170 research outputs found
The Tangled Web: How Nonprofit Board Members Experience Organizational Crisis
The purpose of this grounded theory study was to develop an understanding of what board members experience during a time of organizational crisis. Major corporate and nonprofit failures of previously successful organizations in recent years have raised questions and led to speculation about the role of boards of directors through the crises. In this study twenty board members of nonprofit organizations who had experienced an organizational crisis during their board service were interviewed. Participants were asked to share their perceptions and explore how they identified and made meaning of the events and board processes that went on as the crisis became apparent and progressed. The overall research design was grounded theory guided by Schatzman’s and Charmaz’ methodological contributions. A dimensional analysis was employed to create explanatory matrices that focused on theory development. From dimensional analysis the core dimension, the Tangled Web, and primary dimensions Recognizing, Responding, and Stepping Up emerged. The model of a Tangled Web depicts the processes that obstruct a board’s ability to recognize and respond to signs of crisis. Complexity theory, governance, crisis and turnaround, and group process all contribute to the understanding of the research question. The electronic version of this dissertation is available through the OhioLink ETD Center, www.ohiolink.edu/et
The Tangled Web: How Nonprofit Board Members Experience Organizational Crisis
The purpose of this grounded theory study was to develop an understanding of what board members experience during a time of organizational crisis. Major corporate and nonprofit failures of previously successful organizations in recent years have raised questions and led to speculation about the role of boards of directors through the crises. In this study twenty board members of nonprofit organizations who had experienced an organizational crisis during their board service were interviewed. Participants were asked to share their perceptions and explore how they identified and made meaning of the events and board processes that went on as the crisis became apparent and progressed. The overall research design was grounded theory guided by Schatzman’s and Charmaz’ methodological contributions. A dimensional analysis was employed to create explanatory matrices that focused on theory development. From dimensional analysis the core dimension, the Tangled Web, and primary dimensions Recognizing, Responding, and Stepping Up emerged. The model of a Tangled Web depicts the processes that obstruct a board’s ability to recognize and respond to signs of crisis. Complexity theory, governance, crisis and turnaround, and group process all contribute to the understanding of the research question. The electronic version of this dissertation is available through the OhioLink ETD Center, www.ohiolink.edu/et
Manifestación de la asimetrÃa contractual: el profano frente al experto en la obligación de saneamiento
Al regular la obligación de saneamiento, el Código Civil y Comercial –en adelante, CCC– proyecta una regulación a partir de la distinción experto-profano. Ello se observa, preliminarmente, en varias normas (arts. 1038 inc. b], 1040 útl. párrafo, 1053 inc. b]), las que analizadas en su conjunto permiten advertir una regla de control que impide que el profesional experto se libere de la obligación de saneamiento –y particularmente de la responsabilidad por defectos ocultos– en casos en que, normalmente, podrÃa hacerlo. Resulta conveniente entonces repasar las normas que sostienen nuestra afirmación.Facultad de Ciencias JurÃdicas y Sociale
A Cone Beam CT-Based Study For Clinical Target Definition Using Pelvic Anatomy During Post-Prostatectomy Radiotherapy
Introduction:
Radiation therapy (RT) is delivered after radical prostatectomy (RP) either as salvage treatment for an elevated prostate-specific antigen (PSA) level1-6 or as adjuvant therapy for patients with highrisk pathologic features7-8. Recent prospective data demonstrated a disease-free survival benefit of adjuvant RT for pathologic T3N0 prostate cancer9-10. Despite literature supporting the delivery of post-RP RT to the prostatic fossa (PF), no clear target definition guidelines exist for intensity modulated radiation therapy (IMRT) or image-guided RT (IGRT)11.
Visualization of the PF is limited on standard CT images, with significant interobserver variability and uncertainty in CTV definition12. Efforts to incorporate complementary imaging modalities such as MRI for PF target volume definition have generated neither demonstrably more reliable PF delineation, nor practical contouring guidelines13. Regardless of the imaging modality, direct visualization and delineation of the PF clinical target volume (CTV) is fraught with uncertainty. On the other hand, it is possible to distinguish the borders of important nearby pelvic structures, namely the bladder and the rectum. The reliability of rectal volume definition on helical CT is supported by analysis of rectal contours defined in a prospective trial, suggesting the feasibility of rectal dose-volume data collection in a multicenter setting14. Fiorino et al have described a correlation between PF CTV shift and anterior rectal wall shift for the cranial half of the rectum in their report of rectal and bladder movement during post-RP RT using weekly CT images15. These studies support the reliability of CT-defined rectum contours and a limited correlation between PF CTV and anterior rectal wall, an important tenet in the current study.
Int. J. Radiation Oncol. Biol. Physics, Volume 70, Issue 2, pages 431-436, Feb. 1, 2008
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First Report of NRG Oncology/Radiation Therapy Oncology Group 0622: A Phase 2 Trial of Samarium-153 Followed by Salvage Prostatic Fossa Irradiation in High-Risk Clinically Nonmetastatic Prostate Cancer After Radical Prostatectomy.
PURPOSE: To investigate the utility of 153Sm lexidronam (Quadramet) in the setting of men with prostate cancer status post radical prostatectomy who develop biochemical failure with no clinical evidence of osseous metastases.
PATIENTS AND METHODS: Trial NRG Oncology RTOG 0622 is a single-arm phase 2 trial that enrolled men with pT2-T4, N0-1, M0 prostate cancer status post radical prostatectomy, who meet at least 1 of these biochemical failure criteria: (1) prostate-specific antigen (PSA) \u3e 1.0 ng/mL; (2) PSA \u3e 0.2 ng/mL if Gleason score 9 to 10; or (3) PSA \u3e 0.2 ng/mL if N1. Patients received 153Sm (2.0 mCi/kg intravenously × 1) followed by salvage external beam radiation therapy (EBRT) to the prostatic fossa (64.8-70.2 Gy in 1.8-Gy daily fractions). No androgen deprivation therapy was allowed. The primary objective was PSA response within 12 weeks of receiving 153Sm. The secondary objectives were to: (1) assess the completion rate for the regimen of 153Sm and EBRT; (2) evaluate the hematologic toxicity and other adverse events (AEs) at 12 and 24 weeks; and (3) determine the freedom from progression rate at 2 years.
RESULTS: A total of 60 enrolled eligible patients were included in this analysis. Median follow-up was 3.97 years. A PSA response was achieved in 7 of 52 evaluable patients (13.5%), compared with the 25% hypothesized. The 2-year freedom from progression rate was 25.5% (95% confidence interval 14.4%-36.7%), and the biochemical failure rate was 64.4% (95% CI 50.5%-75.2%). Samarium-153 was well tolerated, with 16 (of 60) grade 3 to 4 hematologic AEs and no grade 5 hematologic AEs. Radiation therapy was also well tolerated, with no grade 3 to 5 acute radiation therapy-related AEs and 1 grade 3 to 4 and no grade 5 late radiation therapy-related AEs.
CONCLUSIONS: Trial NRG Oncology RTOG 0622 did not meet its primary endpoint of PSA response, although the regimen of 153Sm and salvage EBRT was well tolerated. Although the toxicity profile supports study of 153Sm in high-risk disease, it may not be beneficial in men receiving EBRT
Radioactive seed immobilization techniques for interstitial brachytherapy
Purpose In prostate brachytherapy, seeds can detach from their deposited sites and move locally in the pelvis or migrate to distant sites including the pulmonary and cardiac regions. Undesirable consequences of seed migration include inadequate dose coverage of the prostate and tissue irradiation effects at the site of migration. Thus, it is clinically important to develop seed immobilization techniques.
Methods We first analyze the possible causes for seed movement, and propose three potential techniques for seed immobilization: (1) surgical glue, (2) laser coagulation and (3) diathermy coagulation. The feasibility of each method is explored. Experiments were carried out using fresh bovine livers to investigate the efficacy of seed immobilization using surgical glue.
Results Results have shown that the surgical glue can effectively immobilize the seeds. Evaluation of the radiation dose distribution revealed that the non-immobilized seed movement would change the planned isodose distribution considerably; while by using surgical glue method to immobilize the seeds, the changes were negligible.
Conclusions Prostate brachytherapy seed immobilization is necessary and three alternative mechanisms are promising for addressing this issue. Experiments for exploring the efficacy of the other two proposed methods are ongoing. Devices compatible with the brachytherapy procedure will be designed in futur
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Regression, developmental trajectory and associated problems in disorders in the autism spectrum: the SNAP study
We report rates of regression and associated findings in a population derived group of 255 children aged 9-14 years, participating in a prevalence study of autism spectrum disorders (ASD); 53 with narrowly defined autism, 105 with broader ASD and 97 with non-ASD neurodevelopmental problems, drawn from those with special educational needs within a population of 56,946 children. Language regression was reported in 30% with narrowly defined autism, 8% with broader ASD and less than 3% with developmental problems without ASD. A smaller group of children were identified who underwent a less clear setback. Regression was associated with higher rates of autistic symptoms and a deviation in developmental trajectory. Regression was not associated with epilepsy or gastrointestinal problems
Does Intensity Modulated Radiation Therapy (IMRT) prevent additional toxicity of treating the pelvic lymph nodes compared to treatment of the prostate only?
<p>Abstract</p> <p>Background</p> <p>To evaluate the risk of rectal, bladder and small bowel toxicity in intensity modulated radiation therapy (IMRT) of the prostate only compared to additional irradiation of the pelvic lymphatic region.</p> <p>Methods</p> <p>For ten patients with localized prostate cancer, IMRT plans with a simultaneous integrated boost (SIB) were generated for treatment of the prostate only (plan-PO) and for additional treatment of the pelvic lymph nodes (plan-WP). In plan-PO, doses of 60 Gy and 74 Gy (33 fractions) were prescribed to the seminal vesicles and to the prostate, respectively. Three plans-WP were generated with prescription doses of 46 Gy, 50.4 Gy and 54 Gy to the pelvic target volume; doses to the prostate and seminal vesicles were identical to plan-PO. The risk of rectal, bladder and small bowel toxicity was estimated based on NTCP calculations.</p> <p>Results</p> <p>Doses to the prostate were not significantly different between plan-PO and plan-WP and doses to the pelvic lymph nodes were as planned. Plan-WP resulted in increased doses to the rectum in the low-dose region ≤ 30 Gy, only, no difference was observed in the mid and high-dose region. Normal tissue complication probability (NTCP) for late rectal toxicity ranged between 5% and 8% with no significant difference between plan-PO and plan-WP. NTCP for late bladder toxicity was less than 1% for both plan-PO and plan-WP. The risk of small bowel toxicity was moderately increased for plan-WP.</p> <p>Discussion</p> <p>This retrospective planning study predicted similar risks of rectal, bladder and small bowel toxicity for IMRT treatment of the prostate only and for additional treatment of the pelvic lymph nodes.</p
Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition
BACKGROUND: The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT) protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. METHODS: Patients with high risk prostate cancer were included. Sentinel nodes (SN) were localised 1.5–3 hours after injection of 250 MBq (99m)Tc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV). Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week) to the pelvis and 70.0 Gy (5 × 2.0 Gy / week) to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. RESULTS: Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29). 4 of 6 patients showed sentinel node localisations (total 10), that would not have been treated adequately with CT-based planning ('geographical miss') only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG) occurred. CONCLUSION: IMRT based on sentinel lymph node identification is feasible and reduces the probability of a geographical miss. Furthermore, IMRT allows a pronounced sparing of normal tissue irradiation. Thus, the chosen approach will help to increase the curative potential of radiotherapy in high risk prostate cancer patients
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