Characteristics of a novel treatment system for linear accelerator-based stereotactic radiosurgery.

The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image-guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter-free (FFF) beams for both high definition (HD120) MLC and conical cone-based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end-to-end accuracy tests, have been performed. The end-to-end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone-beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy. The deviations between the percent depth-dose curves acquired on the new linac-based system (Edge), and the previously published machine with FFF beams (TrueBeam) beyond D(max) were within 1.0% for both energies. The maximum deviation of output factors between the Edge and TrueBeam was 1.6%. The optimized dosimetric leaf gap values, which were fitted using Eclipse dose calculations and measurements based on representative spine radiosurgery plans, were 0.700 mm and 1.000 mm, respectively. For the conical cones, 6X FFF has sharper penumbra ranging from 1.2-1.8 mm (80%-20%) and 1.9-3.8 mm (90%-10%) relative to 10X FFF, which has 1.2-2.2mm and 2.3-5.1mm, respectively. The relative attenuation measurements of the couch for PA, PA (rails-in), oblique, oblique (rails-out), oblique (rails-in) were: -2.0%, -2.5%, -15.6%, -2.5%, -5.0% for 6X FFF and -1.4%, -1.5%, -12.2%, -2.5%, -5.0% for 10X FFF, respectively, with a slight decrease in attenuation versus field size. The systematic deviation between the OSMS and CBCT was -0.4 ± 0.2 mm, 0.1± 0.3mm, and 0.0 ± 0.1 mm in the vertical, longitudinal, and lateral directions. The mean values and standard deviations of the average deviation and maximum deviation of the daily Winston-Lutz tests over three months are 0.20 ± 0.03 mm and 0.66 ± 0.18 mm, respectively. Initial testing of this novel system demonstrates the technology to be highly accurate and suitable for frameless, linac-based SRS and SBRT treatment.

Leprosy ulcers in a rural hospital of Ethiopia: pattern of aerobic bacterial isolates and drug sensitivities.

BACKGROUND: Plantar ulcers, which commonly occur in leprosy patients, tend to recur increasing physical disability. The aim of this study is to identify both the bacteriological profile of these ulcers and the antibiotic susceptibility of the isolated bacteria. MATERIALS AND METHODS: 68 leprosy patients with chronic ulcers attending the in-patient department of Gambo General Hospital, West Arsi, were included in this study. Proper sample collection, inoculation on culture media, and final identification using biochemical methods were undertaken. RESULTS: 66 patients (97.1%) had a positive culture. A total of 81 microorganisms were isolated. Multiple organisms (two or more) were isolated in 15 (22.7% out of positive culture) patients. The main isolation was Proteus spp (30.9%), followed by Escherichia coli (21.0%), Staphylococcus aureus (18.5%) and Pseudomonas aeruginosa (9.9%). In the total number of the isolated bacteria, the antibiotics with less resistance were gentamicin (18.5%), fosfomycin (22.2%) cefoxitin (24.7%), ceftriaxone (25.9%) ciprofloxacin (25.9%), and amoxicillin-clavulanic acid (28.49%). CONCLUSION: The bacteriological study of plantar ulcers of leprosy patients revealed Enterobacteriaceae and S. aureus as the main pathogens involved in such infections. The results of this study may guide empirical therapy in a rural area hospital where culture and susceptibility testing facilities are scarce.

IMRT and RapidArc commissioning of a TrueBeam linear accelerator using TG-119 protocol cases.

The purpose of this study is to evaluate the overall accuracy of intensity-modulated radiation therapy (IMRT) and RapidArc delivery using both flattening filter (FF) and flattening filter-free (FFF) modalities based on test cases developed by AAPM Task Group 119. Institutional confidence limits (CLs) were established as the baseline for patient specific treatment plan quality assurance (QA). The effects of gantry range, gantry speed, leaf speed, dose rate, as well as the capability to capture intentional errors, were evaluated by measuring a series of Picket Fence (PF) tests using the electronic portal imaging device (EPID) and EBT3 films. Both IMRT and RapidArc plans were created in a Solid Water phantom (30 × 30 × 15 cm3) for the TG-119 test cases representative of normal clinical treatment sites for all five photon energies (6X, 10X, 15X, 6X-FFF, 10X-FFF) and the Exact IGRT couch was included in the dose calculation. One high-dose point in the PTV and one low-dose point in the avoidance structure were measured with an ion chamber in each case for each energy. Similarly, two GAFCHROMIC EBT3 films were placed in the coronal planes to measure planar dose distributions in both high- and low-dose regions. The confidence limit was set to have 95% of the measured data fall within the tolerance. The mean of the absolute dose deviation for variable dose rate and gantry speed during RapidArc delivery was within 0.5% for all energies. The corresponding results for leaf speed tests were all within 0.4%. The combinations of dynamic leaf gap (DLG) and MLC transmission factor were optimized based on the ion chamber measurement results of RapidArc delivery for each energy. The average 95% CLs for the high-dose point in the PTV were 0.030 ± 0.007 (range, 0.022-0.038) for the IMRT plans and 0.029 ± 0.011 (range, 0.016-0.043) for the RapidArc plans. For low-point dose in the avoidance structures, the CLs were 0.029 ± 0.006 (range, 0.024-0.039) for the IMRT plans and 0.027 ± 0.013 (range, 0.017-0.047) for the RapidArc plans. The average 95% CLs using 3%/3 mm gamma criteria in the high-dose region were 5.9 ± 2.7 (range, 1.4-8.6) and 3.9 ± 2.9 (range, 1.5-8.8) for IMRT and RapidArc plans, respectively. The average 95% CLs in the low-dose region were 5.3 ± 2.6 (range, 1.2-7.4) and 3.7 ± 2.8 (range, 1.8-8.3) for IMRT and RapidArc plans, respectively. Based on ion chamber, as well as film measurements, we have established CLs values to ensure the high precision of IMRT and RapidArc delivery for both FF and FFF modalities.

[Construction and validation of a questionnaire to measure behavior, knowledge and attitudes on hand hygiene in health personnel training]. / Construcción y validación de un cuestionario para medir conductas, conocimientos y actitudes sobre la higiene de las manos en personal sanitario en formación.

BACKGROUND: Hand hygiene in the health context is a complex behaviour. There have been rarely given the role of the knowledge and attitudes as predictors of hand hygiene behaviour. The main objective of this work is the description of the development of a questionnaire on hand hygiene and the analysis of their measurement properties. METHOD: An instrument which was designed and validated a questionnaire. It was held in January 2009. It finally has had 50 items that assess risk behaviour intention before and after contact with the patient, declarative knowledge and attitudes about hand hygiene. It has been applied to 431 students of health sciences at the University of Granada. RESULTS: There were three factor analysis, ultimately obtaining a general convergence value that explains 46.01% of the total variance and high reliability (a = 0,843). There is correlation between knowledge and behavior intentions before and after patient contact (p < 0.01).In turn, the attitude correlates only with behavioral intention before (p < 0.05). The hand hygiene behavior refers to a higher mean after the completion of various health activities before the same (4.26 and 3.96 respectively). Both declarative knowledge and attitudes significantly predict behavioral intention, in particular the conduct before the contact with the patient (R² = 0.100, standardized Beta 0.256 for knowledge and 0.145 for attitudes). CONCLUSIONS: The questionnaire shows high internal consistency. We have obtained a valid tool for assessing risk behavior, knowledge and attitudes about students' hand hygiene in health sciences. The tool detects deficiencies in basic skills in students.

Vaccination in patients under monoclonal antibody treatment: an updated comprehensive review.

INTRODUCTION: Monoclonal antibodies (mAbs) have become an increasing source of biological treatments. Clinicians should make an effort to update their knowledge on mechanisms of action, indications, and adverse events of these novel therapies. Most of them have immunosuppressive effects and, therefore, vaccination is indicated. AREAS COVERED: vaccination of patients under mAbs therapies. EXPERT OPINION: Recommendations on vaccination are still based on expert recommendations and have not been updated in recent years. Specific recommendations for each mAb have not been addressed in the current literature. The aim of this comprehensive review was to collect all the therapeutic mAbs approved up to 1 January 2020 and, based on previous recommendations and the pharmaceutical characteristics of each drug, to propose an updated guide with recommendations on vaccination. Influenza, sequential pneumococcal and Hepatitis B vaccination in patients with negative serology were the only consistent recommendations. Hepatitis A vaccination was proposed for mAbs with special hepatotoxic characteristics. Other vaccines are reviewed and discussed. Several non-immunosuppressive mAbs were detected and, therefore, vaccinations not recommended. We hope that this review can serve as a starting point for compiling updated vaccination recommendations and collecting all the therapeutic mAbs approved up to 2020.

Evaluation of a magnetic resonance guided linear accelerator for stereotactic radiosurgery treatment.

INTRODUCTION: The purpose of this study was to investigate the systematic localization accuracy, treatment planning capability, and delivery accuracy of an integrated magnetic resonance imaging guided Linear Accelerator (MR-Linac) platform for stereotactic radiosurgery. MATERIALS AND METHODS: The phantom for the end-to-end test comprises three different compartments: a rectangular MR/CT target phantom, a Winston-Lutz cube, and a rectangular MR/CT isocenter phantom. Hidden target tests were performed at gantry angles of 0, 90, 180, and 270 degrees to quantify the systematic accuracy. Five patient plans with a total of eleven lesions were used to evaluate the dosimetric accuracy. Single-isocenter IMRT treatment plans using 10-15 coplanar beams were generated to treat the multiple metastases. RESULTS: The end-to-end localization accuracy of the system was 1.0 ±â€¯0.1 mm. The conformity index, homogeneity index and gradient index of the plans were 1.26 ±â€¯0.22, 1.22 ±â€¯0.10, and 5.38 ±â€¯1.44, respectively. The average absolute point dose difference between measured and calculated dose was 1.64 ±â€¯1.90%, and the mean percentage of points passing the 3%/1 mm gamma criteria was 96.87%. CONCLUSIONS: Our experience demonstrates that excellent plan quality and delivery accuracy was achievable on the MR-Linac for treating multiple brain metastases with a single isocenter.

The effect of longitudinal CT resolution and pixel size (FOV) on target delineation and treatment planning in stereotactic radiosurgery.

The acquisition of high-quality, anatomic images is essential for the accurate delineation of tumor volumes and critical structures used for stereotactic radiosurgery (SRS) treatment planning. This study investigates the effect of CT slice thickness and field of view (FOV), i.e., longitudinal and axial CT resolution, on volume delineation and treatment planning in SRS and suggests optimal CT acquisition parameters for brain SRS simulation. Optimization of such parameters will maximize clinical efficacy, alter data storage requirements, reduce dosimetric uncertainties, and may ultimately facilitate more favorable clinical outcomes. Changes in the extent, shape and the absolute volume of the GTV were recorded when the longitudinal and axial CT resolution were modified. These changes ultimately impacted the PTV dose coverage. Reducing CT slice thickness from 2mm to 1mm resulted in an average decrease of 8.6%±13.9% (max=52.2%) and 3.0 %±4.3% (max=13.1%) in PTV Dmin and PTV D95, respectively. Increasing CT slice thickness from 2mm to 3mm resulted in an average decrease of 10%±9.9% (max=26.8%) and 5.8%±5.8% (max=17.4%) in PTV Dmin and PTV D95, respectively. Similarly, on average, PTV coverage decreased when FOV decreased. The average decrease in PTV Dmin and PTV D95 for a 350cm FOV was 5.2%±7.2% (max=21.4%) and 1.9%±3.2% (max=7.5%), respectively. Decreasing FOV to 250cm yielded similar results with the average decrease of 5.6%±5.0% (max=13.2%) and 1.6%±2.6% (max=6.3%) in PTV Dmin and PTV D95, respectively. These results suggest that the slice thickness and FOV of CT images affect target delineation and may potentially compromise the quality of the target coverage.

Vaginal cuff dehiscence after vaginal cuff brachytherapy for uterine cancer. A case report.

Vaginal cuff dehiscence is a rare, but potentially serious complication after total hysterectomy. We report a case of vaginal cuff dehiscence after vaginal cuff brachytherapy. A 62 year old female underwent a robotic-assisted laparoscopic hysterectomy with bilateral salpingo-oophorectomy, and was found to have International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IB endometrioid adenocarcinoma of the uterus. The patient was referred for adjuvant vaginal cuff brachytherapy. During the radiation treatment simulation, a computerized tomography (CT) of the pelvis showed abnormal position of the vaginal cylinder. She was found to have vaginal cuff dehiscence that required immediate surgical repair. Vaginal cuff dehiscence triggered by vaginal cuff brachytherapy is very rare with only one case report in the literature.

[Sample size and costs estimate in epidemiological survey of dental caries]. / Tamanho de amostra e estimativa de custo em levantamento epidemiológico de cárie dentária.

This study aimed to analyze how the prevalence and the distribution of dental caries influence the sample size in epidemiological surveys, and how much are the costs. Secondary data of oral health surveys in 12-year-old schoolchildren from Bauru in 1976, 1984, 1990, 1994, and 2001, and from Piracicaba in 2001 and 2005 were studied. Sample sizes were estimated taking into account the mean DMFT and standard deviation of each survey, establishing sampling errors of 1%, 2%, 5%, and 10%. Costs were estimated considering permanent material, consumption material and human resources. The sample size in both towns needed to be increased, ranging from 119 in 1976 to 1,118 in 2001 in Bauru, and from 954 in 2001 to 1,252 in 2005 in Piracicaba, when a sampling error of 10% was considered. The cost of dental caries surveys was verified considering different sampling errors. This cost depends on how acceptable is the margin of difference between the true mean and the one found in the survey. In conclusion, the reduction in the prevalence of dental caries has determined the need for increase in sample size and in costs for conducting the surveys.

Tamanho de amostra e estimativa de custo em levantamento epidemiológico de cárie dentária / Sample size and costs estimate in epidemiological survey of dental caries

O objetivo do presente estudo foi analisar como a prevalência e a distribuição da cárie dentária influenciam o tamanho da amostra em levantamentos epidemiológicos, e os custos para sua realização. Foram utilizados dados de levantamentos realizados em escolares de 12 anos em Bauru nos anos de 1976, 1984, 1990, 1994 e 2001, e em Piracicaba nos anos de 2001 e 2005. Os tamanhos amostrais foram dimensionados considerando-se a média e o desvio padrão obtidos, fixando-se erro amostral em 1 por cento, 2 por cento, 5 por cento e 10 por cento. Os custos foram estimados considerando material permanente, de consumo e recursos humanos. Verificou-se aumento no tamanho das amostras em ambos os municípios, variando de 119 em 1976 para 1.118 em 2001 em Bauru, e de 954 em 2001 para 1.252 em 2005 em Piracicaba, considerando-se um erro amostral de 10 por cento. Considerando-se diferentes erros amostrais, verificou-se o custo para o levantamento, sendo que o mesmo depende do quanto o pesquisador se permite errar em relação ao verdadeiro valor da média da população. Conclui-se que a diminuição da prevalência da cárie dentária determinou o aumento no tamanho das amostras e a elevação dos custos para realização dos levantamentos.

This study aimed to analyze how the prevalence and the distribution of dental caries influence the sample size in epidemiological surveys, and how much are the costs. Secondary data of oral health surveys in 12-year-old schoolchildren from Bauru in 1976, 1984, 1990, 1994, and 2001, and from Piracicaba in 2001 and 2005 were studied. Sample sizes were estimated taking into account the mean DMFT and standard deviation of each survey, establishing sampling errors of 1 percent, 2 percent, 5 percent, and 10 percent. Costs were estimated considering permanent material, consumption material and human resources. The sample size in both towns needed to be increased, ranging from 119 in 1976 to 1,118 in 2001 in Bauru, and from 954 in 2001 to 1,252 in 2005 in Piracicaba, when a sampling error of 10 percent was considered. The cost of dental caries surveys was verified considering different sampling errors. This cost depends on how acceptable is the margin of difference between the true mean and the one found in the survey. In conclusion, the reduction in the prevalence of dental caries has determined the need for increase in sample size and in costs for conducting the surveys.

Evaluación de un taller práctico sobre higiene de manos impartido por estudiantes entrenados / Evaluation of a workshop on hand hygiene taught by instructed students

Introducción. La enseñanza y el aprendizaje de la higiene de manos en el contexto sanitario es una tarea compleja. La intervención del estudiante como líder de su propia formación está muy poco analizada en la bibliografía. El objetivo principal del trabajo es la evaluación de un taller sobre higiene de manos gestionado, dirigido e impartido, bajo tutela experta, por estudiantes al propio colectivo estudiantil. Sujetos y métodos. Evaluación pre-post de la técnica, los conocimientos y las actitudes de los participantes hacia la higiene de manos. Asistieron 40 estudiantes de ciencias de la salud de la Universidad de Granada. Se realizaron dos evaluaciones del taller: mediante un cuestionario diseñado ad hoc con 12 ítems sobre conocimientos y actitudes, y mediante la observación directa de la técnica de higiene de manos y la calidad del proceso utilizando una lámpara de luz ultravioleta y una solución reactiva. Resultados. Tras la realización del taller se aprecia que disminuye de forma significativa el número de zonas contaminadas de las manos (t = 9,278; p < 0,000) y que mejora significativamente la técnica de higiene de manos para cada uno de los siete pasos establecidos por la Organización Mundial de la Salud (p < 0,001). La diferencia entre la media global de las puntuaciones del cuestionario antes y después del taller fue también significativa (t = -4,662; p < 0,000). Conclusiones. El taller impartido mejoró las actitudes, los conocimientos y la técnica de higiene de manos con solución alcohólica entre los participantes (AU)

Introduction. The teaching and learning of hand hygiene in the context of health is a complex task. There is little discussion in the literature regarding the student involvement as the leader of his own background. The main objective of this study is the evaluation of a workshop on hand hygiene managed, directed and delivered, under expert supervision, by students at the same student group. Subjects and methods. An evaluation pre-post about technique, knowledge and attitudes of participants towards hygiene. Attended by 40 students of Health Sciences at the University of Granada. We conducted two evaluations of the workshop by: a questionnaire designed ad hoc with 12 items on knowledge and attitudes, and the direct observation of hand hygiene technique and quality of the processing with an ultraviolet lamp and a reactive solution for it. Results. After the workshop, it shows how significantly reduces the number of contaminated areas hands (t = 9.278; p < 0.000) and how it significantly improves hand hygiene technique for each of the seven steps outlined World Health Organization (p < 0.001). The difference between the overall mean questionnaire scores before and after the workshop was also significant (t = -4.662;p < 0.000). Conclusions. The taught workshop improved attitudes, knowledge and technique of hand hygiene with alcohol solution between the participants (AU)

Construcción y validación de un cuestionario para medir conductas, conocimientos y actitudes sobre la higiene de las manos en personal sanitario en formación / Construction and validation of a questionnaire to measure behavior, knowledge and attitudes on hand hygiene in health personnel training

Fundamento: La higiene de manos en el contexto sanitario es un comportamiento complejo. Rara vez se ha determinado el papel conjunto de los conocimientos y las actitudes como predictores de la conducta de higiene de manos. El objetivo principal del trabajo es la descripción de la elaboración de un cuestionario sobre higiene de manos y el análisis de sus propiedades de medida. Método: Estudio instrumental en el que se diseñó y validó un cuestionario. Se llevó acabo en enero de 2009. Éste constó finalmente de 50 ítems que evalúan la intención de conducta antes y después del contacto con el paciente, los conocimientos declarativos y las actitudes sobre la higiene de manos. Se aplicó a 431 estudiantes de ciencias de la salud de la Universidad de Granada. Resultados: Se han realizado tres análisis factoriales, obteniendo finalmente un valor de convergencia general que explica el 46,01% de la varianza total y una alta fiabilidad (a=0,843). Existe correlación entre los conocimientos y la intención de conducta antes y después del contacto con el paciente (p<0,01). A su vez, la actitud sólo correlaciona con la intención de conducta antes (p<0,05). La conducta de higiene de manos se refiere con una media mayor después de la realización de diversas actividades sanitarias que antes de las mismas (4,26 y 3,96 respectivamente). Tanto los conocimientos declarativos como las actitudes predicen significativamente la intención de conducta, en particular la conducta antes del contacto con el paciente (R2=0,100; Beta estandarizado 0,256 para conocimientos y 0,145 y para actitudes). Conclusiones: El cuestionario muestra una elevada consistencia interna. Se ha obtenido una herramienta válida para evaluar la intención de conducta, los conocimientos y las actitudes sobre higiene de manos en estudiantes de ciencias de la salud. La herramienta detecta deficiencias en conocimientos básicos en los estudiantes(AU)

Background: Hand hygiene in the health context is a complex behaviour. There have been rarely given the role of the knowledge and attitudes as predictors of hand hygiene behaviour. The main objective of this work is the description of the development of a questionnaire on hand hygiene and the analysis of their measurement properties. Method: An instrument which was designed and validated a questionnaire. It was held in January 2009. It finally has had 50 items that assess risk behaviour intention before and after contact with the patient, declarative knowledge and attitudes about hand hygiene. It has been applied to 431 students of health sciences at the University of Granada. Results: There were three factor analysis, ultimately obtaining a general convergence value that explains 46.01% of the total variance and high reliability (a=0,843). There is correlation between knowledge and behavior intentions before and after patient contact (p <0.01).In turn, the attitude correlates only with behavioral intention before (p <0.05). The hand hygiene behavior refers to a higher mean after the completion of various health activities before the same (4.26 and 3.96 respectively). Both declarative knowledge and attitudes significantly predict behavioral intention, in particular the conduct before the contact with the patient (R2 = 0.100, standardized Beta 0.256 for knowledge and 0.145 for attitudes). Conclusions: The questionnaire shows high internal consistency. We have obtained a valid tool for assessing risk behavior, knowledge and attitudes about students’ hand hygiene in health sciences. The tool detects deficiencies in basic skills in students(AU)