Spectra, fluence and absorbed doses in sensitive organs due to scattered X-rays during a chest CT.

The use of ionizing radiation for the treatment and diagnosis of diseases is becoming more frequent. The technologies associated with diagnostic imaging are constantly evolving, allowing faster and cheaper diagnoses to benefit the patient. However, this has caused an increase in the exposure to ionizing radiation of patients and health professionals. One of the diagnostic techniques for obtaining high-resolution anatomical images of patients is computed tomography (CT). Due to the detail and quality of the images obtained with CT, its use is becoming more frequent. The information provided by these images allows the specialist to make better diagnoses; however, exposure to X-rays deposits a dose in the patient. CT represents approximately 20% of all X-ray examinations but it is responsible for 70% of the medical dose accumulated by the patient. During the acquisition of the images, the highest dose is deposited in the area of the body whose image is to be obtained. During the incidence of X-rays, there is dispersion of these that reach sensitive organs whose dose is not evaluated. The objective of this work was to estimate, using Monte Carlo methods, the fluence and X-ray spectra and to obtain a factor that allows knowing the absorbed dose in sensitive organs due to scattered radiation during a chest CT. With the MCNP5 code, the CT equipment and a hybrid anthropomorphic phantom, type BOMAB it was found that the absorbed dose in these organs depends on the size of the organ and the distance between the organ and the surface of the slice on the thorax where the X-rays are incident.

Doses and spectra, of leaking-out and scattered photons from X-ray tubes used in dentistry.

Diagnosis by X-ray image are procedures widely used to improve the diagnosis or to follow the evolution of a medical procedure, also are used to support the cancer treatment with linear accelerators. The procedure involves the X-ray unit and the detection system, while the X-ray beam is projected onto the patient; along this procedure X-rays are scattered out from the patient body and X-rays leak-out from the X-ray unit. Both, the scattered and the leaking out radiation, are important during the evaluation or the design of the shielding barriers. X-ray tube features like voltage, electric current, target and filter are related to the dose due to the scattered and leakage radiation. Also, the dose due to the scattered radiation depends upon the scattering angle; while the dose due to the leaking out radiation, depend upon the X-ray tube housing. The objective of this work was to estimate, using Monte Carlo methods, the X-ray spectra and doses (air Kerma and Ambient dose equivalent) produced by scattered and leaking out radiation of 70, 80 and 90 kV X-ray units.

Effect of changing the neutron moderator in a thermal subcritical nuclear reactor.

Subcritical thermal nuclear reactor is the combination of nuclear fuel, moderator and external neutron source. Nevertheless, the amount of neutrons increases through nuclear fissions in the 235U in the fuel, the absorption and leakage of neutrons maintain the subcriticality condition. There are several subcritical reactors with different features and purposes. The open tank subcritical reactor Nuclear Chicago model 9000 is the heterogeneous combination of natural uranium, in hexagonal lattice, and light water, acting as moderator and reflector of neutrons, that uses a239PuBe neutron source. Worldwide there are several of these reactors mainly used in education, where due to the contact with water the Al tubes have corrosion. A possible solution is to use polyethylene as moderator. Aiming to evaluate the effect of changing the moderator, in this work Monte Carlo methods were used to model the reactor with polyethylene and water as moderators increasing the fuel load. For each model were estimated the keff and the µ parameters, and for Case 10a model was calculated the power, the Ambient dose equivalent and the fluence, of neutrons and γ-rays at five sites outside the reactor.

Implications of Tumor Characteristics and Treatment Modality on Local Recurrence and Functional Outcomes in Children With Chest Wall Sarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: To determine the impact of tumor characteristics and treatment approach on (1) local recurrence, (2) scoliosis development, and (3) patient-reported quality of life in children with sarcoma of the chest wall. SUMMARY OF BACKGROUND DATA: Children with chest wall sarcoma require multimodal therapy including chemotherapy, surgery, and/or radiation. Despite aggressive therapy which places them at risk for functional impairment and scoliosis, these patients are also at significant risk for local recurrence. METHODS: A multi-institutional review of 175 children (median age 13 years) with chest wall sarcoma treated at seventeen Pediatric Surgical Oncology Research Collaborative institutions between 2008 and 2017 was performed. Patient-reported quality of life was assessed prospectively using PROMIS surveys. RESULTS: The most common diagnoses were Ewing sarcoma (67%) and osteosarcoma (9%). Surgical resection was performed in 85% and radiation in 55%. A median of 2 ribs were resected (interquartile range = 1-3), and number of ribs resected did not correlate with margin status ( P = 0.36). Local recurrence occurred in 23% and margin status was the only predictive factor(HR 2.24, P = 0.039). With a median follow-up of 5 years, 13% developed scoliosis (median Cobb angle 26) and 5% required corrective spine surgery. Scoliosis was associated with posteriorrib resection (HR 8.43; P= 0.003) and increased number of ribs resected (HR 1.78; P = 0.02). Overall, patient-reported quality of life is not impaired after chest wall tumor resection. CONCLUSIONS: Local recurrence occurs in one-quarter of children with chest wall sarcoma and is independent of tumor type. Scoliosis occurs in 13% of patients, but patient-reported quality of life is excellent.

Shielding features of seven types on natural quartz.

The shielding features of amethyst, chalcedony, crystal rock, milky, pink, flint, and jasper quartz were calculated. The seven varieties of quartz were collected within the territory of the state of Zacatecas in Mexico. Shielding characteristics include the linear attenuation coefficients, the effective atomic numbers and the mass interaction coefficients for 1 keV to 100 GeV photons. The interaction coefficients were calculated for the coherent scattering, the photoelectric absorption, the Compton scattering, and the pair production occurring in the electric field of the atomic nucleus and the electrons. The linear attenuation coefficients were compared with those of the Portland concrete widely used as radiation shielding. In the low energy region where the photoelectric absorption is dominant the mass interaction coefficients and the total linear attenuation coefficients have three resonances due to the Si, Ca and Fe concentration, these resonances are also noticed in the effective atomic number. For photons below 60 keV the shielding performance of quartz can be used to shield X-ray devices working with less than 60 kV.

Job hazards and respiratory symptoms in Hispanic female domestic cleaners.

The occupational hazards and respiratory symptoms of domestic cleaners in USA are largely unknown. We conducted a cross-sectional study among 56 Hispanic female domestic cleaner on their health status and frequency of cleaning products used and tasks performed. While women used multi-use products (60.0%) and toilet bowl cleaners (51.8%) most days of the week, many (39.3%) reported not using personal protective equipment while cleaning. Itchy/watery eyes (61.8%) and itchy nose (56.4%) were the most frequently reported symptoms. A history of physician-diagnosed asthma was reported by 14.3% while 33.9% had symptoms of bronchial hyperresponsiveness (BHR). In conclusion, this vulnerable population has high prevalence of physician-diagnosis asthma and BHR symptoms and is potentially exposed to myriad occupational hazards. Further research exploring associations between products use, cleaning tasks and respiratory symptoms is warranted.

Úlcera gastroduodenal isquémica como complicación de la quimioembolización transarterial hepática de hepatocarcinoma / Ischemic gastroduodenal ulcer as a complication of hepatic hepatocarcinoma transarterial chemoembolization

La quimioembolización transarterial hepática es uno de los tratamientos del carcinoma hepatocelular irresecable en el que se han descrito de forma infrecuente lesiones isquémicas asociadas. Ante la aparición de sintomatología gastrointestinal alta inusual o que exceda el denominado síndrome postquimiembolización tras el procedimiento debe valorarse la realización de una gastroscopia para descartar la aparición de dichas complicaciones. Las variantes anatómicas con origen común de arterias gástricas y hepáticas pueden favorecer la migración de las microesferas hacia territorio gástrico obligando a valorar la eventual modificación de la técnica para prevenirlo.

Transarterial hepatic chemoembolization is one of the treatments of unresectable hepatocellular carcinoma in which associated ischemic lesions have been described infrequently. When unusual upper gastrointestinal symptoms or exceeding the so-called post-chemoembolization syndrome after the procedure, the performance of a gastroscopy should be assessed to rule out the occurrence of these complications. The anatomical variants with common origin of gastric and hepatic arteries can favor the migration of the microspheres into gastric territory, forcing the possible modification of the technique to prevent it.

Human predecidual stromal cells are mesenchymal stromal/stem cells and have a therapeutic effect in an immune-based mouse model of recurrent spontaneous abortion.

BACKGROUND: Human decidual stromal cells (DSCs) are involved in the maintenance and development of pregnancy, in which they play a key role in the induction of immunological maternal-fetal tolerance. Precursors of DSCs (preDSCs) are located around the vessels, and based on their antigen phenotype, previous studies suggested a relationship between preDSCs and mesenchymal stromal/stem cells (MSCs). This work aimed to further elucidate the MSC characteristics of preDSCs. METHODS: We established 15 human preDSC lines and 3 preDSC clones. Physiological differentiation (decidualization) of these cell lines and clones was carried out by in vitro culture with progesterone (P4) and cAMP. Decidualization was confirmed by the change in cellular morphology and prolactin (PRL) secretion, which was determined by enzyme immunoassay of the culture supernatants. We also studied MSC characteristics: (1) In mesenchymal differentiation, under appropriate culture conditions, these preDSC lines and clones differentiated into adipocytes, osteoblasts, and chondrocytes, and differentiation was confirmed by cytochemical assays and RT-PCR. (2) The expression of stem cell markers was determined by RT-PCR. (3) Cloning efficiency was evaluated by limited dilution. (4) Immunoregulatory activity in vivo was estimated in DBA/2-mated CBA/J female mice, a murine model of immune-based recurrent abortion. (5) Survival of preDSC in immunocompetent mice was analyzed by RT-PCR and flow cytometry. RESULTS: Under the effect of P4 and cAMP, the preDSC lines and clones decidualized in vitro: the cells became rounder and secreted PRL, a marker of physiological decidualization. PreDSC lines and clones also exhibited MSC characteristics. They differentiated into adipocytes, osteoblasts, and chondrocytes, and preDSC lines expressed stem cell markers OCT-4, NANOG, and ABCG2; exhibited a cloning efficiency of 4 to 15%; significantly reduced the embryo resorption rate (P < 0.001) in the mouse model of abortion; and survived for prolonged periods in immunocompetent mice. The fact that 3 preDSC clones underwent both decidualization and mesenchymal differentiation shows that the same type of cell exhibited both DSC and MSC characteristics. CONCLUSIONS: Together, our results confirm that preDSCs are decidual MSCs and suggest that these cells are involved in the mechanisms of maternal-fetal immune tolerance.

Characterization of six types of Mexican Onyx.

Optical, chemical, and radiation shielding characteristics of 6 types of Mexican onyx from the semi-desert of Zacatecas have been determined. Onyx samples are Yellow, Blue, Brown, Orange, Red and Green. Characterization was carried out using Energy dispersed X-Ray fluorescence, Visible Ultraviolet Spectrometry and Infrared Spectroscopy. With these techniques it was possible to study the chemical, physical and optical characteristics of the Mexican Onyx; from where the elemental composition was obtained, the absorption peaks, the vibrational modes and the optical band gap. As well as the interactions of these materials with radiation was studied. From this last study we obtained the Mass interaction coefficient for the coherent and incoherent dispersion, the photoelectric effect, the Compton scattering and the pair production, in the atomic nucleus and the electron field. For all types of onyx the total mass attenuation coefficients are alike showing a resonance due to K-shell of Ca. Mexican onyx has a good shielding features to photons of energy less than 100 keV because the most probable event is the photoelectric effect.

Nuclear pulse generator embedded in FPGA.

This manuscript presents the design and implementation of an intellectual property core, which acts as a generator of nuclear pulses. The design is embedded in a Field programmable gate array. It is capable of forming pulses with an exponential shape such as those from a radiation detector or Gaussian-shaped pulses such as those provided by a spectroscopy amplifier. Its characteristic is that the amplitude and period of these pulses can be configured by the user through a Virtual instrument generated in graphic language through the LabVIEW development platform. This can greatly reduce the volume, cost and energy consumption in relation to commercial analog nuclear electronics pulse generators.

[Ischemic gastroduodenal ulcer as a complication of hepatic hepatocarcinoma transarterial chemoembolization]. / úlcera gastroduodenal isquémica como complicación de la quimioembolización transarterial hepática de hepatocarcinoma.

Transarterial hepatic chemoembolization is one of the treatments of unresectable hepatocellular carcinoma in which associated ischemic lesions have been described infrequently. When unusual upper gastrointestinal symptoms or exceeding the so-called post-chemoembolization syndrome after the procedure, the performance of a gastroscopy should be assessed to rule out the occurrence of these complications. The anatomical variants with common origin of gastric and hepatic arteries can favor the migration of the microspheres into gastric territory, forcing the possible modification of the technique to prevent it.

Extensión metastásica gástrica de carcinoma ductal infiltrante de mama con presentación endoscópica atípica / Gastric metastatic extension of invasive ductal carcinoma of the breast with atypical endoscopic presentation

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Human predecidual stromal cells have distinctive characteristics of pericytes: Cell contractility, chemotactic activity, and expression of pericyte markers and angiogenic factors.

INTRODUCTION: Human decidual stromal cells (DSCs) play a key role in maternal-fetal interactions. Precursors of DSCs (preDSCs) localize around vessels in both the endometrium and decidua. Previous studies suggested a relationship between preDSCs and pericytes because these cells share a perivascular location, alpha smooth muscle actin (α-SM actin) expression and the ability to contract under the effects of cytokines. METHODS: To further study this relationship, we established 15 human preDSC lines and 3 preDSC clones. The preDSC lines and clones were tested by flow cytometry with a panel of 29 monoclonal antibodies, 14 of which are pericyte markers. The expression of angiogenic factors was determined by RT-PCR, chemotactic activity was studied with the migration assay, and cell contractility was evaluated with the collagen cell contraction assay. Confocal microscopy was used to study decidual sections. RESULTS: Under the effect of progesterone and cAMP, these lines decidualized in vitro: the cells became rounder and secreted prolactin, a marker of physiological DSC differentiation (decidualization). The antigen phenotype of these preDSC lines and clones was fully compatible with that reported for pericytes. PreDSC lines displayed pericyte characteristics: they expressed angiogenic factors and showed chemotactic and cytokine-induced contractile activity. Confocal microscopic examination of decidual sections revealed the expression of antigens detected in preDSC lines: α-SM actin colocalized with CD146, CD140b, MFG-E8, nestin, and STRO-1 (all of which are pericyte markers) in cells located around the vessels, a distinctive location of preDSCs and pericytes. DISCUSSION: Taken together, our results show that preDSCs are pericyte-like cells.

Adipose tissue-derived mesenchymal stromal cells as part of therapy for chronic graft-versus-host disease: A phase I/II study.

BACKGROUND AIMS: Despite the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT), the procedure is still associated with high toxicity in patients with refractory graft-versus-host disease (GvHD). Mesenchymal stromal cells (MSCs) are a new mode of therapy in the context of allo-HSCT. The objective of this study was to evaluate the safety and feasibility of the use of adipose tissue-derived MSCs (AT-MSCs) in patients with chronic GvHD. METHODS: Fourteen patients with moderate (n = 7) or severe (n = 7) chronic GvHD received 1 × 106/kg (group A, n = 9) or 3 × 106/kg (group B, n = 5) AT-MSCs with cyclosporine and prednisone as first-line therapy. RESULTS: Ten of the 14 patients were able to continue under the protocol: 80% were in complete remission, and 100% were off of steroids at week 56. The remaining 4 patients either worsened from chronic GvHD (n = 3) or abandoned the study (n = 1). At the end of the study, 11 of 14 patients are alive (overall survival 71.4%, median survival of 45.3 weeks). No suspected unexpected serious adverse reactions occurred during the trial. Neither relapse of underlying disease nor mortality due to infection was observed in this cohort. Biological studies showed increased CD19, CD4 and tumor necrosis factor-α with a temporary decrease in natural killer cells. DISCUSSION: AT-MSCs, in combination with immunosuppressive therapy, may be considered feasible and safe and likely would have an impact on the course of chronic GvHD. More studies are warranted to understand the potential benefits of AT-MSCs in these patients.

Hepatitis aguda por virus de la hepatitis E tras el consumo de carne cruda / Acute hepatitis due to hepatitis E virus after raw meat consumption

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