Laser Interstitial Thermal Therapy in Glioblastoma

Laser interstitial thermal therapy is a minimally invasive ablative technique that continues to gain popularity in treatment of a variety of intracranial and spinal disorders. In the field of neuro-oncology it continues to be used for treatment of a variety of intracranial neoplasms, including glioblastoma—the most common malignant primary brain tumor. Maximizing the extent of resection in patients with glioblastoma was shown to prolong patient survival. Many patients present, however, with tumors that are nonresectable due to proximity to eloquent cortical or subcortical areas, or involvement of deep brain structures. LITT procedure, on the other hand, is minimally invasive and involves placing a laser catheter under stereotactic guidance and monitoring the size of the lesion produced as a result of laser ablation using MR thermography in real time. Therefore, a number of studies explored the potential of laser ablation to accomplish significant cytoreduction and thus potentially improve patient’s outcomes and prolong survival. The following chapter will review the principles of laser ablation and its current role in treatment of glioblastoma

Laser Ablation in Neuro-oncology

Laser interstitial thermal therapy (LITT) has emerged as a potential tool in the armamentarium of neurosurgeons managing patients with deep-seated and difficult-to-access brain tumors. Advances in stereotactic neurosurgery coupled with neuroimaging tools have led to the resurgence of interest in laser therapy for a variety of neurosurgical indications. Stereotactic placement of laser probe using minimally invasive techniques and the ability to monitor the tissue ablation in real time using MR thermometry are two distinct advantages of LITT. Patients with recurrent gliobastoma multiforme (GBM) or newly diagnosed gliomas with significant medical comorbidities, radiation necrosis, radiosurgery-resistant brain metastasis and cancer-related pain pose significant challenges in the field of neuro-oncology. LITT offers an opportunity to obtain stereotactic biopsy and cytoreduction in a minimally invasive nature. In this chapter, we have described the current applications of LITT in neuro-oncology, including malignant gliomas, brain metastatic disease, radiation necrosis and other indications such as cancer-related pain and epilepsy. We have also described the principles, technical nuances and LITT systems currently available in the clinical practice. With growing interest and acceptance of LITT in neuro-oncology, we are likely to obtain high-quality evidence supporting the utility of this modality in patients with a variety of neuro-oncological conditions in the near future

Modeling Flame Propagation of Coal Char Particles in Heterogeneous Media

In the present research, combustion of a quiescent coal char particle cloud has been studied in the media with spatially discrete sources by means of numerical approach. A thermal model based on diffusion-controlled regime of coal char particles has been generated in order to estimate the characteristics of flame propagation in heterogeneous media. The model uses discrete heat sources to analyze dust combustion of particles with the diameter of 50 μm. Oxygen and Nitrogen have been considered as the main oxidizer and the inert gas, respectively. Flame propagation speed in various dust and oxygen concentrations has been studied. Flame speed as a function of particle size has been investigated and comparison between cases with and without consideration of radiation effect has been made. Furthermore, minimum ignition energy as a function of dust concentration for different particle sizes has been studied. Results show a reasonable compatibility with the existing experimental data

Determination of Plasma Parameters as well as Electrons Distribution Function

Abstract In this research we determined the biasing effects on the plas ma electrons distribution function and plas ma displacement in a low beta, large aspect ratio and circular cross section tokamak. Fo r this purpose, a movable biasing system was designed, constructed, and installed, and then the positive voltage applied to an electrode inserted inside the tokamak limiter and the plasma current, part icle distribution function and also the plasma horizontal displacement in the absence and presence of the biasing based on the mult ipole mo ments technique were measured. Measurements result has shown a modification of plas ma confinement by decreasing the plasma displacement

The role of laser interstitial thermal therapy in enhancing progression-free survival of difficult-to-access high-grade gliomas: A multicenter study

Surgical extent-of-resection has been shown to have an impact on high-grade glioma (HGG) outcomes; however, complete resection is rarely achievable in difficult-to-access (DTA) tumors. Controlled thermal damage to the tumor may have the same impact in DTA-HGGs. We report our multicenter results of laser interstitial thermal therapy (LITT) in DTA-HGGs. We retrospectively reviewed 34 consecutive DTA-HGG patients (24 glioblastoma, 10 anaplastic) who underwent LITT at Cleveland Clinic, Washington University, and Wake Forest University (May 2011–December 2012) using the NeuroBlate® System. The extent of thermal damage was determined using thermal damage threshold (TDT) lines: yellow TDT line (43°C for 2 min) and blue TDT line (43°C for 10 min). Volumetric analysis was performed to determine the extent-of-coverage of tumor volume by TDT lines. Patient outcomes were evaluated statistically. LITT was delivered as upfront in 19 and delivered as salvage in 16 cases. After 7.2 months of follow-up, 71% of cases demonstrated progression and 34% died. The median overall survival (OS) for the cohort was not reached; however, the 1-year estimate of OS was 68 ± 9%. Median progression-free survival (PFS) was 5.1 months. Thirteen cases who met the following two criteria—(1) <0.05 cm(3) tumor volume not covered by the yellow TDT line and (2) <1.5 cm(3) additional tumor volume not covered by the blue TDT line—had better PFS than the other 21 cases (9.7 vs. 4.6 months; P = 0.02). LITT can be used effectively for treatment of DTA-HGGs. More complete coverage of tumor by TDT lines improves PFS which can be translated as the extent of resection concept for surgery

Development of a nanobiodegradable drilling fluid using prosopis farcta plant and pomegranate peel powders with metal oxide nanoparticles

One of the inevitable problems encountered during the petroleum well drilling process is lost circulation in which part of the drilling fluid is lost into the formation. A combination of nanoparticles with their unique properties and cost-effective biodegradable materials can play an effective role in treating fluid loss. In this study, our aim was to formulate drilling fluids modified with nanoparticles, pomegranate peel powder, and Prosopis farcta plant powder. The drilling fluids were identified and recognized using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy techniques. Furthermore, experimental tests were conducted in order to investigate the performance of the newly formulated drilling fluid in improving fluid loss characteristics. The obtaining results have shown that adding 0.3 wt % of pomegranate peel powder to the reference (base) drilling fluid reduces the filter loss volume to 7.9 mL compared to the reference fluid (11.6 mL). As the optimal concentration of TiO2 was mixed with 0.3 wt % of pomegranate peel powder then added to the reference fluid, the filter loss volume was reduced to 8.6 mL

Impact of KRAS mutation status on the efficacy of immunotherapy in lung cancer brain metastases

Immune checkpoint inhibitors (ICIs) have resulted in improved outcomes in non-small cell lung cancer (NSCLC) patients. However, data demonstrating the efficacy of ICIs in NSCLC brain metastases (NSCLCBM) is limited. We analyzed overall survival (OS) in patients with NSCLCBM treated with ICIs within 90 days of NSCLCBM diagnosis (ICI-90) and compared them to patients who never received ICIs (no-ICI). We reviewed 800 patients with LCBM who were diagnosed between 2010 and 2019 at a major tertiary care institution, 97% of whom received stereotactic radiosurgery (SRS) for local treatment of BM. OS from BM was compared between the ICI-90 and no-ICI groups using the Log-Rank test and Cox proportional-hazards model. Additionally, the impact of KRAS mutational status on the efficacy of ICI was investigated. After accounting for known prognostic factors, ICI-90 in addition to SRS led to significantly improved OS compared to no-ICI (12.5 months vs 9.1, p \u3c 0.001). In the 109 patients who had both a known PD-L1 expression and KRAS status, 80.4% of patients with KRAS mutation had PD-L1 expression vs 61.9% in wild-type KRAS patients (p = 0.04). In patients without a KRAS mutation, there was no difference in OS between the ICI-90 vs no-ICI cohort with a one-year survival of 60.2% vs 54.8% (p = 0.84). However, in patients with a KRAS mutation, ICI-90 led to a one-year survival of 60.4% vs 34.1% (p = 0.004). Patients with NSCLCBM who received ICI-90 had improved OS compared to no-ICI patients. Additionally, this benefit appears to be observed primarily in patients with KRAS mutations that may drive the overall benefit, which should be taken into account in the development of future trials

Targeted Therapy After Brain Radiotherapy for BRAF-Mutated Melanoma With Extensive Ependymal Disease With Prolonged Survival: Case Report and Review of the Literature

Melanoma brain metastasis with ependymal spread/metastases is uncommon. These cases are frequently classified together with leptomeningeal disease. However, the commonalities and differences in the underlying pathophysiology and clinical outcomes between these two types of spread are not clear. Very few reports on long term outcome and durable central nervous system (CNS) disease control have been reported in the literature. Here, we report a case of a 45 year-old Caucasian lady with BRAF-V600E mutant metastatic melanoma to the brain who had whole brain radiotherapy followed by two Gamma knife radiosurgery treatments for localized disease progression. She then developed extensive ependymal disease progression with no evidence of leptomeningeal spread. She was treated with a repeat course of whole brain radiotherapy and maintained on BRAF and MEK inhibitors with durable CNS disease control for more than a year. This study reviews the management of BRAF-V600E mutant melanoma with ependymal involvement. Management using radiation therapy with maintenance targeted therapy seems to be a reasonable approach to this challenging disease

Disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE) in Iran and its neighboring countries, 1990–2015

BACKGROUND: Summary measures of health are essential in making estimates of health status that are comparable across time and place. They can be used for assessing the performance of health systems, informing effective policy making, and monitoring the progress of nations toward achievement of sustainable development goals. The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) provides disability-adjusted life-years (DALYs) and healthy life expectancy (HALE) as main summary measures of health. We assessed the trends of health status in Iran and 15 neighboring countries using these summary measures. METHODS: We used the results of GBD 2015 to present the levels and trends of DALYs, life expectancy (LE), and HALE in Iran and its 15 neighboring countries from 1990 to 2015. For each country, we assessed the ratio of observed levels of DALYs and HALE to those expected based on socio-demographic index (SDI), an indicator composed of measures of total fertility rate, income per capita, and average years of schooling. RESULTS: All-age numbers of DALYs reached over 19 million years in Iran in 2015. The all-age number of DALYs has remained stable during the past two decades in Iran, despite the decreasing trends in all-age and age-standardized rates. The all-cause DALY rates decreased from 47,200 in 1990 to 28,400 per 100,000 in 2015. The share of non-communicable diseases in DALYs increased in Iran (from 42% to 74%) and all of its neighbors between 1990 and 2015; the pattern of change is similar in almost all 16 countries. The DALY rates for NCDs and injuries in Iran were higher than global rates and the average rate in High Middle SDI countries, while those for communicable, maternal, neonatal, and nutritional disorders were much lower in Iran. Among men, cardiovascular diseases ranked first in all countries of the region except for Bahrain. Among women, they ranked first in 13 countries. Life expectancy and HALE show a consistent increase in all countries. Still, there are dissimilarities indicating a generally low LE and HALE in Afghanistan and Pakistan and high expectancy in Qatar, Kuwait, and Saudi Arabia. Iran ranked 11th in terms of LE at birth and 12th in terms of HALE at birth in 1990 which improved to 9th for both metrics in 2015. Turkey and Iran had the highest increase in LE and HALE from 1990 to 2015 while the lowest increase was observed in Armenia, Pakistan, Kuwait, Kazakhstan, Russia, and Iraq. CONCLUSIONS: The levels and trends in causes of DALYs, life expectancy, and HALE generally show similarities between the 16 countries, although differences exist. The differences observed between countries can be attributed to a myriad of determinants, including social, cultural, ethnic, religious, political, economic, and environmental factors as well as the performance of the health system. Investigating the differences between countries can inform more effective health policy and resource allocation. Concerted efforts at national and regional levels are required to tackle the emerging burden of non-communicable diseases and injuries in Iran and its neighbors