Ultrasound Hyperthermia: Dose Estimation and Device Design

2012 ◽  
Author(s):  
Danica Gordon ◽  
Chandrasekhar Thamire
Keyword(s):  
Cancer Treatment ◽  
Treatment Modality ◽  
Thermal Damage ◽  
Operating Parameter ◽  
Cell Types ◽  
Temperature History ◽  
Device Design ◽  
High Frequency Ultrasound ◽  
Treatment Protocols ◽  
Thermal Coagulation

As a cancer treatment modality, thermal ablation offers the advantages of being less invasive and posing fewer post-procedural complications compared to traditional cancer therapies. It involves destroying cancerous cells by subjecting them to the appropriate amount of heat dose. In the present study, high frequency ultrasound (US) ablation is theoretically examined for effectiveness as a treatment modality for intraluminal and extracorporeal cancer treatment. Objectives of this study are to 1) develop thermal-damage correlations for a variety of cancer cells and 2) design US treatment devices, based on thermal damage correlations developed, and treatment planning protocols. To achieve these goals, thermal damage information for different cell types is first determined from earlier studies or pilot experiments. Required US doses for specific tissues are determined next through numerical experiments. Device design and estimation of thermal coagulation contours is then performed by comparing temperature-history data against the thermal-damage data for a range of device parameters. Treatment protocols are finally developed based on the analysis of the results for a range of applicable device parameters. Results are presented in terms of correlations for the volume and location of ablated tissue corresponding to a range of operating parameter values.

Ultrasound Hyperthermia: Dose Estimation and Device Design for Intraluminal and External Delivery

2012 ◽  
Author(s):  
Danica Gordon ◽  
Chandrasekhar Thamire
Keyword(s):  
Thermal Damage ◽  
Treatment Time ◽  
The Body ◽  
Thermal Therapy ◽  
Surrounding Tissue ◽  
Temperature History ◽  
Published Data ◽  
Device Design ◽  
Treatment Protocols ◽  
Thermal Coagulation

Thermal ablation in the context of this study refers to destroying cancer cells by heating them to supraphysiological temperatures for appropriate times. Once the tumor cells and a small layer of surrounding tissue cells are killed, they are absorbed by the body over time. Compared to open surgery, radiation, and chemotherapy, thermal therapy can be less expensive and pose less risk of harmful post-procedural complications, while possessing the potential to be effective [1]. Currently microwave and radiofrequency ablation are in use for local hyperthermia; however, they lack the ability to focus heat into the target zones effectively or treat larger tumors without affecting the surrounding healthy tissue. In the current study, high frequency ultrasound (US) ablation is examined as a treatment modality because of its ability to focus and control heat effectively. Objectives of this study are to 1) develop thermal-damage correlations for US thermal therapy and 2) design delivery devices and associated treatment planning protocols. To achieve these goals, thermal damage information is first evaluated for a variety of cells and tissues from published data or pilot experiments. Required US dose levels are determined next through numerical experiments, followed by device design and estimation of thermal coagulation contours by comparing the temperature-history data against the thermal-damage data. Based on the analysis of the results for a range of parameters, namely, the applicator power, geometry, frequency, coolant parameters, treatment time, and tissue perfusion, treatment protocols are developed. Intraluminal, external, and interstitial modes of delivery are considered for focal sites in a variety of target areas. In the following sections, methods followed and sample results obtained are presented.

Treatment Planning for Transurethral and Interstitial Thermal Therapy for Benign Prostatic Hyperplasia

2009 ◽  
Author(s):  
Chandrasekhar Thamire ◽  
Rabee Zuberi ◽  
Charlie Choe ◽  
Prabhakar Pandey
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Treatment Planning ◽  
Thermal Damage ◽  
Treatment Time ◽  
Ex Vivo ◽  
Prostatic Hyperplasia ◽  
Bioheat Transfer ◽  
Temperature History ◽  
Target Tissue ◽  
Thermal Coagulation

The purpose of this study is to develop thermal-damage correlations for transurethral and interstitial thermotherapy to aid treatment planning for benign prostatic hyperplasia (BPH). Using an Alternating-direction implicit method, the Pennes bioheat transfer equation is solved for microwave and ultrasound hyperthermia applicators for a range of parameters, including the applicator power, treatment time, and coolant parameters. Thermal coagulation contours are developed by evaluating the temperature-history data against the thermal-damage data obtained in ex-vivo experiments for prostate tissue slices and cells. Treatment protocols are proposed for treatment planning purposes and developing an optimal hyperthermia applicator that can coagulate the target tissue effectively, without destroying the surrounding healthy tissue.

Optical-Thermal Response and Dynamic Thermal Damage of Bio-Tissue During Laser Thermotherapy

2003 ◽  
Author(s):  
G. M. Zhu ◽  
W. Liu ◽  
T. F. Zeng ◽  
K. Yang
Keyword(s):  
Thermal Injury ◽  
Thermal Damage ◽  
Tumor Tissue ◽  
Local Heating ◽  
Damage Model ◽  
Thermal Response ◽  
Tumor Treatment ◽  
Thermal Coagulation ◽  
Laser Head ◽  
Temperature Damage

Laser thermotherapy is a technique used for tumor treatment. It generates a local heating, causes thermal coagulation of living tissue and eliminates the tumor. Precise heating of tumor tissue with healthy minimum thermal injury to adjacent tissue is essential to thermotherapy. Understanding of heat transfer and optical-thermal interaction is important for control of temperature and design of thermotherapy. This study applies the Arrhenius damage model to describe the heat-induced change of optical properties. It calculates the distribution temperature, damage and optical-thermal response of bio-tissue during the laser treatment, and shows how these factors affect the effectiveness of laser thermotherapy. Similar research has been performed by Kim and coworkers [1996], Iizuka and coworkers [2000], and Whelan and coworkers [2000]. This study relaxes some conditions in previous investigations. It reveals the importance and the effect of size of the laser head.

Comparative Study of Oncology Information Systems for Better Patient and Provider Outcomes

2020 ◽  
pp. 228-237
Author(s):  
Muhammad Nadeem Shuakat ◽  
Nilmini Wickramasinghe
Keyword(s):  
Information Systems ◽  
Comparative Study ◽  
Cancer Treatment ◽  
Real Time ◽  
Cancer Patients ◽  
Developed Countries ◽  
High Price ◽  
Treatment Protocols ◽  
Underdeveloped Countries ◽  
Provider Outcomes

Cancer is among the top three chronic diseases both in developed countries as well as underdeveloped countries. The diagnosis, medication, and treatment for cancer is extremely costly. Typically, cancer treatment involves surgery, radiotherapy, and chemotherapy. Owing to the extremely high price of medicine and treatment along with cytotoxicity of medication, cancer treatment warrants extraordinary care in treating cancer patients. Oncology information systems (OIS) provide an all-in-one solution for such problems. The OIS can integrate different treatment protocols and update change in dose and treatment in real time.

scholarly journals A Study on Nonthermal Irreversible Electroporation of the Thyroid

2019 ◽  
Vol 18 ◽  
pp. 153303381987630
Author(s):  
Yanpeng Lv ◽  
Yanfang Zhang ◽  
Jianwei Huang ◽  
Yunlong Wang ◽  
Boris Rubinsky
Keyword(s):  
Electric Fields ◽  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Pulse Sequences ◽  
Cell Swelling ◽  
Tissue Type ◽  
Heterogeneous Structure ◽  
Treatment Protocols ◽  
Thyroid Ablation ◽  
Nonthermal Irreversible Electroporation

Background: Nonthermal irreversible electroporation is a minimally invasive surgery technology that employs high and brief electric fields to ablate undesirable tissues. Nonthermal irreversible electroporation can ablate only cells while preserving intact functional properties of the extracellular structures. Therefore, nonthermal irreversible electroporation can be used to ablate tissues safely near large blood vessels, the esophagus, or nerves. This suggests that it could be used for thyroid ablation abutting the esophagus. This study examines the feasibility of using nonthermal irreversible electroporation for thyroid ablation. Methods: Rats were used to evaluate the effects of nonthermal irreversible electroporation on the thyroid. The procedure entails the delivery of high electric field pulses (1-3 kV/cm, 100 microseconds) between 2 surface electrodes bracing the thyroid. The right lobe was treated with various nonthermal irreversible electroporation pulse sequences, and the left was the control. After 24 hours of the nonthermal irreversible electroporation treatment, the thyroid was examined with hemotoxylin and eosin histological analysis. Mathematical models of electric fields and the Joule heating-induced temperature raise in the thyroid were developed to examine the experimental results. Results: Treatment with nonthermal irreversible electroporation leads to follicular cells damage, associated with cell swelling, inflammatory cell infiltration, and cell ablation. Nonthermal irreversible electroporation spares the trachea structure. Unusually high electric fields, for these types of tissue, 3000 V/cm, are needed for thyroid ablation. The mathematical model suggests that this may be related to the heterogeneous structure of the thyroid-induced distortion of local electric fields. Moreover, most of the tissue does not experience thermal damage inducing temperature elevation. However, the heterogeneous structure of the thyroid may cause local hot spots with the potential for local thermal damage. Conclusion: Nonthermal irreversible electroporation with 3000 V/cm can be used for thyroid ablation. Possible applications are treatment of hyperthyroidism and thyroid cancer. The highly heterogeneous structure of the thyroid distorts the electric fields and temperature distribution in the thyroid must be considered when designing treatment protocols for this tissue type.

Utility of automated counting to determine absolute neutrophil counts and absolute phagocyte counts for pediatric cancer treatment protocols

Cancer ◽  
2004 ◽  
Vol 101 (11) ◽  
pp. 2681-2686 ◽  
Author(s):  
Nobuko Hijiya ◽  
Mihaela Onciu ◽  
Scott C. Howard ◽  
Zhe Zhang ◽  
Cheng Cheng ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Pediatric Cancer ◽  
Treatment Protocols ◽  
Cancer Treatment Protocols

Design of Laser Treatment Protocols for Bacterial Disinfection in Root Canals Using Theoretical Modeling and MicroCT Imaging

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Jennifer Gill ◽  
Dwayne Arola ◽  
Ashraf F. Fouad ◽  
Liang Zhu
Keyword(s):  
Root Canal ◽  
Thermal Damage ◽  
Elevated Temperatures ◽  
Surrounding Tissue ◽  
Tooth Root ◽  
Bioheat Equation ◽  
Human Teeth ◽  
Treatment Protocols ◽  
Theoretical Simulations ◽  
Bacterial Disinfection

Theoretical simulations of temperature elevations in root dentin are performed to evaluate, how heating protocols affect the efficacy of using erbium, chromium; yttrium, scandium, gallium, garnet (Er,Cr;YSGG) pulsed lasers for bacterial disinfection during root canal treatments. The theoretical models are generated based on microcomputer tomography (microCT) scans of extracted human teeth. Heat transfer simulations are performed using the Pennes bioheat equation to determine temperature distributions in tooth roots and surrounding tissue during 500 mW pulsed Er,Cr;YSGG laser irradiation on the root canal for eradicating bacteria. The study not only determines the heat penetration within the deep dentin but also assesses potential thermal damage to the surrounding tissues. Thermal damage is assumed to occur when the tissue is subject to a temperature above at least 47 °C for a minimum duration of 10 s. Treatment protocols are identified for three representative tooth root sizes that are capable of maintaining elevated temperatures in deep dentin necessary to eradicate bacteria, while minimizing potential for collateral thermal tissue damage at the outer root surfaces. We believe that the study not only provides realistic laser heating protocols for various tooth root geometries but also demonstrates utility of theoretical simulations for designing individualized treatments in the future.

A Theoretical Comparison of the Efficacy of Microwave and Ultrasound Applicators Used in Transurethral Thermal Therapy

2005 ◽  
Author(s):  
Chandrasekhar Thamire ◽  
Rao L. Divi ◽  
Mukesh Verma
Keyword(s):  
Thermal Damage ◽  
Thermal Therapy ◽  
Accurate Estimation ◽  
Transient Temperature ◽  
Thermal Lesion ◽  
Thermal Coagulation ◽  
External Cooling ◽  
Alternating Direction ◽  
Damage Data ◽  
Prostate Tumor Cells

Microwave and ultrasound energy sources are commonly used in minimally invasive thermal therapy for benign prostatic hyperplasia. Successful management of the therapy using either of these methods requires an accurate estimation of the thermal dosage. The purpose of this study is to evaluate, theoretically, the thermal damage caused by typical transurethral microwave and ultrasound applicators for different thermal doses and compare the efficacy of the two methods. Using an Alternating-direction implicit method, the Pennes bio-heat transfer equation is solved for different levels of power and heating times. Internal and external cooling is applied to preserve the urethral and rectal lining and to control the temperatures within the tissue. The extent of thermal coagulation is determined from the resulting temperature histories, using the existing experimental thermal damage data for prostate tumor cells. The temperatures and damage contours calculated are validated using an Arrhenius analysis of the temperature and thermal-lesion data from the available experimental results. Results show that the calculated damage zones are in good agreement with those observed in the experiments. Results from calculations for different combinations of the parameters are presented in terms of the transient temperature histories and radial and axial extent of the lesion shapes. These results suggest that both methods can yield comparable thermal damage, though ultrasound appears to possess an improved control of directional heating.

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