Abstract: Scintillators are high-density luminescent materials that convert X-rays to visible light. Thallium doped cesium iodide (CsI:Tl) scintillation materials are widely used as converters for X-rays into visible light, with very high conversion efficiency of 64.000 optical photons/MeV. CsI:Tl crystals are commercially available, but, the possibility of developing these crystals into different geometric shapes, meeting the need for coupling the photosensor and reducing cost, makes this material very attractive for scientific research. The objective of this work was to study the feasibility of using radiation sensors, scintillators type, developed for use in imaging systems for X-rays. In this paper, the CsI:Tl scintillator crystal with nominal concentration of the 10−3 M was grown by the vertical Bridgman technique. The imaging performance of CsI:Tl scintillator was studied as a function of the design type and thickness, since it interferes with the light scattering and, hence, the detection efficiency plus final image resolution. The result of the diffraction X-ray analysis in the grown crystals was consistent with the pattern of a face-centered cubic (fcc) crystal structure. Slices 25 × 2 × 3 mm3 (length, thickness, height) of the crystal and mini crystals of 1 × 2 × 3 mm3 (length, thickness, height) were used for comparison in the imaging systems for X-rays. With these crystals scintillators, images of undesirable elements, such as metals in food packaging, were obtained. One-dimensional array of photodiodes and the photosensor CCD (Coupled Charge Device) component were used. In order to determine the ideal thickness of the slices of the scintillator crystal CsI:Tl, Monte Carlo method was used.

Palavras-Chave: cesium iodides; doped materials; thallium ions; crystal growth; phosphors; image processing; photodiodes; charge-coupled devices

PEREIRA, MARIA da C.C.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; MESQUITA, CARLOS H. de. Characteristics of the CsI:Tl scintillator crystal for X-Ray imaging applications. Materials Sciences and Applications, v. 9, n. 2, p. 268-280, 2018. DOI: 10.4236/msa.2018.92018. Disponível em: http://repositorio.ipen.br/handle/123456789/28986. Acesso em: $DATA.

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Abstract: The retrieval of the extinction coefficients of aerosols and clouds without assumptions is the most important advantage of the high-spectral-resolution lidar (HSRL). The standard method to retrieve the extinction coefficient from HSRL signals depends heavily on the signal-to-noise ratio (SNR). In this work, an iterative image reconstruction (IIR) method is proposed for the retrieval of the aerosol extinction coefficient based on HSRL data, this proposed method manages to minimize the difference between the reconstructed and raw signals based on reasonable estimates of the lidar ratio. To avoid the ill-posed solution, a regularization method is adopted to reconstruct the lidar signals in the IIR method. The results from Monte-Carlo (MC) simulations applying both standard and IIR methods are compared and these comparisons demonstrate that the extinction coefficient and the lidar ratio retrieved by the IIR method have smaller root mean square error (RMSE) and relative bias values than the standard method. A case study of measurements made by Zhejiang University (ZJU) HSRL is presented, and their results show that the IIR method not only obtains a finer structure of the aerosol layer under the condition of low SNR, but it is also able to retrieve more reasonable values of the lidar ratio.

Palavras-Chave: optical radar; aerosols; monte carlo method; signal-to-noise ratio; iterative methods; image processing; climatic change; scattering

XIAO, DA; WANG, NANCHAO; SHEN, XUE; LANDULFO, EDUARDO; ZHONG, TIANFEN; LIU, DONG. Development of ZJU high-spectral-resolution lidar for aerosol and cloud: extinction retrieval. Remote Sensing, v. 12, n. 18, p. 1-18, 2020. DOI: 10.3390/rs12183047. Disponível em: http://200.136.52.105/handle/123456789/31652. Acesso em: $DATA.

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Abstract: Exposure to environmental tobacco smoke (ETS) is associated with high morbidity and mortality, mainly in childhood. Our aim was to evaluate the effects of postnatal ETS exposure in the brain 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) uptake of mice by positron emission tomography (PET) neuroimaging in a longitudinal study. C57BL/6J mice were exposed to ETS that was generated from 3R4F cigarettes from postnatal day 3 (P3) to P14. PET analyses were performed in male and female mice during infancy (P15), adolescence (P35), and adulthood (P65). We observed that ETS exposure decreased 18F-FDG uptake in the whole brain, both left and right hemispheres, and frontal cortex in both male and female infant mice, while female infant mice exposed to ETS showed decreased 18F-FDG uptake in the cerebellum. In addition, all mice showed reduced 18F-FDG uptake in infancy, compared to adulthood in all analyzed VOIs. In adulthood, ETS exposure during the early postnatal period decreased brain 18FFDG uptake in adult male mice in the cortex, striatum, hippocampus, cingulate cortex, and thalamus when compared to control group. ETS induced an increase in 18F-FDG uptake in adult female mice when compared to control group in the brainstem and cingulate cortex. Moreover, male ETS-exposed animals showed decreased 18F-FDG uptake when compared to female ETS-exposed in the whole brain, brainstem, cortex, left amygdala, striatum, hippocampus, cingulate cortex, basal forebrain and septum, thalamus, hypothalamus, and midbrain. The present study shows that several brain regions are vulnerable to ETS exposure during the early postnatal period and these effects on 18F-FDG uptake are observed even a long time after the last exposure. This study corroborates our previous findings, strengthening the idea that exposure to tobacco smoke in a critical period interferes with brain development of mice from late infancy to early adulthood.

Palavras-Chave: tobacco; tobacco smokes; nicotiana; environment; image processing; positron computed tomography; uptake; fluorodeoxyglucose; mice; glucose; longitudinal momentum; brain; children; nerve cells

TORRES, LARISSA H.; REAL, CAROLINE C.; TURATO, WALTER M.; SPELTA, LÍDIA W.; DURÃO, ANA C.C. dos S.; ANDRIOLI, TATIANA C.; POZZO, LORENA; SQUAIR, PETERSON L.; PISTIS, MARCO; FARIA, DANIELE de P.; MARCOURAKIS, TANIA. Environmental tobacco smoke during the early postnatal period of mice interferes with brain 18F-FDG uptake from infancy to early adulthood: a longitudinal study. Frontiers in Neuroscience, v. 14, p. 1-11, 2020. DOI: 10.3389/fnins.2020.00005. Disponível em: http://repositorio.ipen.br/handle/123456789/31363. Acesso em: $DATA.

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Abstract: Monoclonal antibodies as polymeric nanoparticles are quite interesting and endow this new drug category with many advantages, especially by reducing the number of adverse reactions and, in the case of radiopharmaceuticals, also reducing the amount of radiation (dose) administered to the patient. In this study, a nanoradiopharmaceutical was developed using polylactic acid (PLA)/polyvinyl alcohol (PVA)/montmorillonite (MMT)/trastuzumab nanoparticles labeled with technetium-99m (99mTc) for breast cancer imaging. In order to confirm the nanoparticle formation, atomic force microscopy and dynamic light scattering were performed. Cytotoxicity of the nanoparticle and biodistribution with 99mTc in healthy and inducted animals were also measured. The results from atomic force microscopy showed that the nanoparticles were spherical, with a size range of ~200–500 nm. The dynamic light scattering analysis demonstrated that over 90% of the nanoparticles produced had a size of 287 nm with a zeta potential of -14,6 mV. The cytotoxicity results demonstrated that the nanoparticles were capable of reaching breast cancer cells. The biodistribution data demonstrated that the PLA/PVA/MMT/trastuzumab nanoparticles labeled with 99mTc have great renal clearance and also a high uptake by the lesion, as ~45% of the PLA/PVA/MMT/trastuzumab nanoparticles injected were taken up by the lesion. The data support PLA/PVA/MMT/trastuzumab labeled with 99mTc nanoparticles as nanoradiopharmaceuticals for breast cancer imaging.

Palavras-Chave: medicine; neoplasms; radiopharmaceuticals; nanotechnology; mammary glands; molecular structure; image processing; nanostructures; diagnosis; nuclear medicine

SARCINELLI, MICHELLE A.; ALBERNAZ, MARTA de S.; SZWED, MARZENA; ISCAIFE, ALEXANDRE; LEITE, KATIA R.M.; JUNQUEIRA, MARA de S.; BERNARDES, EMERSON S.; SILVA, EMERSON O. da; TAVARES, MARIA I.B.; SANTOS-OLIVEIRA, RALPH. Nanoradiopharmaceuticals for breast cancer imaging: development, characterization, and imaging in inducted animals. OncoTargets and Therapy, v. 9, p. 5847-5854, 2016. DOI: 10.2147/OTT.S110787. Disponível em: http://repositorio.ipen.br/handle/123456789/26786. Acesso em: $DATA.

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Abstract: Uranium aluminide (UAlx) is a mixture of three distinct intermetallic compounds comprised of UAl2, UAl3 and UAl4, where the “x” is used to denote a mixture of those phases. Usually UAlx is formed during the target fabrication process by means of a solid state reaction between the uranium aluminide and aluminum. Quantitative techniques such as image analysis and X-ray diffraction using the Rietveld method were compared for their applicability in the determination of the UAl2, UAl3 and UAl4 concentrations, both in the UAl2 primary ingot and in the UAlx-Al dispersion. The UAlx composition was quantified in all stages of the target manufacturing. The image analysis method was shown to be useful for UAlx phase quantification in the primary UAl2 ingot, but was not applicable in the case of UAlx-Al dispersions. The X-ray diffraction method allowed the quantification of the existing UAlx phases in both the primary ingot and UAlx-Al dispersions. Possible sources of error are discussed. The method of quantification based on X-ray diffraction was shown to be appropriate to monitor the evolution of UAlx phases during the manufacturing process.

Palavras-Chave: diffraction methods; dispersions; image processing; mapping; molybdenum 99; x-ray diffraction

CONTURBIA, G.L.C.R.; DURAZZO, M.; CARVALHO, E.F.U. de; RIELLA, H.G. Phase quantification in UAlx-Al dispersion targets for Mo-99 production. Journal of Nuclear Materials, v. 509, p. 465-477, 2018. DOI: 10.1016/j.jnucmat.2018.07.029. Disponível em: http://repositorio.ipen.br/handle/123456789/29293. Acesso em: $DATA.

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Abstract: Gamma scanning is a nuclear inspection technique widely used for troubleshooting industrial process equipments in refineries and petrochemicals. A radiation source and detector move vertically along the height of the vessel and the radiation readings are used to plot the graph of density profile. In recent years, many improvements have been added to this technique, but essentially the result of gamma scanning still consists of a 1-D density plot. Developed in 2012, the tomographic gamma scan uses image reconstruction techniques to show the result of gamma scan as a 2-D density distribution image. In this work, we present the current status of the technology and the results obtained by applying the technique to real operating process equipment. The results present images that match well with the 1-D density plots obtained by the conventional gamma scan and reveal process and operational problems that has never been visualized before with the traditional technique. The tomographic gamma scan can be immediately applied in practice with low financial investment.

Palavras-Chave: image processing; tomography; gamma radiation; equipment; gamma fuel scanning; nondestructive testing; irradiation; radiation sources; electron scanning; gamma radiography; tomography; gamma radiation; distillation; gamma sources; irradiation

HARAGUCHI, MARCIO I.; KIM, HAE Y.; CALVO, WILSON A.P. Results of process equipment imaging by tomographic gamma scan. Chemical Engineering Transactions, v. 69, p. 649-654, 2018. DOI: 10.3303/CET1869109. Disponível em: http://repositorio.ipen.br/handle/123456789/29424. Acesso em: $DATA.

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