497 research outputs found
Evolving clinical evidence for selective internal radiation therapy in hepatocellular carcinoma
Vancomycin-resistant enterococci from nosocomial, community, and animal sources in the United States.
Interventionally implanted port catheter systems for hepatic arterial infusion of chemotherapy in patients with primary liver cancer: a phase II-study (NCT00356161)
BACKGROUND: Hepatic arterial infusion (HAI) of chemotherapy requires the implantation of a transcatheter application system which is traditionally performed by surgery. This procedure, but particularly the adjacent drug application via pump or port is often hampered by specific complications and device failure. Interventionally implanted port catheter systems (IIPCS) facilitate the commencement of HAI without need for laparatomy, and are associated with favorable complication rates. We here present an evaluation of the most important technical endpoints associated with the use of IIPCS for HAI in patients with primary liver cancers. METHODS: 70 patients (pts) with hepatocellular (HCC, n=33) and biliary tract cancer (BTC, n=37) were enrolled into a phase II -study. Of those, n=43 had recurrent disease and n=31 suffered from liver-predominant UICC-stage IVb. All pts were provided with IIPCSs before being treated with biweekly, intraarterial chemotherapy (oxaliplatin, 5-Flourouracil, folinic acid). The primary objective of the trial was defined as evaluation of device-related complications and port duration. RESULTS: Implantation of port catheters was successful in all patients. Mean treatment duration was 5,8 months, and median duration of port patency was not reached. Disease-progression was the most common reason for treatment discontinuation (44 pts., 63%), followed by chemotherapy-related toxicity (12 pts., 17%), and irreversible device failure (5 pts., 7%). A total of 28 port complications occurred in 21 pts (30%). No unexpected complications were observed. CONCLUSIONS: HAI via interventionally implanted port catheters can be safely applied to patients with primary liver tumors far advanced or/and pretreated
o 029the impact of combining selective internal radiation therapy sirt with sorafenib on overall survival in patients with advanced hepatocellular carcinoma the soramic trial palliative cohort
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Quantitative in vivo assessment of radiation injury of the liver using Gd-EOB-DTPA enhanced MRI: tolerance dose of small liver volumes
<p>Abstract</p> <p>Backround</p> <p>Hepatic radiation toxicity restricts irradiation of liver malignancies. Better knowledge of hepatic tolerance dose is favourable to gain higher safety and to optimize radiation regimes in radiotherapy of the liver. In this study we sought to determine the hepatic tolerance dose to small volume single fraction high dose rate irradiation.</p> <p>Materials and methods</p> <p>23 liver metastases were treated by CT-guided interstitial brachytherapy. MRI was performed 3 days, 6, 12 and 24 weeks after therapy. MR-sequences were conducted with T1-w GRE enhanced by hepatocyte-targeted Gd-EOB-DTPA. All MRI data sets were merged with 3D-dosimetry data. The reviewer indicated the border of hypointensity on T1-w images (loss of hepatocyte function) or hyperintensity on T2-w images (edema). Based on the volume data, a dose-volume-histogram was calculated. We estimated the threshold dose for edema or function loss as the D<sub>90</sub>, i.e. the dose achieved in at least 90% of the pseudolesion volume.</p> <p>Results</p> <p>At six weeks post brachytherapy, the hepatocyte function loss reached its maximum extending to the former 9.4Gy isosurface in median (i.e., ≥9.4Gy dose exposure led to hepatocyte dysfunction). After 12 and 24 weeks, the dysfunctional volume had decreased significantly to a median of 11.4Gy and 14Gy isosurface, respectively, as a result of repair mechanisms. Development of edema was maximal at six weeks post brachytherapy (9.2Gy isosurface in median), and regeneration led to a decrease of the isosurface to a median of 11.3Gy between 6 and 12 weeks. The dose exposure leading to hepatocyte dysfunction was not significantly different from the dose provoking edema.</p> <p>Conclusion</p> <p>Hepatic injury peaked 6 weeks after small volume irradiation. Ongoing repair was observed up to 6 months. Individual dose sensitivity may differ as demonstrated by a relatively high standard deviation of threshold values in our own as well as all other published data.</p
In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapy
<p>Abstract</p> <p>Background</p> <p>To assess brachytherapy catheter positioning accuracy and to evaluate the effects of prolonged irradiation time on the tolerance dose of normal liver parenchyma following single-fraction irradiation with <sup>192 </sup>Ir.</p> <p>Materials and methods</p> <p>Fifty patients with 76 malignant liver tumors treated by computed tomography (CT)-guided high-dose-rate brachytherapy (HDR-BT) were included in the study. The prescribed radiation dose was delivered by 1 - 11 catheters with exposure times in the range of 844 - 4432 seconds. Magnetic resonance imaging (MRI) datasets for assessing irradiation effects on normal liver tissue, edema, and hepatocyte dysfunction, obtained 6 and 12 weeks after HDR-BT, were merged with 3D dosimetry data. The isodose of the treatment plan covering the same volume as the irradiation effect was taken as a surrogate for the liver tissue tolerance dose. Catheter positioning accuracy was assessed by calculating the shift between the 3D center coordinates of the irradiation effect volume and the tolerance dose volume for 38 irradiation effects in 30 patients induced by catheters implanted in nearly parallel arrangement. Effects of prolonged irradiation were assessed in areas where the irradiation effect volume and tolerance dose volume did not overlap (mismatch areas) by using a catheter contribution index. This index was calculated for 48 irradiation effects induced by at least two catheters in 44 patients.</p> <p>Results</p> <p>Positioning accuracy of the brachytherapy catheters was 5-6 mm. The orthogonal and axial shifts between the center coordinates of the irradiation effect volume and the tolerance dose volume in relation to the direction vector of catheter implantation were highly correlated and in first approximation identically in the T1-w and T2-w MRI sequences (<it>p </it>= 0.003 and <it>p </it>< 0.001, respectively), as were the shifts between 6 and 12 weeks examinations (<it>p </it>= 0.001 and <it>p </it>= 0.004, respectively). There was a significant shift of the irradiation effect towards the catheter entry site compared with the planned dose distribution (<it>p </it>< 0.005). Prolonged treatment time increases the normal tissue tolerance dose. Here, the catheter contribution indices indicated a lower tolerance dose of the liver parenchyma in areas with prolonged irradiation (<it>p </it>< 0.005).</p> <p>Conclusions</p> <p>Positioning accuracy of brachytherapy catheters is sufficient for clinical practice. Reduced tolerance dose in areas exposed to prolonged irradiation is contradictory to results published in the current literature. Effects of prolonged dose administration on the liver tolerance dose for treatment times of up to 60 minutes per HDR-BT session are not pronounced compared to effects of positioning accuracy of the brachytherapy catheters and are therefore of minor importance in treatment planning.</p
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Population-based emergence of unfamiliar climates
Time of emergence, which characterizes when significant signals of climate change will emerge from existing variability, is a useful and increasingly common metric. However, a more useful metric for understanding future climate change in the context of past experience may be the ratio of climate signal to noise (S/N)—a measure of the amplitude of change expressed in terms of units of existing variability. Here, we present S/N projections in the context of emergent climates (termed ‘unusual’, ‘unfamiliar’ and ‘unknown’ by reference to an individual’s lifetime), highlighting sensitivity to future emissions scenarios and geographical and human groupings. We show how for large sections of the world’s population, and for several geopolitical international groupings, mitigation can delay the onset of ‘unknown’ or ‘unfamiliar’ climates by decades, and perhaps even beyond 2100. Our results demonstrate that the benefits of mitigation accumulate over several decades, a key metric of which is reducing S/N, or keeping climate as familiar as possible. A relationship is also identified between cumulative emissions and patterns of emergent climate signals. Timely mitigation will therefore provide the greatest benefits to those facing the earliest impacts, many of whom are alive now
18F-PSMA-1007 PET/CT for response assessment in patients with metastatic renal cell carcinoma undergoing tyrosine kinase or checkpoint inhibitor therapy: preliminary results
INTRODUCTION Tyrosine kinase (TKI) and checkpoint inhibitors (CI) prolonged overall survival in metastatic renal cell carcinoma (mRCC). Early prediction of treatment response is highly desirable for the individualization of patient management and improvement of therapeutic outcome; however, serum biochemistry is unable to predict therapeutic efficacy. Therefore, we compared 18F-PSMA-1007 PET imaging for response assessment in mRCC patients undergoing TKI or CI therapy compared to CT-based response assessment as the current imaging reference standard.
METHODS 18F-PSMA-1007 PET/CT was performed in mRCC patients prior to initiation of systemic treatment and 8~weeks after therapy initiation. Treatment response was evaluated separately on 18F-PSMA-PET and CT. Changes on PSMA-PET (SUVmean) were assessed on a per patient basis using a modified PERCIST scoring system. Complete response (CRPET) was defined as absence of any uptake in all target lesions on posttreatment PET. Partial response (PRPET) was defined as decrease in summed SUVmean of > 30%. The appearance of new, PET-positive lesions or an increase in summed SUVmean of > 30% was defined as progressive disease (PDPET). A change in summed SUVmean of ± 30% defined stable disease (SDPET). RECIST 1.1 criteria were used for response assessment on CT. Results of radiographic response assessment on PSMA-PET and CT were compared.
RESULTS Overall, 11 mRCC patients undergoing systemic treatment were included. At baseline PSMA-PET1, all mRCC patients showed at least one PSMA-avid lesion. On follow-up PET2, 3 patients showed CRPET, 3 PRPET, 4 SDPET, and 1 PDPET. According to RECIST 1.1, 1 patient showed PRCT, 9 SDCT, and 1 PDCT. Overall, concordant classifications were found in only 2 cases (2 SDCT + PET). Patients with CRPET on PET were classified as 3 SDCT on CT using RECIST 1.1. By contrast, the patient classified as PRCT on CT showed PSMA uptake without major changes during therapy (SDPET). However, among 9 patients with SDCT on CT, 3 were classified as CRPET, 3 as PRPET, 1 as PDPET, and only 2 as SDPET on PSMA-PET. CONCLUSION On PSMA-PET, heterogeneous courses were observed during systemic treatment in mRCC patients with highly diverging results compared to RECIST 1.1. In the light of missing biomarkers for early response assessment, PSMA-PET might allow more precise response assessment to systemic treatment, especially in patients classified as SD on CT
Vancomycin-resistant enterococci from nosocomial, community, and animal sources in the United States.
The presence of vancomycin-resistant enterococci (VRE) was looked for in fecal samples from 104 healthy volunteers (3 with hospital exposure), 100 selected hospitalized patients, and various environmental sources (44 commercial chickens, 5 farm-raised chickens, 3 turkeys, and 2 chicken farm lagoon slurries). Five probiotic preparations were also studied. No VRE with vanA or vanB genes were isolated from the healthy volunteers without hospital exposure, environmental sources, or probiotic preparations. VRE with vanB were found in the stools of 16% of the high-risk hospitalized patients and in one volunteer with hospital contact. All VRE examined could be classified into one of two clones by pulsed-field gel electrophoresis. VRE from 11 of the colonized patients were quantified and ranged from 10(3) to 10(6) CFU/g of stool. This study, in contrast to findings in Europe, failed to find evidence of VanA- or VanB-type VRE in the community or environmental sources in Houston, Texas, and suggests that these settings are not a likely source of VRE in hospitals in this geographic area
Cost-effectiveness of short-protocol emergency brain MRI after negative non-contrast CT for minor stroke detection
OBJECTIVES To investigate the cost-effectiveness of supplemental short-protocol brain MRI after negative non-contrast CT for the detection of minor strokes in emergency patients with mild and unspecific neurological symptoms. METHODS The economic evaluation was centered around a prospective single-center diagnostic accuracy study validating the use of short-protocol brain MRI in the emergency setting. A decision-analytic Markov model distinguished the strategies \textquotedblno additional imaging\textquotedbl and \textquotedbladditional short-protocol MRI\textquotedbl for evaluation. Minor stroke was assumed to be missed in the initial evaluation in 40% of patients without short-protocol MRI. Specialized post-stroke care with immediate secondary prophylaxis was assumed for patients with detected minor stroke. Utilities and quality-of-life measures were estimated as quality-adjusted life years (QALYs). Input parameters were obtained from the literature. The Markov model simulated a follow-up period of up to 30 years. Willingness to pay was set to 26,304 (CT only: $27,109). Cumulative calculated effectiveness in the CT-only group was 14.25 QALYs (short-protocol MRI group: 14.31 QALYs). In the deterministic sensitivity analysis, additional short-protocol MRI remained the dominant strategy in all investigated ranges. Probabilistic sensitivity analysis results from the base case analysis were confirmed, and additional short-protocol MRI resulted in lower costs and higher effectiveness. CONCLUSION Additional short-protocol MRI in emergency patients with mild and unspecific neurological symptoms enables timely secondary prophylaxis through detection of minor strokes, resulting in lower costs and higher cumulative QALYs. KEY POINTS • Short-protocol brain MRI after negative head CT in selected emergency patients with mild and unspecific neurological symptoms allows for timely detection of minor strokes. • This strategy supports clinical decision-making with regard to immediate initiation of secondary prophylactic treatment, potentially preventing subsequent major strokes with associated high costs and reduced QALY. • According to the Markov model, additional short-protocol MRI remained the dominant strategy over wide variations of input parameters, even when assuming disproportionally high costs of the supplemental MRI scan
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