Investigation of the influence of calibration practices on cytogenetic laboratory performance for dose estimation.

PURPOSE: In the frame of the QA program of RENEB, an inter-laboratory comparison (ILC) of calibration sources used in biological dosimetry was achieved to investigate the influence of calibration practices and protocols on the results of the dose estimation performance as a first step to harmonization and standardization of dosimetry and irradiation practices in the European biological dosimetry network. MATERIALS AND METHODS: Delivered doses by irradiation facilities used by RENEB partners were determined with EPR/alanine dosimetry system. Dosimeters were irradiated in the same conditions as blood samples. A short survey was also performed to collect the information needed for the data analysis and evaluate the diversity of practices. RESULTS: For most of partners the deviation of delivered dose from the targeted dose remains below 10%. Deviations larger than 10% were observed for five facilities out of 21. Origins of the largest discrepancies were identified. Correction actions were evaluated as satisfactory. The re-evaluation of some ILC results for the fluorescence in situ hybridization (FISH) and premature chromosome condensation (PCC) assays has been performed leading to an improvement of the overall performances. CONCLUSIONS: This work has shown the importance of dosimetry in radiobiology studies and the needs of harmonization, standardization in irradiation and dosimetry practices and educational training for biologists using ionizing radiation.

Novel simple templates for reproducible positioning of skin applicators in brachytherapy.

PURPOSE: Esteya and Valencia surface applicators are designed to treat skin tumors using brachytherapy. In clinical practice, in order to avoid errors that may affect the treatment outcome, there are two issues that need to be carefully addressed. First, the selected applicator for the treatment should provide adequate margin for the target, and second, the applicator has to be precisely positioned before each treatment fraction. In this work, we describe the development and use of a new acrylic templates named Template La Fe-ITIC. They have been designed specifically to help the clinical user in the selection of the correct applicator, and to assist the medical staff in reproducing the positioning of the applicator. These templates are freely available upon request. MATERIAL AND METHODS: Templates that were developed by University and Polytechnic Hospital La Fe (La Fe) and Hospital Clínica Benidorm (ITIC) in cooperation with Elekta, consist of a thin sheet made of transparent acrylic. For each applicator, a crosshair and two different circles are drawn on these templates: the inner one corresponds to the useful beam, while the outer one represents the external perimeter of the applicator. The outer circle contains slits that facilitate to draw a circle on the skin of the patient for exact positioning of the applicator. In addition, there are two perpendicular rulers to define the adequate margin. For each applicator size, a specific template was developed. RESULTS: The templates have been used successfully in our institutions for more than 50 patients' brachytherapy treatments. They are currently being used for Esteya and Valencia applicators. CONCLUSIONS: The template La Fe-ITIC is simple and practical. It improves both the set-up time and reproducibility. It helps to establish the adequate margins, an essential point in the clinical outcome.

[Impacts of technological knowledge of small indigenous farmers on food availability in the Mexican southeast]. / Impactos del conocimiento tecnológico sobre la disponibilidad alimentaría de campesinos indígenas en el sureste mexicano.

This study was conducted to evaluate the impact of technological knowledge (acquired in Farmer Field Schools) on the availability of food for poor indigenous farmers, who are mainly dedicated to the production of maize for home consumption in the Cuicateca regi6n, Oaxaca, Mexico. The variables analyzed were 1) Level of technological knowledge, 2) maize yield, and 3) time that the last maize harvest supplied the food needs of the farmers in question (a proxy indicator of food availability). A random sample of 36 participants in the rural training schools and a control group of the same size were given questionnaires at the beginning and end of their study. The statistical analysis was done using the Pearson chi-2 contrast test and the Kolmogorov-Smirnov test. After finding that there was no normal distribution, the Wilcoxon test to contrast paired data was used, and finally, correlations were obtained. It was found that the increase in technological knowledge of 7.29 +/- 1.01 to 46.64 +/- 18.40 did not correlate (P > or = 0.05) with the time that the last maize harvest lasted in providing food. The results show that the increase in technological knowledge does not increase availability of maize as food.

Efectividad del cierre en bloque de la línea media del abdomen / Effectiveness of block closure of the medial line of the abdomen

Objetivo. Evaluar la efectividad del cierre en bloque de la pared abdominal sobre la línea media, con sutura continua de monofilamento sintético no absorbible, en presencia de múltiples factores de riesgo. Sede. Hospital General de segundo nivel de atención. Tipo de estudio. Prospectivo, longitudinal, sin grupo control. Pacientes y método. Se incluyeron los pacientes sometidos a laparotomía media durante el periodo comprendido entre el 1 de octubre de 1990 y el 1 de octubre de 1992, el seguimiento postoperatorio fue de 24 meses. En todos los pacientes, el cierre de la incisión se efectuó con monofilamento sintético no absorbible calibre 0 (polipropileno), la técnica incluyó el cierre continuo del peritoneo, aponeurosis posterior y aponeurosis anterior en un solo plano. Resultados. Se estudiaron 42 pacientes, 22 del sexo masculino, 20 del femenino, el promedio de edad fue de 40 años. Siete de los pacientes tenían más de 60 años, cuatro cursaron con hipotensión transoperatoria y tres tenían cáncer, éstos fueron factores que incrementaron el riesgo de falla en la cicatrización; otros factores como la cirugía de urgencia (40 pacientes) y sepsis intraabdominal (23 pacientes) también estuvieron presentes, todos los pacientes tenían al menos un factor de riesgo asociado. Las complicaciones enocntradas fueron: infección de la herida quirúrgica (3), hematoma (1). No se presentaron dehiscencia, hernia postincisional, tampoco se registró mortalidad durante los 24 meses de seguimiento. Conclusión. Se trata de un método confiable que puede prevenir complicaciones asociadas a la cicatrización de la herida quirúrgica, conserva la anatomía y fisiología de la línea media del abdomen