[Clinical profile and non-recreational methamphetamine abuse (shabu) among stroke patients in the Philippine population]. / Perfil clínico y abuso de metanfetamina no recreativa (shabú) entre los pacientes con ictus en la población filipina.

INTRODUCTION: Chronic non-recreational use of methamphetamine (shabu) is increasing among the Filipino population in Barcelona. The Asian population presents a different stroke pattern, with a higher incidence of haemorrhage, and different vascular risk factors and health behaviours. The objective of this study is to describe the stroke profile and incidence of methamphetamine use in patients of Filipino origin admitted to our centre. PATIENTS AND METHODS: Demographic data, vascular risk factors, clinical data and prognosis were recorded. Methamphetamine exposure was analysed in plasma samples collected on admission, which were then analysed by liquid chromatography-mass spectrometry. RESULTS: Of a total of 6,418 stroke patients, 73 (1.1%) were identified as being of Filipino origin. The mean age was 54.4 ± 12.1 years, 54% were male and the stroke was ischaemic in 64.4% of cases. Arterial hypertension was the main risk factor. Ten (13.7%) patients tested positive for methamphetamine and amphetamine. These results confirm recent substance use prior to the stroke, mostly in men (80%). In patients who were consumers, 60% had a haemorrhagic stroke, with a poor functional prognosis at three months in 55.6% of patients. CONCLUSIONS: In our setting, patients of Filipino ethnicity admitted for stroke related to the consumption of shabu belonged a younger age bracket, with a lower prevalence of vascular risk factors and a predominance of the haemorrhagic subtype. Methamphetamine testing in Filipino stroke patients is recommended due to the high prevalence of methamphetamine use in our country.

TITLE: Perfil clínico y abuso de metanfetamina no recreativa (shabú) entre los pacientes con ictus en la población filipina.Introducción. En la población filipina de Barcelona está aumentando el consumo crónico no recreativo de metanfetaminas (shabú). La población asiática presenta un patrón de ictus diferente, con mayor incidencia de hemorragias, y diferentes factores de riesgo vascular y conductas de salud. El objetivo es describir el perfil de ictus e incidencia de consumo de metanfetaminas en pacientes de origen filipino ingresados en nuestro centro. Pacientes y métodos. Se registraron datos demográficos, factores de riesgo vascular, datos clínicos y pronóstico. Se analizó la exposición a metanfetamina en muestras de plasma recogidas en el ingreso, que se analizaron por cromatografía líquida-espectrometría de masas. Resultados. Del total de 6.418 pacientes con ictus, se identificó a 73 pacientes filipinos (1,1%). La edad media era de 54,4 ± 12,1 años, el 54% eran hombres y el ictus era isquémico en el 64,4%. La hipertensión arterial fue el principal factor de riesgo. Diez (13,7%) pacientes dieron positivo a metanfetamina y anfetamina. Estos resultados confirman un consumo reciente de sustancias previo al ictus, principalmente en hombres (80%). En pacientes consumidores, un 60% presentaba un ictus hemorrágico, con mal pronóstico funcional a tres meses en el 55,6% de los pacientes. Conclusiones. En nuestro medio, los pacientes de etnia filipina ingresados por ictus en relación con consumo de shabú presentaron un perfil de edad más joven, con menor prevalencia de factores de riesgo vascular y predominio del subtipo hemorrágico. Se recomienda la determinación de metanfetamina en los pacientes filipinos con ictus debido a la alta prevalencia del consumo de metanfetamina en nuestro país.

Red-light running behavior of cyclists in Italy: An observational study.

Accident analysis and studies on traffic revealed that cyclists' violation of red-light regulation is a typical infringement committed by cyclists. Furthermore, an association between cyclists' crash involvement and red-light violations has been found across different countries. The literature on red-light running cyclists' behavior in relation to their characteristic is still scarce. The present study, adopted an eye-observational methodology to investigates differences in cyclists' crossing behavior at intersections, with a particular attention to their demographical characteristics. The classification of cyclists' red-light behavior in risk-taking, opportunistic and law-obeying, was adopted and re-adapted to reflect more objective behaviors, eliminating any inference or judgment. Two researchers at a time observed unobtrusively at four different intersections, during morning and late afternoon peak hours, 1381 cyclists approaching the traffic light during the red phase. More than 60% of the observed cyclists violated the traffic control. Results showed that the visual search strategy displayed by the cyclists and the presence of other cyclists at the intersection are important factors in predicting the probability of red-light running behavior.

Single fraction volumetric modulated arc radiosurgery of brain metastases.

PURPOSE: To show the clinical results of the treatment of brain metastases via radiosurgery using Volumetric Modulated Arc Therapy (VMAT). MATERIALS AND METHODS: 52 patients having lung (62 %), breast (17 %), colorectal (8 %) and other cancers (13 %) with one to three brain metastases were treated with 5 non-coplanar VMAT arcs. The treatment dose varied from 12 to 20 Gy, administered in one single session. The volume of metastases ranged from 0.04 to 24.92 cc. Radiosurgery alone was used for 54 % of cases, while 19 % received whole brain radiotherapy due to relapse. Patients were classified according to the Disease-specific graded prognostic assessment (DS-GPA) index and survival was assessed via the Kaplan-Meier model. RESULTS: The median survival time was 7.2 months from the date of radiosurgery. The Karnofsky and DS-GPA indices were the most significant with regard to survival. Patients with a Karnofsky performance status (KPS) over 70 had a longer survival time of 9.2 months, as opposed to those with a KPS below 70 of 3.5 months. No significant differences were found with regard to the type of cancer or the number of lesions. Local tumour control was achieved for 42 metastases (82 %), of which a complete response was achieved for 7 lesions, a partial response for 21; 15 lesions were stabilized. Local progression was observed in 8 lesions (15 %). The median treatment time per patient was 29 min. CONCLUSIONS: The VMAT technique proves to be safe and effective for treating brain metastases via radiosurgery.

Dosimetric validation of a redundant independent calculation software for VMAT fields.

A redundant independent dosimetric calculation (RIDC) prior to treatment has become a basic part of the QA process for 3D conventional radiotherapy, and is strongly recommended in several international publications. On the other hand, the rapid growth in the number of intensity modulated treatments has led to a significant increase in the workflow associated with QA treatments. Diamond ("K&S Associates") is RIDC software which is capable of calculating VMAT (Volumetric Modulated Arc Therapy) fields. Modeling, validation and commissioning are necessary steps thereby making it a useful tool for VMAT QA. In this paper, a procedure for the validation of the calculation algorithm is demonstrated. A set 3D conventional field was verified in two ways: firstly, a comparison was made between Diamond calculations and experimental measures obtaining an average deviation of -0.1 ± 0.7%(1SD), and secondly, a comparison made between Diamond and the treatment planning system (TPS) Eclipse, obtaining an average deviation of 0.4 ± 0.8%(1SD). For both steps, a plastic slab phantom was used. VMAT validation was carried out by analyzing 59 VMAT plans in two ways: first, Diamond calculation versus experimental measurement with an average deviation of -0.2 ± 1.7%(1SD), and second, Diamond calculation versus TPS calculation with an average deviation of 0.0 ± 1.6%(1SD). In this phase a homogeneous cylindrical phantom was used. These results led us to consider this calculation algorithm validated for use in VMAT verifications.

Monte Carlo and experimental derivation of TG43 dosimetric parameters for CSM-type Cs-137 sources.

In this study, complete dosimetric datasets for the CSM2 and CSM3 Cs-137 sources were obtained using the Monte Carlo GEANT4 code. The application of this calculation method was experimentally validated with thermoluminescent dosimetry (TLD). Functions and parameters following the TG43 formalism are presented: the dose rate constant, the radial dose functional, and the anisotropy function. In addition, to aid the quality control process on treatment planning systems, a two-dimensional (2D) rectangular dose rate table (the traditional along-away table), coherent with the TG43 dose calculation formalism, is given. The data given in this study complement existing information for both sources on the following aspects: (i) the source asymmetries were considered explicitly in the Monte Carlo calculations, (ii) TG43 data were derived directly from Monte Carlo calculations, (iii) the radial range of the different tables was increased as well as the angular resolution in the anisotropy function, including angles close to the longitudinal source axis. The CSM2 source TG-43 data of Liu et al. [Med. Phys. 31, 477-483 (2004)] are not consistent with the Williamson 2D along-away data [Int. J. Radiat. Oncol., Biol., Phys. 15, 227-237 (1988)] at distances closer than approximately 2 cm from the source. The data presented here for this source are consistent with this 2D along-away table, and are suitable for use in clinical practice.

Assessment of mammography spectra using compton spectrometry techniques.

The quality control of mammography units is necessary to reduce the dose imparted to women as much as possible. An accurate characterisation of the primary X-ray spectra is very useful for this purpose. Primary spectra can be obtained using Compton spectrometry techniques. In this work, a commercial spectrometer used to characterise a mammography X-ray tube has been simulated using the Monte Carlo method by means of the MCNP code. Using the developed model, a Response matrix is obtained. Owing to the fact that this matrix is ill-conditioned, the inversion is not a simple process. This problem has been solved using the truncated singular value decomposition method. Results obtained when this methodology was applied have been compared with theoretical X-ray spectra.

Monte Carlo dosimetric characterization of the Cs-137 selectron/LDR source: evaluation of applicator attenuation and superposition approximation effects.

The purpose of this study is to calculate the dose rate distribution for the Amersham Cs-137 pellet source used in brachytherapy with the Selectron low-dose-rate remote afterloading system in gynaecological applications using the Monte Carlo code GEANT4. The absolute dose rate distribution for the pellet source was obtained and presented as a one-dimensional absolute dose rate table as well as in the Task Group 43 dose-calculation formalism. In this study, excellent agreement was found between the point source theoretical model using fitted polynomial values and Monte Carlo calculations of the dose rate distribution for the pellet source. A comparison study was also made between the dose rate distribution obtained from a complete Monte Carlo simulation (Cs-137 pellet sources + remote afterloading system plastic guide tube + gynaecological applicator) and that calculated by applying the superposition principle to Monte Carlo data of the individual pellet sources. The data were obtained for a portion of uterine tandem of typical train source configurations. Significant differences with a strong dependence on polar angle have been found that must be kept in mind for clinical dosimetry.

Monte Carlo dosimetric study of best industries and Alpha Omega Ir-192 brachytherapy seeds.

Ir-192 seeds are widely used in the USA for low dose rate interstitial brachytherapy. There are two commercially available models: those manufactured by Best Industries filtered with stainless steel, and those manufactured by Alpha-Omega seeds filtered with Pt. Newly developed 3D correction algorithms for brachytherapy are based on dosimetry data obtained on unbounded phantom size, allowing corrections for heterogeneities and actual tissue boundaries. Published dosimetric datasets for both seeds have been obtained under bounded conditions. The aim of the present study is to obtain dosimetric datasets for these seeds under full scatter conditions. The Monte Carlo GEANT4 code has been used to estimate air-kerma strength and dose rate in water around the Ir-192 seeds. Functions and parameters following the TG43 formalism are obtained and presented in tabular forms: the dose rate constant, the radial dose function, and the anisotropy function. Tables for the anisotropy factor have been obtained in order to apply punctual approximation. Differences between dose rate distributions for both seeds show that specific dataset must be used for each type of seed in clinical dosimetry. The data in the present study improve on published data in the following aspects: (i) dosimetric data were obtained under full scatter conditions, which affect dose values at distances greater than 4-5 cm from the source; (ii) the dose rate tables are given at greater distances from the source; and (iii) the spatial resolution in high dose gradient areas, such as those near the longitudinal source axis, has been improved.

Monte Carlo evaluation of kerma in an HDR brachytherapy bunker.

In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

Technical note: fitted dosimetric parameters of high dose-rate 192Ir sources according to the AAPM TG43 formalism.

Functional fits for the anisotrophy function and the radial dose function, have been studied, in a previous work, in order to characterize dose-rate distributions around some of the high-intensity 192Ir sources. The purpose of the present work is to complete the previous one in order to include all the existing HDR and PDR 192Ir sources. The sources addressed here are: the Buchler source from Amersham, the 12i and Plus PDR sources and the 12i and Plus HDR sources from GammaMed, and the new VariSource HDR source wire model VS2000 from Varian Oncology Systems.

[Spontaneous middle ear meningoencephalic herniation. 2 case reports]. / Herniación meningoencefálica espontánea en oído medio: a propósito de dos casos.

Two cases of idiopathic brain herniation into the middle ear without previous surgery are reported. Brain herniation is an unusual pathology, usually related to middle ear surgery. The idiopathic appearance of this disease is the secondly most frequent cause. Its origin is believed to be related to a congenital defect of tegmen timpani. Two elements, both rare, are emphazised: the spontaneous bilateral presentation in one of the cases, and the CSF leak as an initial symptom. We present a review of the literature, describing epidemiology results and the main accepted etiology theories. We discuss the diagnosis and treatment methods: magnetic resonance imaging and surgery.

Dosimetric characteristics of the CDC-type miniature cylindrical 137Cs brachytherapy sources.

The low dose rate CDC-type miniature cylindrical 137Cs sources are available, with one or three active beads, for use in source trains in automatic and manual afterloading systems for gynecological brachytherapy. Absolute dose rate distributions in water have been calculated around these sources using the Monte Carlo GEANT3 code and they are presented as conventional two-dimensional Cartesian lookup tables. The AAPM Task Group 43 formalism for dose calculation has been also applied. The dose rate constant obtained for the one bead source is lambda = 1.113 +/- 0.003cGyh(-1) U(-1), and the value for the three bead source is A= 1.103 +/- 0.003cGyh(-1) U(-1). Finally, for the treatment planning systems based on Sievert-type algorithms, the attenuation coefficients that best reproduce Monte Carlo dose rate distribution are given.

[Why does a mastoidectomy cavity become suppurative? Our experience and revision of the literature]. / Por qué supura una cavidad de mastoidectomía? Nuestra experiencia y revisión de la literatura.

The main goal for performing surgery for chronic otitis media is to eliminate the disease and improve hearing whenever possible. Persistent drainage of a mastoid cavity means failure of surgery and of achieving the goal. In this study, we present our department's attitude for suppurative mastoid cavities as well as the reasons that do not allow adequate control of them.

[Tympanoplasty using cartilage: 3 years of experience]. / Timpanoplastia con cartílago: 3 años de experiencia.

We present our results in a timpanoplasty technique using autologous cartilage, in a retrospective study of 71 cases within 3 years. We used this technique in revision surgery, large perforations, severe retractions, and atrophic membranes. 32% of cases needed ossicular chain reconstruction. A complete closing of the membrane was obtained in 86% of cases, while 14% remained re-perforated or discontinued between cartilage pieces. These results are comparable to other studies using cartilage graft with several techniques. These results encourage us to continue using this technique in order to acquire more experience and a better knowledge about the efficacy of this technique.

Monte Carlo calculation of dose rate distributions around the Walstam CDC.K-type 137Cs sources.

Basic dosimetric data for the Walstam CDC.K-type low dose rate 137Cs sources in water have been calculated using Monte Carlo techniques. These sources, CDC.K1 -K3 and CDC.K4, are widely used in a range of applicators and moulds for the treatment of intracavitary and superficial cancers. Our purpose is to improve existing data about these sources using the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water have been calculated around these sources and are presented as conventional 2D Cartesian look-up tables. Also the AAPM Task Group 43 formalism for dose calculation has been applied. The calculated dose rate constant for the CDC.K1-K3 source is A = 1.106 +/- 0.001 cGy h(-1) U(-1), and for the CDC.K4 source, A = 1.092 +/- 0.001 cGy h(-1) U(-1). The anisotropy of the sources are accurately studied and F(r, theta) tables are given. Also phi an(r) factors are presented. The radial dose functions are given as a polynomial fit to the calculated data up to 15 cm. Best-fit values of coefficients suitable for use in Sievert integral calculations have been derived.

A monte carlo study of dose rate distribution around the specially asymmetric CSM3-a 137Cs source.

The CSM3 137Cs type stainless-steel encapsulated source is widely used in manually afterloaded low dose rate brachytherapy. A specially asymmetric source, CSM3-a, has been designed by CIS Bio International (France) substituting the eyelet side seed with an inactive material in the CSM3 source. This modification has been done in order to allow a uniform dose level over the upper vaginal surface when this 'linear' source is inserted at the top of the dome vaginal applicators. In this study the Monte Carlo GEANT3 simulation code, incorporating the source geometry in detail, was used to investigate the dosimetric characteristics of this special CSM3-a 137Cs brachytherapy source. The absolute dose rate distribution in water around this source was calculated and is presented in the form of an along-away table. Comparison of Sievert integral type calculations with Monte Carlo results are discussed.

Monte Carlo dosimetry of the Buchler high dose rate 192Ir source.

In this study a complete set of dosimetric data is presented for the high dose rate (HDR) source from Amersham used in the Buchler remote afterloading HDR unit. These data have been calculated by means of the Monte Carlo simulation code GEANT taking into account the detailed geometry of the source. Absolute dose rate distributions in water were calculated around this source and are presented as conventional 2D Cartesian look-up tables. All dosimetric quantities recommended by the AAPM Task Group 43 report have been calculated. Quantities determined are: dose rate constant, radial dose function, anisotropy function, anisotropy factor and anisotropy constant. The dose rate distributions of the Buchler HDR source are compared with those of other HDR sources used in brachytherapy, showing that the differences are large in zones near the long source axis due to oblique filtration. These Monte Carlo simulated data in water can be used for clinical applications.

Dosimetry characteristics of the Plus and 12i Gammamed PDR 192Ir sources.

In this study a complete set of dosimetric data for the Plus and 12i Gammamed PDR (pulsed dose rate) 192Ir sources is presented. These data have been calculated using the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water around these sources were calculated and are presented in form of conventional two dimensional (2D) Cartesian look-up tables. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are dose rate constant, radial dose function, anisotropy function and anisotropy factor. The dose rate distribution of the 12i source was compared with the corresponding data for the microselectron PDR source showing large differences between both sources.

Technical note: Monte-Carlo dosimetry of the HDR 12i and Plus 192Ir sources.

In this study a complete set of dosimetric data for the GammaMed high dose rate (HDR) 12i and Plus 192Ir sources are presented. These data have been calculated by means of the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water are presented as conventional two dimensional (2D) Cartesian look-up tables, and in the TG43 formalism.