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1.
Biomed Phys Eng Express ; 8(6)2022 09 05.
Article in English | MEDLINE | ID: mdl-35961284

ABSTRACT

Objective.The goal of this study was to use Monte Carlo (MC) simulations and measurements to investigate the dosimetric suitability of an interventional radiology (IR) c-arm fluoroscope to deliver low-dose radiotherapy to the lungs.Approach.A previously-validated MC model of an IR fluoroscope was used to calculate the dose distributions in a COVID-19-infected patient, 20 non-infected patients of varying sizes, and a postmortem subject. Dose distributions for PA, AP/PA, 3-field and 4-field treatments irradiating 95% of the lungs to a 0.5 Gy dose were calculated. An algorithm was created to calculate skin entrance dose as a function of patient thickness for treatment planning purposes. Treatments were experimentally validated in a postmortem subject by using implanted dosimeters to capture organ doses.Main results.Mean doses to the left/right lungs for the COVID-19 CT data were 1.2/1.3 Gy, 0.8/0.9 Gy, 0.8/0.8 Gy and 0.6/0.6 Gy for the PA, AP/PA, 3-field, and 4-field configurations, respectively. Skin dose toxicity was the highest probability for the PA and lowest for the 4-field configuration. Dose to the heart slightly exceeded the ICRP tolerance; all other organ doses were below published tolerances. The AP/PA configuration provided the best fit for entrance skin dose as a function of patient thickness (R2 = 0.8). The average dose difference between simulation and measurement in the postmortem subject was 5%.Significance.An IR fluoroscope should be capable of delivering low-dose radiotherapy to the lungs with tolerable collateral dose to nearby organs.


Subject(s)
COVID-19 , Radiotherapy Planning, Computer-Assisted , COVID-19/radiotherapy , Humans , Lung/diagnostic imaging , Monte Carlo Method , Radiology, Interventional , Radiotherapy Planning, Computer-Assisted/methods
2.
Neurocirugía (Soc. Luso-Esp. Neurocir.) ; 33(4): 165-175, jul. - ago. 2022. tab, graf, ilus
Article in Spanish | IBECS | ID: ibc-204450

ABSTRACT

Objetivos: Evaluar la efectividad, la seguridad y los costos perioperatorios del abordaje endonasal endoscópico en pacientes con tumores nasosinusales malignos con invasión cerebral. Pacientes y método: Se realizó un estudio observacional de serie de casos. Se compararon 30 pacientes con tumores nasosinusales malignos e invasión cerebral operados (2015-2017) mediante abordaje endoscópico con una serie histórica de 53 casos operados (2010-2015) mediante cirugía abierta. Se utilizó el método de emparejamiento por puntaje de propensión para controlar el efecto de factores pronósticos. Las variables de respuesta primaria fueron el control local y la supervivencia global a los tres años. Se analizaron variables de costo perioperatorio. Resultados: Después del emparejamiento se identificaron 50 pacientes (25 en cada grupo terapéutico) con edad promedio de 55 años, 62% de sexo masculino. Predominó el carcinoma de células escamosas y la invasión cerebral grado II. El control local de la enfermedad a los tres años, la supervivencia global y libre de progresión fueron superiores en el abordaje endoscópico. El abordaje endoscópico redujo el tiempo quirúrgico en 1 hora y 20 minutos y la estadía hospitalaria en 19 días en comparación con la cirugía abierta. El abordaje endoscópico mejoró la independencia funcional y redujo las complicaciones. El ahorro promedio estimado con el abordaje endoscópico fue de aproximadamente $7.355,18 por paciente. Conclusiones: El abordaje endonasal endoscópico constituye un procedimiento seguro, efectivo y más económico en los pacientes con neoplasias nasosinusales malignas e invasión cerebral (AU)


Objectives: To determine the safety, effectiveness and perioperative costs of endonasal endoscopic approach in brain invasive malignant sinonsal tumors patients. Materials and methods: This was a case series bidirectional study; that included 30 brain invasive malignant sinonsal tumors patients treated by endonasal endoscopic approach (2015-2017) and 53 by open surgery (2010-2015). Propensity score matching was used to compensate the prognostic factors; in a sample of 50 patients (25 per group). Primary response variables was local control and 3-years overall survival. Perioperative cost variables were analyzed. Results: A number of 50 patients were included after matching (25 in each therapeutic group). The age average was 55 years and male proportion was 62%. Squamous cell carcinoma and grade II lesions were the most represented in the sample. Endonasal endoscopic approach reduced surgical time in 1 hour 20 minutes, transfusion needs in 5.5 fold and hospitalization in 19 days; in comparison with open technique. Oncologic control based on surgical free margins, local control, overall survival and progression free survival after three years was higher when the resection was performed endoscopically. Functional status was enhanced and complications diminished by using endoscopic approach. Saving was estimated in $7 355.18 per patient. Conclusions: Endonasal endoscopic approach represents a safe, effective and economic procedure in selected patients with malignant sinonasal tumors and brain invasion (AU)


Subject(s)
Humans , Male , Female , Young Adult , Adult , Middle Aged , Aged , Natural Orifice Endoscopic Surgery , Paranasal Sinus Neoplasms/surgery , Treatment Outcome , Propensity Score , Invasion of Deaths , Neoplasm Invasiveness
3.
Radiat Prot Dosimetry ; 198(16): 1210-1218, 2022 Sep 22.
Article in English | MEDLINE | ID: mdl-35849109

ABSTRACT

The object of this study was to evaluate the dose of scattered radiation in the organs of the operator and assistant located in different positions within a dental room when acquiring intraoral images with a portable handheld X-ray device, using Monte Carlo simulations for recommended and traditional techniques. A typical dental installation was modeled, where the operator and assistant were placed. The beam is represented by 60-kV spectrum. Ten scenarios were simulated, representing different positions and use of the lead apron. The results of the simulations were carried out with typical parameters of the annual workload, showing significant increases in dose in the organs of the operator due to the angulation. The minimum dose in the organs of the assistant occurred when he was located 2-m away and 45° from the direction of the beam. The dose received by the operator is significantly reduced with the use apron.


Subject(s)
Radiation Protection , Dentistry , Monte Carlo Method , Phantoms, Imaging , Radiation Dosage , X-Rays
4.
Phys Med ; 94: 24-34, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34979431

ABSTRACT

PURPOSE: To use MC simulations and phantom measurements to investigate the dosimetry of a kilovoltage x-ray beam from an IR fluoroscope to deliver low-dose (0.3-1.0 Gy) radiotherapy to the lungs. MATERIALS AND METHODS: PENELOPE was used to model a 125 kV, 5.94 mm Al HVL x-ray beam produced by a fluoroscope. The model was validated through depth-dose, in-plane/cross-plane profiles and absorbed dose at 2.5-, 5.1-, 10.2- and 15.2-cm depths against the measured beam in an acrylic phantom. CT images of an anthropomorphic phantom thorax/lungs were used to simulate 0.5 Gy dose distributions for PA, AP/PA, 3-field and 4-field treatments. DVHs were generated to assess the dose to the lungs and nearby organs. Gafchromic film was used to measure doses in the phantom exposed to PA and 4-field treatments, and compared to the MC simulations. RESULTS: Depth-dose and profile results were within 3.2% and 7.8% of the MC data uncertainty, respectively, while dose gamma analysis ranged from 0.7 to 1.0. Mean dose to the lungs were 1.1-, 0.8-, 0.9-, and 0.8- Gy for the PA, AP/PA, 3-field, and 4-field after isodose normalization to cover âˆ¼ 95% of each lung volume. Skin dose toxicity was highest for the PA and lowest for the 4-field, and both arrangements successfully delivered the treatment on the phantom. However, the dose distribution for the PA was highly non-uniform and produced skin doses up to 4 Gy. The dose distribution for the 4-field produced a uniform 0.6 Gy dose throughout the lungs, with a maximum dose of 0.73 Gy. The average percent difference between experimental and Monte Carlo values were -0.1% (range -3% to +4%) for the PA treatment and 0.3% (range -10.3% to +15.2%) for the 4-field treatment. CONCLUSION: A 125 kV x-ray beam from an IR fluoroscope delivered through two or more fields can deliver an effective low-dose radiotherapy treatment to the lungs. The 4-field arrangement not only provides an effective treatment, but also significant dose sparing to healthy organs, including skin, compared to the PA treatment. Use of fluoroscopy appears to be a viable alternative to megavoltage radiation therapy equipment for delivering low-dose radiotherapy to the lungs.


Subject(s)
Radiology, Interventional , Radiometry , Fluoroscopy , Lung/diagnostic imaging , Monte Carlo Method , Phantoms, Imaging , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted
5.
Rev. esp. investig. quir ; 24(1): 3-8, 2021. tab, ilus
Article in Spanish | IBECS | ID: ibc-219083

ABSTRACT

Introducción. El hepatocarcinoma fibrolamelar (CHCFL) es un tumor infrecuente, de aparición en adultos jóvenes y sobre hígado sano. Clásicamente considerado una variante del carcinoma hepatocelular (CHC), difieren en tantos aspectos, que debieranconceptuarse como entidades diferentes. El objetivo de este trabajo es refrescar sus características, haciendo hincapié en las diferenciales, para ser tenido en consideración ante lesiones hepáticas sólidas ocupantes de espacio en pacientes jóvenes. Material ymétodo.Estudio descriptivo retrospectivo de las características de 5 casos de CHCFL intervenidos en la unidad de cirugía hepatobiliopancreática un hospital de tercer nivel. Resultados. Cinco casos, edad media 31.8 años, mujer/hombre 4/1. Todos ellos sobrehígado sano, con clínica inespecífica. Radiológicamente e histopatológicamente cumplen las características típicas de este tumor.Sometidos en todos los casos a resecciones quirúrgicas amplias, y reintervenidos, por recidiva, 2 casos, uno de ellos en forma detrasplante hepático. La tabla 1 recoge todas las características epidemiológicas y clínicas, datos operatorios y supervivencia globaly libre de enfermedad de los pacientes incluidos en el estudio. Discusión. De curso clínico insidioso y silente en muchas ocasiones,el diagnóstico suele ser tardío, con grandes masas tumorales en las pruebas de imagen. Actualmente el tratamiento quirúrgico esel único potencialmente curativo. Pese a una supervivencia prolongada, la tasa de recidiva es muy elevada, precisando en muchoscasos intervenciones reiteradas. Los resultados en nuestra serie son acordes con la literatura y podrían calificarse como paradigmade las características anatomoclínicas, terapéuticas y pronósticas de este tipo de tumor. (AU)


Introduction. Fibrolamellar hepatocellular carcinoma is an infrequent tumour, which appears in young adults and on healthy liver.It has been classically considered a subtype of hepatocellular carcinoma, but they differ in such many aspects they could be considered separately. The objective of this review is to refresh its differential characteristics in order to take into account in the differentialdiagnosis of hepatic solid lessions in young adults. Material and methods. Descriptive retrospective study of the principles characteristics of the five fibrolamellar hepatocellular carcinoma operated patients by the hepatobilliary surgery team of our hospital.Results. Five cases, medium age 31.8 years, women/men 4/1. All of them in healthy liver with inespecific symptoms and radiollogicaland hystopathological typical characteristics. All of them having enlarged hepatic ressections and reoperated two of them becauseof recurrence, in one case in form of hepatic transplantation. Table 1 collect all the epidemiological and clinical characteristics, operation reports, global and recurrence free survival of all patientes included in the study. Discussion. Having insidious and silentdevelopment in many cases, diagnosis can be delayed, appearing big tumoral masses on the imaging tests. Nowadays, surgery is the only curative treatment. Despite long survival periods, the recurrence rate is very high, needing sometimes being reoperated. Our results are in the line of the literature results and could be classified as the paradigm of anatomoclinic, therapeutic and prognostic characteristics of this type of tumour. (AU)


Subject(s)
Humans , Male , Female , Young Adult , Carcinoma, Hepatocellular/classification , Liver Diseases/diagnosis , Liver Diseases/therapy , Liver Neoplasms/diagnosis , Liver Neoplasms/therapy , Epidemiology, Descriptive , Retrospective Studies
6.
Cuad. Hosp. Clín ; 61(1): [11], jul. 2020. ilus.
Article in Spanish | LILACS, LIBOCS | ID: biblio-1118902

ABSTRACT

Los tumores de células gigantes (TDG) llamados también osteoclastomas o tumores pardos cuando se hallan dentro la esfera endocrinológica, son uno de los tumores menos frecuentes, más controversial y menos predecible en su comportamiento. Se producen como consecuencia del exceso de la actividad osteoclastica, como ocurre en el caso del hiperparatiroidismo, mismo que es un desorden endocrino común, por lo general asintomático y diagnosticado por el hallazgo fortuito de hipercalcemia. El diagnóstico de los osteoclastomas suele ser un reto, el alto índice de sospecha es esencial y la biopsia es el estándar de oro para el diagnóstico. Presentamos el caso de un hombre de 42 años quien presentó fracturas patológicas de radio derecho y tibia izquierda, gammagrama óseo con Tc ­ 99m con múltiples lesiones óseas , hormona paratiroidea (PTH) elevada, hipercalcemia, gammagrama de paratiroides con MIBI con presencia de adenoma paratiroideo, la biopsia de las lesiones óseas con presencia de células gigantes multinucleadas correspondientes a osteoclastomas; se llevó a cabo paratiroidectomia y el examen histopatológico confirmó la presencia de un adenoma paratiroideo.


Giant cell tumors (TDG), also called osteoclastomas or brown tumors when they are within the endocrinological sphere, are one of the least frequent, most controversial and least predictable tumors in their behavior. They occur as a consequence of excess osteoclastic activity, as occurs in the case of hyperparathyroidism, which is a common endocrine disorder, generally asymptomatic and diagnosed by the fortuitous finding of hypercalcemia. Diagnosing osteoclastomas is usually challenging, the high index of suspicion is essential, and biopsy is the gold standard for diagnosis. We present the case of a 42-year-old man who presented pathological fractures of the right radius and left tibia, a bone scan with Tc-99m with multiple bone lesions, elevated parathyroid hormone (PTH), hypercalcemia, parathyroid scan with MIBI with the presence of parathyroid adenoma, the biopsy of the bone lesions with the presence of multinucleated giant cells corresponding to osteoclastomas; parathyroidectomy was performed and histopathological examination confirmed the presence of a parathyroid adenoma.


Subject(s)
Male , Adult , Wounds and Injuries , Biopsy , Diagnosis , Hypercalcemia
7.
AJNR Am J Neuroradiol ; 41(3): 408-415, 2020 03.
Article in English | MEDLINE | ID: mdl-32165359

ABSTRACT

BACKGROUND AND PURPOSE: Perfusion MR imaging measures of relative CBV can distinguish recurrent tumor from posttreatment radiation effects in high-grade gliomas. Currently, relative CBV measurement requires normalization based on user-defined reference tissues. A recently proposed method of relative CBV standardization eliminates the need for user input. This study compares the predictive performance of relative CBV standardization against relative CBV normalization for quantifying recurrent tumor burden in high-grade gliomas relative to posttreatment radiation effects. MATERIALS AND METHODS: We recruited 38 previously treated patients with high-grade gliomas (World Health Organization grades III or IV) undergoing surgical re-resection for new contrast-enhancing lesions concerning for recurrent tumor versus posttreatment radiation effects. We recovered 112 image-localized biopsies and quantified the percentage of histologic tumor content versus posttreatment radiation effects for each sample. We measured spatially matched normalized and standardized relative CBV metrics (mean, median) and fractional tumor burden for each biopsy. We compared relative CBV performance to predict tumor content, including the Pearson correlation (r), against histologic tumor content (0%-100%) and the receiver operating characteristic area under the curve for predicting high-versus-low tumor content using binary histologic cutoffs (≥50%; ≥80% tumor). RESULTS: Across relative CBV metrics, fractional tumor burden showed the highest correlations with tumor content (0%-100%) for normalized (r = 0.63, P < .001) and standardized (r = 0.66, P < .001) values. With binary cutoffs (ie, ≥50%; ≥80% tumor), predictive accuracies were similar for both standardized and normalized metrics and across relative CBV metrics. Median relative CBV achieved the highest area under the curve (normalized = 0.87, standardized = 0.86) for predicting ≥50% tumor, while fractional tumor burden achieved the highest area under the curve (normalized = 0.77, standardized = 0.80) for predicting ≥80% tumor. CONCLUSIONS: Standardization of relative CBV achieves similar performance compared with normalized relative CBV and offers an important step toward workflow optimization and consensus methodology.


Subject(s)
Brain Neoplasms/diagnostic imaging , Glioma/diagnostic imaging , Image Interpretation, Computer-Assisted/standards , Magnetic Resonance Imaging/standards , Neuroimaging/methods , Adult , Aged , Brain Neoplasms/pathology , Female , Glioma/pathology , Humans , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Male , Middle Aged , Radiation Injuries/diagnostic imaging , Radiation Injuries/pathology , Tumor Burden
8.
Genes Brain Behav ; 18(3): e12484, 2019 03.
Article in English | MEDLINE | ID: mdl-29691979

ABSTRACT

Prenatal exposure to alcohol causes a wide range of deficits known as fetal alcohol spectrum disorders (FASDs). Many factors determine vulnerability to developmental alcohol exposure including timing and pattern of exposure, nutrition and genetics. Here, we characterized how a prevalent single nucleotide polymorphism in the human brain-derived neurotrophic factor (BDNF) gene (val66met) modulates FASDs severity. This polymorphism disrupts BDNF's intracellular trafficking and activity-dependent secretion, and has been linked to increased incidence of neuropsychiatric disorders such as depression and anxiety. We hypothesized that developmental ethanol (EtOH) exposure more severely affects mice carrying this polymorphism. We used transgenic mice homozygous for either valine (BDNFval/val ) or methionine (BDNFmet/met ) in residue 68, equivalent to residue 66 in humans. To model EtOH exposure during the second and third trimesters of human pregnancy, we exposed mice to EtOH in vapor chambers during gestational days 12 to 19 and postnatal days 2 to 9. We found that EtOH exposure reduces cell layer volume in the dentate gyrus and the CA1 hippocampal regions of BDNFmet/met but not BDNFval/val mice during the juvenile period (postnatal day 15). During adulthood, EtOH exposure reduced anxiety-like behavior and disrupted trace fear conditioning in BDNFmet/met mice, with most effects observed in males. EtOH exposure reduced adult neurogenesis only in the ventral hippocampus of BDNFval/val male mice. These studies show that the BDNF val66met polymorphism modulates, in a complex manner, the effects of developmental EtOH exposure, and identify a novel genetic risk factor that may regulate FASDs severity in humans.


Subject(s)
Anxiety/genetics , Brain-Derived Neurotrophic Factor/genetics , Central Nervous System Depressants/toxicity , Ethanol/toxicity , Hippocampus/drug effects , Mutation, Missense , Prenatal Exposure Delayed Effects/genetics , Animals , Conditioning, Classical , Fear , Female , Hippocampus/growth & development , Male , Mice , Polymorphism, Single Nucleotide , Pregnancy
9.
J Chem Phys ; 147(22): 224501, 2017 Dec 14.
Article in English | MEDLINE | ID: mdl-29246073

ABSTRACT

We have measured the nonlinear dielectric behavior of several highly polar propylene carbonate (PC) derivatives in the vicinity of their glass transition temperatures. Focus is on the effects of a large static electric field on the frequency dependent permittivity and on the cubic susceptibility measured using sinusoidal fields of high amplitude. The case of vinyl-PC shows dielectric saturation as well as an electro-rheological effect, i.e., a field induced increase of dielectric relaxation times, whose magnitude changes linearly with the apparent activation energy. The extent of this shift of the loss profile caused by the field correlates strongly with the peak magnitude of the cubic susceptibility, |χ3|, underlining the notion of a link between the |χ3| "hump" and this electro-rheological behavior. Further support for this picture emerges from the observation that the most polar of these liquids, (S)-(-)-methoxy-PC with εs ≈ 250, lacks both the electro-rheological effect in ε″(ω) and the "hump" typically observed in |χ3(ω)|. The absence of any sensitivity of the dynamics to an electric field is contrary to the expectation that the electro-rheological effect correlates with the field induced entropy change, which is extraordinarily high for this liquid. The results suggest that the dependence of the relaxation time on the electric field is not directly linked to the entropy change.

10.
J Chem Phys ; 147(19): 194504, 2017 Nov 21.
Article in English | MEDLINE | ID: mdl-29166100

ABSTRACT

We prepared films of 4-methyl-3-heptanol by vapor depositing onto substrates held at temperatures between Tdep = 0.6Tg and Tg, where Tg is the glass transition temperature. Using deposition rates between 0.9 and 6.0 nm/s, we prepared films about 5 µm thick and measured the dielectric properties via an interdigitated electrode cell onto which films were deposited. Samples prepared at Tdep = Tg display the dielectric behavior of the ordinary supercooled liquid. Films deposited at lower deposition temperatures show a high dielectric loss upon heating toward Tg, which decreases by a factor of about 12 by annealing at Tg = 162 K. This change is consistent with either a drop of the Kirkwood correlation factor, gk, by a factor of about 10, or an increase in the dielectric relaxation times, both being indicative of changes toward ring-like hydrogen-bonded structure characteristic of the ordinary liquid. We rationalize the high dielectric relaxation amplitude in the vapor deposited glass by suggesting that depositions at low temperature provide insufficient time for molecules to form ring-like supramolecular structures for which dipole moments cancel. Surprisingly, above Tg of the ordinary liquid, these vapor deposited films fail to completely recover the dielectric properties of the liquid obtained by supercooling. Instead, the dielectric relaxation remains slower and its amplitude much higher than that of the equilibrium liquid state, indicative of a structure that differs from the equilibrium liquid up to at least Tg + 40 K.

11.
J Chem Phys ; 147(1): 014502, 2017 Jul 07.
Article in English | MEDLINE | ID: mdl-28688431

ABSTRACT

Physical vapor deposition has been used to prepare glasses of ethanol. Upon heating, the glasses transformed into the supercooled liquid phase and then crystallized into the plastic crystal phase. The dynamic glass transition of the supercooled liquid is successfully measured by AC nanocalorimetry, and preliminary results for the plastic crystal are obtained. The frequency dependences of these dynamic glass transitions observed by AC nanocalorimetry are in disagreement with conclusions from previously published dielectric spectra of ethanol. Existing dielectric loss spectra have been carefully re-evaluated considering a Debye peak, which is a typical feature in the dielectric loss spectra of monohydroxy alcohols. The re-evaluated dielectric fits reveal a prominent dielectric Debye peak, a smaller and asymmetrically broadened peak, which is identified as the signature of the structural α-relaxation and a Johari-Goldstein secondary relaxation process. This new assignment of the dielectric processes is supported by the observation that the AC nanocalorimetry dynamic glass transition temperature, Tα, coincides with the dielectric structural α-relaxation process rather than the Debye process. The combined results from dielectric spectroscopy and AC nanocalorimetry on the plastic crystal of ethanol suggest the occurrence of a Debye process also in the plastic crystal phase.

12.
J Parasit Dis ; 40(4): 1631-1635, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27876999

ABSTRACT

The presence of Notozothecium bethae was investigated in 76 black band myleus (Myleus schomburgkii [Actinopterygii: Charasiformes]) born and kept in captivity in two semi-intensive breeding cages in the northern region of Peru. Among the 76 cultivated specimens of M. schomburgkii examined in the present study, 100 % had monogenean on the gill and the parasites were identified as Notozothecium bethae. During the survey no bacteria was isolated, and no protozoan or other metazoan parasites were found. The prevalence of N. bethae remained constant throughout the present study. Mean intensity of N. bethae in the months of April and May was exceptionally high in both facilities. The massive infection of N. bethae on the gills of M. schomburgkii was associated with mortality. This is the first report of N. bethae in M. schomburgkii born in captivity and cultured in the Amazon region. The mortality due the presence of this parasite emphasise the need for disease control strategies of cultured M. schomburgkii.

13.
J Radiol Prot ; 36(4): 842-857, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27739403

ABSTRACT

Ambient dose equivalent H *(10) is an operational quantity recommended by the IAEA to establish dose constraints in area monitoring for external radiation. The direct measurement of H *(10) is not common due to the complexity in the calibration procedures of radiation monitors involving the use of expanded and aligned radiation fields. Therefore, conversion coefficients are used to assess H *(10) from the physical quantity air-kerma. Conversion coefficients published by international commissions, ICRU and ICRP, present a correlation with the radiation beam quality. However, Brazilian regulation establishes 1.14 Sv Gy-1 as unique conversion coefficient to convert air-kerma into H *(10), disregarding its beam quality dependence. The present study computed mean conversion coefficients from secondary and transmitted x-ray beams in order to improve the current assessment of H *(10). The weighting of conversion coefficients corresponding to monoenergetic beams with the spectrum energy distribution in terms of air-kerma was used to compute the mean conversion coefficients. In order to represent dedicated chest radiographic facilities, an anthropomorphic phantom was used as scatter object of the primary beam. Secondary x-ray spectra were measured in the diagnostic energy range at scattering angles of 30°, 60°, 90° 120° and 150° degrees. Barite mortar plates were used as attenuator of the secondary beam to produce the corresponding transmitted x-ray spectra. Results show that the mean conversion coefficients are about 43% higher than the recommended value accepted by Brazilian regulation. For secondary radiation measured at 100 kV the mean coefficient should be 1.46 Sv Gy-1, which represent the higher value in the mean coefficient set corresponding to secondary beams. Moreover, for transmitted x-ray beams at 100 kV, the recommended mean conversion coefficient is 1.65 Sv Gy-1 for all barite mortar plate thickness and all scattering angles. An example of application shows the discrepancy in the evaluation of secondary shielding barriers in a controlled area when the shielding goals is evaluated. The conclusion based on these results is that a unique coefficient may not be adequate for deriving the H *(10).


Subject(s)
Radiation Dosage , Radiation Monitoring/standards , Radiology , Brazil , Radiation Protection , Scattering, Radiation , X-Rays
14.
Appl Radiat Isot ; 100: 27-31, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25600507

ABSTRACT

Primary X-ray spectra were measured in the range of 80-150kV in order to validate a computer program based on a semiempirical model. The ratio between the characteristic and total air Kerma was considered to compare computed results and experimental data. Results show that the experimental spectra have higher first HVL and mean energy than the calculated ones. The ratios between the characteristic and total air Kerma for calculated spectra are in good agreement with experimental results for all filtrations used.

15.
Appl Radiat Isot ; 100: 32-7, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25599872

ABSTRACT

In this work, the energy response functions of a CdTe detector were obtained by Monte Carlo (MC) simulation in the energy range from 5 to 160keV, using the PENELOPE code. In the response calculations the carrier transport features and the detector resolution were included. The computed energy response function was validated through comparison with experimental results obtained with (241)Am and (152)Eu sources. In order to investigate the influence of the correction by the detector response at diagnostic energy range, x-ray spectra were measured using a CdTe detector (model XR-100T, Amptek), and then corrected by the energy response of the detector using the stripping procedure. Results showed that the CdTe exhibits good energy response at low energies (below 40keV), showing only small distortions on the measured spectra. For energies below about 80keV, the contribution of the escape of Cd- and Te-K x-rays produce significant distortions on the measured x-ray spectra. For higher energies, the most important correction is the detector efficiency and the carrier trapping effects. The results showed that, after correction by the energy response, the measured spectra are in good agreement with those provided by a theoretical model of the literature. Finally, our results showed that the detailed knowledge of the response function and a proper correction procedure are fundamental for achieving more accurate spectra from which quality parameters (i.e., half-value layer and homogeneity coefficient) can be determined.

16.
Bone Marrow Transplant ; 49(9): 1184-6, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25000459

ABSTRACT

The feasibility of selecting cord blood (CB) units at high-resolution HLA match has not been investigated. We analyzed the high-resolution donor-recipient HLA match of 100 double-unit 4-6/6 HLA-A,-B antigen, -DRB1 allele-matched CB grafts (units 1a and 1b) and their back-up units (n=377 units in total). The median cryopreserved graft dose was 2.9 × 10(7)/kg/unit, and at high resolution these units had a median donor-recipient HLA-allele match of 5/8 (range 2-8/8) and 6/10 (range 2-9/10), respectively. We then evaluated how often use of high-resolution HLA-match criteria would change the original graft selection to substitute one or both of the back-up units for units 1a and/or 1b. On using a model in which both a higher eight-allele HLA match and a cell dose ⩾ 2.0 × 10(7)/kg/unit were required, graft selection changed in 33% of transplants with minimal effect on cell dose (8.3% reduction). In summary, while units chosen based on HLA-A,-B antigen and -DRB1 allele match have substantial mismatch at higher resolution, CB selection based on high-resolution HLA match is possible in a significant proportion of patients without compromise in cell dose.


Subject(s)
Cord Blood Stem Cell Transplantation/methods , Fetal Blood/immunology , HLA-B Antigens/genetics , HLA-B Antigens/immunology , Adolescent , Adult , Aged , Alleles , Child , Child, Preschool , Female , Histocompatibility Testing , Humans , Infant , Male , Middle Aged , Tissue Donors , Young Adult
17.
Horiz. méd. (Impresa) ; 14(1): 6-10, ene.-mar. 2014.
Article in Spanish | LILACS, LIPECS | ID: lil-722424

ABSTRACT

Objetivo: Determinar el efecto y actividad antinociceptiva de las hojas de Maytenus macrocarpa (Ruiz & Pav) Briq. ôchuchuhuasiõ mediante la prueba de contorsiones abdominales en roedor. Material y Métodos: Se utilizaron 40 ratones albinos machos, con pesos medios de 25g, se empleó la prueba de contorsiones abdominales para determinar la actividad antinociceptiva. El grupo Control, no recibió ninguna sustancia. Se administró extracto etanólico de las hojas de M. macrocarpa (Ruiz & Pav.) Briq. 2000 mg/kg, Tramadol 10 mg/kg y Diclofenaco sódico 10 mg/kg. Las sustancias fueron administradas por la vía oral una hora antes de la inducción de dolor. Para la validación estadística se usó la prueba de Shapiro-Wilk, ANOVA de una cola, Tukey, y Newman-Keuls. Resultados: El número de contorsiones abdominales fue 41+/- 3.04, 27+/- 3.55, 9 +/- 4.14, y 18 +/- 2.65 respectivamente. El porcentaje de inhibición de la conducta nociceptiva fue: 0%, 34%, 77%, y 55%. La prueba de ANOVA de una vía, demostró diferencias estadísticas (p<0.05, IC 95%), y la prueba de Tukey y Newman-Keuls, demostraron diferencias significativas entre los grupos, frente al control. Conclusiones: Se comprobó el efecto antinociceptivo de las hojas de Maytenus macrocarpa (Ruiz & Pav.) Briq. ôchuchuhuasiõ, en dosis de 2000 mg/kg.


Objetives: To determine the effect and antinociceptive activity of the leaves of Maytenus macrocarpa (Ruiz & Pav ) Briq . ôChuchuhuasi ô by the writhing test in rodents. Material and Methods: 40 male albino mice were used, with average weights of 25g, the writhing test was used to determine the antinociceptive activity. The experimental groups were: Control; received no substance, ethanol extract of the leaves of M. macrocarpa Briq (Ruiz & Pav.) 2000 mg/kg, Tramadol 10 mg/kg and 10mg Sodium Diclofenac /kg. The substances were administered orally one hour before the induction of pain. For statistical validation the Shapiro -Wilk test, one-tailed ANOVA, Tukey, and Newman -Keuls was used. Results: Writhing number was 41 +/- 3.04, 27 +/- 3.55, 9 +/- 4.14, and 18 +/- 2.65 respectively. The inhibition percentage of the nociceptive behavior was: 0%, 34%, 77% and 55%. The test of one-way ANOVA showed statistical differences (p < 0.05, 95% CI), and the Tukey and Newman-Keuls test showed significant differences between groups versus control. Conclusions: Antinociceptive effect of the leaves of Maytenus macrocarpa (Ruiz & Pav.) Briq ôChuchuhuasiô was found at doses of 2000 mg/kg.


Subject(s)
Nociceptive Pain/therapy , Plant Extracts/therapeutic use , Maytenus , Plants, Medicinal , Mice , Control Groups
18.
J Vet Pharmacol Ther ; 37(4): 317-24, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24495176

ABSTRACT

Janus kinase (JAK) enzymes are involved in cell signaling pathways activated by various cytokines dysregulated in allergy. The objective of this study was to determine whether the novel JAK inhibitor oclacitinib could reduce the activity of cytokines implicated in canine allergic skin disease. Using isolated enzyme systems and in vitro human or canine cell models, potency and selectivity of oclacitinib was determined against JAK family members and cytokines that trigger JAK activation in cells. Oclacitinib inhibited JAK family members by 50% at concentrations (IC50 's) ranging from 10 to 99 nm and did not inhibit a panel of 38 non-JAK kinases (IC50 's > 1000 nM). Oclacitinib was most potent at inhibiting JAK1 (IC50 = 10 nM). Oclacitinib also inhibited the function of JAK1-dependent cytokines involved in allergy and inflammation (IL-2, IL-4, IL-6, and IL-13) as well as pruritus (IL-31) at IC50 's ranging from 36 to 249 nM. Oclacitinib had minimal effects on cytokines that did not activate the JAK1 enzyme in cells (erythropoietin, granulocyte/macrophage colony-stimulating factor, IL-12, IL-23; IC50 's > 1000 nM). These results demonstrate that oclacitinib is a targeted therapy that selectively inhibits JAK1-dependent cytokines involved in allergy, inflammation, and pruritus and suggests these are the mechanisms by which oclacitinib effectively controls clinical signs associated with allergic skin disease in dogs.


Subject(s)
Cytokines/antagonists & inhibitors , Dermatologic Agents/pharmacology , Dogs/blood , Enzymes/blood , Janus Kinases/antagonists & inhibitors , Pyrimidines/pharmacology , Sulfonamides/pharmacology , Animals , Cytokines/genetics , Cytokines/metabolism , Dermatologic Agents/chemistry , Gene Expression Regulation/drug effects , Humans , Molecular Structure , Pyrimidines/chemistry , Sulfonamides/chemistry
19.
Article in English | MEDLINE | ID: mdl-25570778

ABSTRACT

The present study aims at designing and evaluating a low-cost, simple and portable system for arm joint angle estimation during grasping-like motions. The system is based on a single RGB-D camera and three customized markers. The automatically detected and tracked marker positions were used as inputs to an offline inverse kinematic process based on bio-mechanical constraints to reduce noise effect and handle marker occlusion. The method was validated on 4 subjects with different motions. The joint angles were estimated both with the proposed low-cost system and, a stereophotogrammetric system. Comparative analysis shows good accuracy with high correlation coefficient (r= 0.92) and low average RMS error (3.8 deg).


Subject(s)
Joints/physiology , Movement , Photogrammetry/economics , Photogrammetry/instrumentation , Adult , Arm/physiology , Biomechanical Phenomena , Female , Hand Strength , Humans , Male , Software , User-Computer Interface
20.
J Biomech ; 46(9): 1531-9, 2013 May 31.
Article in English | MEDLINE | ID: mdl-23602597

ABSTRACT

Inlet boundary conditions (BCs) are important inputs of computational fluid dynamics (CFD) in intracranial aneurysms (IAs). We performed sensibility analysis of CFD to different inlet BCs applied to illustrative patient-specific aneurysm-vessel geometry. BCs corresponding to generic and patient-specific pulsatile flow curves were applied to three vascular geometry models of carotid ophthalmic aneurysm-vessel geometry, in which the inlet lengths were different. CFD outcomes were compared to high frame rate Digital Subtraction Angiography (DSA) sequences. The streamlines were found to match contrast agent (CA) motion pattern in the case where the non-truncated inlet vessel model was coupled to generic Womersley BC solution. Even though dynamic pressure loss (55%) was equal for all models and different BCs, the minimum distance to wall of the fastest velocity fields for the non-truncated model was significantly larger (p=0.002) and mean vorticity sign was different. Significant difference in spatial distributions of wall shear stress (WSS) and oscillating shear stress index (OSI) was found in aneurysm between Womersley and Plugflow BC conditions, only. Reliable CFD for carotid ophthalmic aneurysm would require avoiding truncation of the inlet vessel to be independent of the solution applied to generate CFD.


Subject(s)
Intracranial Aneurysm/physiopathology , Models, Cardiovascular , Cerebrovascular Circulation , Humans , Hydrodynamics , Pulsatile Flow
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