SOLIDUSS: Solid-state diffusion software for radiation protection.

The out-diffusion of radionuclides from activated material in case of a fire may represent a non-negligible contribution to the radiological source term of such an event. In order to assess the contribution of this phenomenon, a software package has been designed and implemented. In the present document we briefly introduce the numerical treatment used to tackle the problem prior to the explanation of the software's logic. The document ends with an exemplary simulation and a study carried out to validate the implementation of the algorithm. The presented tool has been named SOLIDUSS, it is mainly written in C++ and uses a Monte Carlo based approach to simulate the diffusion of radioisotopes within solid materials. It is designed to run coupled with CERN-FLUKA, taking advantage of its geometry kernel to carry out diffusion calculations in arbitrarily complex geometries. The user can provide 3D temperature maps along with many other parameters that allow the program to target a wide range of different scenarios. As results SOLIDUSS provides 3D radionuclide concentration maps as well as the amount of radionuclides out-diffused from the selected materials. So far, this software has undergone numerical validation which will be discussed in this paper. Benchmarking against experimental data is currently ongoing.

BNCT research activities at the Granada group and the project NeMeSis: Neutrons for medicine and sciences, towards an accelerator-based facility for new BNCT therapies, medical isotope production and other scientific neutron applications.

The Granada group in BNCT research is currently performing studies on: nuclear and radiobiological data for BNCT, new boron compounds and a new design for a neutron source for BNCT and other applications, including the production of medical radioisotopes. All these activities are described in this report.

Exploring neutron capture therapy with 33S and 10B.

The 33S(n,α)30Si reaction was proposed as cooperative neutron capturer to 10B(n,α)7Li in Neutron Capture Therapy (NCT). At that moment, the available 33S(n,α)30Si cross-section data were scarce and discrepant in key energy ranges for its use in NCT. Since then, three experiments have been carried out at n_TOF facility at CERN and at Institut Laue-Langevin. These new data are used for the calculation of the dose rate on ICRU-4 tissue by using kerma factors, a simplified model of tissue and a 13.45 keV neutron beam, energy of the most important 33S(n,α)30Si resonance. A significant enhancement of the dose rate due to the presence of 33S is shown. In spite of the limitations, the cooperative action of 33S and 10B is an interesting possibility to be studied for accelerator-based neutron sources with non-moderated neutrons.

SEOM clinical guideline thyroid cancer (2019).

Thyroid carcinoma is the most frequent endocrine malignancy and accounts for around 3% of global cancer incidence. Different histologies and clinical scenarios make necessary a multidisciplinary approach that includes new diagnostic methods and surgical, radiopharmaceutical and systemic therapies. This guideline updates several aspects of management of thyroid cancer.

DOSE EFFECT OF THE 33S(n,α) 30SI REACTION IN BNCT USING THE NEW n_TOF-CERN DATA.

33S is a stable isotope of sulphur which is being studied as a potential cooperative target for Boron Neutron Capture Therapy (BNCT) in accelerator-based neutron sources because of its large (n,α) cross section in the epithermal neutron energy range. Previous measurements resolved the resonances with a discrepant description of the lowest-lying and strongest one (at 13.5 keV). However, the evaluations of the major databases do not include resonances, except EAF-2010 which shows smaller values in this range than the experimental data. Furthermore, the glaring lack of data below 10 keV down to thermal (25.3 meV) has motivated a new measurement at n_TOF at CERN in order to cover the whole energy range. The inclusion of this new 33S(n,α) cross section in Monte Carlo simulations provides a more accurate estimation of the deposited kerma rate in tissue due to the presence of 33S. The results of those simulations represent the goal of this work.

Using a Tandem Pelletron accelerator to produce a thermal neutron beam for detector testing purposes.

Active thermal neutron detectors are used in a wide range of measuring devices in medicine, industry and research. For many applications, the long-term stability of these devices is crucial, so that very well controlled neutron fields are needed to perform calibrations and repeatability tests. A way to achieve such reference neutron fields, relying on a 3 MV Tandem Pelletron accelerator available at the CNA (Seville, Spain), is reported here. This paper shows thermal neutron field production and reproducibility characteristics over few days.

(33)S as a cooperative capturer for BNCT.

(33)S is a stable isotope of sulfur for which the emission of an α-particle is the dominant exit channel for neutron-induced reactions. In this work the enhancement of both the absorbed and the equivalent biologically weighted dose in a BNCT treatment with 13.5keV neutrons, due to the presence of (33)S, has been tested by means of Monte Carlo simulations. The kerma-fluence factors for the ICRU-4 tissue have been calculated using standard weighting factors. The simulations depend crucially on the scarce (33)S(n,α)(30)Si cross-section data. The presence of a high resonance at 13.5keV was established by previous authors providing discrepant resonance parameters. No experimental data below 10keV are available. All of this has motivated a proposal of experiment at the n_TOF facility at CERN. A setup was designed and tested in 2011. Some results of the successful test will be shown. The experiment is scheduled for the period November to December 2012.

Trastuzumab or lapatinib with standard chemotherapy for HER2-positive breast cancer: results from the GEICAM/2006-14 trial.

BACKGROUND: The addition of trastuzumab (T) and lapatinib (L) to neoadjuvant chemotherapy increases the pathological complete response (pCR) rate in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. We investigated the efficacy of T or L with neoadjuvant chemotherapy and specific efficacy biomarkers. METHODS: Patients with stages I-III (including inflammatory) HER2-positive breast cancer were randomised to receive epirubicin (E) plus cyclophosphamide (C) × 4 cycles followed by docetaxel (D) plus either T (EC-DT) or L (EC-DL). End points included pCR (primary), clinical response, toxicity, and pCR-predictive biomarkers. RESULTS: We randomised 102 patients to EC-DT (50) and EC-DL (52). Median age was 48, 56% were premenopausal and 58% had oestrogen receptor (ER)-positive tumours. Pathological complete response in breast was 52.1% (95% CI:38.0-66.2%) for EC-DT and 25.5% (95% CI:13.5-37.5%) for EC-DL (P=0.0065). Pathological complete response in breast and axilla was 47.9% for EC-DT and 23.5% for EC-DL (P=0.011). Grade 3-4 toxicity did not differ across treatments, except for diarrhoea (2% in EC-DT vs 13.5% in EC-DL, P=0.030). Multivariate analyses showed that treatment (P=0.036) and ER (P=0.014) were the only predictors of pCR in both groups. CONCLUSION: EC-DT exhibited higher efficacy and lower toxicity than EC-DL. Of the different biomarkers studied, only the absence of ER expression was associated with increased pCR.

Análisis de varias medidas de contención del gasto farmacéutico ambulatorio en una Unidad de Cirugía Mayor Ambulatoria / Analysis of several containment measures of pharmaceutical expenditure in an Ambulatory Surgery Centre

OBJETIVO: En el actual contexto de crisis, la sostenibilidad del Sistema Nacional de Salud debe considerarse prioritaria. Este estudio se propone comparar varias medidas de ahorro en el gasto farmacéutico debido al tratamiento farmacológico ambulatorio posquirúrgico de una Unidad de Cirugía Mayor Ambulatoria de tipo autónomo. MATERIAL Y MÉTODO: Análisis farmacoeconómico retrospectivo de minimización de costes del gasto debido a la prestación farmacéutica ambulatoria de una Unidad de Cirugía Mayor Ambulatoria durante 2011. Se incluyeron 3.346 pacientes intervenidos quirúrgicamente y dados de alta el mismo día. Los tratamientos se recogieron del informe de alta de cada paciente. Se compararon los cambios en el gasto farmacéutico ambulatorio real después de aplicar, por separado, cada una de las siguientes medidas: 1) aumento del copago; 2) mejora de la calidad de la prescripción; 3) dispensación por unidades en las oficinas de farmacia, y 4) dispensación a través del Servicio de Farmacia Hospitalaria. RESULTADOS: El gasto farmacéutico ambulatorio real fue de 29.454,21 €. El aumento del copago supone una transferencia de 2.091,82 € del gasto de financiadores a usuarios. Mejorar la calidad de las prescripciones, dispensar por unidades en las oficinas de farmacia, y dispensar a través del Servicio de Farmacia Hospitalaria situaron el gasto farmacéutico en 24.215,14 €, 21.766,24 € y 7.827,71 €, respectivamente. CONCLUSIONES: La sola consideración del copago para contener el gasto farmacéutico derivado de la prescripción ambulatoria de medicamentos en una Unidad de Cirugía Mayor Ambulatoria es la medida menos eficaz. La más eficaz, para este fin, es la dispensación de los medicamentos a través del Servicio de Farmacia Hospitalaria

OBJECTIVE: In the context of the current crisis, sustainability of National Health Service must be considered a priority issue. To compare several cost saving measures in drug expenditure due to outpatient drug treatment after surgery in an Ambulatory Surgical Centre. Material and method. Pharmaco-economic analysis of cost minimization of ambulatory pharmaceutical services during the year 2011. A total of 3,346 patients were operated on and discharged on the same day, were included. Treatments were collected from the discharge report of each patient. We compared changes in real outpatient drug spending after separately applying each of the following measures: 1) increasing the co-payment; 2) improving the quality of prescribing; 3) dispensing by units of drugs through pharmacies, and 4) dispensing through the hospital pharmacy service. RESULTS: The real outpatient pharmaceutical expenditure was 29,454.21 €. Increasing the co-payment mean a transfer of 2,091.82 € from the funding institutions to users. Improving the quality of prescriptions, dispensing through units of drugs in the pharmacy, and dispensing through the hospital pharmacy service led to a pharmaceutical expenditure of 24,215.14 €, 21,766.24 € and 7,827.71 €, respectively. CONCLUSIONS: Only considering co-payment to contain pharmaceutical expenditure arising from prescribing in an Ambulatory Surgical Centre is the least effective measure. The most effective measure, for this purpose, is the supply of drugs through the hospital pharmacy service

Bevacizumab plus preoperative chemotherapy in operable HER2 negative breast cancer: biomarkers and pathologic response

PURPOSE: The primary aim of this trial was to assess the rate of pathologic complete responses (pCR) of doxorubicin/cyclophosphamide (AC) followed by bevacizumab/docetaxel (BT), as neoadjuvant therapy for breast cancer (BC). Furthermore, the association between biomarkers and the pCR was explored. METHODS: Patients with HER-negative operable stage II-III BC ≥ 2 cm were enrolled. Four cycles of AC (A 60 mg/m(2) and C 600 mg/m(2), every 3 weeks) followed by 4 cycles of BT (B 15 mg/kg and T 75 mg/m(2), every 3 weeks), were planned. A core-biopsy was performed for biological markers assessment. RESULTS: Seventy-two women were included. Forty-three (63 %) patients were hormone receptor-positive. Sixty-four (89 %) completed the planned treatment, and 66 evaluable patients underwent surgery (92 %): a pCR was achieved in 16 of them (24, 95 % CI 15-36 %). pCR was significantly higher in tumors hormone receptor-negative, and in those with Angiotensin II type 1 receptor (AGTR1) protein overexpression. The overall clinical response rate was 86 % (95 % CI 76-93 %), including 42 complete responses. No unexpected toxicities or treatment-related deaths were observed. CONCLUSION: This regimen showed a remarkable clinical and pathological activity: the suggested relation between pCR and AGTR1 overexpression should be confirmed in larger trials (AU)

[Analysis of several containment measures of pharmaceutical expenditure in an Ambulatory Surgery Centre]. / Análisis de varias medidas de contención del gasto farmacéutico ambulatorio en una Unidad de Cirugía Mayor Ambulatoria.

OBJECTIVE: In the context of the current crisis, sustainability of National Health Service must be considered a priority issue. To compare several cost saving measures in drug expenditure due to outpatient drug treatment after surgery in an Ambulatory Surgical Centre. MATERIAL AND METHOD: Pharmaco-economic analysis of cost minimization of ambulatory pharmaceutical services during the year 2011. A total of 3,346 patients were operated on and discharged on the same day, were included. Treatments were collected from the discharge report of each patient. We compared changes in real outpatient drug spending after separately applying each of the following measures: 1) increasing the co-payment; 2) improving the quality of prescribing; 3) dispensing by units of drugs through pharmacies, and 4) dispensing through the hospital pharmacy service. RESULTS: The real outpatient pharmaceutical expenditure was 29,454.21€. Increasing the co-payment mean a transfer of 2,091.82€ from the funding institutions to users. Improving the quality of prescriptions, dispensing through units of drugs in the pharmacy, and dispensing through the hospital pharmacy service led to a pharmaceutical expenditure of 24,215.14€, 21,766.24€ and 7,827.71€, respectively. CONCLUSIONS: Only considering co-payment to contain pharmaceutical expenditure arising from prescribing in an Ambulatory Surgical Centre is the least effective measure. The most effective measure, for this purpose, is the supply of drugs through the hospital pharmacy service.

Bevacizumab plus preoperative chemotherapy in operable HER2 negative breast cancer: biomarkers and pathologic response.

PURPOSE: The primary aim of this trial was to assess the rate of pathologic complete responses (pCR) of doxorubicin/cyclophosphamide (AC) followed by bevacizumab/docetaxel (BT), as neoadjuvant therapy for breast cancer (BC). Furthermore, the association between biomarkers and the pCR was explored. METHODS: Patients with HER-negative operable stage II-III BC ≥ 2 cm were enrolled. Four cycles of AC (A 60 mg/m(2) and C 600 mg/m(2), every 3 weeks) followed by 4 cycles of BT (B 15 mg/kg and T 75 mg/m(2), every 3 weeks), were planned. A core-biopsy was performed for biological markers assessment. RESULTS: Seventy-two women were included. Forty-three (63 %) patients were hormone receptor-positive. Sixty-four (89 %) completed the planned treatment, and 66 evaluable patients underwent surgery (92 %): a pCR was achieved in 16 of them (24, 95 % CI 15-36 %). pCR was significantly higher in tumors hormone receptor-negative, and in those with Angiotensin II type 1 receptor (AGTR1) protein overexpression. The overall clinical response rate was 86 % (95 % CI 76-93 %), including 42 complete responses. No unexpected toxicities or treatment-related deaths were observed. CONCLUSION: This regimen showed a remarkable clinical and pathological activity: the suggested relation between pCR and AGTR1 overexpression should be confirmed in larger trials.

Sulfur-33 nanoparticles: a Monte Carlo study of their potential as neutron capturers for enhancing boron neutron capture therapy of cancer.

In this paper, the potential effect of enhancing BNCT near the surface of the target volume by means of the addition of the sulfur isotope (33)S is studied. By means of Monte Carlo simulations, it is found a noticeable enhancement effect (local increase of the dose at the isotope site) when it is present at local concentrations that in principle can be reached by means of sulfur nanoparticles. A neutron beam with a high component of 13.5 keV would be required to produce this effect. Some open problems are discussed.

[Assessment of standard parenteral nutrition in children]. / Evaluación de nutrición parenteral estandarizada en niños.

INTRODUCTION: Nowadays, there is a stronger consensus on the proceedings of nutritional support with parenteral nutrition (PN) in paediatrics, the prescription standards, its formulation, elaboration, and nutritional requirements in order to improve the process quality and the patient's safety. The use of standardized PN solutions in children is rare due to the difficulty to adapt them to every pathophysiologic condition. In order to do so, in 2006 we designed and validated a big range of standard solutions for children weighing more than 10 kg or being older than 1 year. OBJECTIVE: To assess the use of standard PN solutions and their suitability in children from January of 2006 until June of 2008: the frequency of prescription of standard solutions by age, weight, and indication, as well as their modifications. We compared the nutrients given by individualized PN solutions versus the recommendations of the Reference Guidelines and standardised PN. RESULTS: 47 children with a mean weight of 26.6 kg (9-50) and mean age 6.8 years (1-14) received 539 units of PN. Standardized PN (437) were used in 83% of the patients. Their total energy requirements were reached within 1-3 days by using one to three types of formulas. Only 4% (22) of them were modified, with easily feasible changes: volume increase (16), glucose lowering (3), and potassium increase (3). The analysis of the individualized PN in 8 children shows the same trend, with a caloric intake lower than 33% of the recommended one. CONCLUSION: Standardized PN meet the nutritional requirements in most of the patients according to their morbid condition, highlighting their adaptability and versatility. Their use has eased the prescription-validation-preparation circuit and has improved the efficiency of the process.

Evaluación de nutrición parenteral estandarizada en niños / Assessment of standard parenteral nutrition in children

Introducción: En la actualidad existe un mayor consenso en el proceso de soporte nutricional con Nutrición Parenteral (NP) en pediatría, en los estándares de la prescripción, formulación, elaboración y en los requerimientos nutricionales, para mejorar la calidad del proceso y seguridad en el paciente. La utilización de soluciones estandarizadas de NP en niños es minoritaria por la dificultad de adaptación a las distintas situaciones fisiopatológicas. Para hacerlo viable, en el 2006 diseñamos y validamos un amplio rango de soluciones estandarizadas para niños mayores de 10 kg y/o mayores de 1 año. Objetivo: Evaluar la utilización e idoneidad de las soluciones de NP estandarizadas en un Hospital de Tercer Nivel desde su implantación. Método: Analizamos todas las prescripciones y formulaciones de NP de los niños desde enero de 2006 hasta junio de 2008: la frecuencia de prescripción de soluciones estándar según edad, peso e indicación y sus modificaciones. Comparamos los nutrientes aportados con las soluciones NP individualizados frente a las recomendaciones de las Guías de referencia y las NP estandarizadas. Resultados: 47 niños con un peso medio de 26,6 kg (9-50) y edad media 6,8 años (1-14) recibieron 539 unidades de NP. Las NP estandarizadas (437) fueron utilizadas en el 83% de los pacientes. Sus requerimientos totales energéticos se alcanzaron de1 a 3 días , utilizando de una a tres tipos fórmulas . De ellas solo tuvieron modificación un 4% (22), con cambios fácilmente aplicables : aumento del volumen (16), disminución de la glucosa (3), y aumento del potasio (3). El análisis de las NP individualizadas en 8 niños, muestran una misma tendencia, menor aporte calórico en un 33% al recomendado. Conclusión: Las soluciones de PN estandarizadas se adecuaron a las necesidades nutricionales de la mayoría de los pacientes, según su estado y patología, destacando su adaptabilidad y versatilidad. Su utilización, ha agilizado el circuito prescripción-validación-preparación y ha mejorado la eficiencia del proceso (AU)

Introduction: Nowadays, there is a stronger consensus on the proceedings of nutritional support with parenteral nutrition (PN) in paediatrics, the prescription standards, its formulation, elaboration, and nutritional requirements in order to improve the process quality and the patient's safety. The use of standardized PN solutions in children is rare due to the difficulty to adapt them to every pathophysiologic condition. In order to do so, in 2006 we designed and validated a big range of standard solutions for children weighing more than 10 kg or being older than 1 year. Objective: To assess the use of standard PN solutions and their suitability in children from January of 2006 until June of 2008: the frequency of prescription of standard solutions by age, weight, and indication, as well as their modifications. We compared the nutrients given by individualized PN solutions versus the recommendations of the Reference Guidelines and standardised PN. Results: 47 children with a mean weight of 26.6 kg (9-50) and mean age 6.8 years (1-14) received 539 units of PN. Standardized PN (437) were used in 83% of the patients. Their total energy requirements were reached within 1-3 days by using one to three types of formulas. Only 4% (22) of them were modified, with easily feasible changes: volume increase (16), glucose lowering (3), and potassium increase (3). The analysis of the individualized PN in 8 children shows the same trend, with a caloric intake lower than 33% of the recommended one. Conclusion: Standardized PN meet the nutritional requirements in most of the patients according to their morbid condition, highlighting their adaptability and versatility. Their use has eased the prescription-validation-preparation circuit and has improved the efficiency of the process (AU)

[Study into the use of cetuximab in metastatic colorectal cancer in a third level hospital]. / Estudio de utilización de cetuximab en cáncer colorrectal metastásico en un hospital de tercer nivel.

OBJECTIVES: In this study we will analyse the use of cetuximab in the treatment of metastatic colorectal cancer (MCC) in a third level hospital. We will establish the usage conditions in our centre in keeping with those approved in current technical records. We will also record the treatment duration under the different usage conditions and use the information available in material that has been published to date. METHODS: An indication-prescription study of cetuximab in MCC was carried out on all patients treated with cetuximab for colorectal cancer in the period between 2004 and 2007 in our hospital. The number of prescriptions that do not fit the approved recommendations for cetuximab in MCC treatment (and why they do not fit) is determined. Descriptive statistical analysis was carried out for the different variables collected, and a Kaplan-Meier analysis was carried out for the treatment duration variable, so as to determine whether there is a difference in effectiveness for the common uses in our hospital. RESULTS: Data was recorded for 74 patients treated with cetuximab. The average cost per patient was 14,399 Euro and on average, 15.3 dosages were administered per patient. The average initial dosage was 710 mg with an average dosage of 446 mg after that. The average duration of the treatments was 15.4 weeks. cetuximab was administered to 7 patients as first-line treatment and to 32 patients who had not used Irinotecan previously. Irinotecan was not associated with cetuximab treatment in 9 patients, and it was used in 14 patients resulting in a negative outcome for the EFGR test. Treatment duration was longer in the case of its use as first-line treatment (27.7 weeks), if Irinotecan had not been used before (23.3 weeks), if Irinotecan was used (20.5 weeks) and in patients with positive EFGR results (19.6 weeks.) The median treatment duration, under the different conditions, was less than the average but with no major differences between them. 70.3 % of prescriptions did not fit with the data sheet. CONCLUSIONS: The use of cetuximab under different conditions to those approved on the technical data sheet creates an increase in the number of patients treated and a longer duration of the treatments which implies an increase in intake. The average and the mean treatment times for the usage conditions found did not present any significant statistical differences. There are a small number of patients who benefit from this treatment which can be seen by the large average, in comparison with the mean, without any of the conditions in which the analysis was carried out seeming to determine a higher response. The treatment duration in our study was similar to the durations recorded in relevant literature for these usage conditions.

Estudio de utilización de cetuximab en cáncer colorrectal metastásico en un hospital de tercer nivel / Study into the use of cetuximab in metastatic colorectal cancer in a third level hospital

Objetivos: En este trabajo se analiza la utilización de cetuximab en el tratamiento de cáncer colorrectal metastásico (CCRm) en un hospital de tercer nivel, determinando las condiciones de uso en los pacientes de nuestro centro con relación a las aprobadas en ficha técnica en el momento. También, se compara la duración del tratamiento en las distintas condiciones de uso y con los datos disponibles en la bibliografía publicada hasta la fecha de realización de este trabajo. Métodos: Se realizó un estudio de indicación-prescripción de cetuximab en CCRm para todos los pacientes tratados con cetuximab en CCR en el período 2004-2007 en nuestro hospital. Se determina el número de prescripciones que no se ajusta a la ficha técnica aprobada para cetuximab en CCRm y el motivo por el que no se adapta. Se realiza el análisis estadístico descriptivo para las distintas variables recogidas y un análisis de Kaplan-Meier para la variable duración de tratamiento para determinar si hay diferencia de efectividad para los usos habituales en nuestro hospital. Resultados: Se recogieron los datos de 74 pacientes tratados con cetuximab. El coste medio por paciente fue de 14.399 ¿ y un número medio de dosis administradas de 15,3 por paciente. La dosis media de inicio fue 710 mg y la de mantenimiento, de 446 mg. La duración media de los tratamientos fue 15,4 semanas. Cetuximab se administró a 7 pacientes en primera línea de tratamiento, y a 32 pacientes sin que previamente se hubiese utilizado irinotecan. En 9 pacientes no se asoció irinotecan al tratamiento con cetuximab y se empleó en 14 pacientes con resultado negativo para la prueba de EFGR. La duración de los tratamientos fue mayor en caso de utilización en primera línea de tratamiento (27,7 semanas), si no se empleó irinotecan previo (23,3 semanas), si se asociaba irinotecan al tratamiento (20,5 semanas) y en pacientes EFGR (..) (AU)

Objectives: In this study we will analyse the use of cetuximab in the treatment of metastatic colorectal cancer (MCC) in a third level hospital. We will establish the usage conditions in our centre in keeping with those approved in current technical records. We will also record the treatment duration under the different usage conditions and use the information available in material that has been published to date. Methods: An indication-prescription study of cetuximab in MCC was carried out on all patients treated with cetuximab for colorectal cancer in the period between 2004 and 2007 in our hospital. The number of prescriptions that do not fit the approved recommendations for cetuximab in MCC treatment (and why they do not fit) is determined. Descriptive statistical analysis was carried out for the different variables collected, and a Kaplan-Meier analysis was carried out for the treatment duration variable, so as to determine whether there is a difference in effectiveness for the common uses in our hospital. Results: Data was recorded for 74 patients treated with cetuximab. The average cost per patient was ¿14,399 and on average, 15.3 dosages were administered per patient. The average initial dosage was 710 mg with an average dosage of 446 mg after that. The average duration of the treatments was 15.4 weeks. cetuximab was administered to 7 patients as first-line treatment and to 32 patients who had not used Irinotecan previously. Irinotecan was not associated with cetuximab treatment in 9 patients, and it was used in 14 patients resulting in a negative outcome for the EFGR test. Treatment duration was longer in the case of its use as first-line treatment (27.7 weeks), if Irinotecan had not been used before (23.3 weeks), if Irinotecan was used (20.5 weeks) and in patients with positive EFGR results (19.6 weeks.) The median treatment duration, under the different conditions, was less than the average but with no major differences (..) (AU)

Simple analytical expressions for the dose of point photon sources in homogeneous media.

The contributions to the dose of a point photon source in homogeneous media due to primary and first, second, ..., nth scattered photons are investigated. Assuming a simple statistical model, an analytical form comes out for each of these contributions. It includes a polynomial and a single exponential and depends on three parameters which have a physical meaning. The values of these parameters for different energies and for water, as a test case, are obtained from numerical fits to the results of a Monte Carlo simulation with the code PENELOPE. The average differences between the model and the Monte Carlo results, after the fitting process, are below 1%. Our model permits to obtain improved versions of the classical approach of Berger in a straightforward way. The expressions obtained also describe the dose build-up of the primary photons.

Enhancement of neutron radiation dose by the addition of sulphur-33 atoms.

The use of neutrons in radiotherapy allows the possibility of producing nuclear reactions in a specific target inserted in the medium. (10)B is being used to induce reactions (n, alpha), a technique called boron neutron capture therapy. I have studied the possibility of inducing a similar reaction using the nucleus of (33)S, for which the reaction cross section presents resonances for keV neutrons, the highest peak occurring at 13.5 keV. Here shown, by means of Monte Carlo simulation of point-like sources of neutrons in this energy range, is an enhancement effect on the absorbed dose in water by the addition of (33)S atoms. In addition to this, as the range of the alpha particle is of the order of a mammalian cell size, the energy deposition via this reaction results mainly inside the cells adjacent to the interaction site. The main conclusion of the present work is that the insertion of these sulphur atoms in tumoral cells would enhance the effect of neutron irradiation in the keV range.