Computer Assisted Simulation Model in Cryosurgery for Prostate Tumor

2009 ◽  
Author(s):  
Chih-Wei Chen ◽  
Hong-Sen Kou ◽  
Hsueh-Erh Liu ◽  
Cheng-Keng Chuang ◽  
Li-Jen Wang
Keyword(s):  
Medical Imaging ◽  
Three Dimensional ◽  
Solid Modeling ◽  
Prostate Tumor ◽  
Bioheat Transfer ◽  
Computer Assisted ◽  
Transfer Model ◽  
Prostate Tumors ◽  
Commercial Software ◽  
The Third

Cryosurgery is also called as cryoablation or cryoleision. The third generation of cryo-machine use argon gas for cooling and helium for rewarming to destroy cancer cells. The probes may be put into the tumor during surgery or through the skin (percutaneously). After cryosurgery, the frozen tissue thaws and is either naturally absorbed by the body (for internal tumors), or it dissolves and forms a scab (for external tumors). The main purpose of this paper is to establish a preliminary computer assisted simulation in prostate tumor cryosurgery. A radiologist and an urologist in a medical center in addition to the engineering specialist from the university participated in this interdisciplinary research program. The first step of this simulation protocol is to trim hundreds of two-dimensional medical imaging photos from a patient through the imaging reconstructive software into building a three-dimensional solid modeling. The image data for each patient can be obtained from the x-ray computed tomography (CT), or magnetic resonance imaging (MRI) in the imaging department of hospital. It has successfully built up the related knowledge to overcome the complicacy between the medical imaging modalities and engineering graphic solid modeling with high resolution. It is worthy to mention here that the present solid modeling of prostate can demonstrate the variable diameters and courses of the prostate urethra in vivo. The second step focuses on thermal calculation. So far, there has been no existing commercial software for the specific purpose of the bioheat transfer problem. Hence, user subroutines must be added to the existing commercial software to simulate the clinical situation of cryosurgery. For example, the occurrence of phase change during some specified temperature range and the latent heat of fusion are also incorporated into bio-heat transfer model. It has successfully incorporated bioheat transfer model into the software program to fit the reality in thermal medicine. The third step supplies the data and knowledge concerned with the position of a tumor and the related mechanism of metabolism of living tissue and vessels. The number of probes, the position of each probe, and the operating time of each probe will be explored to ensure a complete killing of the tumor tissue while saving as much healthy surrounding tissue as possible. In this study, the three-dimensional transient temperature distributions based on cryosurgery for prostate tumors have been performed for several cases to find the optimal operating conditions. Different cryoprobes with different freezing time are considered to find the temperature distribution. The simulation results for cryosurgery of prostate tumors will be supplied for practicing physicians as reference to greatly improve the effectiveness of cryosurgery.

Computer Assisted Simulation Model for Cryoablation of Prostate Cancer Including the Possible Injury of Rectum

2010 ◽  
Author(s):  
Chih-Wei Chen ◽  
Hong-Sen Kou ◽  
Hsueh-Erh Liu ◽  
Cheng-Keng Chuang ◽  
Li-Jen Wang
Keyword(s):  
Prostate Cancer ◽  
Heat Transfer ◽  
Simulation Model ◽  
Three Dimensional ◽  
Heat Transfer Model ◽  
Transient Temperature ◽  
Thermal Calculation ◽  
Computer Assisted ◽  
Transfer Model ◽  
Time Duration

This study is to establish a preliminary computer assisted simulation model for cryoablation of a prostate cancer. It is hoped that the results from this study can supply valuable data for the clinician to refer to before a real cryosurgery or cryotherapy. In order to reach the goal of real implementation, a radiologist and an urologist in a medical center in addition to the engineering specialist from the university participated in this interdisciplinary research program. Firstly, hundreds of the two-dimensional medical imaging photos for the patient are obtained from the magnetic resonance imaging (MRI) in the imaging department of hospital. Through the imaging reconstructive software, these photos are trimmed into building a three-dimensional solid modeling. In this step, the urethra, bladder, prostate and rectum are segmented separately into an engineering graphic solid model with high resolution. Secondly, the number of probes, the position of each probe, and the operating time duration of each probe are determined in advance according to the clinical experience from a surgeon. Meanwhile, these data are transferred into the software package of thermal calculation for numerical simulations. Thirdly, the energy equation in the commercial software is modified to behave bio-heat transfer model by the input of user subroutines. Moreover, the occurrence of phase change during some specified temperature range and the latent heat of fusion are also incorporated into bio-heat transfer model to simulate the clinical situation for cryoablation of prostate cancer. In the simulation model, the three-dimensional transient temperature distributions based on cryosurgery for prostate cancer have been demonstrated precisely. The cryoprobes with various freezing time are considered to observe the temperature distribution. In addition, the frozen rectum is displayed in a region enclosed by a critical isotherm of 0°C. The simulated results for cryosurgery of prostate cancer can be supplied for practicing physicians as reference to greatly improve the effectiveness of cryosurgery.

Optimization of Multiprobe Cryosurgery

1992 ◽  
Vol 114 (4) ◽  
pp. 796-801 ◽  
Author(s):  
R. G. Keanini ◽  
B. Rubinsky
Keyword(s):  
Optimization Algorithm ◽  
Iterative Procedure ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Bioheat Transfer ◽  
Simplified Model ◽  
Transfer Model ◽  
Illustrative Case ◽  
Minimization Algorithm ◽  
General Technique

This paper describes a general technique for optimizing cryosurgical procedures. The method, which is based on the simplex minimization algorithm, minimizes unnecessary freezing by optimizing various surgical parameters. The optimization procedure is illustrated using a simplified model of prostatic cryosurgery. In this illustrative case, the function to be minimized, F, defined as the volume of healthy tissue destroyed during complete freezing of the prostate, is assumed to depend on three parameters: the number of cryoprobes used, the freezing length per cryoprobe, and the cryoprobe diameter. Using an iterative procedure, the optimization algorithm first alters these parameters, then calculates F by solving a three-dimensional bioheat transfer model of multiprobe cryosurgery, and finally determines whether F is minimized. The iterative procedure continues until unnecessary freezing is minimized. For the model considered here, the optimization code indicates that unnecessary freezing during cryoprostatectomy is minimized using approximately 5 cryoprobes, each 7.5 mm in length and 4 mm in diameter.

scholarly journals Three-dimensional cranio-facial landmark detection in CT slices from a publicly available database, using multi-phased regression networks on a personal computer.

2021 ◽  
Author(s):  
Soh Nishimoto ◽  
Takuya Saito ◽  
Hisako Ishise ◽  
Toshihiro Fujiwara ◽  
Kenichiro Kawai ◽  
...  
Keyword(s):  
Deep Learning ◽  
Three Dimensional ◽  
Ct Images ◽  
Learning System ◽  
Computer Assisted ◽  
Second Phase ◽  
Dimensional Error ◽  
The Third ◽  
Third Phase ◽  
Ct Slices

Aim: Geometrical assessments to comprehend the shape of an object are done based on characteristic landmarks. Computer assisted tomography (CT) images, horizontal slices as two-dimensional pictures, can be digitally restructured into virtual three-dimensional objects. Automatic detection of the landmarks, if developed, will be a great help not only medically, but also for anthropologically. The aim of this study is to develop an automated system to predict three-dimensional coordinate values of cranio-facial landmarks in sequences of CT slices. Methods: CT images were obtained from a publicly available database. Digital reconstruction was done to obtain three dimensional models. Sixteen landmarks were plotted on the models and coordinate values of them were recorded. Multi-phased deep learning system was constructed. For the first phase, 512 x 512 pixels images were resized to 96 x 96 pixels. A regression deep learning network was trained with 90 training data. For the second phase, for each landmark, 100 x 100 pixels images were cropped from the original images. Sixteen models were trained. For the third phase, 50 x 50 pixels images were cropped, and models were trained. Results: Three-dimensional error for the first phase, testing 30 data, was 11.60 pixels in average. (1 pixel = 500 / 512 mm) For the second phase, it was significantly improved to 4.66 pixels. For the third phase, it was significantly progressed to 2.89. This was comparable to the gaps between the landmarks, plotted by two experienced practitioners. Discussion: The calculation volume required to process three-dimensional pile of images is tremendous. One solution may be to compress the images, but detailed information may be lost during the process. Our proposing method of multi-phased prediction, coarse detection first and narrowing down the detection area, may be a possible solution, within the physical limitation of memory and computation.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Computer Assisted Image Reconstruction of Oligomer Structure

1976 ◽  
Vol 34 ◽  
pp. 472-473
Author(s):  
A.M. Jones ◽  
A. Max Fiskin
Keyword(s):  
Three Dimensional ◽  
Depth Of Field ◽  
Computer Assisted ◽  
Projection Data ◽  
Two Dimensional ◽  
Single Particles ◽  
Dimensional Reconstruction ◽  
Computer Assisted Image ◽  
The Fourier Transform ◽  
Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

Clinical Value of Computer-Assisted Taylor Three-dimensional External Fixation in the Treatment of Tibiofibular Fracture (Preprint)

2020 ◽  
Author(s):  
Hongfeng Sheng ◽  
Weixing Xu ◽  
Bin Xu ◽  
Hongpu Song ◽  
Di Lu ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Internal Fixation ◽  
External Fixation ◽  
External Fixator ◽  
Theoretical Basis ◽  
New Technology ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Clinical Value

UNSTRUCTURED The retrospective study of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures provides a theoretical basis for the application of this technology. The paper collected 28 patients with tibiofibular fractures from the Department of Orthopaedics in our hospital from March 2015 to June 2018. After the treatment, the follow-up evaluation of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures and concurrency the incidence of the disease, as well as the efficacy and occurrence of the internal fixation of the treatment of tibial fractures in our hospital. The results showed that Taylor's three-dimensional external fixator was superior to orthopaedics in the treatment of tibiofibular fractures in terms of efficacy and complications. To this end, the thesis research can be concluded as follows: Taylor three-dimensional external fixation in the treatment of tibiofibular fractures is more effective, and the incidence of occurrence is low, is a new technology for the treatment of tibiofibular fractures, it is worthy of clinical promotion.

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

scholarly journals Modeling of dense well block point bar architecture based on geological vector information: A case study of the third member of Quantou Formation in Songliao Basin

2021 ◽  
Vol 13 (1) ◽  
pp. 39-48
Author(s):  
Chao Luo ◽  
Ailin Jia ◽  
Jianlin Guo ◽  
Wei Liu ◽  
Nanxin Yin ◽  
...  
Keyword(s):  
River Sediments ◽  
Three Dimensional ◽  
Songliao Basin ◽  
Point Bar ◽  
Meandering River ◽  
Architecture Model ◽  
The Third ◽  
Continuous Convergence ◽  
Vector Information ◽  
Architecture Modeling

Abstract Although stochastic modeling methods can achieve multiple implementations of sedimentary microfacies model in dense well blocks, it is difficult to realize continuous convergence of well spacing. Taking the small high-sinuosity meandering river sediments of the third member of Quantou Formation in Songliao Basin as an example, a deterministic modeling method based on geological vector information was explored in this article. Quantitative geological characteristics of point bar sediments were analyzed by field outcrops, modern sediments, and dense well block anatomy. The lateral extension distance, length, and spacing parameters of the point bar were used to quantitatively characterize the thickness, dip angle, and frequency of the lateral layer. In addition, the three-dimensional architecture modeling of the point bar was carried out in the study. The established three-dimensional architecture model of well X24-1 had continuous convergence near all wells, which conformed to the geological knowledge of small high-sinuosity meandering river, and verified the reliability of this method in the process of geological modeling in dense well blocks.

Computer assisted three-dimensional reconstruction of scene in firearm homicide

2021 ◽  
pp. 002581722110183
Author(s):  
MA Kislov ◽  
M Chauhan ◽  
SN Zakharov ◽  
SV Leonov ◽  
YP Shakiryanova
Keyword(s):  
Causes Of Death ◽  
Scientific Evidence ◽  
Three Dimensional ◽  
Crime Scene ◽  
Forensic Sciences ◽  
Computer Assisted ◽  
Three Dimensional Reconstruction ◽  
Scientific Model ◽  
Dimensional Reconstruction ◽  
Promising Application

Worldwide advances in computer techniques are not yet recognised in the practice of forensic medicine. A promising application is their use in making a three-dimensional reconstruction of the crime scene. This study analyses this technique in a homicide by firearm. Queries regarding the direction and number of shots, position of the victim inside the car when shot at and presence of the accused at the crime scene were answered by a scientific model. Similar reconstruction of the scene, nailing the accused in a heinous crime, has not previously been reported as a study or a case. The paper anticipates impetus to the growth of literature in criminology and forensic sciences. It will also expedite the delivery of justice based on scientific evidence in controversial causes of death.

Sign in / Sign up

Export Citation Format

Share Document