Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
J Appl Clin Med Phys ; 18(4): 116-122, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28585732

RESUMO

To investigate the inter- and intra-fraction motion associated with the use of a low-cost tape immobilization technique as an alternative to thermoplastic immobilization masks for whole-brain treatments. The results of this study may be of interest to clinical staff with severely limited resources (e.g., in low-income countries) and also when treating patients who cannot tolerate standard immobilization masks. Setup reproducibility of eight healthy volunteers was assessed for two different immobilization techniques. (a) One strip of tape was placed across the volunteer's forehead and attached to the sides of the treatment table. (b) A second strip was added to the first, under the chin, and secured to the table above the volunteer's head. After initial positioning, anterior and lateral photographs were acquired. Volunteers were positioned five times with each technique to allow calculation of inter-fraction reproducibility measurements. To estimate intra-fraction reproducibility, 5-minute anterior and lateral videos were taken for each technique per volunteer. An in-house software was used to analyze the photos and videos to assess setup reproducibility. The maximum intra-fraction displacement for all volunteers was 2.8 mm. Intra-fraction motion increased with time on table. The maximum inter-fraction range of positions for all volunteers was 5.4 mm. The magnitude of inter-fraction and intra-fraction motion found using the "1-strip" and "2-strip" tape immobilization techniques was comparable to motion restrictions provided by a thermoplastic mask for whole-brain radiotherapy. The results suggest that tape-based immobilization techniques represent an economical and useful alternative to the thermoplastic mask.


Assuntos
Análise Custo-Benefício , Irradiação Craniana , Cabeça , Imobilização/instrumentação , Voluntários Saudáveis , Humanos , Imobilização/métodos , Máscaras , Reprodutibilidade dos Testes
2.
Med Dosim ; 45(4): 334-338, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32471604

RESUMO

Whole-pelvis pencil beam scanning (PBS) proton therapy is utilized in both the intact and post-operative settings in patients with prostate cancer. As whole pelvis prostate radiotherapy has traditionally been delivered with standard photon beams, limited evidence and technical descriptions have been reported regarding the use of proton therapy. Here we present two robust three-field treatment planning approaches utilized to maximize target coverage in the presence of anatomic and delivery uncertainties. Both techniques, conventional optimization (CO) and robust optimization (RO), create treatment plans with acceptable target coverage and sparing of organs at risk (OAR). While the RO method is less time intensive and may theoretically allow for superior OAR sparing and improved robustness, the CO method can be implemented by institutions who do not have RO capabilities.


Assuntos
Neoplasias da Próstata , Terapia com Prótons , Radioterapia de Intensidade Modulada , Humanos , Masculino , Pelve , Neoplasias da Próstata/radioterapia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
3.
Science ; 170(3959): 743-5, 1970 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-5529568

RESUMO

Negatively stained slime mold actomyosin examined by electron microscopy consists mainly of actin-like filaments with occasional angular projections. If some of the actin is removed, the myosin-enriched actomyosin appears as continuous arrowhead structures similar to those of vertebrate striated muscle actomyosin. Together with other evidence, the findings suggest that cytoplasmic streaming in Physarum may involve a contractile process operating at a relatively low myosin-actin ratio.


Assuntos
Proteínas Musculares , Mixomicetos , Corrente Citoplasmática , Microscopia Eletrônica , Ultracentrifugação
4.
Science ; 262(5137): 1252-5, 1993 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-17772648

RESUMO

Global warming caused by an increase in the concentrations of greenhouse gases, is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered, this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes, the largest contributor was the carbon dioxide radiation parameterizations of the models.

5.
J Ethnopharmacol ; 225: 128-135, 2018 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-29944892

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: This is the first study of global trade in fruits of the widely used traditional medicine, Helicteres isora L. It is used in Ayurvedic, Siddha, Unani medical systems and/or local folk traditional medicines in Bangladesh, India and Pakistan. The roots are used in Traditional Chinese Medicines in China and the fruits in jamu products in Indonesia, Malaysia and Thailand. In addition, H. isora fruits are also used in "traditional" medical systems far beyond the natural distribution of this species, for example in Zulu herbal medicine (South Africa) and Kurdish herbal medicines (Iraq). AIMS OF THE STUDY: This study had three aims: (i) to assess the global trade in H. isora fruits; (ii) to study the H. isora trade from West Timor to Java in terms of actors and prices along the value chain and (iii) to get a better understanding of the potential of this species to improve household income in eastern Indonesia. MATERIALS AND METHODS: This study uses historical records, a contemporary analysis of global trade data (2014-2016) and field assessments of value chains and the biological factors influencing H. isora fruit production. RESULTS: Globally, the major exporter of H. isora fruits is India, which exports H. isora fruits to 19 countries, far beyond the natural geographical distribution of this species. Over a 36-month period (January 2014-December 2016), India exported 392 t of H. isora fruits, with a Free-On-Board (FOB) value of Indian rupiah (INR) 18,337,000 (US$ 274,055). This represents an average annual export quantity of about 130,526 kg/year. Over this three year period, most of these exports (85.5%) were to Indonesia (346.58 t), followed by Thailand (6.85%). Indian H. isora exports are also used in many other medical systems, including Kurdish and Zulu "traditional" medicines in Iraq and South Africa. Formation of an Indian diaspora in Bahrain, Mauritius, South Africa, Tanzania and Trinidad and Tobago over the past 130 years is one of the drivers of H. isora fruit trade outside the natural geographic distribution of the species. In Indonesia, demand for H. isora fruits is supplemented by an intra-island trade in Java and an inter-island trade from East Nusa Tenggara. West Timor, for example, exports around 31-37 t of air-dried H. isora fruits per year to Java. At the farm gate, local harvesters in West Timor get 4000 IDR (c. 0.3 US$) per kg, with businesses in Java paying 25,000 IDR (c.US$2) per kg for H. isora fruits. This is similar to the price paid for H. isora fruits imported from India to Java. CONCLUSIONS: India is the major exporter of whole dried H. isora fruits, including to countries where this species has never been in traditional use. In Indonesia, H. isora fruit extracts are used in the cosmetic industry as well as in jamu herbal medicines, including "Tolak Angin", the country's most popular commercial "jamu" preparation. Indonesia also is the major importer of H. isora fruits from India. In eastern Indonesia, improved income to local villagers from the H. isora fruit trade could come from improved H. isora fruit quality due to better drying techniques. This would also reduce health risks along the supply chain from to mycotoxins that have been recorded on poorly dried H. isora fruits. There also is an opportunity for cultivation of H. isora in small-holder teak plantations in Indonesia, with harvest of H. isora fruits as well as the medicinal bark.


Assuntos
Comércio , Frutas , Malvaceae , Humanos , Renda , Indonésia , Medicina Tradicional/economia
6.
Bone Marrow Transplant ; 40(8): 747-52, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17704796

RESUMO

The presence of clonal gammopathies (CG) has been reported following both conventional myeloablative and autologous haematopoietic stem cell transplantation (HSCT). We monitored the occurrence of CG in a cohort of patients with myeloid malignancies receiving FBC (fludarabine-busulphan-alemtuzumab)-based reduced intensity conditioned (RIC) HSCT, and assessed its correlation with infections, graft-versus-host disease (GvHD) and survival. Serial serum protein electrophoresis was analysed in a total of 138 patients and CG were detected in 49 patients (36%). The predominant Ig isotype was IgG (82%). There was no difference in the incidence of viral infections between patient groups. However, patients with gammopathies were more likely to have had prior chronic GvHD (OR 2.7, 95% CI 1.3-5.5, P<0.001). On multivariate analysis, the only factors that were found to influence overall survival (OS) were presence of gammopathies, which was associated with an improved OS (OR 0.35 95% CI 0.14-0.86, P=0.02) as well as disease stage, patients with advanced disease having a higher risk of death (OR 2.20 95% CI 1.18-4.11, P=0.02). Disease stage was the only variable that influenced relapse incidence on multivariate analysis (OR 4.22 95% CI 1.82-9.78, P<0.01). Clonal gammopathies are a frequent but benign occurrence following alemtuzumab-based RIC HSCT, and their appearance may define a group of patients with a favourable overall outcome.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Anticorpos Antineoplásicos/administração & dosagem , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Gamopatia Monoclonal de Significância Indeterminada/etiologia , Adulto , Idoso , Alemtuzumab , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Anticorpos Antineoplásicos/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Análise de Sobrevida , Condicionamento Pré-Transplante
7.
Brain ; 129(Pt 1): 224-34, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16280352

RESUMO

Spasticity is most commonly defined as an inappropriate, velocity dependent, increase in muscle tonic stretch reflexes, due to the amplified reactivity of motor segments to sensory input. It forms one component of the upper motor neuron syndrome and often leads to muscle stiffness and disability. Spasticity can, therefore, be measured through electrophysiological, biomechanical and clinical evaluation, the last most commonly using the Ashworth scale. None of these techniques incorporate the patient experience of spasticity, nor how it affects people's daily lives. Consequently, we set out to construct a rating scale to quantify the perspectives of the impact of spasticity on people with multiple sclerosis. Qualitative methods (in-depth patient interviews and focus groups, expert opinion and literature review) were used to develop a conceptual framework of spasticity impact, and to generate a pool of items with the potential to convert this framework into a rating scale with multiple dimensions. This item pool was administered, in the form of a questionnaire, to a sample of people with multiple sclerosis and spasticity. Guided by Rasch analysis, we constructed and validated a rating scale for each component of the conceptual framework. Decisions regarding item selection were based on the integration and assimilation of seven specific analyses including clinical meaning, ordering of thresholds, fit statistics and differential item functioning. The qualitative phase (17 patient interviews, 3 focus groups) generated 144 potential scale items and a conceptual model with eight components addressing symptoms (muscle stiffness, pain and discomfort and muscle spasms,), physical impact (activities of daily living, walking and body movements) and psychosocial impact (emotional health, social functioning). The first postal survey was sent to 272 people with multiple sclerosis and had a response rate of 88%. Findings supported the development of scales for each component but demonstrated that five item response options were too many. The 144-item questionnaire, reformatted with four-item response options, was administered with four validating instruments to an independent sample of 259 people with multiple sclerosis (response rate 78%). From the responses, an 88-item instrument with eight subscales was developed that satisfied criteria for reliable and valid measurement. Correlations with other measures were consistent with predictions. The 88-item Multiple Sclerosis Spasticity Scale (MSSS-88) is a reliable and valid, patient-based, interval-level measure of the impact of spasticity in multiple sclerosis. It has the potential to advance outcomes measurement in clinical trials and clinical practice, and provides a new perspective in the clinical evaluation of spasticity.


Assuntos
Avaliação da Deficiência , Esclerose Múltipla/diagnóstico , Espasticidade Muscular , Atividades Cotidianas , Adulto , Idoso , Feminino , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/psicologia , Psicometria , Perfil de Impacto da Doença , Inquéritos e Questionários
8.
Med Phys ; 44(8): 4159-4168, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28513864

RESUMO

PURPOSE: To assess the influence of non-rigid anatomy and differences in patient positioning between CT acquisition and endoscopic examination on endoscopy-CT image registration in the head and neck. METHODS: Radiotherapy planning CTs and 31-35 daily treatment-room CTs were acquired for nineteen patients. Diagnostic CTs were acquired for thirteen of the patients. The surfaces of the airways were segmented on all scans and triangular meshes were created to render virtual endoscopic images with a calibrated pinhole model of an endoscope. The virtual images were used to take projective measurements throughout the meshes, with reference measurements defined as those taken on the planning CTs and test measurements defined as those taken on the daily or diagnostic CTs. The influence of non-rigid anatomy was quantified by 3D distance errors between reference and test measurements on the daily CTs, and the influence of patient positioning was quantified by 3D distance errors between reference and test measurements on the diagnostic CTs. The daily CT measurements were also used to investigate the influences of camera-to-surface distance, surface angle, and the interval of time between scans. RESULTS: Average errors in the daily CTs were 0.36 ± 0.61 cm in the nasal cavity, 0.58 ± 0.83 cm in the naso- and oropharynx, and 0.47 ± 0.73 cm in the hypopharynx and larynx. Average errors in the diagnostic CTs in those regions were 0.52 ± 0.69 cm, 0.65 ± 0.84 cm, and 0.69 ± 0.90 cm, respectively. All CTs had errors heavily skewed towards 0, albeit with large outliers. Large camera-to-surface distances were found to increase the errors, but the angle at which the camera viewed the surface had no effect. The errors in the Day 1 and Day 15 CTs were found to be significantly smaller than those in the Day 30 CTs (P < 0.05). CONCLUSIONS: Inconsistencies of patient positioning have a larger influence than non-rigid anatomy on projective measurement errors. In general, these errors are largest when the camera is in the superior pharynx, where it sees large distances and a lot of muscle motion. The errors are larger when the interval of time between CT acquisitions is longer, which suggests that the interval of time between the CT acquisition and the endoscopic examination should be kept short. The median errors found in this study are comparable to acceptable levels of uncertainty in deformable CT registration. Large errors are possible even when image alignment is very good, indicating that projective measurements must be made carefully to avoid these outliers.


Assuntos
Endoscopia , Posicionamento do Paciente , Tomografia Computadorizada por Raios X , Algoritmos , Cabeça/diagnóstico por imagem , Humanos , Pescoço/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador
9.
PLoS One ; 12(5): e0177886, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28542331

RESUMO

PURPOSE: Endoscopic examinations are frequently-used procedures for patients with head and neck cancer undergoing radiotherapy, but radiation treatment plans are created on computed tomography (CT) scans. Image registration between endoscopic video and CT could be used to improve treatment planning and analysis of radiation-related normal tissue toxicity. The purpose of this study was to explore the feasibility of endoscopy-CT image registration without prospective physical tracking of the endoscope during the examination. METHODS: A novel registration technique called Location Search was developed. This technique uses physical constraints on the endoscope's view direction to search for the virtual endoscope coordinates that maximize the similarity between the endoscopic video frame and the virtual endoscopic image. Its performance was tested on phantom and patient images and compared to an established registration technique, Frame-To-Frame Tracking. RESULTS: In phantoms, Location Search had average registration errors of 0.55 ± 0.60 cm for point measurements and 0.29 ± 0.15 cm for object surface measurements. Frame-To-Frame Tracking achieved similar results on some frames, but it failed on others due to the virtual endoscope becoming lost. This weakness was more pronounced in patients, where Frame-To-Frame tracking could not make it through the nasal cavity. On successful patient video frames, Location Search was able to find endoscope positions with an average distance of 0.98 ± 0.53 cm away from the ground truth positions. However, it failed on many frames due to false similarity matches caused by anatomical structural differences between the endoscopic video and the virtual endoscopic images. CONCLUSIONS: Endoscopy-CT image registration without prospective physical tracking of the endoscope is possible, but more development is required to achieve an accuracy suitable for clinical translation.


Assuntos
Endoscopia , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada por Raios X , Adulto , Algoritmos , Estudos de Viabilidade , Feminino , Humanos , Masculino , Imagens de Fantasmas
10.
Ear Nose Throat J ; 85(3): 190-2, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16615604

RESUMO

Respiratory epithelial adenomatoid (READ) hamartoma is a recently described entity characterized by abnormal glandular formations arising from the epithelium of the nasal cavity. The etiology of the lesion is unclear and may be secondary to either sinonasal inflammation or developmental error. We present a case of a 54-year-old man with a unilateral nasal mass found to be consistent with READ hamartoma upon pathologic review. Although READ hamartomas are thought to be rare, awareness of the lesion is important since it may be confused with sinonasal adenocarcinoma, leading to overly aggressive treatment. Therefore, READ hamartoma should be included in the differential diagnosis of a unilateral nasal mass.


Assuntos
Hamartoma/diagnóstico , Hamartoma/patologia , Doenças Nasais/diagnóstico , Doenças Nasais/patologia , Mucosa Respiratória/patologia , Diagnóstico Diferencial , Endoscopia , Hamartoma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Cavidade Nasal/diagnóstico por imagem , Cavidade Nasal/patologia , Doenças Nasais/cirurgia , Tomografia Computadorizada por Raios X
11.
Nucl Instrum Methods Phys Res A ; 776: 15-20, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25705066

RESUMO

Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator's stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent.

12.
J Am Coll Surg ; 189(2): 145-50; discussion 150-1, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10437835

RESUMO

BACKGROUND: The Focused Assessment for the Sonographic Examination of the Trauma patient (FAST) sequentially surveys for the presence or absence of blood in dependent abdominal regions including the right upper quadrant, left upper quadrant, and the pelvis. But it does not readily identify intraparenchymal or retroperitoneal injuries, and a CT scan of the abdomen may be needed to reduce the incidence of missed injuries. We hypothesized that select patients who are considered high risk for occult injuries should undergo a CT scan of the abdomen when the FAST is negative so that occult injuries can be detected. STUDY DESIGN: An algorithm was prospectively tested for the evaluation of select injured patients over a 3 1/2-year period. Entrance criteria included adult patients with a blunt mechanism of trauma, a negative FAST examination, and a spine fracture (with or without cord injury), or a pelvic fracture. Trauma team members performed the FAST on patients during the Advanced Trauma Life Support secondary survey. Data recorded included the patient's mechanism and type of injury, the results of the FAST and CT scan examinations, operative or postmortem findings or both, and patient outcomes. Patients with spine injuries were grouped according to spine level and the presence or absence of neurologic deficit. The patients with pelvic fractures were grouped according to the Young and Resnick classification. RESULTS: One hundred two of 1,490 patients (6.8%) who had FAST examinations were entered into this study. Thirty-two patients (30.5%) had spine injuries, with only one false-negative ultrasound result. Seventy patients (68.6%) had pelvic fractures with 13 false-negative ultrasound results: 11 ring (9 from motor vehicle crashes, 2 from pedestrians struck), 1 acetabular, and 1 isolated pelvic fracture. Nine patients underwent nonoperative management for solid organ injuries, and 4 patients needed surgery. CONCLUSIONS: Based on these preliminary data, we conclude that patients with pelvic ring-type fractures should have CT scans of the abdomen because of the higher yield for occult injuries.


Assuntos
Traumatismos Abdominais/diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito , Fraturas da Coluna Vertebral/diagnóstico , Ultrassonografia/instrumentação , Ferimentos não Penetrantes/diagnóstico , Traumatismos Abdominais/cirurgia , Adolescente , Adulto , Idoso , Algoritmos , Diagnóstico Diferencial , Feminino , Fraturas Ósseas/diagnóstico , Fraturas Ósseas/cirurgia , Hemoperitônio/diagnóstico , Hemoperitônio/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Ossos Pélvicos/lesões , Estudos Prospectivos , Sensibilidade e Especificidade , Traumatismos da Medula Espinal/diagnóstico , Traumatismos da Medula Espinal/cirurgia , Fraturas da Coluna Vertebral/cirurgia , Tomografia Computadorizada por Raios X , Ferimentos não Penetrantes/cirurgia
13.
Am J Surg ; 176(6): 538-43, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9926786

RESUMO

BACKGROUND: The explosion of a bomb 75 to 100 yards away from attendees at a concert who were in the process of being evacuated from Centennial Olympic Park at approximately 1:25 AM on July 27, 1996, resulted in a multiple-casualty event involving primarily four hospitals in proximity to the blast. The purpose of this study was to review triage and care of the victims, emphasizing those with significant injuries. METHODS: Retrospective review of triage and care of injured patients. RESULTS: Ninety-six of the 111 victims of the blast were triaged in the first half hour to four hospitals within 3 miles of the bombing. Only four minor operations were performed in 61 patients evaluated at community hospitals. Ten of 35 patients evaluated at the regional trauma center underwent emergency or urgent operations, and all who were seriously injured did well. CONCLUSIONS: Although overtriage to the regional trauma center occurred, outcome was excellent in all seriously injured victims treated there.


Assuntos
Avaliação de Resultados em Cuidados de Saúde , Centros de Traumatologia/normas , Triagem , Violência , Ferimentos e Lesões/cirurgia , Planejamento em Desastres , Georgia , Humanos , Esportes , Resultado do Tratamento
14.
Am J Surg ; 182(6): 670-5, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11839336

RESUMO

BACKGROUND: The morbidity and mortality of various open abdominal techniques remains unclear. METHODS: A retrospective review was made of all trauma or general surgery patients who underwent an open abdominal closure from January 1997 to December 2000, at a large urban acute care hospital. Data are mean +/- SD. RESULTS: From 1997 to 2000, 181 patients (aged 39.8 +/- 16.5 years) had an open abdomen for abdominal infection, planned reexploration, abdominal compartment syndrome, inability to reapproximate fascia, or as part of a "damage control" procedure. Twenty-three patients went on to develop an abdominal compartment syndrome. Gastrointestinal fistulas occurred in 26 patients, and 9 patients had a dehiscence. The overall mortality was 44.7%. Of the survivors, 52% went on to fascial closure, requiring 1 to 7 additional abdominal operations. CONCLUSIONS: The morbidity of the open abdomen varies with the particular indication. Gastrointestinal fistulas are the most common acute complication and an abdominal wall hernia, the most common chronic complication.


Assuntos
Abdome/cirurgia , Técnicas de Sutura , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Síndromes Compartimentais/etiologia , Estado Terminal , Fístula Gástrica/etiologia , Hérnia Ventral/etiologia , Humanos , Fístula Intestinal/etiologia , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Reoperação , Estudos Retrospectivos , Deiscência da Ferida Operatória
15.
Am Surg ; 67(6): 565-70; discussion 570-1, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11409805

RESUMO

This is a report of a 10-year experience (1989-1998) with 300 consecutive patients found to have an injury to a named abdominal vessel at the time of an exploratory laparotomy for trauma. An abdominal gunshot wound was the mechanism of injury in 78 per cent of patients, and injury to more than one named abdominal vessel was present in 42 per cent. The abdominal aorta, inferior vena cava, and external iliac artery and vein were the most commonly injured vessels. When management for the five most commonly injured arteries was grouped, exsanguination before attempts at repair occurred in 11 to 15 per cent of patients and the mean survival in the remainder was 46 per cent. When management for the five most commonly injured veins was grouped, exsanguination before attempts at repair occurred in 5 per cent of patients and the mean survival in the remainder was 64 per cent. A number of administrative and medical changes in the management of patients with abdominal trauma occurred from 1992 through 1994. Despite significantly increased Injury Severity Scores for patients treated from 1993 through 1998 as compared with those treated from 1989 through 1992 survival rates for patients with injuries to the abdominal aorta and inferior vena cava were unchanged. Survival rates for injuries to the external iliac artery and vein increased significantly. The local changes in management should be considered for prospective studies in other urban trauma centers.


Assuntos
Aorta Abdominal/lesões , Artéria Ilíaca/lesões , Veia Ilíaca/lesões , Veia Cava Inferior/lesões , Ferimentos não Penetrantes/cirurgia , Ferimentos Penetrantes/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Aorta Abdominal/cirurgia , Criança , Pré-Escolar , Feminino , Georgia/epidemiologia , Humanos , Artéria Ilíaca/cirurgia , Veia Ilíaca/cirurgia , Escala de Gravidade do Ferimento , Laparotomia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Análise de Sobrevida , Veia Cava Inferior/cirurgia , Ferimentos não Penetrantes/epidemiologia , Ferimentos Penetrantes/epidemiologia
19.
Med Phys ; 39(6Part11): 3729, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28517156

RESUMO

PURPOSE: Organic liquid scintillators are currently under investigation for use in proton dosimetry. The purpose of this work is to evaluate the water equivalence of these materials as a preliminary step to identify scintillators that are well-suited to this purpose. METHODS: Stopping powers were calculated for 0.001-1000 MeV protons in water, polystyrene, and two organic liquid scintillators: BC-531 and OptiPhase 'Hi-Safe' 3 at 0%, 25%, and 50% concentrations of water. Angular scatter was quantified by theta0, a characteristic multiple Coulomb scattering angle analogous to the standard deviation of a Gaussian distribution of proton angles relative to the incident beam axis. Theta0 was calculated as a function of depth over the range of 200 MeV protons in these materials. RESULTS: Collisional stopping power in BC-531 ranged from +44% to +1% ofthat in water. It remained within 6% from 2-600 MeV. OptiPhase ranged from +24% to -2%, with smaller deviations at increased water concentrations. At all concentrations, OptiPhase showed smaller deviations than polystyrene and BC-531 and remained within 1% of water from 2-600 MeV.Theta0 was very similar for all materials, with deviations from water of 5 milliradians or less over the majority of the proton range. BC-531 showed deviations of 10 milliradians or more in the last few millimeters of the range. OptiPhase showed smaller deviations than BC-531 or polystyrene, and these deviations decreased with increasing water concentration. CONCLUSIONS: OptiPhase was found to be more water equivalent than BC-531 or polystyrene in stopping power and angular scatter, and increased water concentration improved both quantities. Large deviations in stopping power were only found below 2 MeV for any material, where proton range is less than 0.1 millimeter. The deviations from water found in angular scatter were less significant, and probably too small to affect measurement.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA