhol, utilizando as palavras-chave «artrite reumatoide¼, «sinovite¼, «FDG¼, «PET¼, «metabolismo glicolítico¼ e «atividade da doença¼. Resultados 142 artigos foram inicialmente identificados, dos quais apenas 40 relacionavam-se diretamente ao tema. Foram selecionados 12 artigos originais e três relatos de caso que preenchiam os critérios de inclusão. Discussão A presença de fibroblastos e macrófagos ativados no pannus é responsável pela intensa captação periarticular de FDG-18F. Os padrões de captação não permitem o diagnóstico diferencial com outras artrites. A intensidade de captação e o número de articulações envolvidas são parâmetros metabólicos de atividade da doença que apresentam boa correlação com os índices compostos. Estudos longitudinais de PET têm se mostrado úteis na avaliação da resposta ao tratamento com anti-TNF. Quando realizado precocemente, PET pode predizer a resposta terapêutica. Conclusão Embora o real papel dessa nova técnica na investigação da AR ainda não esteja estabelecido, PET com FDG-18F é uma ferramenta ...

Introduction Rheumatoid arthritis (RA) is a disease characterized by inflammation of the synovial membrane. Several authors have investigated the role of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (18F-FDG) in RA. Objectives To systematically review the current literature on the role of 18F-FDG PET in the diagnosis, determination of disease activity and assessment of treatment response in patients with RA. Methods Searches were conducted in Medline, Cochrane Library, Lilacs, Pubmed and Scopus in Portuguese, English and Spanish languages, using the keywords «rheumatoid arthritis¼, «synovitis¼, «FDG¼, «PET¼, «glycolytic metabolism¼ and «disease activity¼. Results One hundred and forty-two articles were initially identified, of which only 40 were related directly to the subject. Twelve original articles and three case reports that met the inclusion criteria were selected. Discussion The presence of activated macrophages and fibroblasts in pannus are responsible for the intense periarticular uptake of 18F-FDG. The uptake patterns do not allow the differential diagnosis with other arthritides. The uptake intensity and the number of joints involved are metabolic parameters of disease activity that correlate well with the composite indices. Longitudinal studies of PET have proven useful in assessing the response to treatment with anti-TNF. When performed early, PET can predict the therapeutic response. Conclusion Although the actual role of this new technique for the investigation of RA is not yet established, 18F-FDG PET is a promising tool in determining the activity and prediction of response to treatment of patients with RA. .

Processamento de estruturas tridimensionais de Medicina Nuclear na modalidade PET / Processing of three-dimensional structures of Nuclear Medicine in PET modality

A Medicina Nuclear, como especialidade de obtenção de imagens médicas é um dos principais procedimentos utilizados hoje nos centros de saúde, tendo como grande vantagem a capacidade de analisar o comportamento metabólico do paciente. Este projeto está baseado em imagens médicas obtidas através da modalidade PET (Positron Emission Tomography). Para isso, foi desenvolvida uma estrutura de processamento de imagens tridimensionais PET, constituída por etapas sucessivas que se iniciam com a obtenção das imagens padrões (gold standard), sendo utilizados para este fim volumes simulados do Ventrículo Esquerdo do Coração criadas como parte do projeto, assim como phantoms gerados com o software NCAT-4D. A seguir, nos volumes simulados é introduzido ruído Poisson que é o ruído característico das imagens PET. Na sequência é executada uma etapa de pré-processamento, utilizando alguns filtros 3D tais como o filtro da mediana, o filtro da Gaussiana ponderada e o filtro Anscombe/Wiener. Posteriormente é aplicada a etapa de segmentação, processo baseado na teoria de Conectividade Fuzzy sendo implementadas quatro diferentes abordagens 3D: Algoritmo Genérico, LIFO, kTetaFOEMS e Pesos Dinâmicos. Finalmente, um procedimento de avaliação conformado por três parâmetros (Verdadeiro Positivo, Falso Positivo e Máxima Distância) foi utilizado para mensurar o nível de eficiência e precisão do processo. Constatou-se que o par Filtro - Segmentador constituído pelo filtro Anscombe/Wiener junto com o segmentador Fuzzy baseado em Pesos Dinâmicos proporcionou os melhores resultados, com taxas de VP e FP na ordem de 98,49 ± 0,27% e 2,19 ± 0,19%, respectivamente, para o caso do volume do Ventrículo Esquerdo simulado. Com o conjunto de escolhas feitas ao longo da estrutura de processamento, encerrou-se o projeto analisando um número reduzido de volumes pertencentes a um exame PET real, obtendo-se a quantificação dos volumes.

The Nuclear medicine, as a specialty to obtain medical images is very important, and it has became one of the main procedures utilized in Health Care Centers to analyze the metabolic behavior of the patient. This project was based on medical images obtained by the PET modality (Positron Emission Tomography). Thus, we developed a framework for processing Nuclear Medicine three-dimensional images of the PET modality, which is composed of consecutive steps that start with the generation of standard images (gold standard) by using simulated images of the Left Ventricular Heart, such as phantoms obtained from the NCAT-4D software. Then, Poisson quantum noise was introduced into the whole volume to simulate the characteristic noises in PET images. Subsequently, the pre-processing step was executed by using specific 3D filters, such as the median filter, the weighted Gaussian filter, and the Anscombe/Wiener filter. Then the segmentation process, which is based on the Fuzzy Connectedness theory, was implemented. For that purpose four different 3D approaches were implemented: Generic, LIFO, kTetaFOEMS, and Dynamic Weight algorithm. Finally, an assessment procedure was used as a measurement tool to quantify three parameters (True Positive, False Positive and Maximum Distance) that determined the level of efficiency and precision of our process. It was found that the pair filter - segmenter formed by the Anscombe/Wiener filter together with the Fuzzy segmenter based on Dynamic Weights provided the best results, with VP and FP rates of 98.49 ± 0.27% and 2.19 ± 0.19%, respectively, for the simulation of the Left Ventricular volume. Along with the set of choices made during the processing structure, the project was finished with the analysis of a small number of volumes that belonged to a real PET test, thus the quantification of the volumes was obtained.

Curent advances and stretegies for reducing the side effects of radiation therapies used for various types of cancers.

Cancer originates from the abnormal expression or activation of positive regulators and functional suppression of negative regulators. The World Health Organization (WHO) estimates that 84 million people will die of cancer between 2005 and 2015 without intervention. Research suggests that one-third of cancer deaths can be avoided through prevention. Major cancer treatment modalities are surgery, radiation therapy and chemotherapy. Radiation therapy is an important cancer treatment method and is used for approximately 50% of all cancer patients with varying success. Therapy uses high-energy waves or particles to destroy cancer cells. It can be used basically for three main reasons: to achieve high radiation dose into tumors; minimizing dose into surrounding normal tissues; to avoid complications as far as possible. The recent advances in this treatment method have led to the improvement in cancer death statistics. It can also be combined with surgery or chemotherapy for better results. This review covers general applications, various side effects/agents and factors affecting to get rid of these effects and strategies to improve radiation therapy.

Adequação de modelo compartimental para exames de tomografia por emissão de pósitrons / Adequacy of compartmental model for positron emission tomography examinations

O presente trabalho objetiva a seleção do modelo compartimental mais adequado ao estudo da dinâmica fisiológica em exames de tomografia por emissão de pósitrons (PET). Para tanto, propõe-se utilizar o critério de informação de Akaike para a seleção do modelo, e a metodologia de equações de sensibilidade e o algoritmo de Levenberg-Marquardt para a tarefa de estimação de parâmetros característicos e, consequentemente, do erro residual da estimativa. São consideradas três estruturas compartimentais compostas, respectivamente, por dois compartimentos e duas constantes características, três compartimentos e quatro constantes características e quatro compartimentos e seis constantes características. Os dados considerados neste trabalho foram sintetizados preocupando-se em reunir as principais características de um exame de tomografia real, tais como tipo e nível de ruído e morfologia de função de excitação do sistema. Aplicando-se a metodologia proposta em três níveis de ruído (baixo, médio e alto), obteve-se concordância do melhor modelo em graus forte e considerável (com índices de Kappa iguais a 0,95, 0,93 e 0,63, respectivamente). Observou-se que, com elevado nível de ruído e modelos mais complexos (quatro compartimentos), a classificação se deteriora devido ao pequeno número de dados para a decisão. Foram desenvolvidos programas e uma interface gráfica que podem ser utilizados na investigação, elaboração, simulação, estimativa de parâmetros e identificação do modelo compartimental para apoio e análise de diagnósticos clínicos e práticas científicas.

The objective of this work is the determination of the most adequate compartmental model for the study of physiological dynamics based on positron emission tomography (PET) exams. We propose the use of Akaike’s information criterion for the optimal model selection, and Levenberg-Marquardt algorithm with sensitivity equations for the task of estimating the characteristic parameters of the differential equations describing the models. We have considered three compartmental structures represented, respectively, by two compartments and two characteristic constants, three compartments and four characteristic constants and four compartments and six characteristics constants. The data considered in this work were synthesized taking into account key features of a real tomography exam, such as type and level of noise and morphology of the input function of the system. Applying the proposed methodology with three noise levels (low, medium and high), we obtained agreement of the best model with strong and considerable degrees (with Kappa indexes equal to  0.95, 0.93 and  0.63, respectively). It was observed that, with high noise level and more complex models (four compartments), the classification is deteriorated due to lack of data for the decision. Programs have been developed and a graphical interface that can be used in research, development, simulation and parameter identification of compartmental models, supporting analysis of clinical diagnostics and scientific practices.

Failure mode, effects and criticality analysis research on human factors in clinical PET application / 中华放射医学与防护杂志

Objective To identify the steps with potentially higher risk through the analysis of human factors in clinical PET application so as to provide the efficient measures to reduce the risk of potential exposures.Methods The basic data were obtained through field investigation, questionnaire,failure mode, risk identification, FMECA and expert's evaluation, with statistical analysis made.Comparison was made of the relative risk values of automatic encapsulation equipment and manual encapsulation ones.Results The 10 steps with potentially higher risks were identified through analyzing human factors of clinical PET application, of which 8 occurred in the phase of chemical synthesis.The measures to control risk were addressed for the steps with higher risk.The results show that the relative risk value of the clinical process with automatic encapsulation equipment was 2.28 ± 0.99 and the one with manual encapsulation equipment was 3.20 ± 2.01 ( t = 2.56, P ＜ 0.05 ), with the latter being 76% of the former.Conclusions Failure mode and FMECA are effective in risk evaluation of clinical PET application, which can provide important basis for risk control.

The Ability of FDG Uptake Ratio and Glut-1 Expression to Predict Mediastinal Lymph Node Metastasis in Resected Non-small Cell Lung Cancer / 대한흉부외과학회지

BACKGROUND: This study was designed to evaluate the FDG uptake ratio of mediastinal node and primary tumors using integrated PET/CT imaging combined with Glut-1 expression of the primary tumor in order to predict the N2 status more accurately in NSCLC patients. MATERIAL AND METHOD: Patients who underwent integrated PET/CT scanning with a detectable mSUV for both primary tumors and mediastinal lymph nodes were eligible for this study. The FDG uptake ratio between the mediastinal node and the primary tumor was calculated. RESULT: The average mSUV of primary tumors and mediastinal nodes were, respectively, 7.4+/-2.2 and 4.2+/-2.2 in N2-positive patients and 7.6+/-3.7 and 2.8+/-6.9 in N2-negative patients. The mean FDG uptake ratio of mediastinal node to primary tumor were 0.58+/-0.23 for malignant N2 lymph nodes and 0.45+/-0.20 for benign lymph nodes (p<0.05). Models which combined Glut-1 expression with an FDG ratio have better diagnostic power than models that use the FDG uptake ratio alone. CONCLUSION: In some patients with a previous history of pulmonary tuberculosis or other inflammatory lung diseases, an FDG uptake ratio combined with Glut-1 expression may be useful in diagnosing mediastinal node metastasis more exactly.