Assessment of body composition in cystic fibrosis: agreement between skinfold measurement and densitometry / Evaluación de la composición corporal en adultos con fibrosis quística: concordancia entre la densitometría y la antropometría

Introduction: few studies have evaluated body composition (BC) through different techniques, and the degree of agreement between them in adults with cystic fibrosis (CF). Objectives: to describe BC using techniques to assess nutritional status and to test their concordance in CF. Methods: a cross-sectional study in CF patients in a clinically stable situation. Nutritional assessment was performed using skinfold measurement (SM) and densitometry (DXA). Fat-free mass index (FFMI) was also determined. The diagnosis of malnutrition was established if body mass index (BMI) < 18.5 kg/m2. Fat-free mass (FFM) malnutrition was diagnosed when FFMI was < 17 kg/m2 in males and < 15 kg/m2 in females (FFMI: fat-free mass in kg/height in m2). Results: forty-one patients were studied (twenty-two females, 53.7 %); median age was 29.8 (interquartile range, 20.9-33.7); BMI was 21.6 (19.8-23.0). Only four (9.8 %) patients had a BMI < 18.5. By DXA, FFM (kg) results were: median, 52.8 (47.8-56.9) with FFMI of 17.9 (16.7-19.3) in males and 36.7 (33.1-38.9) in females, FFMI of 14.7 (14.2-15.8). Twenty (48.6 %) patients presented FFM malnutrition, with 16.7 % of males and 59.1 % of females being affected. By SM, the FFMI was 18.7 (17.2-20.0) in males and 14.9 (14.2-15.8) in females; moreover, sixteen (39.1 %) patients presented malnutrition of FFM, with 20.8 % of males and 61.8 % of females being affected. For FFM (kg), high concordance was obtained between SM and DXA (intraclass correlation coefficient of 0.950); likewise when they were compared by applying the ESPEN criteria for FFM malnutrition. However, when the techniques were compared to classify malnutrition according to FFMI, the kappa coefficient was only moderate (k = 0.440). The mean difference between FFM by DXA and SM was +1.44 ± 0.62 kg in favor of SM, with greater dispersion as FFM increased. Conclusions: the prevalence of FFM malnutrition is high in adult CF patients, despite a normal BMI, especially in females (AU)

Introducción: pocos estudios han evaluado la composición corporal (BC) mediante diferentes técnicas y el grado de concordancia entre ellas en adultos con fibrosis quística (FQ). Objetivos: describir la BC mediante técnicas de evaluación Nutricional y comprobar su concordancia en la FQ. Métodos: estudio transversal de adultos con FQ en situación de estabilidad clínica. La evaluación Nutricional se realizó mediante medición de pliegues cutáneos (SM) y densitometría (DXA). También se determinó el índice de masa libre de grasa (FFMI). El diagnóstico de desnutrición se estableció si el índice de masa corporal (IMC) era < 18,5 kg/m2. Se diagnosticó desnutrición por masa libre de grasa (FFM) cuando el FFMI era < 17 kg/m2 en los hombres y < 15 kg/m2 en las mujeres (FFMI: masa libre de grasa en kg/estatura en m2). Resultados: se estudiaron cuarenta y un pacientes (veintidós mujeres (53,7 %), con una edad media de 29,8 años (rango intercuartílico, 20,9-33,7) y un IMC de 21,6 (19,8-23,0). Solo cuatro (9,8 %) pacientes tenían un IMC < 18,5. Mediante DXA, los resultados de FFM (kg) fueron (mediana y RIC): 52,8 (47,8-56,9) con FFMI de 17,9 (16,7-19,3) en los varones y 36,7 (33,1-38,9) en las mujeres con FFMI de 14,7 (14,2-15,8). Veinte (48,6 %) pacientes presentaban desnutrición del FFM, con el 16,7 % de varones y el 59,1 % de mujeres afectados. Mediante el SM, el FFMI fue de 18,7 (17,2-20,0) en los varones y de 14,9 (14,2-15,8) en las mujeres; además, dieciséis (39,1 %) pacientes presentaban malnutrición del FFMI, con el 20,8 % de varones y el 61,8 % de mujeres afectados. En el caso de la FFM (kg), se obtuvo una alta concordancia entre el SM y la DXA (coeficiente de correlación intraclase de 0,950); igualmente cuando se compararon las técnicas aplicando los criterios ESPEN para la desnutrición de la FFM. Sin embargo, cuando se compararon las técnicas para clasificar la malnutrición según el FFMI, el coeficiente kappa fue solo moderado (coeficiente kappa = 0,440) (AU)

Successful management of the open abdomen with hydrocolloid dressing in a resource-constrained setting.

PURPOSE: To evaluate and detail the management of a difficult, long-term, open abdomen in a resource constraint setting with the use of Hydrocolloid dressing. METHOD: An observational retrospective study was conducted at a single level-1 trauma center. Over a 5-year period, all the open abdomen patients were evaluated and the cohorts who were treated with Hydrocolloid dressings were described in detail from their admission to their discharge. RESULTS: During this period, there were 147 open abdomens. 7.5% (11) patients required long-term open abdomen management, in which Hydrocolloid dressing was utilized. Of this group, there were no entero/colonic-atmospheric fistulas, and there was either de-novo complete skin coverage, successful skin graft placement, or definitive abdominal wall repair in all the patients. De-novo complete skin coverage took an average of 7.4 months. All the patients were discharged home after an average of 107 days hospitalized. CONCLUSION: Despite not being an optimal management of an open abdomen, there are always a small group of these patients who lose abdominal domain, are critically ill or injured, and have prolonged hospitalization with an open abdomen. In this cohort, and especially in resource constraint settings, Hydrocolloid dressing is a cost-efficient, simple, and effective method to treat the 'long-term' open abdomens.

Fracasos de la embolización en el tratamiento del mioma uterino / Embolization failures in the treatment of uterine myoma

La embolización de la arteria uterina ha sido descrita como un método efectivo y seguro en el tratamiento de los miomas sintomáticos. Se presentan 3 casos de pacientes con útero miomatoso sintomático, y su tratamiento mediante esta técnica. En estos 3 casos, las complicaciones postembolización de los miomas hizo necesaria la práctica de una histerectomía. Así mismo se describen otras complicaciones derivadas de la técnica señaladas en la revisión bibliográfica realizada

Uterine artery embolization has been described as an effective and safe treatment for women with symptomatic uterine leiomyomata. We report three cases of women with symptomatic myomatous uterus and their treatment by this approach. In these three cases, hysterectomy was required due to complications following the embolizations. We also describe other complications of this therapeutic approach that came to light in the literature review

Estudio inmunohistoquímico de los factores de trancripción de desarrollo neural (TTF1, ASCL1 y BRN2) en los tumores neuroendocrinos de próstata / Immunohistochemical study of the neural development transcription factors (TTF1, ASCL1 and BRN2) in neuroendocrine prostate tumours

Objetivo: El carcinoma neuroendocrino de célula pequeña de próstata es una neoplasia infrecuente que supone el 0,5-1% de todas las neoplasias prostáticas. La mediana de supervivencia cáncer-específica de los pacientes con carcinoma neuroendocrino de célula pequeña de próstata es de 19 meses, y el 60,5% de los pacientes presentan enfermedad metastásica. Los factores de transcripción de desarrollo neural son moléculas implicadas en la organogénesis del sistema nervioso central y de precursores neuroendocrinos de diversos tejidos, que incluyen la glándula suprarrenal, el tiroides, el pulmón y la próstata, entre otros órganos. Material y métodos: Presentamos 3 casos de esta infrecuente entidad, aplicando los nuevos criterios de la OMS. Realizamos estudios mediante tinción de H-E y analizamos la expresión de los factores de transcripción de desarrollo neurales Achaete-scute homolog like 1, Thyroid transcription factor 1 y los factores de transcripción clase iii/iv POU, como nueva línea de investigación en la carcinogénesis de los tumores neuroendocrinos de próstata. Resultados: En el caso 1 no se observó inmunoexpresión para TTF1. Los casos 2 y 3 presentaron inmunotinción positiva para ASCL1, e inmunotinción negativa en el caso 1. La inmunotinción para BRN2 fue negativa en el caso 1 y positiva en los casos 2 y 3. Conclusión: Actualmente, la OMS no reconoce ningún marcador molecular ni genético con valor pronóstico. ASCL-1 está relacionado con las vías de señalización NOTCH y WNT. ASCL-1, TTF1 y BRN2 podrían usarse para el diagnóstico precoz y como factor pronóstico y diana terapéutica

Objective: Prostatic small-cell neuroendocrine carcinoma is an uncommon malignancy that constitutes 0.5-1% of all prostate malignancies. The median cancer-specific survival of patients with prostatic small-cell neuroendocrine carcinoma is 19 months, and 60.5% of the patients have metastatic disease. Neural development transcription factors are molecules involved in the organogenesis of the central nervous system and of neuroendocrine precursors of various tissues, including the suprarenal gland, thyroid glands, lungs and prostate. Material and methods: We present 3 cases of this uncommon condition, applying the new World Health Organisation criteria. We conducted studies through haematoxylin and eosin staining and analysed the expression of the neural development transcription factors achaete-scute homolog like 1, thyroid transcription factor 1 and the class III/IV POU transcription factors, as a new research line in the carcinogenesis of prostatic neuroendocrine tumours. Results: In case 1, there was no TTF1 immunoexpression. Cases 2 and 3 had positive immunostaining for ASCL1, and Case 1 had negative immunostaining. BRN2 immunostaining was negative in case 1 and positive in cases 2 and 3. Conclusion: The World Health Organisation does not recognise any molecular or genetic marker with prognostic value. ASCL-1 is related to the NOTCH and WNT signalling pathways. ASCL-1, TTF1 and BRN2 could be used for early diagnosis and as prognostic factors and therapeutic targets

Immunohistochemical study of the neural development transcription factors (TTF1, ASCL1 and BRN2) in neuroendocrine prostate tumours. / Estudio inmunohistoquímico de los factores de trancripción de desarrollo neural (TTF1, ASCL1 y BRN2) en los tumores neuroendocrinos de próstata.

OBJECTIVE: Prostatic small-cell neuroendocrine carcinoma is an uncommon malignancy that constitutes 0.5-1% of all prostate malignancies. The median cancer-specific survival of patients with prostatic small-cell neuroendocrine carcinoma is 19 months, and 60.5% of the patients have metastatic disease. Neural development transcription factors are molecules involved in the organogenesis of the central nervous system and of neuroendocrine precursors of various tissues, including the suprarenal gland, thyroid glands, lungs and prostate. MATERIAL AND METHODS: We present 3 cases of this uncommon condition, applying the new World Health Organisation criteria. We conducted studies through haematoxylin and eosin staining and analysed the expression of the neural development transcription factors achaete-scute homolog like 1, thyroid transcription factor 1 and the class III/IV POU transcription factors, as a new research line in the carcinogenesis of prostatic neuroendocrine tumours. RESULTS: In case 1, there was no TTF1 immunoexpression. Cases 2 and 3 had positive immunostaining for ASCL1, and Case 1 had negative immunostaining. BRN2 immunostaining was negative in case 1 and positive in cases 2 and 3. CONCLUSION: The World Health Organisation does not recognise any molecular or genetic marker with prognostic value. ASCL-1 is related to the NOTCH and WNT signalling pathways. ASCL-1, TTF1 and BRN2 could be used for early diagnosis and as prognostic factors and therapeutic targets.

Calculation of Coincidence Summing Correction Factors for an HPGe detector using GEANT4.

The aim of this paper was to calculate the True Coincidence Summing Correction Factors (TSCFs) for an HPGe coaxial detector in order to correct the summing effect as a result of the presence of (88)Y and (60)Co in a multigamma source used to obtain a calibration efficiency curve. Results were obtained for three volumetric sources using the Monte Carlo toolkit, GEANT4. The first part of this paper deals with modeling the detector in order to obtain a simulated full energy peak efficiency curve. A quantitative comparison between the measured and simulated values was made across the entire energy range under study. The True Summing Correction Factors were calculated for (88)Y and (60)Co using the full peak efficiencies obtained with GEANT4. This methodology was subsequently applied to (134)Cs, and presented a complex decay scheme.

A comparative cross-cultural study of the prevalence of late life depression in low and middle income countries.

BACKGROUND: Current estimates of the prevalence of depression in later life mostly arise from studies carried out in Europe, North America and Asia. In this study we aimed to measure the prevalence of depression using a standardised method in a number of low and middle income countries (LMIC). METHODS: A one-phase cross-sectional survey involving over 17,000 participants aged 65 years and over living in urban and rural catchment areas in 13 sites from 9 countries (Cuba, Dominican Republic, Puerto Rico, Mexico, Venezuela, Peru, China, India and Nigeria). Depression was assessed and compared using ICD-10 and EURO-D criteria. RESULTS: Depression prevalence varied across sites according to diagnostic criteria. The lowest prevalence was observed for ICD-10 depressive episode (0.3 to 13.8%). When using the EURO-D depression scale, the prevalence was higher and ranged from 1.0% to 38.6%. The crude prevalence was particularly high in the Dominican Republic and in rural India. ICD-10 depression was also associated with increased age and being female. LIMITATIONS: Generalisability of findings outside of catchment areas is difficult to assess. CONCLUSIONS: Late life depression is burdensome, and common in LMIC. However its prevalence varies from culture to culture; its diagnosis poses a significant challenge and requires proper recognition of its expression.

Actitud ante las malformaciones congénitas pulmonares / Attitude facing congenital lung malformations

Introducción: Las malformaciones congénitas pulmonares (MCP) son infrecuentes y generalmente cursan de forma asintomática en el periodo neonatal. Actualmente, su detección se realiza mediante estudios antenatales, confirmándose en el momento del nacimiento mediante pruebas de imagen. Aunque puede mantenerse una actitud expectante en los pacientes asintomáticos, es recomendable realizar una cirugía programada a los 3-6 meses de vida, dadas las graves complicaciones que pueden presentar estos pacientes. Casos clínicos: Presentamos 4 casos de MCP detectados antenatalmente en nuestro centro en los últimos 6 años, valorando su diagnóstico, características y evolución posterior. Resultados: Los 4 casos fueron malformaciones unilaterales detectadas antenatalmente mediante la ecografía del segundo trimestre, y en 3 de ellos también por resonancia magnética. Uno de ellos es una lesión híbrida, malformación adenomatoidea pulmonar congénita asociada a un secuestro intralobar en el pulmón contralateral. En el momento del nacimiento sólo 1 paciente presentó dificultad respiratoria; los otros estaban asintomáticos. La radiografía simple y la tomografía computarizada (TC) realizadas posnatalmente confirmaron el diagnóstico en 3 pacientes, pero en 1 la radiografía fue normal y la TC posterior demuestra una lesión compatible con atresia bronquial. Se realizó una lobectomía del paciente con dificultad respiratoria neonatal y del paciente con MCP-secuestro, que había presentado una infección pulmonar a los 3 meses. Conclusiones: Nuestra serie aporta 4 casos de excepcional observación. Al tratarse de una patología potencialmente grave, es importante que la conozcan todos los pediatras, así como una implicación multidisciplinaria que permita unificar criterios para proporcionar el mejor manejo posible a nuestros pacientes (AU)

Introduction: Congenital lung malformations are rare and generally have an asymptomatic development in the neonatal period. The detection of this condition is done by antenatal studies and it is later confirmed at birth with imaging tests. Although an expectant attitude towards asymptomatic patients may be adopted, the recommendation is to perform a surgical resection programmed between 3-6 months of life, given the serious complications these patients can suffer. Clinical cases: This study presents 4 cases of congenital lung malformations –detected antenatally in our center in the last 6 years– focusing on their diagnosis, characteristics and further development. Results: All four cases were unilateral malformations detected antenatally by the second quarter ultrasound, of which three were also detected by nuclear magnetic resonance. One of them was a hybrid lesion (congenital malformation of the lung-pulmonary sequestration) associated with an intralobar sequestration in the contralateral lung. Only one of the cases presented respiratory distress at birth, the others being asymptomatic. The chest-X-ray and axial tomography (CT) done postnatally confirmed the diagnosis in three of the patients; the fourth patient was diagnosed after a CT showed bronchial atresia, despite having a normal chest-X-ray. Lobectomy was performed on the patient with neonatal distress and the patient with the hybrid lesion, who had had a pulmonary infection at 3 months of life. Conclusions: This study provides 4 cases of exceptional observation. Congenital lung malformation is a potentially serious pathology, so it is important for all pediatricians to know about it. Thus, a multidisciplinary involvement is needed so as to unify criteria in order to provide patients with the best specialised care (AU)

Gastrointestinal stromal tumors (GISTs): CD117, DOG-1 and PKCθ expression. Is there any advantage in using several markers?

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. Expression of CD117, DOG1 and PKCθ was investigated immunohistochemically in a series of 99 paraffin-embedded GISTs in order to determine the sensitivity and diagnostic value of these markers. KIT exons 9, 11, 13 and 17 and PDGFRA exons 12 and 18 were amplified by PCR and sequenced. A total of 94/99 (94%) GISTs stained positive for CD117, 81/99 (82%) for PKCθ and 90/99 (91%) for DOG-1. A significant correlation was noted between CD117 and DOG-1 expression (p=0.0001). All three markers were expressed in 74% (73/99) of GISTs. Of the five CD117-negative cases, two were PKCθ-negative/DOG1-negative and had mutations in KIT exon 11. Two were PKCθ-positive/DOG1-positive and had mutations in PDGFRA (one each in exons 12 and 18), and one was DOG1-negative/PKCθ-positive, with a PDGFRA exon 18 mutation. The most sensitive marker was CD117, followed by DOG-1 and PKCθ. Although PKCθ was less sensitive, and its staining is more challenging and difficult to interpret, the use of this marker is highly recommended, particularly in CD117-negative/DOG-1-negative GISTs.

X-ray simulation with the Monte Carlo code PENELOPE. Application to Quality Control.

A realistic knowledge of the energy spectrum is very important in Quality Control (QC) of X-ray tubes in order to reduce dose to patients. However, due to the implicit difficulties to measure the X-ray spectrum accurately, it is not normally obtained in routine QC. Instead, some parameters are measured and/or calculated. PENELOPE and MCNP5 codes, based on the Monte Carlo method, can be used as complementary tools to verify parameters measured in QC. These codes allow estimating Bremsstrahlung and characteristic lines from the anode taking into account specific characteristics of equipment. They have been applied to simulate an X-ray spectrum. Results are compared with theoretical IPEM 78 spectrum. A sensitivity analysis has been developed to estimate the influence on simulated spectra of important parameters used in simulation codes. With this analysis it has been obtained that the FORCE factor is the most important parameter in PENELOPE simulations. FORCE factor, which is a variance reduction method, improves the simulation but produces hard increases of computer time. The value of FORCE should be optimized so that a good agreement of simulated and theoretical spectra is reached, but with a reduction of computer time. Quality parameters such as Half Value Layer (HVL) can be obtained with the PENELOPE model developed, but FORCE takes such a high value that computer time is hardly increased. On the other hand, depth dose assessment can be achieved with acceptable results for small values of FORCE.

La comunicación: llave maestra para la aplicación de valores humanísticosy altruistas en el cuidado de niños / Communication: master key to apply humanistic and altruistic values in childcare

Objetivo: Describir la aplicación de algunos factores como la inculcación de la fe-esperanza, desarrollo de unarelación de ayuda-confianza y aceptación de la expresión de sentimientos positivos y negativos en el cuidado queofrecen las enfermeras a niños hospitalizados. Metodología: Se utilizó la fenomenología porque facilita a laspersonas relaten sus experiencias como son vividas. Para recoger la información se utilizó la entrevista enprofundidad. Seis enfermeras a cargo el servicio de hospitalización fueron entrevistadas hasta obtener saturaciónde información. Hallazgos: Se identificaron tres temas: la fe y la esperanza como sincretismo en la recuperacióndel niño; sintiendo las carencias del otro: una manera de fomentar la ayuda y la confianza y finalmente, la actitudcomo puente para facilitar la expresión de sentimientos positivos y negativos. El eje dinamizador en los temas fue la comunicación pues facilitaba a la enfermera conocer la concepción fenomenológica de su mundo permitiendoentender sus comportamientos y reacciones emocionales. Conclusión: Las participantes reconocen cómo elafecto, el diálogo con lenguaje sencillo y la capacidad de escucha, entre otros, les ayuda en la ejecución del cuidado y ello a su vez, contribuye en la recuperación de la salud de los niños hospitalizados.

Objective: To describe the application of some factors like inculcating faith-hope, the development of an aidconfidence relationship, and acceptance of the expression of positive and negative feelings in the care offered by nursing professionals to hospitalized children. Methodology: The phenomenology was used because it helps people relate their experiences as they are lived. In-depth interviews were used to gather information. Six nursing professionals in charge of hospitalization services were interviewed until obtaining the saturation of information. Findings: Three themes were identified: Faith and hope as syncretism in child recovery; sensing the deficiencies of others: a way of fomenting aid and confidence, and, finally, attitude as a bridge to facilitate the expression of positive and negative feelings. Communication was the dynamic axis in the themes, given that it helped nursing professionals get to know the phenomenological conception of their world allowing them to understand their behavior and emotional reactions. Conclusion: The participants recognize how affection, dialogue with simple language and the capacity to listen, among others, helps them in the execution of care while contributing to health recovery of hospitalized children.

Intususcepción intestinal secundaria a metástasis de melanoma: caso clínico / Intestinal intussusception secondary to a metastatic melanoma: case report

Cutaneous melanoma is one of the extra-abdominal cancers that more commonly originates metastases in the gastrointestinal tract. We report a 63 years old male presenting with iron deficiency anemia and episodes of gastrointestinal bleeding, with a history of a melanoma of the lower eyelid excised 13 years ago, with negative surgical margins. During the follow up, the patient consulted in the emergency room for an intestinal obstruction. An abdominal CAT scan showed an ileal-ileal intussusception. The patient was operated and the involved intestinal segment was excised. The pathological study of the surgical piece disclosed a pigmented polypoid metastatic melanoma. The patient had an uneventful postoperative evolution.

El melanoma cutáneo es uno de los cánceres extra-abdominales que más frecuentemente originan metástasis viscerales en el tracto gastrointestinal. Su presentación clínica suele ser silente e insidiosa, generalmente desapercibida, atentando contra las posibilidades terapéuticas y paliativas de este grupo de pacientes. El objetivo de este trabajo es presentar el caso clínico de un paciente tratado trece años antes de un melanoma del párpado inferior izquierdo, resecado con márgenes negativos, sin evidencias de recurrencia hasta 3 meses previo a su ingreso, en que mientras estaba en estudio por una anemia ferropriva de origen digestivo, se presenta con un íleo mecánico de intestino delgado por una intususcepción íleo-ileal secundaria a una metástasis visceral pedunculada de su melanoma. Se describe el caso, se comunican los elementos clínicos y de imágenes necesarios para su diagnóstico y se realiza una revisión de la literatura pertinente.

Uncertainty analysis in MCNP5 calculations for brachytherapy treatment.

The Monte Carlo (MC) method can be applied to simulate brachytherapy treatment planning. The MCNP5 code gives, together with results, a statistical uncertainty associated with them. However, the latter is not the only existing uncertainty related to the simulation and other uncertainties must be taken into account. A complete analysis of all sources of uncertainty having some influence on results of the simulation of brachytherapy treatment is presented in this paper. This analysis has been based on the recommendations of the American Association for Physicist in Medicine (AAPM) and of the International Standard Organisation (ISO).

Parametric study of the X-ray primary spectra obtained with the MTSVD unfolding method.

The modified truncated singular value decomposition (MTSVD) unfolding method is applied to obtain primary spectra for X-ray tubes in radiodiagnostic. Three parameters - voltage, anode angle and filter thickness - of the tube are tested. Unfolded spectra are compared with theoretical extracted from IPEM-78 catalogue. A 2σ error criterion is applied to assess the minimum variations in tested parameters that permits distinguishing between close spectra.

Analysis of dose rates received around the storage pool for irradiated control rods in a BWR nuclear power plant.

BWR control rods are activated by neutron reactions in the reactor. The dose produced by this activity can affect workers in the area surrounding the storage pool, where activated rods are stored. Monte Carlo (MC) models for neutron activation and dose assessment around the storage pool have been developed and validated. In this work, the MC models are applied to verify the expected reduction of dose when the irradiated control rod is hanged in an inverted position into the pool.

Uncertainty analysis in the simulation of X-ray spectra in the diagnostic range using the MCNP5 code.

An accurate knowledge of the photonic spectra emitted by X-ray tubes in radiodiagnostics is essential to better estimate the imparted dose to patients and to improve the image quality obtained with these devices. In this work, several X-ray spectra have been simulated using the MCNP5 code to simulate X-ray production in a commercial device. To validate the Monte Carlo results, simulated spectra have been compared to those extracted from the IPEM 78 database. The uncertainty associated to some geometrical features of the tube and its effect on the simulated spectra has been analyzed using the Noether-Wilks formula. This analysis has been focused on the thickness of collimators, filters, shielding and barrel shutter. Furthermore, results show that the uncertainty due to geometrical parameters (0.98% in terms of Root Mean Squared) is higher than the statistical uncertainty associated to the MCNP5 calculations.

Analysis of image quality parameter of conventional and dental radiographic digital images.

The image quality obtained by a radiographic equipment is very useful to characterize the physical properties of the image radiographic chain, in a quality control of the radiographic equipment. In the radiographic technique it is necessary that the evaluation of the image can guarantee the constancy of its quality to carry out a suitable diagnosis. In this work we have designed some radiographic phantoms for different radiographic digital devices, as dental, conventional, equipments with computed radiography (phosphor plate) and direct radiography (sensor) technology. Additionally, we have developed a software to analyse the image obtained by the radiographic equipment with digital processing techniques, as edge detector, morphological operators, statistical test for the detected combinations‥ The design of these phantoms let the evaluation of a wide range of operating conditions of voltage, current and time of the digital equipments. Moreover, the image quality analysis by the automatic software, let study it with objective parameters.

Application of Tikhonov and MTSVD methods to unfold experimental X-ray spectra in the radiodiagnostic energy range.

A thorough knowledge of the primary spectrum is very important for Quality Control (QC) of X-ray tubes. A methodology to assess primary spectrum using a Compton spectrometer has been simulated with the MCNP5 code based on the Monte Carlo (MC) method. The Pulse Height Distribution (PHD) recorded in the detector is related with the primary X-ray spectrum by means of a Response matrix. Tikhonov and Modified Truncated Singular Values Decomposition (MTSVD) unfolding methods have been applied to the Response matrix to assess the primary spectrum. Both methods are tested comparing unfolded results with theoretical spectra from IPEM-78 catalogue.