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1.
Eur J Cancer Care (Engl) ; 29(4): e13238, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32369244

RESUMO

INTRODUCTION: Rehabilitation and exercise interventions are beneficial for the physical and psychological health of cancer survivors. Current clinic-based performance status measures do not accurately capture the survivor's functioning, or rehabilitation and exercise needs. Our primary objective was to explore the feasibility of performing a performance-based functional assessment with brain tumour survivors as a means to inform needs for rehabilitation and exercise. METHODS: A feasibility study was conducted with survivors of brain and other neurological cancers attending new patient or follow-up clinics. Survivors were assessed using the Short Physical Performance Battery (SPPB), grip strength and Rosow-Breslau Physical Activity Self-Assessment (RSB). RESULTS: We approached 40 survivors with brain tumours, and 30 agreed to participate in the study. The SPPB was inversely correlated with Eastern Cooperative Oncology Group (ECOG) scores (r = -.73; p < .01), but scores on the SPPB for individuals classified as ECOG 1 ranged from 5 to 12 out of 12, indicating a large variability in functional scores within this ECOG grade. CONCLUSION: Implementation of objective functional testing is feasible in the neuro-oncology outpatient clinic. The SPPB appears to best inform the functional status of survivors with brain tumours, facilitating more individualised exercise and rehabilitation referrals.


Assuntos
Astrocitoma/fisiopatologia , Neoplasias Encefálicas/fisiopatologia , Sobreviventes de Câncer , Glioblastoma/fisiopatologia , Oligodendroglioma/fisiopatologia , Desempenho Físico Funcional , Adulto , Idoso , Astrocitoma/reabilitação , Neoplasias Encefálicas/reabilitação , Estudos de Viabilidade , Feminino , Estado Funcional , Glioblastoma/reabilitação , Força da Mão/fisiologia , Humanos , Extremidade Inferior/fisiopatologia , Masculino , Pessoa de Meia-Idade , Oligodendroglioma/reabilitação , Equilíbrio Postural/fisiologia , Autorrelato , Velocidade de Caminhada/fisiologia
2.
N Engl J Med ; 374(14): 1344-55, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-27050206

RESUMO

BACKGROUND: Grade 2 gliomas occur most commonly in young adults and cause progressive neurologic deterioration and premature death. Early results of this trial showed that treatment with procarbazine, lomustine (also called CCNU), and vincristine after radiation therapy at the time of initial diagnosis resulted in longer progression-free survival, but not overall survival, than radiation therapy alone. We now report the long-term results. METHODS: We included patients with grade 2 astrocytoma, oligoastrocytoma, or oligodendroglioma who were younger than 40 years of age and had undergone subtotal resection or biopsy or who were 40 years of age or older and had undergone biopsy or resection of any of the tumor. Patients were stratified according to age, histologic findings, Karnofsky performance-status score, and presence or absence of contrast enhancement on preoperative images. Patients were randomly assigned to radiation therapy alone or to radiation therapy followed by six cycles of combination chemotherapy. RESULTS: A total of 251 eligible patients were enrolled from 1998 through 2002. The median follow-up was 11.9 years; 55% of the patients died. Patients who received radiation therapy plus chemotherapy had longer median overall survival than did those who received radiation therapy alone (13.3 vs. 7.8 years; hazard ratio for death, 0.59; P=0.003). The rate of progression-free survival at 10 years was 51% in the group that received radiation therapy plus chemotherapy versus 21% in the group that received radiation therapy alone; the corresponding rates of overall survival at 10 years were 60% and 40%. A Cox model identified receipt of radiation therapy plus chemotherapy and histologic findings of oligodendroglioma as favorable prognostic variables for both progression-free and overall survival. CONCLUSIONS: In a cohort of patients with grade 2 glioma who were younger than 40 years of age and had undergone subtotal tumor resection or who were 40 years of age or older, progression-free survival and overall survival were longer among those who received combination chemotherapy in addition to radiation therapy than among those who received radiation therapy alone. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00003375.).


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Astrocitoma/tratamento farmacológico , Astrocitoma/radioterapia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Oligodendroglioma/tratamento farmacológico , Oligodendroglioma/radioterapia , Adulto , Astrocitoma/mortalidade , Neoplasias Encefálicas/mortalidade , Terapia Combinada , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Lomustina/administração & dosagem , Masculino , Gradação de Tumores , Oligodendroglioma/mortalidade , Procarbazina/administração & dosagem , Análise de Sobrevida , Vincristina/administração & dosagem , Adulto Jovem
3.
Bull Math Biol ; 80(5): 1259-1291, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28493055

RESUMO

Gliomas are primary brain tumours arising from the glial cells of the nervous system. The diffuse nature of spread, coupled with proximity to critical brain structures, makes treatment a challenge. Pathological analysis confirms that the extent of glioma spread exceeds the extent of the grossly visible mass, seen on conventional magnetic resonance imaging (MRI) scans. Gliomas show faster spread along white matter tracts than in grey matter, leading to irregular patterns of spread. We propose a mathematical model based on Diffusion Tensor Imaging, a new MRI imaging technique that offers a methodology to delineate the major white matter tracts in the brain. We apply the anisotropic diffusion model of Painter and Hillen (J Thoer Biol 323:25-39, 2013) to data from 10 patients with gliomas. Moreover, we compare the anisotropic model to the state-of-the-art Proliferation-Infiltration (PI) model of Swanson et al. (Cell Prolif 33:317-329, 2000). We find that the anisotropic model offers a slight improvement over the standard PI model. For tumours with low anisotropy, the predictions of the two models are virtually identical, but for patients whose tumours show higher anisotropy, the results differ. We also suggest using the data from the contralateral hemisphere to further improve the model fit. Finally, we discuss the potential use of this model in clinical treatment planning.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Glioma/diagnóstico por imagem , Modelagem Computacional Específica para o Paciente , Anisotropia , Simulação por Computador , Imagem de Tensor de Difusão/estatística & dados numéricos , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento Tridimensional , Conceitos Matemáticos , Invasividade Neoplásica/diagnóstico por imagem
4.
Neurosciences (Riyadh) ; 18(4): 349-55, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24141458

RESUMO

OBJECTIVE: To examine whether adjuvant temozolomide treatment improved glioblastoma patients` survival in a large Canadian cohort. METHODS: We retrospectively studied 364 glioblastoma patients who received different modalities of treatment in 2 Canadian tertiary care centers in Edmonton and Halifax, Canada, between January 2000 and December 2006. The primary outcome was survival following the treatment protocol. RESULTS: The following variables were associated with an increased risk of death: The hazard risk (HR) of on-gross total resection was 0.50 (95% confidence interval [CI]: 0.39-0.64). The HR for the surgery-only group was 5.2 (95% CI: 3.85-7.06). The standard treatment group (surgery, radiation therapy [RT], and temozolomide) had an HR of 0.52 (95% CI: 0.37-0.74). The HR for patients who presented with seizure or whose presentation included seizures was 0.88 (95% CI: 0.55-0.89). Patient entry into trials had an HR of 0.74 (95% CI: 0.57-0.96). Finally, the HR for age was 1.02 (95% CI: 1.01-1.03) for every extra year. CONCLUSION: Concomitant temozolomide with RT and surgery was associated with longer survival compared with RT with surgery alone. We also found that younger age, surgical resection, seizure presence, and entry into trials are important prognostic factors for longer survival.


Assuntos
Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/terapia , Dacarbazina/análogos & derivados , Glioblastoma/terapia , Idoso , Neoplasias Encefálicas/mortalidade , Canadá , Quimioterapia Adjuvante/métodos , Dacarbazina/administração & dosagem , Feminino , Glioblastoma/mortalidade , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Radioterapia , Estudos Retrospectivos , Temozolomida , Resultado do Tratamento
5.
Curr Oncol ; 31(1): 24-41, 2023 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-38275828

RESUMO

OBJECTIVE: The purpose of this guideline update is to reassess and update recommendations in the prior guideline from 2016 on the appropriate management of patients with uveal melanoma. METHODS: In 2021, a multidisciplinary working group from the Provincial Cutaneous Tumour Team, Cancer Care Alberta, Alberta Health Services was convened to update the guideline. A comprehensive review of new research evidence in PubMed as well as new clinical practice guidelines from prominent oncology groups informed the update. An enhancement in methodology included adding levels of evidence and strength of recommendations. The updated guideline was circulated to all members of the Provincial Cutaneous Tumour Team for review and endorsement. RESULTS: New and modified recommendations address provider training requirements, diagnostic imaging for the detection of metastases, neo-adjuvant pre-enucleation radiotherapy, intravitreal anti-vascular endothelial growth factor agents for radiation retinopathy, genetic prognostic testing, surveillance following definitive local therapy, and systemic therapy for patients with metastatic uveal melanoma. DISCUSSION: The recommendations represent evidence-based standards of care agreed to by a large multidisciplinary group of healthcare professionals.


Assuntos
Melanoma , Neoplasias Cutâneas , Neoplasias Uveais , Humanos , Alberta , Melanoma/diagnóstico , Melanoma/terapia , Melanoma/patologia , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/terapia , Neoplasias Uveais/patologia
6.
Int J Radiat Oncol Biol Phys ; 112(5): 1115-1122, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34740768

RESUMO

PURPOSE: We report efficacy of a prospective phase 2 trial (NCT00450411) of salvage low-dose-rate (LDR) prostate brachytherapy (BT) for local failure (LF) after prior external beam radiation therapy (EBRT) with minimum 5-years' follow-up. METHODS AND MATERIALS: Eligible patients had low/intermediate risk prostate cancer (PCa) before EBRT and biopsy-proven LF >30 months after EBRT, with prostate-specific antigen <10 ng/mL and no regional/distant disease. The primary endpoint, late gastrointestinal and genitourinary adverse events (Common Terminology Criteria for Adverse Events v3.0) grade ≥3 were 14%. With minimum 5-year follow-up after salvage BT, secondary clinical outcomes including disease-free survival (DFS; includes death from any cause), disease-specific survival, and overall survival (OS) were estimated using the Kaplan-Meier method and modelled using Cox proportional hazards regression. Local tumor progression (ie, LF), distant failure (DF), and biochemical failure (BF) were estimated using cumulative incidence. Time to LF, DF, and BF were modeled by cause-specific Cox proportional hazards regression. RESULTS: From May 2007 to January 2014, 20 centers registered 100 patients (92 analyzable). Median follow-up is 6.7 years (range, 0.3-11.2); median age 70 years (range, 55-82); median prior EBRT dose 74 Gy [interquartile range (IQR):70 - 76] at a median of 85 months prior (IQR 60-119 months). Androgen deprivation was combined with salvage BT in 16%. Ten-year OS is 70% [95% confidence interval (CI) 58% - 83%]. Nineteen patients died (5 PCa, 10 other, 4 unknown). Ten-year failure rates are local 5% (95% CI, 1-11), distant 19% (95% CI, 10-29), and biochemical 46% (95% CI, 34-57). DFS is 61% at 5 years and 33% at 10 years. No baseline characteristic was significantly associated with any clinical outcome. CONCLUSIONS: This is the first prospective multicenter trial reporting outcomes of salvage LDR BT for LF after EBRT. Five-year freedom from BF is 68%, comparable to other salvage modalities. Although further LF is rare (5%), BF climbs to 46% by 10 years.


Assuntos
Braquiterapia , Neoplasias da Próstata , Idoso , Idoso de 80 Anos ou mais , Antagonistas de Androgênios/uso terapêutico , Braquiterapia/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Próstata/patologia , Antígeno Prostático Específico , Neoplasias da Próstata/patologia , Estudos Retrospectivos , Terapia de Salvação
7.
Pract Radiat Oncol ; 11(5): 384-393, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33705985

RESUMO

PURPOSE: Hypofractionated radiation therapy (HFRT) may offer treatment advantages for patients with prostate cancer. However, HFRT may also increase the risk of gastrointestinal (GI) or genitourinary (GU) toxicity compared with conventionally fractionated radiation therapy (CFRT). Several large trials have found that HFRT is well tolerated in mixed risk population studies. Here, we report on a phase II, randomized controlled study conducted to evaluate these endpoints in exclusively high-risk patients with prostate cancer treated with prostate and pelvic nodal radiation. METHODS AND MATERIALS: After giving informed consent, patients with high-risk prostate cancer were randomly assigned to prostate plus pelvic nodal radiation therapy with either HFRT (68 Gy in 25 fractions) or CFRT (78 Gy in 39 fractions) and 18 months of androgen suppression therapy. Toxicity was scored using the Common Terminology Criteria for Adverse Events (version 4.0). Biochemical failure was determined by the Phoenix definition. Patients were analyzed on an intention-to-treat basis. RESULTS: From 2012 to 2018, 111 patients with high-risk prostate cancer were enrolled and 109 patients were treated. The cumulative incidence of grade 2 or higher acute GI toxicity was not significantly different between the arms (HFRT 18.9% vs CFRT 21.8%; P = .812). Similarly, acute GU (HFRT 30.2% vs CFRT 30.9%; P = 1.00), late GI (HFRT 16.0% vs CFRT 10.0%; P = .554), and late GU (HFRT 16.0% vs CFRT 6.0%; P = .200) were not significantly different between the arms. Median follow-up was 38.0 months (4.8-77.8 months). The 3-year biochemical recurrence-free survival was not significantly different between the 2 arms (97.3% for HFRT vs 91.0% for CFRT; P = .606). The 3-year overall survival was 94.8% in the HFRT arm and 100.0% in the CFRT arm (P = .116). CONCLUSIONS: HFRT and CFRT using intensity modulated radiation therapy were both well tolerated for patients with high-risk prostate cancer and resulted in similar 3-year biochemical recurrence-free survival and overall survival.


Assuntos
Neoplasias da Próstata , Radioterapia de Intensidade Modulada , Fracionamento da Dose de Radiação , Humanos , Masculino , Estudos Prospectivos , Neoplasias da Próstata/radioterapia , Hipofracionamento da Dose de Radiação , Radioterapia de Intensidade Modulada/efeitos adversos
8.
J Appl Clin Med Phys ; 11(3): 3175, 2010 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-20717083

RESUMO

In recent years, a number of approaches have been applied to the problem of deformable registration validation. However, the challenge of assessing a commercial deformable registration system - in particular, an automatic registration system in which the deformable transformation is not readily accessible - has not been addressed. Using a collection of novel and established methods, we have developed a comprehensive, four-component protocol for the validation of automatic deformable image registration systems over a range of IGRT applications. The protocol, which was applied to the Reveal-MVS system, initially consists of a phantom study for determination of the system's general tendencies, while relative comparison of different registration settings is achieved through postregistration similarity measure evaluation. Synthetic transformations and contour-based metrics are used for absolute verification of the system's intra-modality and inter-modality capabilities, respectively. Results suggest that the commercial system is more apt to account for global deformations than local variations when performing deform-able image registration. Although the protocol was used to assess the capabilities of the Reveal-MVS system, it can readily be applied to other commercial systems. The protocol is by no means static or definitive, and can be further expanded to investigate other potential deformable registration applications.


Assuntos
Imageamento Tridimensional/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador , Software , Algoritmos , Humanos , Imageamento por Ressonância Magnética , Imagens de Fantasmas , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X
9.
J Clin Oncol ; 38(29): 3407-3417, 2020 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-32706640

RESUMO

PURPOSE: NRG Oncology/RTOG 9802 (ClinicalTrials.gov Identifier: NCT00003375) is a practice-changing study for patients with WHO low-grade glioma (LGG, grade II), as it was the first to demonstrate a survival benefit of adjuvant chemoradiotherapy over radiotherapy. This post hoc study sought to determine the prognostic and predictive impact of the WHO-defined molecular subgroups and corresponding molecular alterations within NRG Oncology/RTOG 9802. METHODS: IDH1/2 mutations were determined by immunohistochemistry and/or deep sequencing. A custom Ion AmpliSeq panel was used for mutation analysis. 1p/19q codeletion and MGMT promoter methylation were determined by copy-number arrays and/or Illumina 450K array, respectively. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Hazard ratios (HRs) were calculated using the Cox proportional hazard model and tested using the log-rank test. Multivariable analyses (MVAs) were performed incorporating treatment and common prognostic factors as covariates. RESULTS: Of the eligible patients successfully profiled for the WHO-defined molecular groups (n = 106/251), 26 (24%) were IDH-wild type, 43 (41%) were IDH-mutant/non-codeleted, and 37(35%) were IDH-mutant/codeleted. MVAs demonstrated that WHO subgroup was a significant predictor of PFS after adjustment for clinical variables and treatment. Notably, treatment with postradiation chemotherapy (PCV; procarbazine, lomustine (CCNU), and vincristine) was associated with longer PFS (HR, 0.32; P = .003; HR, 0.13; P < .001) and OS (HR, 0.38; P = .013; HR, 0.21; P = .029) in the IDH-mutant/non-codeleted and IDH-mutant/codeleted subgroups, respectively. In contrast, no significant difference in either PFS or OS was observed with the addition of PCV in the IDH-wild-type subgroup. CONCLUSION: This study is the first to report the predictive value of the WHO-defined diagnostic classification in a set of uniformly treated patients with LGG in a clinical trial. Importantly, this post hoc analysis supports the notion that patients with IDH-mutant high-risk LGG regardless of codeletion status receive benefit from the addition of PCV.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Glioma/genética , Glioma/terapia , Isocitrato Desidrogenase/genética , Adulto , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Ensaios Clínicos Fase III como Assunto , Metilação de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Feminino , Glioma/tratamento farmacológico , Glioma/radioterapia , Humanos , Imuno-Histoquímica , Lomustina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Procarbazina/administração & dosagem , Regiões Promotoras Genéticas , Modelos de Riscos Proporcionais , Proteínas Supressoras de Tumor/genética , Vincristina/administração & dosagem
10.
J Appl Clin Med Phys ; 10(4): 165-176, 2009 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-19918237

RESUMO

Daily image guidance for helical tomotherapy prostate patients is based on the registration of pre-treatment megavoltage CT (MVCT) images and the original planning CT. The goal of registration, whether manual or automatic, is the overlap of the prostate; otherwise prostate misplacement may compromise the efficacy of treatment or lead to increased toxicity. A previous study demonstrated that without the aid of implanted fiducials, manual registration results in inaccurate prostate positioning. The objective of this work is to quantify prostate misplacement that results from automatic bone matching (BM) and image matching (IM) registration algorithms. 204 MVCT images from 8 high risk tomotherapy prostate patients were incorporated into this retrospective study. BM and IM registration algorithms--based on maximization of mutual information of bony anatomy only and the entire image, respectively--were used to independently register MVCT images to their respective planning images. A correlation coefficient based algorithm that uses known planning CT contour information was used for automatic prostate localization in each MVCT image. Daily prostate misplacement was determined by repositioning as calculated from the BM and the IM algorithms. Mean (+/- SD) and maximum 3D prostate positioning errors were 3.7 +/- 2.1 mm and 11.8 mm for bone matching and 4.6 +/- 2.3 mm and 11.5 mm for image matching. In terms of translational directions, IM would lead to prostate positioning error > or = 3 mm in any of the LR, AP or SI directions in 62% of treatment fractions. The corresponding value for BM is 51%. The values for positioning errors > or = 5 mm were 29% and 17% for IM and BM, respectively. This data suggests automatic daily image guidance for tomotherapy prostate patients should be based on bone matching instead of image matching.


Assuntos
Próstata/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Humanos , Masculino
11.
BMJ Open ; 9(9): e029975, 2019 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519676

RESUMO

INTRODUCTION: Cancer care has expanded from a disease-focused, survival-oriented model to an approach that now considers how survivors can live well in the aftermath of intensive therapy, where they may deal with significant changes to their bodies, mental health or emotional well-being. Research evidence supports the benefit of exercise during and following cancer treatments for cancer-related symptoms, physical functioning and fitness, and health-related quality of life. To move this efficacy evidence into practice, we designed and launched a 5-year study to evaluate the relative benefit from implementing a clinic-to-community-based cancer and exercise model of care. METHODS AND ANALYSIS: A hybrid effectiveness and implementation trial design is being used to evaluate the effectiveness of delivery of community-based exercise and to collect data on implementation of the programme. The study opened in January 2017, with estimated completion by January 2022. The programme will be delivered in seven cities across the province of Alberta, Canada, with sites including three academic institutions, six YMCA locations, Wellspring Edmonton and Calgary, and six municipal fitness centres. Participants are adult cancer survivors (n=2500) from all tumour groups and stages and at any time point along their cancer treatment trajectory, up to 3 years post treatment completion. Survivors take part in a minimum of 60 min of mild-to-moderate intensity full body exercise twice weekly for a 12-week period. The primary effectiveness outcome is the proportion of participants meeting or exceeding 150 min of moderate intensity exercise per week at 1-year follow-up. The Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework will be utilised to capture individual-level and organizational-level impact of the exercise programme at 12 and 24 weeks and 1-year follow-up. The cohort of survivors participating in the study will allow for long-term (>5-year) evaluation of rates of cancer recurrence and secondary cancers beyond the funding period. ETHICS AND DISSEMINATION: The study was approved by the Health Research Ethics Board of Alberta. The study is funded by Alberta Innovates and the Alberta Cancer Foundation. The study will help to answer critical questions on the effectiveness of cancer-specific community-based exercise programming in both the short-term and the long-term. Collectively, the findings will help to inform the acceptability, adoption, feasibility, reach and sustainability of community-based exercise. TRIAL REGISTRATION NUMBER: NCT02984163; Pre-results.


Assuntos
Sobreviventes de Câncer , Atenção à Saúde/métodos , Exercício Físico , Promoção da Saúde/métodos , Neoplasias , Aptidão Física , Qualidade de Vida , Canadá , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/prevenção & controle , Neoplasias/psicologia , Avaliação de Processos e Resultados em Cuidados de Saúde , Aptidão Física/fisiologia , Aptidão Física/psicologia , Desempenho Físico Funcional , Prevenção Secundária/métodos
12.
Math Biosci Eng ; 14(3): 673-694, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28092958

RESUMO

The von Mises and Fisher distributions are spherical analogues to the Normal distribution on the unit circle and unit sphere, respectively. The computation of their moments, and in particular the second moment, usually involves solving tedious trigonometric integrals. Here we present a new method to compute the moments of spherical distributions, based on the divergence theorem. This method allows a clear derivation of the second moments and can be easily generalized to higher dimensions. In particular we note that, to our knowledge, the variance-covariance matrix of the three dimensional Fisher distribution has not previously been explicitly computed. While the emphasis of this paper lies in calculating the moments of spherical distributions, their usefulness is motivated by their relationship to population statistics in animal/cell movement models and demonstrated in applications to the modelling of sea turtle navigation, wolf movement and brain tumour growth.


Assuntos
Migração Animal , Movimento Celular , Interpretação Estatística de Dados , Modelos Biológicos , Animais , Neoplasias Encefálicas/patologia , Simulação por Computador , Humanos , Tartarugas/fisiologia , Lobos
13.
Brachytherapy ; 16(2): 306-312, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28161433

RESUMO

PURPOSE: The quality of a prostate brachytherapy implant depends on the accurate placement of sources. This study quantifies the misplacement of 125I sources from the intended location using intraoperative ultrasound images. METHODS AND MATERIALS: 125I sources were manually identified in the postimplant ultrasound images and compared to the preoperative plan. Due to the subjective nature of the identifying sources, only sources identified with high confidence were included in the analysis. Misplacements from the original intended coordinate were measured along the X, Y, and Z axes and were stratified between overall misplacements and regions of the prostate gland. RESULTS: A total of 1619 125I sources using 357 strands were implanted in 15 patients' prostate glands, with 1197 (74%) confidently identified for misplacement analysis. The overall mean displacement was 0.49 cm and in the X, Y, and Z direction was 0.13, 0.15, and 0.38 cm, respectively. Greater source misplacement occurred in the anterior part of the prostate gland than the posterior part of the prostate gland by a factor 1.33 (p < 0.0001). Comparing sources in the lateral vs. medial regions of the prostate, no statistically significant differences on source misplacement were observed. Comparing misplacement in the base vs. midgland vs. apex identified the greatest difference between the base and midgland by a factor of 1.29 (p < 0.0001). CONCLUSIONS: This study has identified significant misplacement of 125I sources from their intended locations with the greatest error misplacement occurring in the Z direction. Source misplacement tends to occur more commonly in the anterior gland and in the base of the prostate.


Assuntos
Braquiterapia/métodos , Radioisótopos do Iodo/administração & dosagem , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Ultrassonografia de Intervenção/métodos , Idoso , Humanos , Cuidados Intraoperatórios/métodos , Radioisótopos do Iodo/uso terapêutico , Masculino , Pessoa de Meia-Idade , Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Implantação de Prótese/métodos , Dosagem Radioterapêutica
14.
Mol Cancer Res ; 2(10): 557-66, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15498930

RESUMO

Exposure to environmental radiation and the application of new clinical modalities, such as radioimmunotherapy, have heightened the need to understand cellular responses to low dose and low-dose rate ionizing radiation. Many tumor cell lines have been observed to exhibit a hypersensitivity to radiation doses <50 cGy, which manifests as a significant deviation from the clonogenic survival response predicted by a linear-quadratic fit to higher doses. However, the underlying processes for this phenomenon remain unclear. Using a gel microdrop/flow cytometry assay to monitor single cell proliferation at early times postirradiation, we examined the response of human A549 lung carcinoma, T98G glioma, and MCF7 breast carcinoma cell lines exposed to gamma radiation doses from 0 to 200 cGy delivered at 0.18 and 22 cGy/min. The A549 and T98G cells, but not MCF7 cells, showed the marked hypersensitivity at doses <50 cGy. To further characterize the low-dose hypersensitivity, we examined the influence of low-dose radiation on cell cycle status and apoptosis by assays for active caspase-3 and phosphatidylserine translocation (Annexin V binding). We observed that caspase-3 activation and Annexin V binding mirrored the proliferation curves for the cell lines. Furthermore, the low-dose hypersensitivity and Annexin V binding to irradiated A549 and T98G cells were eliminated by treating the cells with pifithrin, an inhibitor of p53. When p53-inactive cell lines (2800T skin fibroblasts and HCT116 colorectal carcinoma cells) were examined for similar patterns, we found that there was no hyperradiosensitivity and apoptosis was not detectable by Annexin V or caspase-3 assays. Our data therefore suggest that low-dose hypersensitivity is associated with p53-dependent apoptosis.


Assuntos
Adenocarcinoma , Apoptose/fisiologia , Apoptose/efeitos da radiação , Neoplasias Pulmonares , Proteína Supressora de Tumor p53/fisiologia , Neoplasias Encefálicas , Neoplasias da Mama , Divisão Celular/fisiologia , Divisão Celular/efeitos da radiação , Linhagem Celular Tumoral/fisiologia , Linhagem Celular Tumoral/efeitos da radiação , Fibroblastos/citologia , Fibroblastos/efeitos da radiação , Glioma , Humanos , Doses de Radiação , Radiação Ionizante
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