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Objectives: This study aimed to examine the influence of changes in CT values on PET images, specifically focusing on errors in CT-based attenuation correction and scatter coincidence correction (CTAC/SC) caused by gastrointestinal gas. Furthermore, it aimed to demonstrate the effectiveness of time-of-flight (TOF) PET in reducing CTAC/SC errors. Methods: PET images were reconstructed using multiple CT images with varying CT values. The study then compared the fluctuations in pixel values of the PET images corresponding to the different CT values utilized for CTAC/SC between non-TOF and TOF acquisitions. Results: PET pixel values fluctuated with changes in CT values. In the phantom study, TOF showed a significantly smaller change in PET pixel value of 1.00±0.27 kBq/mL compared to 3.72±1.33 kBq/mL in the non-TOF at sites with a CT change of +1000 HU. In the patient study, a linear regression analysis was performed to determine the effect of changes in CT values due to gastrointestinal gas migration on standard uptake value (SUV).The results showed that the TOF group had a lower ratio of change in SUV to change in CT values compared to the non-TOF group. These findings revealed that PET pixel values exhibited fluctuations in response to changes in CT values, and TOF-PET effectively mitigated CTAC/SC errors arising from gastrointestinal gas. Conclusions: TOF-PET has the potential to reduce the occurrence of suspicious accumulation.
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High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HDC/ASCT) has been useful in relapsed or refractory classic Hodgkin lymphoma (RRcHL). Furthermore, a ranimustine, cytarabine, etoposide, and cyclophosphamide (MCVAC) conditioning regimen has been effective in diffuse large B-cell lymphoma. However, limited data are available regarding this conditioning regimen for cHL. In this study, we investigated the efficacy and toxicity of MCVAC for RRcHL. We retrospectively analyzed 10 patients with RRcHL who underwent ASCT preceded by the MCVAC conditioning regimen between January 2009 and December 2021 at our institution. A total of 10 patients (median [range] age, 36 [23-64] years), including 5 (50%) men and 5 (50%) women, were treated with the MCVAC regimen followed by ASCT. The median follow-up duration of the 10 patients was 25.0 months. The 36-month PFS and OS rates were 43.8% (95% CI, 11.9%-72.6%) and 64.0% (95% CI, 22.6%-87.5%), respectively. Two patients died because of treatment-related factors, and one patient died because of disease progression. Based on our findings, recognizing the risk factors for adverse events (AEs) associated with this treatment, MCVAC may be a valid treatment option for the management of RRcHL.
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Nocardia infections have been reported to occur in immunocompromised patients. Early diagnosis and therapeutic intervention are especially important for disseminated nocardiosis because of its high mortality rate. A case of disseminated nocardiosis after allogeneic hematopoietic stem cell transplantation, which was promptly treated after identification of the organism by genetic analysis, is presented. A 43-year-old man was diagnosed with T-cell prolymphocytic leukemia and underwent allogeneic hematopoietic stem cell transplantation. Subsequently, during long-term prednisolone administration for chronic graft-versus-host disease, he developed mass lesions throughout his body at 1033 days after transplantation. Pus culture and genetic testing of the parotid mass showed Nocardia farcinica, which improved with treatment with sulfamethoxazole, trimethoprim, and imipenem cilastatin, and there has been no recurrence. When multiple mass lesions occur after hematopoietic stem cell transplantation, and the diagnosis is difficult, disseminated nocardiosis should be included in the differential diagnosis, and appropriate laboratory testing and treatment should be performed.
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BACKGROUND: It is important to understand the career motivations and perceptions of students who intend to become dental health professionals. Both dental and dental hygiene students may have different opinions about the profession and future work prospects. To our knowledge, no study has compared the career motivations and career perceptions of Japanese dental and dental hygiene students after admission to dental or dental hygiene school. This cross-sectional study examined the motivations of dental and dental hygiene students for their future career perceptions. METHODS: First-year students of dental and dental hygiene schools in the academic years 2021 and 2022 participated in the study. Group 1 comprised 104 female dental hygiene students, Group 2-1 comprised 55 female dental students, and Group 2-2 comprised 61 male dental students. A self-administered questionnaire survey was conducted on opinions of the work and prospects of future work with four-point Likert scales ranging from "strongly agree" to "strongly disagree," according to the items. RESULTS: Dental hygiene students consider that they would like to work as professionals and would also like to earn efficiently. Specifically, female dental students prioritized contributing to society by working long-term in a fulfilling environment rather than earning an income, whereas male dental students would like to work as a professional while also effectively earning income. CONCLUSIONS: Small but significant differences were found in opinions of the dental hygienist/dentist profession in terms of attractiveness and credibility. Small but significant differences were found for income and working hours when considering future job prospects. The results of this study revealed differences in the first year students between dental and dental hygiene school in their attitudes toward career motivation and prospects for future work.
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Motivação , Estudantes de Odontologia , Humanos , Masculino , Feminino , Estudos Transversais , Faculdades de Odontologia , Japão , Higiene Bucal , Escolha da Profissão , Inquéritos e QuestionáriosRESUMO
Respiration gating is used in PET to prevent image quality degradation due to respiratory effects. In this study, we evaluated a type of data-driven respiration gating for continuous bed motion, OncoFreeze AI, which was implemented to improve image quality and the accuracy of semiquantitative uptake values affected by respiratory motion. Methods: 18F-FDG PET/CT was performed on 32 patients with lung lesions. Two types of respiration-gated images (OncoFreeze AI with data-driven respiration gating, device-based amplitude-based OncoFreeze with elastic motion compensation) and ungated images (static) were reconstructed. For each image, we calculated SUV and metabolic tumor volume (MTV). The improvement rate (IR) from respiration gating and the contrast-to-noise ratio (CNR), which indicates the improvement in image noise, were also calculated for these indices. IR was also calculated for the upper and lower lobes of the lung. As OncoFreeze AI assumes the presence of respiratory motion, we examined quantitative accuracy in regions where respiratory motion was not present using a 68Ge cylinder phantom with known quantitative accuracy. Results: OncoFreeze and OncoFreeze AI showed similar values, with a significant increase in SUV and decrease in MTV compared with static reconstruction. OncoFreeze and OncoFreeze AI also showed similar values for IR and CNR. OncoFreeze AI increased SUVmax by an average of 18% and decreased MTV by an average of 25% compared with static reconstruction. From the IR results, both OncoFreeze and OncoFreeze AI showed a greater IR from static reconstruction in the lower lobe than in the upper lobe. OncoFreeze and OncoFreeze AI increased CNR by 17.9% and 18.0%, respectively, compared with static reconstruction. The quantitative accuracy of the 68Ge phantom, assuming a region of no respiratory motion, was almost equal for the static reconstruction and OncoFreeze AI. Conclusion: OncoFreeze AI improved the influence of respiratory motion in the assessment of lung lesion uptake to a level comparable to that of the previously launched OncoFreeze. OncoFreeze AI provides more accurate imaging with significantly larger SUVs and smaller MTVs than static reconstruction.
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Neoplasias Pulmonares , Técnicas de Imagem de Sincronização Respiratória , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Respiração , Tomografia por Emissão de Pósitrons/métodos , Pulmão , Movimento (Física) , Fluordesoxiglucose F18 , Técnicas de Imagem de Sincronização Respiratória/métodosRESUMO
A 76-year-old woman with leukocytosis and thrombocytopenia was admitted to our hospital. A bone marrow examination showed a composition of 82.0% blasts, i.e., positive for TdT, CD10, CD19, CD34, and HLA-DR and negative for cyCD3, CD13, CD33, MPO, and cyµ. The reverse transcription-polymerase chain reaction analysis revealed a minor BCR-ABL1 fusion gene, leading to a diagnosis of acute lymphocytic leukemia (ALL) with a BCR-ABL1 fusion gene. G-band assay was negative for Philadelphia (Ph) chromosome and also revealed add (21) (q22. 1) and del (20) (q11. 2q13.3). Fluorescence in situ hybridization (FISH) assaying revealed a positive BCR-ABL1 fusion signal. Thus, this patient was diagnosed as Ph chromosome-negative and BCR-ABL1-positive fusion gene ALL, which suggested the presence of ALL with the "masked" Ph chromosome found in approximately 1% of chronic myeloid leukemia. Therefore, the FISH analysis may complement cytogenetic analysis when cytogenetic and molecular genetic findings are contradictory in ALL.
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Cromossomo Filadélfia , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Hibridização in Situ Fluorescente , Citogenética , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genéticaRESUMO
Background: There is no phantom for image quality test in magnetic resonance imaging combined with positron emission tomography systems (PET/MRI systems). In MRI, radioactive water phantom containing 2-deoxy-2-[F-18] fluoro-D-glucose (18F-FDG) cannot be used due to the dielectric effect. Even for phantoms filled with MR-available solutions, the source current of the RF coil is strongly disturbed as the diameter of the phantom increases. Stable MR images require proper phantom size and solution selection. Previous reports have not provided these details. Other than that, few existing phantoms evaluate negative signals such as N-13 ammonia (13N-NH3). We created a phantom for PET/MRI system for image quality test. Methods: The phantom for the PET/MRI system was assembled in two portions. One portion is a signal part containing 18F-FDG radioactive water. The other portion is filled with polyvinyl alcohol glue to construct MRI image to generate µ-map. The glue part is allowed to rewrite the table position overlaps with the first layer, and attenuation correction is performed. Signals are set as positive (4 times and twice higher than background radioactivity) and negative (no radioactivity) columns with different sizes (15 mm φ and 7 mm φ). The PET images with X-ray computed tomography-based attenuation correction (CT-AC) and MRI-AC were evaluated by %-contrasts, variation and uniformity. Results: The %-contrasts of the positive shallow signals with PET/magnetic resonance (MR) and PET/CT were 41.8% and 45.4%, respectively. And it of the positive deep signals with PET/MR and PET/CT were 40.7% and 44.9%. On the other hand, the %-contrasts of the negative shallow signals with PET/MR and PET/CT were 62.3% and 65.6%, respectively. And it of the negative deep signals with PET/MR and PET/CT were 60.7% and 63.7%. Moreover, the % Nj index of uniformity was 2.0% on PET/MRI images and 0.34% on PET/CT images. For negative signals that assume a decrease in myocardial blood flow, The image quality of MR-AC was almost the same as that of CT-AC. Consistency between the images after CT-AC and MR-AC correction were confirmed, and in particular, a stable MR-AC µ-map was obtained in the phantom study. Conclusion: The suggested prototype phantom for generating µ-map is reasonable and useful for evaluating PET/MRI image quality, based on the present standard.
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A 62-year-old woman was presented at our hospital with visual disturbance. An ocular examination revealed bilateral Roth spots. Laboratory data revealed leukocytosis (236,200 µl) with an excess blast (11%). Physical examination and computed tomography (CT) showed systemic lymphadenopathy. A bone marrow examination revealed a composition of 9.2% blast. Chromosomal analysis on bone marrow cells revealed 46,XX,t (3;12)(q26.2;p13),t (9;22)(q34.1;q11.2) in 80% of metaphases (16/20). Inguinal lymph node biopsy revealed diffuse proliferation of myeloperoxidase (MPO)-positive abnormal cells. Fluorescence in situ hybridization analysis was used to detect the BCR-ABL1 fusion gene and split the signals of MECOM and ETV6. She was diagnosed with de-novo chronic myeloid leukemia (CML) extramedullary blast crisis. She received tyrosine kinase inhibitor (TKI) combination chemotherapy and allogeneic hematopoietic stem cell transplantation and achieved a major molecular response. In this study, we reported a case of CML in blast-phase initially presenting as extramedullary, in which cytogenetic and molecular analyses were useful in the staging method.
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Crise Blástica , Leucemia Mielogênica Crônica BCR-ABL Positiva , Feminino , Humanos , Pessoa de Meia-Idade , Crise Blástica/genética , Crise Blástica/patologia , Hibridização in Situ Fluorescente , Leucemia Mielogênica Crônica BCR-ABL Positiva/diagnóstico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Análise Citogenética , Linfonodos/patologiaRESUMO
Coronavirus disease 2019 (COVID-19) has spread around the world. Its effects go far beyond health care: education has to be conducted so as to prevent infection among students and faculty. Accordingly, changes have occurred in Japan's educational institutions, including methods of preparing students for examinations for nuclear medicine. To assess the quality of training for radiologic technologists, we investigated the related changes undertaken at educational institutions. We investigated the lecture format for teaching nuclear medicine technology at Japanese institutions during COVID-19 and efforts to ensure the quality of conventional education. Methods: We sent a questionnaire to 19 Japanese institutions. It addressed the lecture format and initiatives in examinations for nuclear medicine technology in the first and second semesters of 2020. Results: We obtained responses from 17 institutions. In the first semester of 2020, the lecture format for nuclear medicine technology included remote, hybrid (combination of remote and face-to-face), and video-on-demand lectures. To reinforce the effect of the new teaching formats, institutions adopted various methods, such as enhancing the possibility of allowing students to ask questions, increasing the number of quizzes during lectures, delivering lectures to YouTube, and introducing an e-learning system. In the second semester of 2020, the lecture format included face-to-face, remote, hybrid, and video-on-demand lectures. In that second semester, the number of institutions providing face-to-face lectures while taking thorough measures against infection showed a marked increase. Conclusion: The institutions introduced various educational techniques and initiatives. They prioritized students' understanding of lecture content and applied what they considered the best teaching methods. Sharing information about the changes adopted at different institutions should help promote good radiologic technologists-even during a pandemic.
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COVID-19 , Medicina Nuclear , Humanos , Japão , Pandemias/prevenção & controle , SARS-CoV-2 , Inquéritos e Questionários , TecnologiaRESUMO
Variable-speed continuous bed motion 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT), a reliable imaging technique, allows setting the bed motion speed for arbitrary sections of the body. The purpose of this study was to evaluate the relationship between the PET image quality and the bed speed following shortening of the scanning time for the lower extremities to achieve whole-body acquisition optimization of the examination time. Four sets of images were created by editing four-phase dynamic whole-body PET/CT images acquired at a bed speed of 6 and 14 mm/s in the trunk and lower extremities, respectively. The signal-to-noise ratio (SNR) was calculated using regions of interest in the liver, gluteus muscles, thigh, and lower legs, and the relationship between the bed speed and the SNR was assessed. The number of patients with findings in the lower extremities among 967 cases was evaluated. Based on this relationship between the SNR and bed motion speed, it is reasonable to increase the speed of the lower extremities by up to three times that of the trunk. The findings from whole-body FDG-PET imaging revealed that the number of patients with detected lesions in the lower extremities was 6.6% (64/967), bone metastases were found in 2.6%, soft lesions in 1.8%, and inflammation in 2.3%. Images of the lower extremities, which have a better SNR than the trunk, can be acquired at a faster bed speed using the variable-speed continuous bed motion PET.
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Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Imagem Corporal Total , Fluordesoxiglucose F18 , Humanos , Extremidade Inferior/diagnóstico por imagem , Tomografia por Emissão de PósitronsRESUMO
PURPOSE: The aim of this study was to clarify the artifacts that occurred in the non-activity signal with computed tomography (CT)-based attenuation correction (CTAC) error due to image misregistration. METHODS: We used a cylindrical phantom containing a test tube with a diameter of 15 mm as the non-activity signal part. Positron emission tomography (PET) images were acquired for 30 minutes using the phantom with water in the non-activity signal part and 18F-fluoro-2-deoxy-d-glucose (18F-FDG) (5.3 kBq/ml) in the background area. CT scanning was performed by replacing the water with contrast agents at different dilutions to obtain arbitrary CT numbers (-1000 to 1000). The PET images were attenuation-corrected individually by the CT images in which the CT number of the non-activity signal part had changed. The relationship between the CT numbers and the CTAC artifact was determined by measuring the PET value in the non-activity signal part of the PET images and comparing Ci. RESULTS: As the CT number of the CT images increased, Ci of the artifact increased. The CT number and Ci had a correlation of y=1.48x+2.86×103 (R2 =0.99) when CTAC was performed in units of CT numbers above 0 for PET data of water (0 HU) and a correlation of y=3.15x+6.26×103 (R2 =0.97) when CTAC was performed in units of CT numbers below 0 for PET data of air (-1000 HU). Although the original CT image was air, the artifacts due to CTAC errors with different Hounsfield units showed larger changes. In particular, positive artifacts were recognized in the PET images after CTAC depending on the Hounsfield units. CONCLUSIONS: When the CT number was different from the original in CTAC, the PET value was different. CTAC should be performed with caution as there may be image misregistration.
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Artefatos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios XRESUMO
The number of patients with the extremely rare disease gastroenteropancreatic (GEP) neuroendocrine tumor (NET) has increased rapidly in recent years. 111In-pentetreotide SPECT in somatostatin receptor scintigraphy has been used for the assessment of GEP NET patients. To diagnose GEP NET, appropriate selection of image correction parameters is critical. Correction methods may improve the 111In-pentetreotide SPECT image quality, but there is currently no standard technique. The purpose of this study was to determine the optimal correction parameter settings for 111In-pentetreotide SPECT. Methods: A phantom study produced images with a tumor-to-background ratio of as high as 16:1. A triple energy window was used for scatter correction (SC), and attenuation correction (AC) was CT-based. Correlation analysis was performed in 4 groups: no correction (NC), SC, AC, and combined SC with AC (CC). The 111In-pentetreotide SPECT results for 20 randomly selected patients (13 men and 7 women; age range, 37-81 y) with confirmed GEP NET were analyzed using data collected 4 h after injection of 111 MBq of 111In-pentetreotide. Emission data were reconstructed using ordered-subset expectation maximization (OSEM) with different settings. Different combinations of the correction parameters were used to analyze the contrast-to-noise ratios (CNRs) obtained with the phantom. In the clinical study, 20 GEP NET patients were used to evaluate the GEP NET lesion CNR by 4 different image correction methods obtained from 111In-pentetreotide SPECT images: NC, SC, AC, and CC. NC was used as a reference method. Results: The phantom study revealed that the optimal energy window in the photopeak for somatostatin receptor scintigraphy was 171 keV ± 10% and 245 keV ± 7.5%, and the optimal OSEM reconstruction conditions were 8 subsets and 6 iterations. Among the OSEM collection conditions, CC produced a significantly higher CNR than NC or SC (P < 0.05). In the clinical study, CC was found to increase the CNR (P < 0.05). Conclusion: CC improves the correction in 111In-pentetreotide SPECT studies, compared with NC, providing better contrast and sharper outlines of lesions and organs.
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Neoplasias Intestinais/diagnóstico por imagem , Tumores Neuroendócrinos/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Somatostatina/análogos & derivados , Neoplasias Gástricas/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: I-123-ioflupane single photon emission computed tomography (FP-CIT-SPECT) has been used to assess dopamine transporter (DAT) loss in Parkinson's disease. The specific binding ratio (SBR), a quantitative parameter of DAT density in the striatum, may be affected by differences in age, sex, and SPECT system. The purpose of this study was to evaluate the utility of FP-CIT-SPECT using the Japanese normal database (NDB) in the diagnosis of Parkinson's disease. METHODS: To standardize the quantitative outcome measures of DAT density obtained with different SPECT systems, striatal phantoms filled with striatal to background materials at ratios between 8:1 and 1:1 were measured using a gamma camera (ECAM) in our institute. Consecutive fifty patients (23 men and 27 women; age range, 40-86 years) with suspected PD undergoing FP-CIT SPECT brain imaging during the period from April to October 2016 were enrolled in this retrospective study. Their final diagnoses were PD in 28 patients and PD in 22 patients. SBRs of the patients were calculated using either new (Japanese database with different age and sex; NEWver) or old (non-Japanese database not specifying age and sex; OLDver) version software (AZE Virtual Place Hayabusa [DaTView], AZE, Ltd. Tokyo, Japan). The McNemar test was used to compare the diagnostic accuracy between old and new versions. RESULTS: Based on the phantom study, the calibrated SBR could be calculated by Y=1.25×Measured SBR+0.78. The sensitivities for OLDver and NEWver were 100% and 93%, respectively (p=0.5), and the specificities were 55% and 100% (p=0.002). The diagnostic accuracy of NEWver (96%) was better than that of OLDver (80%, p<0.001). CONCLUSION: FP-CIT-SPECT using the Japanese NDB improved the diagnostic accuracy of PD by improving specificity.
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Regressive lymphoproliferative disorders (R-LPD) after methotrexate (MTX) withdrawal are one of the specific features of methotrexate - associated lymphoproliferative disorders (MTX-LPD). Although the impact of the absolute lymphocyte count (ALC) on the pathogenesis of R-LPD has been recently emphasized, understanding relapse/regrowth events (RRE) and differences among LPD subtypes is necessary. In this study, we confirmed ALC recovery in the regressive group (R-G; R-LPD without RRE) and relapse/regrowth group (R/R-G; R-LPD with RRE). The increase in ALC lasted at least 2 years in R-G, whereas it decreased within 3 years in R/R-G, supporting the better overall survival (OS) in R-G, as previously reported. In addition, our study suggested that an ALC of 1000/µL at the time of development of LPD is a significant predictor for treatment-free survival (TFS). Furthermore, an ALC of 1000/µL at 6 months after MTX withdrawal was found to be a significant indicator of TFS and OS for R-G and R/R-G. The ALC decreased gradually before LPD development in R/R-G, whereas it decreased 6 months before LPD development in R-G, confirming the important role of ALC in the pathogenesis of MTX-LPD such as regressive events and RRE. In addition to ALC, other predictive factors, such as serum C-reactive protein and soluble interleukin-2 receptors, may be helpful in the management of MTX-LPD, including the decision making for an additional chemotherapy for regressive LPD after MTX withdrawal.
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Antirreumáticos/efeitos adversos , Transtornos Linfoproliferativos/induzido quimicamente , Metotrexato/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Antirreumáticos/uso terapêutico , Artrite Reumatoide/complicações , Artrite Reumatoide/tratamento farmacológico , Feminino , Humanos , Contagem de Linfócitos , Transtornos Linfoproliferativos/sangue , Transtornos Linfoproliferativos/diagnóstico , Masculino , Metotrexato/uso terapêutico , Pessoa de Meia-Idade , Prognóstico , Estudos RetrospectivosRESUMO
To date, there have been 160 regulatory approvals for environmental safety in Japan for the major genetically modified (GM) crops, including corn, soybean, canola and cotton. Confined field trials (CFTs) have been conducted in Japan for all single events, which contain various traits. The accumulated information from these previously conducted CFTs, as well as the agronomic field study data from other countries, provides a rich source of information to establish "familiarity" with the crops. This familiarity can be defined as the knowledge gained through experience over time, and used to inform the environmental risk assessments (ERA) of new GM crops in Japan. In this paper, we compiled agronomic data from the CFTs performed in Japan for 11 GM soybean events which obtained food, feed and environmental safety approvals from regulatory agencies in Japan. These CFTs were conducted by multiple developers according to Japan regulations to support the ERA of these GM soybean, covering standard measurement endpoints evaluated across developers in Japan. With this dataset, we demonstrate how familiarity gained from the CFTs of GM soybeans in Japan can be used to inform on the ERA of new GM soybean events. By leveraging this concept of familiarity, we discuss potential enhancements to the ERA process for GM soybean events in Japan.
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Produtos Agrícolas/genética , Exposição Ambiental/prevenção & controle , Alimentos Geneticamente Modificados/normas , Glycine max/genética , Plantas Geneticamente Modificadas/efeitos adversos , Medição de Risco/métodos , Qualidade de Produtos para o Consumidor , Produtos Agrícolas/crescimento & desenvolvimento , Humanos , Japão , Glycine max/crescimento & desenvolvimentoRESUMO
Time-course study of individual dose equivalents of 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography (18F-FDG PET) was conducted in different hospital workers, and the daily work duties were analyzed. For the measurements, a semiconductor dosimeter was used. The values at intervals of 1 min and 1 h, the monthly cumulative and daily cumulative doses, and trend graphs were acquired with dedicated software and displayed on the reader. The following radiation workers with duties involving maximum external exposure work were included: doctors making diagnoses (4.8 µSv/procedure), nurses removing injection needles (3.1 µSv/procedure), pharmacists performing quality control tests (2.9 µSv/procedure), nuclear medicine technologists assisting patient positioning (6.5 µSv/procedure), and cyclotron engineers performing daily checks (13.4 µSv/procedure). The results of analysis of daily work duties revealed the influencing factors of external exposure dose. To reduce the external exposure dose, investigators should shorten the patient's contact time with the 18F-FDG source or patient tracer.
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Tomografia por Emissão de Pósitrons , Monitoramento de Radiação/instrumentação , Radiometria/métodos , Ciclotrons , Campos Eletromagnéticos , Fluordesoxiglucose F18 , Humanos , Medicina Nuclear , Exposição Ocupacional/análise , Segurança do Paciente , Doses de Radiação , Monitoramento de Radiação/métodos , Semicondutores , Fatores de TempoRESUMO
Although it may not be well known, the Annals of Nuclear Medicine (ANM) Editorial Committee includes one specialty editor of nuclear medicine physics, one of nuclear medicine technology, one of molecular imaging, and two of radiopharmacology. In addition, a statistics editor and a language editor are also on the committee. Manuscripts submitted to ANM can be peer-reviewed by such specialty editors similar to those submitted to highly ranked journals, which is a great pride and joy to us. To offer our readers a condensed global view on the high-quality research work in the field of nuclear medicine, we have published a mini-review article every year under the joint authorship of the ANM associate editors since 2016. This is our fourth serial review article written by the ANM specialty editors from their respective expert viewpoints.
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Medicina Nuclear , Biofísica , Humanos , Publicações Periódicas como Assunto , Tomografia por Emissão de Pósitrons , Radiometria , Compostos Radiofarmacêuticos/uso terapêuticoRESUMO
Human parvovirus B19 (HPV-B19) causes hemophagocytic lymphohistiocytosis (HLH). Here we describe a 35-year-old female with hereditary spherocytosis (HS) who developed HLH due to HPV-B19 infection. Upon admission, she had high fever and diarrhea. Laboratory findings included severe pancytopenia and elevated serum triglyceride and ferritin levels. Moreover, high HPV-B19 levels in the peripheral blood and increased reactive lymphocytosis in the bone marrow led to a diagnosis of HLH due to HPV-B19 infection. With supportive therapy and a blood transfusion, HLH symptoms, including fever and myelosuppression, improved in 1 week. However, symptoms of heart failure (HF) suddenly developed, and an echocardiography revealed diffuse systolic dysfunction, suggesting viral myocarditis due to HPV-B19 infection. Conservative management with diuretics gradually improved HF symptoms over a period of 2 weeks. HPV-B19 infection in adult patients with HS rarely results in severe HLH, but conservative therapy may improve the symptoms. Nonetheless, a careful follow-up is required after HLH improves because viral myocarditis can develop, as was seen in our patient.
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Linfo-Histiocitose Hemofagocítica/virologia , Miocardite/virologia , Infecções por Parvoviridae/diagnóstico , Parvovirus B19 Humano , Esferocitose Hereditária , Adulto , Feminino , Humanos , Infecções por Parvoviridae/complicaçõesRESUMO
The bone scan index (BSI) is calculated from a whole-body bone scan image; it shows the tumor burden in bone as a percentage of total skeletal mass. It has been used to determine the prognosis and to assess treatment effects; however, little has been reported on whether the BSI calculated using a two-dimensional image can accurately evaluate the three-dimensional spread in tumor volume. We investigated the relationship between tumor volume and BSI using Monte Carlo simulation (MCS). We simulated a gamma camera and constructed a voxel phantom based on an anthropomorphic phantom computed tomography (CT) image and gamma rays emitted from each part according to technetium-99m-labeled methylene diphosphonate (99mTc-MDP) uptake (bone 1, soft tissue 0.2, tumor 2-32). We constructed bone scan images from the obtained counts and analyzed them using the BSI calculation software. The BSI increased with increased tumor uptake (two- to 32-fold). However, there was not always a significant difference between change in BSI and tumor uptake of eight times or greater than that of bone. When BSI was calculated with a tumor having an uptake of four-to-eight times higher than that of bone, the BSI was consistent with tumor volume, but decreased to about half the tumor volume when tumors were in the thoracic spine (Th-spine) segment. The BSI can be a good indicator of tumor volume in most segments, even though it is affected by the tumor's 99mTc-MDP uptake. Nevertheless, values calculated from the Th-spine should be interpreted carefully.
Assuntos
Neoplasias Ósseas/patologia , Método de Monte Carlo , Imagens de Fantasmas , Cintilografia/métodos , Neoplasias da Coluna Vertebral/patologia , Imagem Corporal Total/métodos , Neoplasias Ósseas/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias da Coluna Vertebral/diagnóstico por imagem , Medronato de Tecnécio Tc 99m , Carga TumoralRESUMO
Recently, attention has been focused on methotrexate-induced lymphoproliferative disease (MTX-LPD), and atypical phenotypes are occasionally documented. We encountered two patients with rheumatoid arthritis (RA) who were diagnosed with non-specific LPD (LPD-nos). Biopsy samples were not obtained during the initial examination when the LPD development was discovered, and the patients achieved a complete response after MTX cessation (case 1) or steroid pulse therapy (case 2). However, the tumors flared up 1.5 years later, and LPD-nos was determined following biopsies of the lymph node (LN, case 1) and liver (case 2). Prednisolone was subsequently administered instead of chemotherapy; however, multiple masses, including in the spine (case 1), and severe icterus with liver dysfunction (case 2) were exacerbated within a few months. Although the re-biopsy of LN proved the presence of HL and radiation followed by aggressive chemotherapy rescued the patient (case 1), the superficially accessible biopsy site was not found, and autopsy finally revealed HL (case 2). In both cases, the underlying pathogenesis along with the B symptoms and laboratory abnormalities suggested MTX-LPD, HL in particular. Therefore, even if the pathological diagnosis does not confirm the specific LPD subtype, the administration of aggressive chemotherapy should be considered if the LPD activity flares severely.