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1.
Artículo en Inglés | MEDLINE | ID: mdl-38427510

RESUMEN

PURPOSE: This study explored family satisfaction and perceived quality of care in a pediatric neuromuscular care clinic to assess the value of the multidisciplinary clinic (MDC) model in delivering coordinated care to children with neuromuscular disorders, such as cerebral palsy. METHODS: Caregivers of 22 patients were administered a qualitative survey assessing their perceptions of clinic efficiency, care coordination, and communication. Surveys were audio-recorded and transcribed. Thematic analysis was completed using both deductive and inductive methods. RESULTS: All caregivers reported that providers adequately communicated next steps in the patient's care, and most reported high confidence in caring for the patient as a result of the clinic. Four major themes were identified from thematic analysis: Care Delivery, Communication, Care Quality, and Family-Centeredness. Caregivers emphasized that the MDC model promoted access to care, enhanced efficiency, promoted provider teamwork, and encouraged shared care planning. Caregivers also valued a physical environment that was suitable for patients with complex needs. CONCLUSION: This study demonstrated that caregivers believed the MDC model was both efficient and convenient for pediatric patients with neuromuscular disorders. This model has the potential to streamline medical care and can be applied more broadly to improve care coordination for children with medical complexity.

2.
J Prim Care Community Health ; 13: 21501319221138196, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36404761

RESUMEN

INTRODUCTION AND OBJECTIVE: The lack of precision to identify patients with early-stage diabetic kidney disease (DKD) at near-term risk for progressive decline in kidney function results in poor disease management often leading to kidney failure requiring unplanned dialysis. The KidneyIntelX is a multiplex, bioprognostic, immunoassay consisting of 3 plasma biomarkers and clinical variables that uses machine learning to generate a risk score for progressive decline in kidney function over 5-year in adults with early-stage DKD. Our objective was to assess the impact of KidneyIntelX on management and outcomes in a Health System in the real-world evidence (RWE) study. METHODS: KidneyIntelX was introduced into a large metropolitan Health System via a population health-defined approved care pathway for patients with stages 1 to 3 DKD between [November 2020 to March 2022]. Decision impact on visit frequency, medication management, specialist referral, and selected lab values was assessed. We performed an interim analysis in patients through 6-months post-test date to evaluate the impact of risk level with clinical decision-making and outcomes. RESULTS: A total of 1686 patients were enrolled in the RWE study and underwent KidneyIntelX testing and subsequent care pathway management. The median age was 68 years, 52% were female, 26% self-identified as Black, and 94% had hypertension. The median baseline eGFR was 59 ml/minute/1.73 m2, urine albumin-creatinine ratio was 69 mg/g, and HbA1c was 7.7%. After testing, a clinical encounter in the first month occurred in 13%, 43%, and 53% of low-risk, intermediate-risk, and high-risk patients, respectively and 46%, 61%, and 71% had at least 1 action taken within the first 6 months. High-risk patients were more likely to be placed on SGLT2 inhibitors (OR = 4.56; 95% CI 3.00-6.91 vs low-risk), and more likely to be referred to a specialist such as a nephrologist, endocrinologist, or dietician (OR = 2.49; 95% CI 1.53-4.01) compared to low-risk patients. CONCLUSIONS: The combination of KidneyIntelX, clinical guidelines and educational support resulted in changes in clinical management by clinicians. After testing, there was an increase in visit frequency, referrals for disease management, and introduction to guideline-recommended medications. These differed by risk category, indicating an impact of KidneyIntelX risk stratification on clinical care.


Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Adulto , Humanos , Femenino , Anciano , Masculino , Nefropatías Diabéticas/tratamiento farmacológico , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Biomarcadores , Diálisis Renal , Factores de Riesgo , Diabetes Mellitus/tratamiento farmacológico
3.
Prim Care ; 46(4): 529-538, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31655749

RESUMEN

As systems shift to value from fee-for-service, new tools are needed to manage networks and operations, and more importantly, make meaningful impacts on patient lives. The integration of data from electronic health records and claims as well as from patients and caregivers has become a key element in any population health management strategy. Visualization of the most appropriate data at the right time and place, while often overlooked, can make the difference between effective use and poor use of data. We provide a summary and guidance on the appropriate tools needed to be successful in population health management efforts.


Asunto(s)
Intercambio de Información en Salud , Registros de Salud Personal , Gestión de la Salud Poblacional , Humanos , Educación del Paciente como Asunto , Participación del Paciente , Integración de Sistemas
4.
N C Med J ; 78(4): 245-247, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28724674

RESUMEN

Mission Health Partners Accountable Care Organization's population health strategy is based on the idea that improvements in outcomes are best achieved by addressing social determinants gaps for its members. Our network of service providers and a process for referrals and tracking streamlines the limited resources available to meet these needs.


Asunto(s)
Organizaciones Responsables por la Atención/organización & administración , Determinantes Sociales de la Salud , Humanos , Medicare , North Carolina , Estados Unidos
5.
Front Public Health Serv Syst Res ; 5(3): 28-34, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33052298

RESUMEN

The research community faces a growing need to deliver useful data and actionable evidence to support health systems and policymakers on ways to optimize the health of populations. Translating science into policy has not been the traditional strong suit of investigators, who typically view a journal publication as the endpoint of their work. They are less accustomed to seeing their data as an input to the work of communities and policymakers to improve population health. This article offers four suggestions as potential solutions: (1) shaping a research portfolio around user needs, (2) understanding the decision-making environment, (3) engaging stakeholders, and (4) strategic communication.

6.
Am J Public Health ; 105 Suppl 2: S288-94, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25689176

RESUMEN

OBJECTIVES: We examined the perceived importance of scientific resources for decision-making among local health department (LHD) practitioners in the United States. METHODS: We used data from LHD practitioners (n = 849). Respondents ranked important decision-making resources, methods for learning about public health research, and academic journal use. We calculated descriptive statistics and used logistic regression to measure associations of individual and LHD characteristics with importance of scientific resources. RESULTS: Systematic reviews of scientific literature (24.7%) were most frequently ranked as important among scientific resources, followed by scientific reports (15.9%), general literature review articles (6.5%), and 1 or a few scientific studies (4.8%). Graduate-level education (adjusted odds ratios [AORs] = 1.7-3.5), larger LHD size (AORs = 2.0-3.5), and leadership support (AOR = 1.6; 95% confidence interval = 1.1, 2.3) were associated with a higher ranking of importance of scientific resources. CONCLUSIONS: Graduate training, larger LHD size, and leadership that supports a culture of evidence-based decision-making may increase the likelihood of practitioners viewing scientific resources as important. Targeting communication channels that practitioners view as important can also guide research dissemination strategies.


Asunto(s)
Toma de Decisiones , Práctica Clínica Basada en la Evidencia , Gobierno Local , Administración en Salud Pública , Adulto , Femenino , Humanos , Liderazgo , Masculino , Persona de Mediana Edad , Investigación , Estados Unidos
7.
Annu Rev Public Health ; 36: 463-82, 2015 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-25581146

RESUMEN

Among the challenges facing research translation-the effort to move evidence into policy and practice-is that key questions chosen by investigators and funders may not always align with the information priorities of decision makers, nor are the findings always presented in a form that is useful for or relevant to the decisions at hand. This disconnect is a problem particularly for population health, where the change agents who can make the biggest difference in improving health behaviors and social and environmental conditions are generally nonscientists outside of the health professions. To persuade an audience that does not read scientific journals, strong science may not be enough to elicit change. Achieving influence in population health often requires four ingredients for success: research that is responsive to user needs, an understanding of the decision-making environment, effective stakeholder engagement, and strategic communication. This article reviews the principles and provides examples from a national and local initiative.


Asunto(s)
Salud Pública/métodos , Investigación Biomédica Traslacional/métodos , Comunicación , Investigación Participativa Basada en la Comunidad , Medicina Basada en la Evidencia/métodos , Conductas Relacionadas con la Salud , Educación en Salud , Promoción de la Salud/métodos , Humanos
8.
BMC Health Serv Res ; 14: 564, 2014 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-25398652

RESUMEN

BACKGROUND: Preparing the public health workforce to practice evidence-based decision making (EBDM) is necessary to effectively impact health outcomes. Few studies report on training needs in EBDM at the national level in the United States. We report competency gaps to practice EBDM based on four U.S. national surveys we conducted with the state and local public health workforce between 2008 and 2013. METHODS: We compared self-reported data from four U.S. national online surveys on EBDM conducted between 2008 and 2013. Participants rated the importance of each EBDM competency then rated how available the competency is to them when needed on a Likert scale. We calculated a gap score by subtracting availability scores from importance scores. We compared mean gaps across surveys and utilized independent samples t tests and Cohen's d values to compare state level gaps. In addition, participants in the 2013 state health department survey selected and ranked three items that "would most encourage you to utilize EBDM in your work" and items that "would be most useful to you in applying EBDM in your work". We calculated the percentage of participants who ranked each item among their top three. RESULTS: The largest competency gaps were consistent across all four surveys: economic evaluation, communicating research to policymakers, evaluation designs, and adapting interventions. Participants from the 2013 state level survey reported significantly larger mean importance and availability scores (p <0.001, d =1.00, and p <0.001, d = .78 respectively) and smaller mean gaps (p <0.01, d = .19) compared to the 2008 survey. Participants most often selected "leaders prioritizing EBDM" (67.9%) among top ways to encourage EBDM use. "EBDM training for specific areas" was most commonly ranked as important in applying EBDM (64.3%). CONCLUSION: Perceived importance and availability of EBDM competencies may be increasing as supports for EBDM continue to grow through trends in funding, training, and resources. However, more capacity building is needed overall, with specific attention to the largest competency gaps. More work with public health departments to both situate trainings to boost competency in these areas and continued improvements for organizational practices (leadership prioritization) are possible next steps to sustain EBDM efforts.


Asunto(s)
Toma de Decisiones , Práctica Clínica Basada en la Evidencia/educación , Personal de Salud/educación , Salud Pública/educación , Adulto , Anciano , Anciano de 80 o más Años , Competencia Clínica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Estados Unidos , Adulto Joven
9.
Am J Prev Med ; 46(1): 49-57, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24355671

RESUMEN

BACKGROUND: There are sparse data showing the extent to which evidence-based public health is occurring among local health departments. PURPOSE: The purpose of the study was to describe the patterns and predictors of administrative evidence-based practices (structures and activities that are associated with performance measures) in a representative sample of local health departments in the U.S. METHODS: A cross-sectional study of 517 local health department directors was conducted from October through December 2012 (analysis in January-March 2013). The questions on administrative evidence-based practices included 19 items based on a recent literature review (five broad domains: workforce development, leadership, organizational climate and culture, relationships and partnerships, financial processes). RESULTS: There was a wide range in performance among the 19 individual administrative evidence-based practices, ranging from 35% for providing access to current information on evidence-based practices to 96% for funding via a variety of sources Among the five domains, values were generally lowest for organizational climate and culture (mean for the domain=49.9%) and highest for relationships and partnerships (mean for the domain=77.1%). Variables associated with attaining the highest tertile of administrative evidence-based practices included having a population jurisdiction of 25,000 or larger (adjusted ORs [aORs] ranging from 4.4 to 7.5) and state governance structure (aOR=3.1). CONCLUSIONS: This research on the patterns and predictors of administrative evidence-based practices in health departments provides information on gaps and areas for improvement that can be linked with ongoing quality improvement processes.


Asunto(s)
Práctica Clínica Basada en la Evidencia/estadística & datos numéricos , Administración en Salud Pública/estadística & datos numéricos , Adulto , Estudios Transversales , Femenino , Humanos , Gobierno Local , Masculino , Persona de Mediana Edad , Estados Unidos
10.
Med Phys ; 40(7): 071720, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23822424

RESUMEN

PURPOSE: The purpose of this study was to document the improved accuracy of the pencil beam redefinition algorithm (PBRA) compared to the pencil beam algorithm (PBA) for bolus electron conformal therapy using cylindrical patient phantoms based on patient computed tomography (CT) scans of retromolar trigone and nose cancer. METHODS: PBRA and PBA electron dose calculations were compared with measured dose in retromolar trigone and nose phantoms both with and without bolus. For the bolus treatment plans, a radiation oncologist outlined a planning target volume (PTV) on the central axis slice of the CT scan for each phantom. A bolus was designed using the planning.decimal(®) (p.d) software (.decimal, Inc., Sanford, FL) to conform the 90% dose line to the distal surface of the PTV. Dose measurements were taken with thermoluminescent dosimeters placed into predrilled holes. The Pinnacle(3) (Philips Healthcare, Andover, MD) treatment planning system was used to calculate PBA dose distributions. The PBRA dose distributions were calculated with an in-house C++ program. In order to accurately account for the phantom materials a table correlating CT number to relative electron stopping and scattering powers was compiled and used for both PBA and PBRA dose calculations. Accuracy was determined by comparing differences in measured and calculated dose, as well as distance to agreement for each measurement point. RESULTS: The measured doses had an average precision of 0.9%. For the retromolar trigone phantom, the PBRA dose calculations had an average ± 1σ dose difference (calculated - measured) of -0.65% ± 1.62% without the bolus and -0.20% ± 1.54% with the bolus. The PBA dose calculation had an average dose difference of 0.19% ± 3.27% without the bolus and -0.05% ± 3.14% with the bolus. For the nose phantom, the PBRA dose calculations had an average dose difference of 0.50% ± 3.06% without bolus and -0.18% ± 1.22% with the bolus. The PBA dose calculations had an average dose difference of 0.65% ± 6.21% without bolus and 1.75% ± 5.94% with the bolus. From a clinical perspective an agreement of 5% or better between planned (calculated) and delivered (measured) dose is desired. Statistically, this was true for 99% (± 2σ) of the dose points for three of the four cases for the PBRA dose calculations, the exception being the nose without bolus for which this was true for 89% (± 1.6σ) of the dose points. For the retromolar trigone, with and without bolus, the PBA showed agreement of 5% or better for approximately 86% (± 1.5σ) of the dose points. For the nose, with and without bolus, the PBA showed agreement of 5% or better for only approximately 58% (± 0.8σ) of the dose points. CONCLUSIONS: The measured data, whose high precision makes them useful for evaluation of the accuracy of electron dose algorithms, will be made publicly available. Based on the spread in dose differences, the PBRA has at least twice the accuracy of the PBA. From a clinical perspective the PBRA accuracy is acceptable in the retromolar trigone and nose for electron therapy with and without bolus.


Asunto(s)
Algoritmos , Electrones/uso terapéutico , Fantasmas de Imagen , Dosis de Radiación , Radioterapia Conformacional/instrumentación , Humanos , Dosificación Radioterapéutica , Dosimetría Termoluminiscente
11.
J Phys Act Health ; 10(3): 335-42, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22820087

RESUMEN

BACKGROUND: Few studies of the built environment and physical activity or other health behaviors have examined minority populations specifically. The purpose of this study was to examine associations between the built environment and multiple health behaviors and outcomes among Hispanic adults. METHODS: Community partners distributed surveys (n = 189) in 3 communities in southwest Kansas. Logistic regression was used to examine relationships between neighborhood perceptions and 4 outcomes. RESULTS: Meeting physical activity recommendations was associated with the presence of sidewalks and a safe park, and inversely related to higher crime. Residential density and shops nearby were related to active commuting. Sedentary behavior was inversely related to having a bus stop, bike facilities, safe park, interesting things to look at, and seeing people active. Finally, seeing people active was positively associated with being overweight. CONCLUSIONS: This study suggests that among Hispanics, many built environment variables are related to health behaviors and should be targets for future neighborhood change efforts and research.


Asunto(s)
Planificación Ambiental , Conductas Relacionadas con la Salud , Hispánicos o Latinos , Adulto , Crimen , Femenino , Humanos , Kansas , Masculino , Características de la Residencia , Conducta Sedentaria , Encuestas y Cuestionarios
12.
Radiat Oncol ; 6: 178, 2011 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-22204477

RESUMEN

BACKGROUND AND PURPOSE: To investigate combining unmodulated electron beams with intensity-modulated radiation therapy to improve dose distributions for superficial head and neck cancers, and to compare mixed beam plans with helical tomotherapy. MATERIALS AND METHODS: Mixed beam and helical tomotherapy dose plans were developed for two patients with parotid gland tumors and two patients with nasal cavity tumors. Mixed beam plans consisted of various weightings of a enface electron beam and IMRT, which was optimized after calculation of the electron dose to compensate for heterogeneity in the electron dose distribution within the target volume. RESULTS: Helical tomotherapy plans showed dose conformity and homogeneity in the target volume that was equal to or better than the mixed beam plans. Electron-only plans tended to show the lowest doses to normal tissues, but with markedly worse dose conformity and homogeneity than in the other plans. However, adding a 20% IMRT dose fraction (i.e., IMRT:electron weighting = 1:4) to the electron plan restored target conformity and homogeneity to values comparable to helical tomotherapy plans, while maintaining lower normal tissue dose. CONCLUSIONS: Mixed beam treatments offer some dosimetric advantages over IMRT or helical tomotherapy for target depths that do not exceed the useful range of the electron beam. Adding a small IMRT component (e.g., IMRT:electron weighting = 1:4) to electron beam plans markedly improved target dose homogeneity and conformity for the cases examined in this study.


Asunto(s)
Electrones/uso terapéutico , Cavidad Nasal/patología , Neoplasias Nasales/radioterapia , Neoplasias de la Parótida/radioterapia , Radioterapia de Intensidad Modulada/métodos , Anciano , Anciano de 80 o más Años , Humanos , Persona de Mediana Edad , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador
13.
Med Dosim ; 36(4): 397-403, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21377865

RESUMEN

Helical tomotherapy plans using a combination of pitch and jaw width settings were developed for 3 patients previously treated for head and neck cancer. Three jaw widths (5, 2.5, and 1 cm) and 4 pitches (0.86, 0.43, 0.287, and 0.215) were used with a (maximum) modulation factor setting of 4. Twelve plans were generated for each patient using an identical optimization procedure (e.g., number of iterations, objective weights, and penalties, etc.), based on recommendations from TomoTherapy (Madison, WI). The plans were compared using isodose plots, dose volume histograms, dose homogeneity indexes, conformity indexes, radiobiological models, and treatment times. Smaller pitches and jaw widths showed better target dose homogeneity and sparing of normal tissue, as expected. However, the treatment time increased inversely proportional to the jaw width, resulting in delivery times of 24 ± 1.9 min for the 1-cm jaw width. Although treatment plans produced with the 2.5-cm jaw were dosimetrically superior to plans produced with the 5-cm jaw, subsequent calculations of tumor control probabilities and normal tissue complication probabilities suggest that these differences may not be radiobiologically meaningful. Because treatment plans produced with the 5-cm jaw can be delivered in approximately half the time of plans produced with the 2.5-cm jaw (5.1 ± 0.6 min vs. 9.5 ± 1.1 min), use of the 5-cm jaw in routine treatment planning may be a viable approach to decreasing treatment delivery times from helical tomotherapy units.


Asunto(s)
Neoplasias de Cabeza y Cuello/radioterapia , Maxilares/anatomía & histología , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Neoplasias de Cabeza y Cuello/diagnóstico por imagen , Humanos , Radiometría , Dosificación Radioterapéutica , Factores de Tiempo , Tomografía Computarizada Espiral/métodos
15.
Laryngoscope ; 119(6): 1120-4, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19358193

RESUMEN

OBJECTIVES/HYPOTHESIS: To review our results with positron emission tomography and computed tomography fusion imaging (PET-CT) surveillance of the postchemoradiotherapy neck in patients with advanced head and neck squamous cell carcinoma. STUDY DESIGN: Retrospective. METHODS: Four hundred twenty-eight patients with advanced head and neck squamous cell carcinoma were treated with nonsurgical therapy from September 2002 to March 2007 and followed with post-treatment PET-CT surveillance of the neck. Fifty-two patients meeting inclusion criteria were analyzed. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET-CT were determined. RESULTS: Ten patients had a positive post-treatment PET-CT for residual neck disease, and 42 patients had negative scans. The NPV and PPV were 100% and 40%, respectively. The sensitivity, specificity, and accuracy were 100%, 87.5%, and 88%, respectively. CONCLUSIONS: Planned neck dissection can be deferred with a negative post-treatment PET-CT. Assuming a complete response at the primary site and a negative PET-CT scan, there may be a role for serial PET-CT surveillance in patients with residual palpable cervical lymphadenopathy. Laryngoscope, 2009.


Asunto(s)
Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/radioterapia , Aumento de la Imagen , Procesamiento de Imagen Asistido por Computador , Metástasis Linfática/radioterapia , Recurrencia Local de Neoplasia/diagnóstico por imagen , Neoplasia Residual/diagnóstico por imagen , Neoplasias de Oído, Nariz y Garganta/tratamiento farmacológico , Neoplasias de Oído, Nariz y Garganta/radioterapia , Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/diagnóstico por imagen , Carcinoma de Células Escamosas/patología , Terapia Combinada , Progresión de la Enfermedad , Femenino , Fluorodesoxiglucosa F18 , Estudios de Seguimiento , Humanos , Metástasis Linfática/diagnóstico por imagen , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Disección del Cuello , Estadificación de Neoplasias , Neoplasias de Oído, Nariz y Garganta/diagnóstico por imagen , Neoplasias de Oído, Nariz y Garganta/patología , Radioterapia Conformacional , Sensibilidad y Especificidad
16.
J Appl Clin Med Phys ; 9(3): 43-57, 2008 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-18716591

RESUMEN

This study assessed the potential of using megavoltage CT (MVCT) images taken with high density skin collimation in place for electron beam treatment planning. MVCT images were taken using the TomoTherapy Hi-Art system (TomoTherapy Inc., Madison, WI), and the CT numbers were converted to density by calibrating the Hi-Art system using an electron density phantom. Doses were computed using MVCT images and kVCT images and compared by calculating dose differences in the uniform dose region ( > 90%, excluding buildup region) and calculating distance-to-agreement (DTA) in high dose-gradient regions (penumbra and distal falloff, 90%-10%). For 9 and 16 MeV electron beams of 10 x 10 cm calculated on a homogeneous CIRS Plastic Water (Computerized Imaging Research Systems Inc., Norfolk, VA) phantom without skin collimation, the maximum dose differences were 2.3% and the maximum DTAs were 2.0 mm for both beams. The same phantom was then MVCT scanned nine times with square skin collimators of Cerrobend on its surface - field sizes of 3 x 3, 6 x 6, and 10 x 10 cm and thicknesses of 6, 8, and 10 mm. Using the Philips Pinnacle 3 treatment planning system (Philips Medical Systems, N.A., Bothwell, WA), a treatment plan was created for combinations of electron energies of 6, 9, 12, and 16 MeV and each field size. The same treatment plans were calculated using kVCT images of the phantom with regions-of-interest (ROI) manually drawn to duplicate the sizes, shapes, and density of the skin collimators. With few exceptions, the maximum dose differences exceeded +/-5% and the DTAs exceeded 2 mm. We determined that the dose differences were due to small distortions in the MVCT images created by the high density material and manifested as errors in the phantom CT numbers and in the shape of the skin collimator edges. These results suggest that MVCT images without skin collimation have potential for use in patient electron beam treatment planning. However, the small distortion in images with skin collimation makes them unsuitable for clinical use.


Asunto(s)
Electrones/uso terapéutico , Fantasmas de Imagen , Planificación de la Radioterapia Asistida por Computador/métodos , Cabeza/anatomía & histología , Humanos , Tomógrafos Computarizados por Rayos X
18.
Int J Radiat Oncol Biol Phys ; 70(3): 883-91, 2008 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-18164857

RESUMEN

PURPOSE: To investigate helical tomotherapy (HT) intensity-modulated radiotherapy (IMRT) as a postoperative treatment for parotid gland tumors. METHODS AND MATERIALS: Helical tomotherapy plans were developed for 4 patients previously treated with segmental multileaf collimator (SMLC) IMRT. A primary planning target volume (PTV64) and two secondary PTVs (PTV60, PTV54) were defined. The clinical goals from the SMLC plans were applied as closely as possible to the HT planning. The SMLC plans included bolus, whereas HT plans did not. RESULTS: In general, the HT plans showed better target coverage and target dose homogeneity. The minimum doses to the desired coverage volume were greater, on average, in the HT plans for all the targets. Minimum PTV doses were larger, on average, in the HT plans by 4.6 Gy (p = 0.03), 4.8 Gy (p = 0.06), and 4.9 Gy (p = 0.06) for PTV64, PTV60, and PTV54, respectively. Maximum PTV doses were smaller, on average, by 2.9 Gy (p = 0.23), 3.2 Gy (p = 0.02), and 3.6 Gy (p = 0.03) for PTV64, PTV60, and PTV54, respectively. Average dose homogeneity index was statistically smaller in the HT plans, and conformity index was larger for PTV64 in 3 patients. Tumor control probabilities were higher for 3 of the 4 patients. Sparing of normal structures was comparable for the two techniques. There were no significant differences between the normal tissue complication probabilities for the HT and SMLC plans. CONCLUSIONS: Helical tomotherapy treatment plans were comparable to or slightly better than SMLC plans. Helical tomotherapy is an effective alternative to SMLC IMRT for treatment of parotid tumors.


Asunto(s)
Adenocarcinoma/radioterapia , Neoplasias de la Parótida/radioterapia , Radioterapia de Intensidad Modulada/métodos , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/patología , Carcinoma Adenoide Quístico/diagnóstico por imagen , Carcinoma Adenoide Quístico/patología , Carcinoma Adenoide Quístico/radioterapia , Humanos , Neoplasias de la Parótida/diagnóstico por imagen , Neoplasias de la Parótida/patología , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Tomografía Computarizada Espiral , Carga Tumoral
19.
Phys Med Biol ; 52(9): 2459-81, 2007 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-17440246

RESUMEN

The purpose of the present study is to demonstrate that the use of an electron applicator with energy-dependent source-to-collimator distances (SCDs) will significantly improve the dose homogeneity for abutted electron fields in segmented-field electron conformal therapy (ECT). Multiple Coulomb scattering theory was used to calculate and study the P(80-20) penumbra width of off-axis dose profiles as a function of air gap and depth. Collimating insert locations with air gaps (collimator-to-isocenter distance) of 5.0, 7.5, 11.5, 17.5 and 19.5 cm were selected to provide equal P(80-20) at a depth of 1.5 cm in water for energies of 6, 9, 12, 16 and 20 MeV, respectively, for a Varian 2100EX radiation therapy accelerator. A 15 x 15 cm(2) applicator was modified accordingly, and collimating inserts used in the variable-SCD applicator for segmented-field ECT were constructed with diverging edges using a computer-controlled hot-wire cutter, which resulted in 0.27 mm accuracy in the abutted edges. The resulting electron beams were commissioned for the pencil-beam algorithm (PBA) on the Pinnacle(3) treatment planning system. Four hypothetical planning target volumes (PTVs) and one patient were planned for segmented-field ECT using the new variable-SCD applicator, and the resulting dose distributions were compared with those calculated for the identical plans using the conventional 95 cm SCD applicator. Also, a method for quality assurance of segmented-field ECT dose plans using the variable-SCD applicator was evaluated by irradiating a polystyrene phantom using the treatment plans for the hypothetical PTVs. Treatment plans for all four of the hypothetical PTVs using the variable-SCD applicator showed significantly improved dose homogeneity in the abutment regions of the segmented-field ECT plans. This resulted in the dose spread (maximum dose-minimum dose), sigma, and D(90-10) in the PTV being reduced by an average of 32%, 29% and 32%, respectively. Reductions were most significant for abutted fields of nonadjacent energies. Planning segmented-field ECT using the variable-SCD applicator for a patient with recurrent squamous cell carcinoma of the left ear showed the dose spread, sigma, and D(90-10) of the dose distribution in the PTV being reduced by an average of 38%, 22% and 22%, respectively. The measured and calculated dose in a polystyrene phantom resulting from the variable-SCD, segmented-field ECT plans for the hypothetical PTVs showed good agreement; however, isolated differences between dose calculation and measurement indicated the need for a more accurate dose algorithm than the PBA for segmented-field ECT. These results confirmed our hypothesis that using the variable-SCD applicator for segmented-field ECT results in the PTV dose distribution becoming more homogenous and being within the range of 85-105% of the 'given dose'. Clinical implementation of this method requires variable-SCD applicators, and the design used in the present work should be acceptable, as should our methods for construction of the inserts. Dose verification measurements in a polystyrene phantom and the recommended improvements in dose calculation should be appropriate for quality assurance of segmented-field ECT.


Asunto(s)
Electrones , Radioterapia Conformacional/métodos , Carcinoma de Células Escamosas/radioterapia , Neoplasias del Oído/radioterapia , Humanos , Recurrencia Local de Neoplasia , Radioterapia Conformacional/instrumentación
20.
J Biomech Eng ; 128(6): 943-56, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17154697

RESUMEN

BACKGROUND: There is a clear need for a prosthesis that improves postural stability in the balance impaired. Such a device would be used as a temporary aid during recovery from ablative inner-ear surgery, a postural monitor during rehabilitation (for example, hip surgery), and as a permanent prosthesis for those elderly prone to falls. METHOD OF APPROACH: Recently developed, small instruments have enabled wearable prostheses to augment or replace vestibular functions. The current prosthesis communicates by vibrators mounted on the subject's trunk. In this paper we emphasize the unique algorithms that enable tilt indication with modestly performing micromachined gyroscopes and accelerometers. RESULTS: For large angles and multiple axes, gyro drift and unwanted lateral accelerations are successfully rejected. In single-axis tests, the most dramatic results were obtained in standard operating tests where balance-impaired subjects were deprived of vision and proprioceptive inputs. Balance-impaired subjects who fell (into safety restraints) when not aided were able to stand with the prosthesis. Initial multiaxis tests with healthy subjects have shown that sway is reduced in both forward-back and sideward directions. CONCLUSIONS: Positive results in initial testing and a sound theoretical basis for the hardware warrant continued development and testing, which is being conducted at three sites.


Asunto(s)
Aceleración , Estimulación Física/instrumentación , Equilibrio Postural , Auxiliares Sensoriales , Transductores , Enfermedades Vestibulares/rehabilitación , Vibración/uso terapéutico , Diseño Asistido por Computadora , Análisis de Falla de Equipo , Humanos , Estimulación Física/métodos , Diseño de Prótesis
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