Automated review of patient position in DIBH breast hybrid IMRT with EPID images.

Deep Inspiration Breath Hold (DIBH) is a respiratory-gating technique adopted in radiation therapy to lower cardiac irradiation. When performing DIBH treatments, it is important to have a monitoring system to ensure the patient's breath hold level is stable and reproducible at each fraction. In this retrospective study, we developed a system capable of monitoring DIBH breast treatments by utilizing cine EPID images taken during treatment. Setup error and intrafraction motion were measured for all fractions of 20 left-sided breast patients. All patients were treated with a hybrid static-IMRT technique, with EPID images from the static fields analyzed. Ten patients had open static fields and the other ten patients had static fields partially blocked with the multileaf collimator (MLC). Three image-processing algorithms were evaluated on their ability to accurately measure the chest wall position (CWP) in EPID images. CWP measurements were recorded along a 61-pixel region of interest centered along the midline of the image. The median and standard deviation of the CWP were recorded for each image. The algorithm showing the highest agreement with manual measurements was then used to calculate intrafraction motion and setup error. To measure intrafraction motion, the median CWP of the first EPID frame was compared with that of the subsequent EPID images of the treatment. The maximum difference was recorded as the intrafraction motion. The setup error was calculated as the difference in median CWP between the MV DRR and the first EPID image of the lateral tangential field. The results showed that the most accurate image-processing algorithm can identify the chest wall within 1.2 mm on both EPID and MV DRR images, and measures intrafraction motion and setup errors within 1.4 mm.

The use of 0.5rcav as an effective point of measurement for cylindrical chambers may result in a systematic shift of electron percentage depth doses.

Electron dosimetry can be performed using cylindrical chambers, plane-parallel chambers, and diode detectors. The finite volume of these detectors results in a displacement effect which is taken into account using an effective point of measurement (EPOM). Dosimetry protocols have recommended a shift of 0.5 rcav for cylindrical chambers; however, various studies have shown that the optimal shift may deviate from this recommended value. This study investigated the effect that the selection of EPOM shift for cylindrical chamber has on percentage depth dose (PDD) curves. Depth dose curves were measured in a water phantom for electron beams with energies ranging from 6 to 18 MeV. The detectors investigated were of three different types: diodes (Diode-E PTW 60017 and SFD IBA), cylindrical (Semiflex PTW 31010, PinPoint PTW 31015, and A12 Exradin), and parallel plate ionization chambers (Advanced Markus PTW 34045 and Markus PTW 23343). Depth dose curves measured with Diode-E and Advanced Markus agreed within 0.2 mm at R50 except for 18 MeV and extremely large field size. The PDDs measured with the Semiflex chamber and Exradin A12 were about 1.1 mm (with respect to the Advanced Markus chamber) shallower than those measured with the other detectors using a 0.5 rcav shift. The difference between the PDDs decreased when a Pinpoint chamber, with a smaller cavity radius, was used. Agreement improved at lower energies, with the use of previously published EPOM corrections (0.3 rcav ). Therefore, the use of 0.5 rcav as an EPOM may result in a systematic shift of the therapeutic portion of the PDD (distances < R90 ). Our results suggest that a 0.1 rcav shift is more appropriate for one chamber model (Semiflex PTW 31010).

A modern mold room: Meshing 3D surface scanning, digital design, and 3D printing with bolus fabrication.

PURPOSE: This case series represents an initial experience with implementing 3-dimensional (3D) surface scanning, digital design, and 3D printing for bolus fabrication for patients with complex surface anatomy where traditional approaches are challenging. METHODS AND MATERIALS: For 10 patients requiring bolus in regions with complex contours, bolus was designed digitally from 3D surface scanning data or computed tomography (CT) images using either a treatment planning system or mesh editing software. Boluses were printed using a fused deposition modeling printer with polylactic acid. Quality assurance tests were performed for each printed bolus to verify density and shape. RESULTS: For 9 of 10 patients, digitally designed boluses were used for treatment with no issues. In 1 case, the bolus was not used because dosimetric requirements were met without the bolus. QA tests revealed that the bulk density was within 3% of the reference value for 9 of 12 prints, and with more judicious selection of print settings this could be increased. For these 9 prints, density uniformity was as good as or better than our traditional sheet bolus material. The average shape error of the pieces was less than 0.5 mm, and no issues with fit or comfort were encountered during use. CONCLUSIONS: This study demonstrates that new technologies such as 3D surface scanning, digital design and 3D printing can be safely and effectively used to modernize bolus fabrication.

EstudioDescriptivo: CaracterísticasdelCáncerdePielnoMelanoma en Pacientes de Consulta Externa de Dermatología del Hospital Vicente Corral Moscoso. Cuenca ­ Ecuador, 2013-2017 / Descriptive Study: Characteristics of Non Melanoma Skin Cancer in Dermatology Outpatients of Vicente Corral Moscoso Hospital. Cuenca - Ecuador, 2013-2017

INTRODUCCIÓN: El cáncer de piel no melanoma es una de las patologías más prevalentes y con gran impacto a nivel mundial; sus variantes incluyen principalmente el carcinoma basocelular y espinocelular. El objetivo de este estudio fue determinar las características del cáncer de piel no melanoma en pacientes de consulta externa de dermatología del Hospital Vicente Corral Moscoso, 2013 a 2017. MÉTODOS: Se realizó un estudio observacional retrospectivo, el universo incluyó a 278 pacientes diagnosticados de cáncer de piel no melanoma del Hospital Vicente Corral Moscoso. Se estudiaron distintas variables clínicas y demográficas, los datos fueron analizados utilizando estadística descriptiva mediante el programa SPSS versión 24.0. RESULTADOS: Se incluyó a 278 pacientes en el estudio, el 56.5% (n=157) femenino y el 43.5% (n=121) masculino; la edad media fue 72.9 años (±15.3). Las patologías más frecuentes fueron el carcinoma basocelular 75.9% (n=211) y el carcinoma espinocelular 24.1% (n=67); la cabeza fue el lugar de presentación más frecuente para los dos tipos de cáncer con un 91.5% (n=193) y 59.7% (n=40) respectivamente. La opción terapéutica más comúnmente usada fue la cirugía con un 92.4% (n=195) y 83.6% (n=56). CONCLUSIONES: El carcinoma basocelular fue el tipo de cáncer de piel no melanoma más frecuente en esta población; se presentó principalmente en pacientes mayores de 65 años, siendo la cirugía el tratamiento de elección. Se requiere fomentar políticas de promoción y prevención destinadas a mejorar el control de estas patologías.(au)

OBJECTIVE: Non-melanoma skin cancer is one of the most prevalent and impactful pathologies worldwide; the variants mainly include basal cell and squamous cell carcinoma. The aim of this study was to determine the characteristics of non-melanoma skin cancer in dermatology outpatients of Vicente Corral Moscoso Hospital, 2013 to 2017. METHODS: A retrospective observational study was performed; the universe included 278 patients diagnosed with non-melanoma skin cancer from the Vicente Corral Moscoso Hospital. Different clinical and demographic variables were studied; the data were analyzed using descriptive statistics through SPSS program version 24.0. RESULTS: 278 patients were included, 56.5% (n=157) female and 43.5% (n=121) male; the average age was 72.9 years (± 15.3). The most frequent pathologies were basal cell carcinoma 75.9% (n=211) and squamous cell carcinoma 24.1% (n=67); the head was the most frequent place of presentation for the two types of cancer with 91.5% (n=193) and 59.7% (n=40) respectively. The most frequent treatment was surgery with 92.4% (n = 195) and 83.6% (n = 56). CONCLUSIÓN: Basal cell carcinoma was the most frequent type of non-melanoma skin cancer in this population; occurs mainly in patients older than 65 years, being surgery the treatment of choice. It is necessary to promote promotion and prevention policies with the objective to improve the control of these pathologies.(au)

Low-cost optical scanner and 3-dimensional printing technology to create lead shielding for radiation therapy of facial skin cancer: First clinical case series.

PURPOSE: Three-dimensional printing has been implemented at our institution to create customized treatment accessories, including lead shields used during radiation therapy for facial skin cancer. To effectively use 3-dimensional printing, the topography of the patient must first be acquired. We evaluated a low-cost, structured-light, 3-dimensional, optical scanner to assess the clinical viability of this technology. METHODS AND MATERIALS: For ease of use, the scanner was mounted to a simple gantry that guided its motion and maintained an optimum distance between the scanner and the object. To characterize the spatial accuracy of the scanner, we used a geometric phantom and an anthropomorphic head phantom. The geometric phantom was machined from plastic and included hemispherical and tetrahedral protrusions that were roughly the dimensions of an average forehead and nose, respectively. Polygon meshes acquired by the optical scanner were compared with meshes generated from high-resolution computed tomography images. Most optical scans contained minor artifacts. Using an algorithm that calculated the distances between the 2 meshes, we found that most of the optical scanner measurements agreed with those from the computed tomography scanner within approximately 1 mm for the geometric phantom and approximately 2 mm for the head phantom. We used this optical scanner along with 3-dimensional printer technology to create custom lead shields for 10 patients receiving orthovoltage treatments of nonmelanoma skin cancers of the face. Patient, tumor, and treatment data were documented. RESULTS: Lead shields created using this approach were accurate, fitting the contours of each patient's face. This process added to patient convenience and addressed potential claustrophobia and medical inability to lie supine. CONCLUSIONS: The scanner was found to be clinically acceptable, and we suggest that the use of an optical scanner and 3-dimensional printer technology become the new standard of care to generate lead shielding for orthovoltage radiation therapy of nonmelanoma facial skin cancer.

Creation of knowledge-based planning models intended for large scale distribution: Minimizing the effect of outlier plans.

Knowledge-based planning (KBP) can be used to estimate dose-volume histograms (DVHs) of organs at risk (OAR) using models. The task of model creation, however, can result in estimates with differing accuracy; particularly when outlier plans are not properly addressed. This work used RapidPlan™ to create models for the prostate and head and neck intended for large-scale distribution. Potential outlier plans were identified by means of regression analysis scatter plots, Cook's distance, coefficient of determination, and the chi-squared test. Outlier plans were identified as falling into three categories: geometric, dosimetric, and over-fitting outliers. The models were validated by comparing DVHs estimated by the model with those from a separate and independent set of clinical plans. The estimated DVHs were also used as optimization objectives during inverse planning. The analysis tools lead us to identify as many as 7 geometric, 8 dosimetric, and 20 over-fitting outliers in the raw models. Geometric and over-fitting outliers were removed while the dosimetric outliers were replaced after re-planning. Model validation was done by comparing the DVHs at 50%, 85%, and 99% of the maximum dose for each OAR (denoted as V50, V85, and V99) and agreed within -2% to 4% for the three metrics for the final prostate model. In terms of the head and neck model, the estimated DVHs agreed from -2.0% to 5.1% at V50, 0.1% to 7.1% at V85, and 0.1% to 7.6% at V99. The process used to create these models improved the accuracy for the pharyngeal constrictor DVH estimation where one plan was originally over-estimated by more than twice. In conclusion, our results demonstrate that KBP models should be carefully created since their accuracy could be negatively affected by outlier plans. Outlier plans can be addressed by removing them from the model and re-planning.

Polymorphisms in Genes Involved in the Leptin-Melanocortin Pathway are Associated with Obesity-Related Cardiometabolic Alterations in a Southern Chilean Population.

BACKGROUND: Polymorphisms in genes encoding proteins of the leptin-melanocortin pathway have been associated with obesity. The involvement of these polymorphisms with changes in body mass index (BMI) and anthropometric measures could also imply a contribution to the risk of metabolic syndrome (MetS) and metabolic alterations. We evaluated the relationship of leptin-melanocortin system polymorphisms with obesity, MetS, and other metabolic alterations in Southern Chilean individuals. METHODS: Two-hundred individuals were grouped as normoweight (BMI 18.0-24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), and obese (BMI ≥ 30 kg/m2) or according to MetS status. Anthropometric measures (BMI, abdominal circumference, waist-to-hip ratio [WHR]) and biochemical parameters (glycemia and lipid profile) were evaluated. Polymorphisms LEP rs7799039, LEPR rs1137101, MC3R rs3746619 and rs3827103, and MC4R rs17782313 were evaluated by real-time PCR using allelic discrimination assays. RESULTS: LEPR rs1137101 GG genotype was related to reduced risk of obesity (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.08-0.79; p = 0.018) and MetS (OR 0.36, 95% CI 0.15-0.88; p = 0.024), but it was not significant after Bonferroni correction for multiple tests as compared to the AA genotype (p > 0.01). Moreover, LEPR rs1137101 allele G (AG + GG) was related to lower BMI and WHR (p < 0.01). Further multiple linear regression analysis demonstrated that this genotype was also responsible for reduced BMI in 2.44 kg/m2 and WHR in 0.033 units. MC4R rs17782313 allele C (TC + CC) was slightly associated with diminished risk of MetS (OR 0.48, 95% CI 0.23-0.98; p = 0.040) and reduced BMI values in 1.95 kg/m2 (p < 0.05). Regarding lipid profile, LEPR rs1137101 allele G carriers had lower triglycerides and very-low-density lipoprotein (VLDL) cholesterol, whereas individuals carrying the MC4R rs17782313 allele C had higher high-density lipoprotein (HDL) cholesterol (p < 0.01). LEP rs7799039 allele A (GA + AA) was slightly associated with reduced total and low-density lipoprotein (LDL) cholesterol (p < 0.05). CONCLUSIONS: These results suggest that polymorphisms at LEP, LEPR, and MC4R may be useful biomarkers of obesity-related cardiometabolic alterations in our population.

Polymorphisms in Genes Involved in the Leptin-Melanocortin Pathway are Associated with Obesity-Related Cardiometabolic Alterations in a Southern Chilean Population

BACKGROUND:Polymorphisms in genes encoding proteins of the leptin-melanocortin pathway have been associated with obesity. The involvement of these polymorphisms with changes in body mass index (BMI) and anthropometric measures could also imply a contribution to the risk of metabolic syndrome (MetS) and metabolic alterations. We evaluated the relationship of leptin-melanocortin system polymorphisms with obesity, MetS, and other metabolic alterations in Southern Chilean individuals.METHODS:Two-hundred individuals were grouped as normoweight (BMI 18.0-24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), and obese (BMI ≥ 30 kg/m2) or according to MetS status. Anthropometric measures (BMI, abdominal circumference, waist-to-hip ratio [WHR]) and biochemical parameters (glycemia and lipid profile) were evaluated. Polymorphisms LEP rs7799039, LEPR rs1137101, MC3R rs3746619 and rs3827103, and MC4R rs17782313 were evaluated by real-time PCR using allelic discrimination assays.

Morbimortalidad en Pacientes con Diagnóstico de Fractura de Cadera Atendidos en el Hospital de Especialidades José Carrasco Arteaga, 2015 / Morbidity and Mortality of Patients Diagnosed with Hip Fracture at José Carrasco Arteaga Specialties Hospital. 2015

INTRODUCCIÓN: La incidencia de fractura de cadera en el Ecuador se estima en 314 casos por 100.000 habitantes al año. El objetivo del presente estudio fue establecer la incidencia y factores de riesgo asociados a morbimortalidad en pacientes con diagnóstico de fractura de cadera. MÉTODO: Estudio retrospectivo y analítico de cohorte que estudió la incidencia y riesgo asociado a morbimortalidad. Se incluyeron todos los pacientes diagnosticados con fractura de cadera que fueron tratados en el Hospital de Especialidades José Carrasco Arteaga durante el año 2015. Para el análisis se utilizó la estadística básica descriptiva, chi-cuadrado y análisis de riesgo relativo con un intervalo de confianza al 95% (p: <0.05) para determinar significancia estadística. RESULTADOS: Se estudiaron 81 pacientes. Las complicaciones más frecuentes fueron: infección del sitio quirúrgico (13.58 %), neumonía (12.34 %) y fallo de osteosíntesis (9.87 %). La mortalidad general fue de 32.1 %. Los pacientes con dos o más complicaciones tuvieron casi dos veces más riesgo de fallecimiento (RR: 2.94; IC ­ 95 %: 1.78 ­ 4.85; p: 0.016), similar a lo observado en los pacientes con infección de la herida quirúrgica y/u osteomielitis (RR: 2.76; IC- 95 %: 1.60 ­ 4.79; p: 0.001) y en aquellos con diagnóstico de TEP (RR: 2.72; IC ­ 95 %: 1.48 ­ 4.97; p: 0.055). No se determinó asociación estadísticamente significativa entre la presencia de comorbilidades y desarrollo de complicaciones o fallecimiento. CONCLUSIÓN: El desarrollo de al menos una complicación duplica el riesgo de mortalidad y es aún mayor en los pacientes complicados con infección de la herida, osteomielitis y/o TEP; la presencia de dos o más complicaciones determina un riesgo 2 veces mayor de fallecimiento.(AU)

BACKGROUND: The incidence of hip fractures in Ecuador is around 314/100.000 people per year. The aim of this study was to establish the incidence and risk factors associated to morbidity and mortality in patients diagnosed with hip fracture. METHODS: This is a retrospective analytic-cohort research, it studied incidence and associated risks to morbidity and mortality. Patients diagnosed with hip fracture and treated at José Carrasco Arteaga Hospital during 2015 were included. Basic descriptive statistics, chi-square and relative risk (with 95% confidence interval) were used to analyze data. P value under 0.05 was used to determine statistical significance. RESULTS: 81 patients were part of the study. Most common complications were: surgical site infection (13.58 %), pneumonia (12.34 %) and osteosynthesis failure (9.87 %). General mortality reached 32.1 %. Patients with 2 or more complications had near double risk of death (RR: 2.94; 95 % - CI: 1.78 ­ 4.85; p: 0.016) as observed in those with surgical site infections or osteomyelitis (RR: 2.76; 95 % - CI: 1.60 ­ 4.79; p: 0.001) and in patients diagnosed with pulmonary embolism (RR: 2.72; 95 % - CI: 1.48 ­ 4.97; p: 0.055). Statistically significant association was not determined between presence of comorbidities and death or complications. CONCLUSION: Development of at least one complication after hip fracture duplicates death risk and is even higher in those patients with surgical site infections, osteomyelitis and/or pulmonary embolism; presence of two or more complications increased risk of death twice. (AU)

Morbimortalidad en Pacientes con Diagnóstico de Fractura de Cadera Atendidos en el Hospital de Especialidades José Carrasco Arteaga, 2015 / Morbidity and Mortality of Patients Diagnosed with Hip Fracture at José Carrasco Arteaga Specialties Hospital. 2015

INTRODUCCIÓN: La incidencia de fractura de cadera en el Ecuador se estima en 314 casos por 100.000 habitantes al año. El objetivo del presente estudio fue establecer la incidencia y factores de riesgo asociados a morbimortalidad en pacientes con diagnóstico de fractura de cadera. MÉTODO: Estudio retrospectivo y analítico de cohorte que estudió la incidencia y riesgo asociado a morbimortalidad. Se incluyeron todos los pacientes diagnosticados con fractura de cadera que fueron tratados en el Hospital de Especialidades José Carrasco Arteaga durante el año 2015. Para el análisis se utilizó la estadística básica descriptiva, chi-cuadrado y análisis de riesgo relativo con un intervalo de confianza al 95% (p: <0.05) para determinar significancia estadística. RESULTADOS: Se estudiaron 81 pacientes. Las complicaciones más frecuentes fueron: infección del sitio quirúrgico (13.58 %), neumonía (12.34 %) y fallo de osteosíntesis (9.87 %). La mortalidad general fue de 32.1 %. Los pacientes con dos o más complicaciones tuvieron casi dos veces más riesgo de fallecimiento (RR: 2.94; IC ­ 95 %: 1.78 ­ 4.85; p: 0.016), similar a lo observado en los pacientes con infección de la herida quirúrgica y/u osteomielitis (RR: 2.76; IC- 95 %: 1.60 ­ 4.79; p: 0.001) y en aquellos con diagnóstico de TEP (RR: 2.72; IC ­ 95 %: 1.48 ­ 4.97; p: 0.055). No se determinó asociación estadísticamente significativa entre la presencia de comorbilidades y desarrollo de complicaciones o fallecimiento. CONCLUSIÓN: El desarrollo de al menos una complicación duplica el riesgo de mortalidad y es aún mayor en los pacientes complicados con infección de la herida, osteomielitis y/o TEP; la presencia de dos o más complicaciones determina un riesgo 2 veces mayor de fallecimiento.(AU)

BACKGROUND: The incidence of hip fractures in Ecuador is around 314/100.000 people per year. The aim of this study was to establish the incidence and risk factors associated to morbidity and mortality in patients diagnosed with hip fracture. METHODS: This is a retrospective analytic-cohort research, it studied incidence and associated risks to morbidity and mortality. Patients diagnosed with hip fracture and treated at José Carrasco Arteaga Hospital during 2015 were included. Basic descriptive statistics, chi-square and relative risk (with 95% confidence interval) were used to analyze data. P value under 0.05 was used to determine statistical significance. RESULTS: 81 patients were part of the study. Most common complications were: surgical site infection (13.58 %), pneumonia (12.34 %) and osteosynthesis failure (9.87 %). General mortality reached 32.1 %. Patients with 2 or more complications had near double risk of death (RR: 2.94; 95 % - CI: 1.78 ­ 4.85; p: 0.016) as observed in those with surgical site infections or osteomyelitis (RR: 2.76; 95 % - CI: 1.60 ­ 4.79; p: 0.001) and in patients diagnosed with pulmonary embolism (RR: 2.72; 95 % - CI: 1.48 ­ 4.97; p: 0.055). Statistically significant association was not determined between presence of comorbidities and death or complications. CONCLUSION: Development of at least one complication after hip fracture duplicates death risk and is even higher in those patients with surgical site infections, osteomyelitis and/or pulmonary embolism; presence of two or more complications increased risk of death twice. (AU)

Caso Clínico: Fractura de Tobillo Weber B, Tratamiento Quirúrgico con Doble Sistema Tightrope® / Case Report: Weber B Ankle Fracture, Surgical Treatment with Double Tightrope® Fixation System

INTRODUCCIÓN: Las fracturas de tobillo representan un motivo frecuente de visita a los servicios de emergencias, constituyen el 25 % de las fracturas de miembro inferior. Al manejarse inadecuadamente pueden generar artrosis, por lo que adquiere importancia el manejo adecuado y oportuno que permita recuperar la movilidad temprana. CASO CLÍNICO: Paciente femenino de 17 años de edad, deportista (danza profesional), sinantecedentes patológicos de importancia, acudió al servicio de emergencias por sufrir caída de 2 metros de altura, mientras practicaba deporte, sufriendo trauma directo en miembro inferior izquierdo. Al examen físico el tobillo izquierdo se evidenció deformidad, dolor a la digitopresión, imposibilidad de apoyar el pie, inestabilidad de la articulación tibioperónea indicando lesión de la sindesmosis, tumefacción, equimosis, pulso pedio y tibial posterior presente, llenado capilar normal, y sensibilidad distal conservada. El diagnóstico fue fractura de tobillo tipo B de Weber. EVOLUCIÓN: Se realizó una reducción con osteosíntesis «tercio de caña¼ y fijación interna mediante doble sistema Tightrope®, luego del procedimiento permaneció 4 semanas con yeso cerrado, evidenciándose un adecuado proceso consolidativo en los controles radiográficos posteriores. Luego de un mes de terapia física presentó recuperación de la movilidad y negó presentar dolor o sensación de disconfort; el resultado funcional fue satisfactorio y luego de dos meses retomó su actividad regular. CONCLUSIÓN: El manejo activo con cirugía y fijación mediante sistema Tightrope® en fracturas de tobillo constituye una opción de tratamiento alternativa y eficaz en lugar de clavos sindesmales. En pacientes deportistas o con alta demanda de actividad física evita una reintervención quirúrgica y permite un retorno precoz a las actividades habituales.(AU)

BACKGROUND: Ankle fractures are a frequent reason of consult at emergency services. They represent 25 % of lower limb fractures. If are not handled properly it may lead to arthrosis, so the proper and timely treatment are important for early recovery of mobility. CASE REPORT: A 17-year old female patient, athlete and with no important medical precedents who attended to emergency department after suffering a 2-meter fall, she suffered direct trauma in lower left limb. Left ankle was painful and had swelling, ecchymosis and functional impotence. Diagnosis was Weber B ankle fracture. EVOLUTION: An open reduction with double Tightrope® fixation system was performed. She stood with a closed plaster for 4 weeks after procedure. Subsequent radiographic controls showed an adequate consolidation process. Mobility was recovered after one month of physical therapy, she did not refer pain or discomfort so the functional outcome was satisfactory. CONCLUSION: Active surgical management and fixation with Tightrope® system on ankle fractures is a fair option of treatment. It avoids reoperation and allows an early return to regular activities in athletes or in those patients with a high demand of physical activity./AU)

[Validation and clinical application of MammaPrint® in patients with breast cancer]. / Validación y aplicación clínica de MammaPrint® en pacientes con cáncer de mama.

BACKGROUND: In recent years, advances in molecular biology have resulted in innovations in breast cancer diagnostics and therapeutics. The development of genomics has revolutionized our understanding of this disease. MammaPrint® was developed as a diagnostic tool to predict risk of breast cancer recurrence using the expression of 70 genes altering the clinicopathologic paradigm of selection of patients for adjuvant cytotoxic chemotherapy. MATERIALS AND METHODS: A study of stage i-ii breast cancer patients on whom the MammaPrint® genomic assay was performed. RESULTS: The use of the MammaPrint® assay was a decisive factor for the recommendation of adjuvant treatment with chemotherapy and/or hormone therapy in patients with high risk for relapse. In our group, the patients with low-risk have not presented local or systemic recurrences DISCUSSION: The determination of the genetic characteristics and its alterations in breast cancer, is fundamentally important for a better identification of risk, as well as a better selection of cancer therapy. CONCLUSION: MammaPrint® is an effective study to determine risk of recurrence of in early stage breast cancer.

Composite electronic materials based on poly(3,4-propylenedioxythiophene) and highly charged poly(aryleneethynylene)-wrapped carbon nanotubes for supercapacitors.

Supercapacitor charge storage media were fabricated using the semiconducting polymer poly(3,4-propylenedioxythiophene) (PProDOT) and single-walled carbon nanotubes (SWNTs) that were helically wrapped with ionic, conjugated poly[2,6-{1,5-bis(3-propoxysulfonicacidsodiumsalt)}naphthylene]ethynylene (PNES). These PNES-wrapped SWNTs (PNES-SWNTs) enable efficient dispersion of individualized nanotubes in a wide range of organic solvents. PNES-SWNT film-modified Pt electrodes were prepared by drop casting PNES-SWNT suspensions in MeOH; high stability, first-generation PProDOT/PNES/SWNT composites were realized via electropolymerization of the ProDOT parent monomer (3,4-propylenedioxythiophene) in a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/propylene carbonate solution at the PNES-SWNT-modified electrode. The electrochemical properties of PProDOT and PProDOT/PNES/SWNT single electrodes and devices were examined using cyclic voltammetric methods. The hybrid composites were found to enhance key supercapacitor figures of merit (charge capacity and capacitance) by approximately a factor of 2 relative to those determined for benchmark Type I devices that exploited a classic PProDOT-based electrode material. The charge/discharge stability of the supercapacitors was probed by repeated rounds of cyclic voltammetric evaluation at a minimum depth of discharge of 73%; these experiments demonstrated that the hybrid PProDOT/PNES/SWNT composites retained ~90% of their initial charge capacity after 21,000 charge/discharge cycles, contrasting analogous data obtained for PProDOT-based devices, which showed only 84% retention of their initial charge capacity.

Conocimientos, actitudes y práctica sobre el VIH/sida en docentes de la Facultad de Medicina, Universidad Mayor de San Simón / Knowledge, attitudes and practice on HIV / AIDS in teachers of the Faculty of Medicine, Universidad Mayor de San Simon

Objetivos: describir el nivel de conocimiento que tienen los y las docentes sobre el VIH, las actitudes hacia las personas con VIH o sida (normas sociales, machismo, homosexualidad) y sus prácticas en la atención de pacientes con VIH y su comportamiento sexual individual. Métodos: es un estudio cuantitativo, descriptivo transversal, en el que se utilizó un cuestionario de 63 preguntas sobre VIH y sexualidad, dirigido a docentes de la carrera de Medicina de la Universidad Mayor de San Simón (UMSS). Los instrumentos fueron validados en 10 docentes de diferentes cursos de la UMSS, que fueron excluídos del estudio principal. Se seleccionaron 4 encuestadores en total (dos hombres y dos mujeres) que realizaron la encuesta a 97 docentes. Los datos obtenidos fueron introducidos en una base de datos diseñada en el programa SPSS 19.0. Resultados: se entrevistaron a 97 docentes, 65% hombres y 35% mujeres. La edad media es de 46 ± 8,1 años (mínima 28 y máxima 65 años). El promedio de conocimientos sobre el VIH es de 62%. El 58,8% no sabe que Santa Cruz es el departamento más afectado en Bolivia, el 68% no conoce la acción de los ARVs. El 69% no conoce la Ley del sida y 40% consideran a donadores de sangre como población de riesgo. El promedio de actitudes adecuadas fue de 92%. El 84% refiere que las personas con comportamientos de riesgo son más vulnerables a la infección. El promedio de prácticas sexuales seguras es del 77%. El 6% refiere que usa siempre condón, a veces el 51% y nunca el 17%. El 71% realizó alguna vez el test para el VIH. Conclusiones: los conceptos sobre el VIH/sida en la población estudiada son insuficientes, en tanto las actitudes y prácticas presentan mejores niveles. Existe confusión en los conceptos de riesgo en cuanto a la donación de sangre.

Objectives: to describe the level of knowledge among the teachers about HIV, attitudes towards people with HIV or AIDS (social norms, sexism, homosexuality) and practices in the care of HIV patients and their individual sexual behavior. Methods: a quantitative study is transversal study, which used a questionnaire of 63 questions about HIV and sexuality, for teachers of the School of Medicine of the Universidad Mayor de San Simón (UMSS). The instruments were validated in 10 teachers of different grades of UMSS, which were excluded from the main study. 4 interviewers were selected in total (two men and two women) who conducted the survey to 97 teachers. The data were entered into a database designed in SPSS 19.0. Results: we interviewed 97 teachers, 65% men and 35% female. The mean age was 46 ± 8.1 years (minimum 28 and maximum 65 years). The average knowledge of HIV is 62%. Overall, 58.8% did not know that Santa Cruz is the most affected department in Bolivia, 68% do not know the action of ARVs. 69% do not know the Law of AIDS and 40% consider blood donors and populations at risk. The average proper attitudes was 92%. The 84% refers to people with risky behaviors are more vulnerable to infection. The average safe sex is 77%. The 6% reported using a condom, sometimes 51% and 17% never. 71% ever performed the test for HIV. Conclusions: concepts about HIV / AIDS in the study population is inadequate, while attitudes and practices have better levels. There is confusion in the concepts of risk with regard to blood donation.

A novel hybrid reconstruction algorithm for first generation incoherent scatter CT (ISCT) of large objects with potential medical imaging applications.

This work presents a first generation incoherent scatter CT (ISCT) hybrid (analytic-iterative) reconstruction algorithm for accurate ρ{e}imaging of objects with clinically relevant sizes. The algorithm reconstructs quantitative images of ρ{e} within a few iterations, avoiding the challenges of optimization based reconstruction algorithms while addressing the limitations of current analytical algorithms. A 4π detector is conceptualized in order to address the issue of directional dependency and is then replaced with a ring of detectors which detect a constant fraction of the scattered photons. The ISCT algorithm corrects for the attenuation of photons using a limited number of iterations and filtered back projection (FBP) for image reconstruction. This results in a hybrid reconstruction algorithm that was tested with sinograms generated by Monte Carlo (MC) and analytical (AN) simulations. Results show that the ISCT algorithm is weakly dependent on the ρ{e} initial estimate. Simulation results show that the proposed algorithm reconstruct ρ{e} images with a mean error of -1% ± 3% for the AN model and from -6% to -8% for the MC model. Finally, the algorithm is capable of reconstructing qualitatively good images even in the presence of multiple scatter. The proposed algorithm would be suitable for in-vivo medical imaging as long as practical limitations can be addressed.

A 1st generation scatter CT algorithm for electron density breast imaging which accounts for bound incoherent, coherent and multiple scatter: A Monte Carlo study.

Breast CT is an emerging modality that reconstructs 3D linear attenuation coefficient (µ) images of the breast. Its tomographic nature reduces the overlap of structures and may improve tissue visualization. Current prototype systems produce large levels of scatter that could be used to reconstruct electron density (ρ _{e}) images. This could potentially enhance diagnosis. We are developing a first generation bench top CT system to investigate the benefits of simultaneous imaging µ and ρ _{e} of the intact breast. The system uses an algorithm capable of reconstructing ρ _{e} images from single Klein-Nishina scatter. It has been suggested that this algorithm may be impractical since measurements include coherent, bound incoherent and multiple scatter. To investigate this, the EGSnrc Monte Carlo (MC) code was used to simulate scans using a first generation system. These simulations were used to quantify the dose per scan, to provide raw data for the ρ _{e} reconstructions and to investigate corrections for multiple and coherent scatter since these can not be directly related to ρ _{e}. MC simulations show that the dose coefficients are similar to those of cone beam breast CT. Coherent scatter is only ∼9% concentrated in scattering angles < 8°. Electron binding reduces the number of incoherently scattered photons but this reduction can be included in the quantification of scatter measured by the system. Multiple scatter was found to be the major source of errors and, if not corrected for, can result in an overestimation of ρ _{e} by more than a factor of two. Empirical corrections, based on breast thickness or radiological path, can be used to reconstruct images where the variance in ρ _{e} error is half of that found in images derived from primary photons only. Although some practical challenges remain in creating a laboratory system, this work has shown that it is possible to reconstruct scatter images of the breast with a 4 mGy dose and further experimental evaluation of this technique is warranted.

Field effect devices and sensors based on electrospun polymer assisted tin oxide nanoribbons.

Electrospinning is presented as a facile method of preparing relatively long tin oxide (SnO2) nanofibers that are robust and stable in air. Upon heat treatment, the fibers collapse into a ribbon-like structure with surfaces that are not smooth, rather, are marked with several interconnected pathways. These nanoribbons were electrically characterized in a field effect transistor configuration in vacuum, with and without ultra violet (UV) light exposure. The resultant variable resistor device exhibits n-type behavior having an on/off ratio of approximately 6000. The devices show a direct response to UV with faster response times upon exposure to longer wavelength light. In the presence of UV, the device conductance and mobility increases, reaching a value approximately 2 cm2/-s for the 364 nm UV light source, comparable to amorphous Si.

Electrical characterization of a single electrospun porous nanostructured tin oxide ribbon.

A single nanostructured porous tin oxide ribbon, with its length, width and thickness of more than 1 mm, around 20 microm and around 20 nm, respectively, were fabricated using electrospinning, and electrically characterized in a temperature range between 300 K and 90 K, a magnetic field range from -9 to 9 T (negative sign stands for the reverse direction), and the environment of air and vacuum. The electrical conductivity (sigma) of the ribbon was found insensitive to magnetic field, but sensitive to temperature and environment. Its response time to air evacuation is 67+7 s. The strong temperature dependence of sigma in vacuum is controlled by the three-dimension variable-range hopping of localized electrons.

Bioconjugation of alkaline phosphatase to mechanically processed, aqueous suspendible electrospun polymer nanofibers for use in chemiluminescent detection assays.

Aqueous suspendible polymer nanostructures were prepared by simple microtome processing of electrospun nylon 6 nanofibers and were used to immobilize calf intestinal alkaline phosphatase (ALP) by either covalent or noncovalent bioconjugation chemistries. It was found that noncovalent immobilization of ALP to the mechanically cut nanofibers (mean length approximately 4 microm; mean diameter approximately 80 nm) using a multi-stacked, layer-by-layer (LBL) approach with the cationic polymer Sapphire II resulted in the highest enzyme loading (48.1 +/- 0.4 microg . mg(-1) nanofiber) when compared to other covalent immobilization methods based on glutaraldehyde crosslinking. The biofunctionalized nanofibers were also characterized for their chemiluminescent activity with the dioxetane substrate, CSPD. The results indicate that the kinetic parameters, K(m) and V(max), for the catalytic activity of the nanostructure-bound ALP enzyme were influenced by the particular types of immobilization methods employed. In terms of the overall catalytic performance of the various immobilized ALP systems, a single-stacked LBL assembly approach resulted in the highest level of enzymatic activity per unit mass of nanofiber support. To the best of our knowledge, this study represents the first report examining the preparation of mechanically shortened, aqueous dispersed electrospun polymer nanofibers for potential application as enzyme scaffolds in chemiluminescent-based assay systems.