scholarly journals WIRE-MESH CAPACITANCE TOMOGRAPHY FOR TREATMENT PLANNING SYSTEM OF ELECTRO-CAPACITIVE CANCER THERAPY

2021 ◽  
Vol 83 (6) ◽  
pp. 109-115
Author(s):  
Anis Nisma Yanti ◽  
Marlin Ramadhan Baidillah ◽  
Triwikantoro Triwikantoro ◽  
Endarko Endarko ◽  
Warsito Purwo Taruno
Keyword(s):  
Electric Field ◽  
Grey Matter ◽  
Human Head ◽  
Wire Mesh ◽  
Planning System ◽  
Treatment Planning System ◽  
Head Model ◽  
Simulation Studies ◽  
Average Electric Field ◽  
Capacitance Tomography

The wire-mesh capacitance tomography (WMCT) has been applied to visualize 2D of the distribution of electric field intensity in the treatment planning system (TPS) of electro-capacitive cancer therapy (ECCT) using human head model. WMCT is proposed in this study to estimate accurately the distribution of electric field intensity which is the main optimum factors of ECCT in order to compensate the inaccuracy of TPS ECCT simulation. The experimental and simulation studies were conducted with wire-mesh sensor consisted of 8×8 wire matrix of copper in human head model using two type of helmet ECCT. The result of electric field value at the intersection wire-mesh have been compared between experimental studies and simulation studies. The electric field average value resulted from ECCT helmet-1 is higher than ECCT helmet-2. The average electric field generated by the ECCT helmet-1 is 1585.72 V/m in an air medium, 97.43 V/m in grey matter and 80.58 V/m in the cancer. While the average electric field generated by the ECCT helmet-2 is 1413.28 V/m in an air medium, 64.20 V/m in grey matter and 52.65 V/m in the cancer. ECCT helmet-1 and helmet-2 result the different of electric field distribution pattern. ECCT helmet-1 is more optimal for used to patient has cancer position in the right and bottom, while ECCT helmet-2 is more optimal for used to patient has cancer position in the top and bottom. 

scholarly journals A NOVEL METHOD FOR MEASUREMENT OF ELECTRIC FIELD IN EMULATED HUMAN BODY TISSUE USING WIRE MESH SENSOR

2019 ◽  
Vol 81 (5) ◽  
Author(s):  
Anis Nismayanti ◽  
Marlin R. Baidillah ◽  
Mahfudz Al Huda ◽  
Bambang Prihandoko ◽  
Triwikantoro Triwikantoro ◽  
...  
Keyword(s):  
Electric Field ◽  
Human Body ◽  
Copper Wire ◽  
Back Propagation ◽  
Wire Mesh ◽  
Body Tissue ◽  
Planning System ◽  
Treatment Planning System ◽  
Cross Point ◽  
The Wire

Wire mesh sensor has been successfully fabricated and used for measurement of the electric field in emulated human body tissue. Measurement of electric field in human body tissue needs to be done, because the electric field is very useful for the treatment especially cancer treatment and also important for health. In this study, we propose a novel electric field measurement method by using wire mesh sensor (wms), that is all channels on the wire act as receivers, and each cross point of the wire are interconnected. While in existing wire mesh sensors, there are two perpendicular channels of transmitter and receiver, and each channel is unrelated, there is a distance between the two channels. At present, wire mesh sensors 3 × 3 and 8 × 8 were used to measure the value of electric field at each wire intersection point. The wire mesh sensor consists of copper wire in a cylindrical body model with diameter 14 [cm]. The emulated human body tissue were inserted in the wire mesh sensor. Furthermore, linear back propagation technique and bilinear interpolation used for image reconstruction of the electric field distribution. The result showed that the wire mesh sensor 8 × 8 has better resolution than wire mesh sensor 3 × 3. The characterisation of wire mesh sensor 8 × 8  for measurement of electric field in emulated human body tissue is obtained lower than measurement in the air with a ratio of 82%. Meanwhile, the wire mesh sensor 3 × 3 could be achieved at 61.8%. This study can be a new science in measuring electric field so that electric field-based treatment planning system can be more optimal.

scholarly journals MRI-Based Multiscale Model for Electromagnetic Analysis in the Human Head with Implanted DBS

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Maria Ida Iacono ◽  
Nikos Makris ◽  
Luca Mainardi ◽  
Leonardo M. Angelone ◽  
Giorgio Bonmassar
Keyword(s):  
Electric Field ◽  
Ex Vivo ◽  
Human Head ◽  
Multiscale Model ◽  
Head Model ◽  
Tissue Heating ◽  
Electromagnetic Simulations ◽  
Anatomical Detail ◽  
Magnetic Resonance Imaging Mri ◽  
Deep Brain

Deep brain stimulation (DBS) is an established procedure for the treatment of movement and affective disorders. Patients with DBS may benefit from magnetic resonance imaging (MRI) to evaluate injuries or comorbidities. However, the MRI radio-frequency (RF) energy may cause excessive tissue heating particularly near the electrode. This paper studies how the accuracy of numerical modeling of the RF field inside a DBS patient varies with spatial resolution and corresponding anatomical detail of the volume surrounding the electrodes. A multiscale model (MS) was created by an atlas-based segmentation using a 1 mm3head model (mRes) refined in the basal ganglia by a 200 μm2ex-vivo dataset. Four DBS electrodes targeting the left globus pallidus internus were modeled. Electromagnetic simulations at 128 MHz showed that the peak of the electric field of the MS doubled (18.7 kV/m versus 9.33 kV/m) and shifted 6.4 mm compared to the mRes model. Additionally, the MS had a sixfold increase over the mRes model in peak-specific absorption rate (SAR of 43.9 kW/kg versus 7 kW/kg). The results suggest that submillimetric resolution and improved anatomical detail in the model may increase the accuracy of computed electric field and local SAR around the tip of the implant.

scholarly journals Finite-element analysis of microwave scattering from a three-dimensional human head model for brain stroke detection

2018 ◽  
Vol 5 (7) ◽  
pp. 180319
Author(s):  
Awais Munawar Qureshi ◽  
Zartasha Mustansar ◽  
Samah Mustafa
Keyword(s):  
Finite Element ◽  
Dielectric Properties ◽  
Electric Field ◽  
Three Dimensional ◽  
Human Head ◽  
Head Model ◽  
Different Types ◽  
Brain Stroke ◽  
Human Head Model ◽  
Brain Stroke Detection

In this paper, a detailed analysis of microwave (MW) scattering from a three-dimensional (3D) anthropomorphic human head model is presented. It is the first time that the finite-element method (FEM) has been deployed to study the MW scattering phenomenon of a 3D realistic head model for brain stroke detection. A major contribution of this paper is to add anatomically more realistic details to the human head model compared with the literature available to date. Using the MRI database, a 3D numerical head model was developed and segmented into 21 different types through a novel tissue-mapping scheme and a mixed-model approach. The heterogeneous and frequency-dispersive dielectric properties were assigned to brain tissues using the same mapping technique. To mimic the simulation set-up, an eight-elements antenna array around the head model was designed using dipole antennae. Two types of brain stroke (haemorrhagic and ischaemic) at various locations inside the head model were then analysed for possible detection and classification. The transmitted and backscattered signals were calculated by finding out the solution of the Helmholtz wave equation in the frequency domain using the FEM. FE mesh convergence analysis for electric field values and comparison between different types of iterative solver were also performed to obtain error-free results in minimal computational time. At the end, specific absorption rate analysis was conducted to examine the ionization effects of MW signals to a 3D human head model. Through computer simulations, it is foreseen that MW imaging may efficiently be exploited to locate and differentiate two types of brain stroke by detecting abnormal tissues’ dielectric properties. A significant contrast between electric field values of the normal and stroke-affected brain tissues was observed at the stroke location. This is a step towards generating MW scattering information for the development of an efficient image reconstruction algorithm.

scholarly journals Multi-channel transorbital electrical stimulation for effective stimulation of posterior retina

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sangjun Lee ◽  
Jimin Park ◽  
Jinuk Kwon ◽  
Dong Hwan Kim ◽  
Chang-Hwan Im
Keyword(s):  
Electrical Stimulation ◽  
Electric Field ◽  
Electric Fields ◽  
Anterior Part ◽  
Posterior Part ◽  
Human Head ◽  
Electrical Current ◽  
Field Analysis ◽  
Head Model ◽  
Stimulation Of

AbstractTransorbital electrical stimulation (tES) has been studied as a new noninvasive method for treating intractable eye diseases by delivering weak electrical current to the eye through a pair of electrodes attached to the skin around the eye. Studies have reported that the therapeutic effect of tES is determined by the effective stimulation of retinal cells that are densely distributed in the posterior part of the retina. However, in conventional tES with a pair of electrodes, a greater portion of the electric field is delivered to the anterior part of the retina. In this study, to address this issue, a new electrode montage with multiple electrodes was proposed for the effective delivery of electric fields to the posterior retina. Electric field analysis based on the finite element method was performed with a realistic human head model, and optimal injection currents were determined using constrained convex optimization. The resultant electric field distributions showed that the proposed multi-channel tES enables a more effective stimulation of the posterior retina than the conventional tES with a pair of electrodes.

scholarly journals Clinical Usage of Tissue Electrical Conductivity during the Electroporation: An Essential and Useful Factor

2021 ◽  
Author(s):  
Amir Khaorasani
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
Treatment Planning ◽  
The Body ◽  
Planning System ◽  
Treatment Planning System ◽  
Accurate Estimation ◽  
Cell Kill ◽  
Accurate Treatment ◽  
Vital Factor

Electric field intensity at each point is responsible for pore creation in the cell membrane during the electroporation process. These pores can increase the tissue electrical conductivity in the electroporation. Changes in electrical conductivity through the electroporation is a useful factor for imaging and tracking of electroporation inside the body. Electrical conductivity is set to become a vital factor for accurate estimation of the electric field and cell kill probability distribution in the course of electroporation for treatment planning purposes. Therefore, for more accurate treatment, tissue electrical conductivity changes due to electroporation should be considered in the treatment planning system. This paper describes the advantages of tissue electrical conductivity as a useful factor in the clinic.

Modelling of the electric field distribution in the brain during tDCS

2016 ◽  
Vol 31 (5) ◽  
Author(s):  
Alexander V. Ashikhmin ◽  
Rubin R. Aliev
Keyword(s):  
Spatial Distribution ◽  
Electric Field ◽  
Field Distribution ◽  
Direct Current ◽  
Electric Field Distribution ◽  
Human Head ◽  
Head Model ◽  
Electrode Size ◽  
Common Electrode ◽  
The Brain

AbstractWe simulated the electric current distribution in the brain during transcranial direct current stimulation (tDCS) using an anatomically accurate human head model. We estimated an effect of common electrode montages on spatial distribution of the electric field during tDCS procedure and analyzed a sensitivity of the technique to variations of electrode size and orientation. We concluded that the used electrode montages are stable with respect to minor changes in electrode size and position, while an assumption of homogeneity and isotropy of the head model results in crucial changes of the electric field distribution. We determined the electrode montages suited to deliver strong effect on hippocampus and cerebellum.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

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