Interbank Lending Decisions in an Economic Downturn: an Agent-Based Approach

Interbank lending is one mechanism that can make shock, which is accepted by one bank spread to other banks (contagion). There are several researchers that focused their research on analyzing the effect of interbank lending to systemic risk. However, there is a few research that analyzed the effect of banks' decision maker's behavior, especially on the bank interbank lending to the systemic risk. In this research, the author creates an agent-based simulation of the banking system to analyze the effect of banks' decision maker's behavior to systemic risk in economic downturn condition. The preliminary result from this research is for an economic downturn in a long time period, the banking system with a low net worth to the asset's ratio threshold will produce more default bank than the banking system with a high net worth to the asset's ratio threshold. However, for an economic downturn in small time period, banking system which all bank in their system has the higher net worth to assets ratio threshold will have the default bank first than the banking system which has the lower net worth to the asset's ratio threshold

Remifentanil versus dexmedtomidine for posterior spinal fusion surgery

Background: Controlling the hemodynamic situation of patients who have spinal operation is of prime importance, and maintaining the heart rate and blood pressure in normal or low- normal levels in these patients can reduce their bleeding loss. One of the commonly used drugs for this purpose is remifentanil. Another sedative-hypnotic-analgesic drug, with acceptable effects is dexmedetomidine. The aim of this study was to compare the effect of dexmedetomidine with remifentanil in spinal operation. Methods: In a double blind randomized clinical trial, using random sampling method, 60 patients with the age range of 15-65 years who were candidates for posterior spinal fusion operation were included. Induction of anesthesia was performed, and both groups received isoflurane 1 during the surgery. Remifentanil was injected via infusion pump in one group. The patients in the trial group received dexmedetomidine. As trial outcomes, heart rate and blood pressure were measured before, after induction and during the operation. Pain score, sedation score and the need to analgesic therapy were recorded in the recovery room and the ward. Independent sample t-test and chi-square were used for statistical analysis. Results: Dexmedetomidine had a significant lowering impact on intraoperative blood pressure and heart rate compared to remifentanil (p<0.001). The mean of sedation scores after extubation in patients who received dexmedetomidine was significantly higher than the sedation scores in patients who received remifentanil (p<0.001). The mean of post-extubation and recovery pain score in patients taking remifentanil was significantly higher than patients taking dexmedetomidine (p<0.05). Conclusion: Dexmedetomidine in patients with spinal operation is associated with lower postoperative pain score and intraoperative bleeding. Hemodynamic effects are significantly better in patients received dexmedetomidine

Partial volume correction strategies for quantitative FDG PET in oncology

Purpose: Quantitative accuracy of positron emission tomography (PET) is affected by partial volume effects resulting in increased underestimation of the standardized uptake value (SUV) with decreasing tumour volume. The purpose of the present study was to assess accuracy and precision of different partial volume correction (PVC) methods. Methods: Three methods for PVC were evaluated: (1) inclusion of the point spread function (PSF) within the reconstruction, (2) iterative deconvolution of PET images and (3) calculation of spill-in and spill-out factors based on tumour masks. Simulations were based on a mathematical phantom with tumours of different sizes and shapes. Phantom experiments were performed in 2-D mode using the National Electrical Manufacturers Association (NEMA) NU2 image quality phantom containing six differently sized spheres. Clinical studies (2-D mode) included a test-retest study consisting of 10 patients with stage IIIB and IV non-small cell lung cancer and a response monitoring study consisting of 15 female breast cancer patients. In all studies tumour or sphere volumes of interest (VOI) were generated using VOI based on adaptive relative thresholds. Results: Simulations and experiments provided similar results. All methods were able to accurately recover true SUV within 10% for spheres equal to and larger than 1 ml. Reconstruction-based recovery, however, provided up to twofold better precision than image-based methods. Cl

Focal dose escalation using FDG-PET-guided intensity-modulated radiation therapy boost for postoperative local recurrent rectal cancer: a planning study with comparison of DVH and NTCP

<p>Abstract</p> <p>Background</p> <p>To evaluate the safety of focal dose escalation to regions with standardized uptake value (SUV) >2.0 using intensity-modulated radiation therapy (IMRT) by comparison of radiotherapy plans using dose-volume histograms (DVHs) and normal tissue complication probability (NTCP) for postoperative local recurrent rectal cancer</p> <p>Methods</p> <p>First, we performed conventional radiotherapy with 40 Gy/20 fr. (CRT 40 Gy) for 12 patients with postoperative local recurrent rectal cancer, and then we performed FDG-PET/CT radiotherapy planning for those patients. We defined the regions with SUV > 2.0 as biological target volume (BTV) and made three boost plans for each patient: 1) CRT boost plan, 2) IMRT without dose-painting boost plan, and 3) IMRT with dose-painting boost plan. The total boost dose was 20 Gy. In IMRT with dose-painting boost plan, we increased the dose for BTV+5 mm by 30% of the prescribed dose. We added CRT boost plan to CRT 40 Gy (<it>summed plan 1</it>), IMRT without dose-painting boost plan to CRT 40 Gy (<it>summed plan 2</it>) and IMRT with dose-painting boost plan to CRT 40 Gy (<it>summed plan 3</it>), and we compared those plans using DVHs and NTCP.</p> <p>Results</p> <p>D_meanof PTV-PET and that of PTV-CT were 26.5 Gy and 21.3 Gy, respectively. V₅₀of small bowel PRV in <it>summed plan 1 </it>was significantly higher than those in other plans ((<it>summed plan 1 </it>vs. <it>summed plan 2 </it>vs. <it>summed plan 3</it>: 47.11 ± 45.33 cm³vs. 40.63 ± 39.13 cm³vs. 41.25 ± 39.96 cm³(p < 0.01, respectively)). There were no significant differences in V₃₀, V₄₀, V₆₀, D_meanor NTCP of small bowel PRV.</p> <p>Conclusions</p> <p>FDG-PET-guided IMRT can facilitate focal dose-escalation to regions with SUV above 2.0 for postoperative local recurrent rectal cancer.</p

The future of hybrid imaging—part 2: PET/CT

Since the 1990s, hybrid imaging by means of software and hardware image fusion alike allows the intrinsic combination of functional and anatomical image information. This review summarises the state-of-the-art of dual-modality imaging with a focus on clinical applications. We highlight selected areas for potential improvement of combined imaging technologies and new applications. In the second part, we briefly review the background of dual-modality PET/CT imaging, discuss its main applications and attempt to predict technological and methodological improvements of combined PET/CT imaging. After a decade of clinical evaluation, PET/CT will continue to have a significant impact on patient management, mainly in the area of oncological diseases. By adopting more innovative acquisition schemes and data processing PET/CT will become a fast and dose-efficient imaging method and an integral part of state-of-the-art clinical patient management

Comparative methods for PET image segmentation in pharyngolaryngeal squamous cell carcinoma

Several methods have been proposed for the segmentation of ¹⁸F-FDG uptake in PET. In this study, we assessed the performance of four categories of ¹⁸F-FDG PET image segmentation techniques in pharyngolaryngeal squamous cell carcinoma using clinical studies where the surgical specimen served as the benchmark