Dosimetria de pacientes submetidos a exames de PET/CT cerebral para diagnóstico de comprometimento cognitivo leve

Santana, Priscila do Carmo; Mourão, Arnaldo Prata; Oliveira, P. M. C. de; Bernardes, Felipe Dias; Mamede, Marcelo; Silva, Teógenes Augusto da

doi:10.1590/0100-3984.2013.1800

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Several objective tests have been developed for early AD detection and diagnosis including cerebro-spinal fluid (CSF) analysis to measure beta amyloid (Aβ), total tau proteins and phosphorylated tau peptides quantification (8, 88), and magnetic resonance imaging (MRI) imaging of the brain and positron emission tomography (PET) scan measuring the brain Aβ plaque burden (6, 7, 89). These modalities are expensive, invasive and potentially dangerous (90, 91). In addition, they detect only structural and not functional changes in AD.…”

Section: A Potential Role For Pupillometry In a Multi-modal Approach mentioning

confidence: 99%

Light-Induced Pupillary Responses in Alzheimer's Disease

et al. 2019

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The impact of Alzheimer's disease (AD) on the pupillary light response (PLR) is controversial, being dependent on the stage of the disease and on the experimental pupillometric protocols. The main hypothesis driving pupillometry research in AD is based on the concept that the AD-related neurodegeneration affects both the parasympathetic and the sympathetic arms of the PLR (cholinergic and noradrenergic theory), combined with additional alterations of the afferent limb, involving the melanopsin expressing retinal ganglion cells (mRGCs), subserving the PLR. Only a few studies have evaluated the value of pupillometry as a potential biomarker in AD, providing various results compatible with parasympathetic dysfunction, displaying increased latency of pupillary constriction to light, decreased constriction amplitude, faster redilation after light offset, decreased maximum velocity of constriction (MCV) and maximum constriction acceleration (MCA) compared to controls. Decreased MCV and MCA appeared to be the most accurate of all PLR parameters allowing differentiation between AD and healthy controls while increased post-illumination pupillary response was the most consistent feature, however, these results could not be replicated by more recent studies, focusing on early and pre-clinical stages of the disease. Whether static or dynamic pupillometry yields useful biomarkers for AD screening or diagnosis remains unclear. In this review, we synopsize the current knowledge on pupillometric features in AD and other neurodegenerative diseases, and discuss potential roles of pupillometry in AD detection, diagnosis and monitoring, alone or in combination with additional biomarkers.

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Section: A Potential Role For Pupillometry In a Multi-modal Approach mentioning

confidence: 99%

Light-Induced Pupillary Responses in Alzheimer's Disease

et al. 2019

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“…The female and male Alderson Rando anthropomorphic phantoms have physical properties similar to that of a patient, such as geometry, weight and equivalent materials to human body tissues. The use of radiochromic films in anthropomorphic phantoms has allowed obtaining absorbed dose profiles in different places considered as radiosensitive organs [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Dosimetry Study in Head and Neck of Anthropomorphic Phantoms in Computed Tomography Scans

2020

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Objectives: To determine the CT absorbed dose profiles for routine adult scan parameters in adults, using male and female anthropomorphic phantoms. Compare the levels of absorbed dose of the phantoms and perform image quality analysis by making noise percentage measurements on the CT images obtained. Methods: Radiochromic film strips were introduced in the central region of the phantoms for to record the dose profile in head and neck in order to determine the amount of the dose deposited along the central axis of the phantoms. The scans were performedon a 64 - channel CT scanner (General Electric), programmed in helical scaning mode. In addition to the routine acquisition protocol with fixed current value, it was performed other three scans with the voltage of 80, 100 and 120 kV, using automatic exposure control. Results: Absorbed dose values were found between 15.54 to 24.38 mGy on average for anthropomorphic male phantom and values of 13.13 to 21.49 mGy for anthropomorphic female phantom. Noise analysis was performed, finding that all are acceptable diagnostic parameters according to ministerial order 453/98 of the Brazilian Ministry of Health. The acquisition parameters of CT images were found that deposited on average less doses in the head and neck for both phantoms, maintaining the image quality for diagnosis.

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“…brain (10-36 mGy), heart (16-51 mGy), kidneys (97-23 mGy) and bladder (13-233 mGy) [1]. However majority of organs are irradiated with 4-9 mGy absorbed dose and 6-10 mSv whole body effective dose [1,8,9]. During standard clinical procedure, the initial administration of 18 F-FDG varies between 350-750 MBq and provides a whole body residence time of 2-3 h [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…However majority of organs are irradiated with 4-9 mGy absorbed dose and 6-10 mSv whole body effective dose [1,8,9]. During standard clinical procedure, the initial administration of 18 F-FDG varies between 350-750 MBq and provides a whole body residence time of 2-3 h [8,9]. Depending on the energy, linear energy transfer (LET) radiations have different biological effects and different relative biological effect (RBE).…”

Section: Introductionmentioning

confidence: 99%

DNA double strand breaks, repair and apoptosis following 511 keVγ-rays exposure using 18 fluorine positron emitter: anin-vitrostudy

Mondal

Nautiyal

Patwari

et al. 2018

Biomed. Phys. Eng. Express

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Purpose: 2-[ 18 F] fluoro-2-deoxy-d-glucose is a positron emitting isotope, which emits 511 keV γ-rays through annihilation process. These γ-rays can induce a variety of DNA damages in animal tissues. It is known that during PET-CT procedure most tissues irradiated with 4-9 mGy absorbed dose and 6-10 mSv whole body effective dose. The biological effects including DNA damages with different dose of fluorine 18 ( 18 F) is still the part of observation and recent research. After knowing the 18 F mediated DNA damage and its repair using time dependent radiation dose study in in-vitro cellular model may clear the understanding of radiation absorbed dose and their side effects including genotoxic effects at specific point of time. Methods: to check the early and late apoptosis in irradiated peripheral blood mononuclear cells (PBMCs), annexin V FITC tagged microscopic imaging was examined. To detect DNA double-strand breaks (DSBs), apoptosis and DNA repair, comet assay and γ-H2AX assay was used. BrdU incorporation assay was also performed to label the fragmented DNA. Results: significant amount of apoptotic cells were observed in PBMC after being irradiated for 120 min with absorbed dose of 8.22 mGy. The appearance of comets and number of foci are increasing in the cells irradiated with 8.22 mGy for 120 min and the amount of FITC tagged BrdU stain percentage confirms the presence of DSBs and apoptosis for longer exposure time (120 min). In DNA repair study, 24 h is the necessary time to repair the damaged cells. Conclusions: our time-and dosedependent study shows that radiation induced DSBs generation and cell apoptosis at low dose radiation of 18 F. 18 F has the capacity to damage DNA and induce apoptosis only if the cells are exposed for the longer period of time. However, all the damages are repaired within 24 h.

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Dosimetria de pacientes submetidos a exames de PET/CT cerebral para diagnóstico de comprometimento cognitivo leve

Cited by 5 publications

References 15 publications

Light-Induced Pupillary Responses in Alzheimer's Disease

Light-Induced Pupillary Responses in Alzheimer's Disease

Dosimetry Study in Head and Neck of Anthropomorphic Phantoms in Computed Tomography Scans

DNA double strand breaks, repair and apoptosis following 511 keVγ-rays exposure using 18 fluorine positron emitter: anin-vitrostudy

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