scholarly journals INTERRELATIONSHIP BETWEEN CONTROL PARAMETERS AND TUMOR/BONE CONDITIONS FOR EXTERNAL ULTRASOUND HYPERTHERMIA

2001 ◽  
Vol 13 (04) ◽  
pp. 199-212 ◽  
Author(s):  
CHIHNG-TSUNG LIAUH ◽  
WIN-LI LIN ◽  
YUNG-YAW CHEN ◽  
JIA-YUSH YEN
Keyword(s):  
Tumor Size ◽  
Search Algorithm ◽  
Window Size ◽  
Blood Perfusion ◽  
Control Parameters ◽  
Tumor Depth ◽  
Acoustic Window ◽  
Ultrasound Frequency ◽  
Ultrasound Hyperthermia ◽  
The Relationship

The purpose of this paper is to examine the relationship between the control parameters and the tumor/bone conditions, and also to determine the domain determined by the treatable tumor size and tumor depth for an external ultrasound hyperthermia. This work employs computer simulation programs based on a simplified model of a scanned ultrasound transducer power deposition, the steadystate bio-heat transfer equation, and a search algorithm. The low bounds of SR (specific absorption rate ratio) and f · SR (f : ultrasound frequency) are determined based on the temperature distributions for large ranges of blood perfusion and ultrasound frequencies. These low bounds of SR and f · SR are then used to investigate the relationship between the control parameters and the tumor/bone conditions and to determine the treatable domain. The control parameters considered are the acoustic window size, ultrasound frequency; and the tumor/bone conditions are tumor size, tumor depth, and the depth of post-target bone. Simulation results demonstrate that a) the low bounds of SR and f · SR are functions of blood perfusion; b) the ultrasound frequency to obtain the largest treatable tumor size depends on the tumor depth and the depth of post-target bone, however it is independent of the acoustic window size; and c) the treatable domain is proportional to the acoustic window size and the depth of post-target bone, and a proper frequency can result in a larger treatable domain. The results of this study can be a guideline for designing an optimal ultrasound heating system, arranging the transducers, and implementing further treatment planning for the external ultrasound hyperthermia.

Experimental Assessment of Effect of Backlash Control Parameters on Quadrant Protrusions of Circular Tests for CNC Machine Tools

2020 ◽  
Vol 19 (01) ◽  
pp. 65-85
Author(s):  
Chuan-Hsun Hsu ◽  
Chi-Hsiang Wang ◽  
Syh-Shiuh Yeh
Keyword(s):  
Machine Tool ◽  
Feed Rate ◽  
Machine Tools ◽  
Search Algorithm ◽  
Cnc Machine Tools ◽  
Control Parameters ◽  
Cnc Machine ◽  
Circular Test ◽  
Binary Search Algorithm ◽  
The Relationship

Backlash, friction, and servo lag factors often result in protrusion or segment difference phenomenon in the moving speed reversal of a machine tool’s moving table. This phenomenon can be improved by adjusting the backlash control parameters of the machine tool controller, but the control parameters must vary with the feed rate and payload of the moving table. Therefore, this study performed the circular test process for CNC machine tools, and used different feed rate, radius, and payload motion conditions to discuss the effect of backlash control parameters on quadrant protrusions. First, this study used parameter-range reduction combined with the Taguchi method and the binary search algorithm to search for the optimal backlash control parameters in the parameter setting range, so that the machine tool could have preferable quadrant protrusion performance when executing circular tests. Afterward, the correlation of the moving table feed rate, radius, and payload to the quadrant protrusion was analyzed according to the experimental results. The results indicated that the machine tool moving table feed rate had the most apparent effect on quadrant protrusions, and the relationship between the payload and quadrant protrusion was influenced by the moving table feed rate and circular radius simultaneously.

O-046 CT Screening for lung cancer: The relationship of disease stageto tumor size

Lung Cancer ◽  
2005 ◽  
Vol 49 ◽  
pp. S18
Author(s):  
C. Henschke ◽  
S. Sone ◽  
S. Markowitz ◽  
M. Tockman ◽  
D. Shaham ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Tumor Size ◽  
Ct Screening ◽  
Relationship Of ◽  
The Relationship

scholarly journals Minimization of Risks of Voltage and Frequency Violations in Islanded Microgrids using Robust Probabilistic Optimal Power Flow

2021 ◽  
Author(s):  
Elton A. Chagas ◽  
Anselmo B. Rodrigues ◽  
Maria G. Silva
Keyword(s):  
Power Flow ◽  
Optimal Power Flow ◽  
Search Algorithm ◽  
Gravitational Search Algorithm ◽  
Computational Cost ◽  
Forecast Errors ◽  
Droop Control ◽  
Control Parameters ◽  
Distributed Generators ◽  
Optimal Power

The main aim of this paper is to propose a robust probabilistic optimal power flow model to determine the droop control parameters for the Distributed Generators (DG) of a islanded microgrid. The term robust is related to the droop control parameters being immune to uncertainties associated with: load forecast errors, DG outages and variability of power output in renewable DG. This optimization problem is solved by an improved gravitational search algorithm (GSA). The test results demonstrated that the proposed method can achieve significant reductions in the load curtailments due to frequency and voltage violations. In addition, a comparison between GSA and the Particle Swarm Optimization (PSO) demonstrated that GSA is more suitable for evaluating the droop control parameters than PSO in relation to the computational cost and the optimal quality of the solution.

Prognostic factors in adult patients with locally controlled soft tissue sarcoma. A study of 546 patients from the French Federation of Cancer Centers Sarcoma Group.

1996 ◽  
Vol 14 (3) ◽  
pp. 869-877 ◽  
Author(s):  
J M Coindre ◽  
P Terrier ◽  
N B Bui ◽  
F Bonichon ◽  
F Collin ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Adjuvant Chemotherapy ◽  
Local Recurrence ◽  
Tumor Size ◽  
Adjuvant Radiotherapy ◽  
Tumor Depth ◽  
Cancer Centers ◽  
Grade 3 ◽  
Metastatic Risk ◽  
Deep Location

PURPOSE To define the prognostic factors in adult patients with locally controlled soft tissue sarcoma (STS) and to determine which patients should be considered for adjuvant treatment. PATIENTS AND METHODS Five hundred forty-six patients with a nonmetastatic and locally controlled STS, collected in a cooperative data base by the French Federation of Cancer Centers (FNCLCC) Sarcoma Group from 1980 and 1989, were studied. Histologic slides of all patients were collegially reviewed. Initial treatment consisted of complete tumor resection with amputation in only 4% of the patients. Adjuvant radiotherapy was administered to 57.9% and adjuvant chemotherapy to 31%. Relationships between tumor characteristics were analyzed, and univariate and multivariate analyses were performed using Cox models for the hazards rate of tumor mortality, development of distant metastasis, and strictly local recurrence. RESULTS Unfavorable characteristics with an independent prognostic value for tumor mortality were: grade 3 (P = 3 x 10(-10)), male sex (P = 1.5 x 10(-5)), no adjuvant chemotherapy (P = 5.4 x 10(-5)), tumor size > or = 5 cm (P = 3.8 x 10(-3)), and deep location (P = 4.6 x 10(-3)). Unfavorable characteristics for the development of distant metastasis were: grade 3 (P = 4 x 10(-12)), no adjuvant chemotherapy (P = 6.4 x 10(-4)), tumor size > or = 10 cm (P = 9.8 x 10(-4)), and deep location (P = 1.3 x 10(-3)). For the development of local recurrence, the unfavorable characteristics were: no adjuvant radiotherapy (P = 3.6 x 10(-6)), poor surgery (local excision) (P = 2 x 10(-4)), grade 3 (P = 7.6 x 10(-4)), and deep location (P = 10(-2)). Grade, depth, and tumor size were used to define groups of patients according to the metastatic risk. Adjuvant chemotherapy was beneficial in terms of overall survival and metastasis-free survival in grade 3 tumor patients only. Despite worse characteristics concerning tumor depth, tumor-node-metastasis (TNM) and American Joint Committee (AJC)/International Union Against Cancer (UICC) classifications and grade in patients with adjuvant radiotherapy, the latter experienced significantly fewer local recurrences than patients with no radiotherapy. CONCLUSION Grade, tumor depth, and tumor size could be used to select patients with a high metastatic risk, for which adjuvant chemotherapy could be beneficial.

scholarly journals Change in Tumor Size by RECIST Correlates Linearly With Overall Survival in Phase I Oncology Studies

2012 ◽  
Vol 30 (21) ◽  
pp. 2684-2690 ◽  
Author(s):  
Rajul K. Jain ◽  
J. Jack Lee ◽  
Chaan Ng ◽  
David Hong ◽  
Jing Gong ◽  
...  
Keyword(s):  
Overall Survival ◽  
Phase I ◽  
Anticancer Agents ◽  
Tumor Size ◽  
Continuous Variable ◽  
Phase I Trials ◽  
Management Options ◽  
Cox Models ◽  
Kaplan Meier ◽  
The Relationship

Purpose RECIST is used to quantify tumor changes during exposure to anticancer agents. Responses are categorized as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Clinical trials dictate a patient's management options based on the category into which his or her response falls. However, the association between response and survival is not well studied in the early trial setting. Patients and Methods To study the correlation between response as quantified by RECIST and overall survival (OS, the gold-standard survival outcome), we analyzed 570 participants of 24 phase I trials conducted between October 2004 and May 2009, of whom 468 had quantifiable changes in tumor size. Analyses of Kaplan-Meier estimates of OS by response and null Martingale residuals of Cox models were the primary outcome measures. All analyses are landmark analyses. Results Kaplan-Meier analyses revealed strong associations between change in tumor size by RECIST and survival (P = 4.5 × 10−6 to < 1 × 10−8). The relationship was found to be near-linear (R2 = 0.75 to 0.92) and confirmed by the residual analyses. No clear inflection points were found to exist in the relationship between tumor size changes and survival. Conclusion RECIST quantification of response correlates with survival, validating RECIST's use in phase I trials. However, the lack of apparent boundary values in the relationship between change in tumor size and OS demonstrates the arbitrary nature of the CR/PR/SD/PD categories and questions emphasis placed on this categorization scheme. Describing tumor responses as a continuous variable may be more informative than reporting categoric responses when evaluating novel anticancer therapies.

Procedure to Estimate Thermophysical and Geometrical Parameters of Embedded Cancerous Lesions Using Thermography

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Jose Manuel Luna ◽  
Ricardo Romero-Mendez ◽  
Abel Hernandez-Guerrero ◽  
Francisco Elizalde-Blancas
Keyword(s):  
Research Work ◽  
Blood Perfusion ◽  
Skin Surface ◽  
Geometrical Parameters ◽  
Estimation Of Parameters ◽  
Perfusion Rate ◽  
Unknown Parameters ◽  
Cancerous Lesions ◽  
The Relationship ◽  
Inverse Procedure

Based on the fact that malignant cancerous lesions (neoplasms) develop high metabolism and use more blood supply than normal tissue, infrared thermography (IR) has become a reliable clinical technique used to indicate noninvasively the presence of cancerous diseases, e.g., skin and breast cancer. However, to diagnose cancerous diseases by IR, the technique requires procedures that explore the relationship between the neoplasm characteristics (size, blood perfusion rate and heat generated) and the resulting temperature distribution on the skin surface. In this research work the dual reciprocity boundary element method (DRBEM) has been coupled with the simulated annealing technique (SA) in a new inverse procedure, which coupled to the IR technique, is capable of estimating simultaneously geometrical and thermophysical parameters of the neoplasm. The method is of an evolutionary type, requiring random initial values for the unknown parameters and no calculations of sensitivities or search directions. In addition, the DRBEM does not require any re-meshing at each proposed solution to solve the bioheat model. The inverse procedure has been tested considering input data for simulated neoplasms of different sizes and positions in relation to the skin surface. The successful estimation of unknown neoplasm parameters validates the idea of using the SA technique and the DRBEM in the estimation of parameters. Other estimation techniques, based on genetic algorithms or sensitivity coefficients, have not been capable of obtaining a solution because the skin surface temperature difference is very small.

scholarly journals Endocrine function and gland volume after endoscopic transsphenoidal surgery for nonfunctional pituitary macroadenomas

2019 ◽  
Vol 131 (4) ◽  
pp. 1142-1151 ◽  
Author(s):  
Maya Harary ◽  
Aislyn C. DiRisio ◽  
Hassan Y. Dawood ◽  
John Kim ◽  
Nayan Lamba ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Tumor Size ◽  
Transsphenoidal Surgery ◽  
Endocrine Function ◽  
Pituitary Function ◽  
Pituitary Hormone ◽  
Tumor Diameter ◽  
Endoscopic Transsphenoidal Surgery ◽  
Gland Volume ◽  
The Relationship

OBJECTIVELoss of pituitary function due to nonfunctional pituitary adenoma (NFPA) may be due to compression of the pituitary gland. It has been proposed that the size of the gland and relative perioperative gland expansion may relate to recovery of pituitary function, but the extent of this is unclear. This study aims to assess temporal changes in hormonal function after transsphenoidal resection of NFPA and the relationship between gland reexpansion and endocrine recovery.METHODSPatients who underwent endoscopic transsphenoidal surgery by a single surgeon for resection of a nonfunctional macroadenoma were selected for inclusion. Patients with prior pituitary surgery or radiosurgery were excluded. Patient characteristics and endocrine function were extracted by chart review. Volumetric segmentation of the pre- and postoperative (≥ 6 months) pituitary gland was performed using preoperative and long-term postoperative MR images. The relationship between endocrine function over time and clinical attributes, including gland volume, were examined.RESULTSOne hundred sixty eligible patients were identified, of whom 47.5% were female; 56.9% of patients had anterior pituitary hormone deficits preoperatively. The median tumor diameter and gland volume preoperatively were 22.5 mm (interquartile range [IQR] 18.0–28.8 mm) and 0.18 cm3 (IQR 0.13–0.28 cm3), respectively. In 55% of patients, endocrine function normalized or improved in their affected axes by median last clinical follow-up of 24.4 months (IQR 3.2–51.2 months). Older age, male sex, and larger tumor size were associated with likelihood of endocrine recovery. Median time to recovery of any axis was 12.2 months (IQR 2.5–23.9 months); hypothyroidism was the slowest axis to recover. Although the gland significantly reexpanded from preoperatively (0.18 cm3, IQR 0.13–0.28 cm3) to postoperatively (0.33 cm3, IQR 0.23–0.48 cm3; p < 0.001), there was no consistent association with improved endocrine function.CONCLUSIONSRecovery of endocrine function can occur several months and even years after surgery, with more than 50% of patients showing improved or normalized function. Tumor size, and not gland volume, was associated with preserved or recovered endocrine function.

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