Pilot point temperature regulation for thermal lesion control during ultrasound thermal therapy

2004 ◽  
Vol 42 (2) ◽  
pp. 178-188 ◽  
Author(s):  
H. -L. Liu ◽  
Y. -Y. Chen ◽  
J. -Y. Yen ◽  
W. -L. Lin
Keyword(s):  
Temperature Regulation ◽  
Thermal Therapy ◽  
Thermal Lesion ◽  
Point Temperature

scholarly journals THERMAL LESION FORMATION AND DETERMINATION FOR EXTERNAL ULTRASOUND THERMAL THERAPY

2003 ◽  
Vol 15 (03) ◽  
pp. 124-132 ◽  
Author(s):  
HAO-LI LIU ◽  
YUNG-YAW CHEN ◽  
JIA-YUSH YEN ◽  
WIN-LI LIN
Keyword(s):  
Blood Perfusion ◽  
Heating System ◽  
Target Volume ◽  
Thermal Therapy ◽  
Bioheat Transfer ◽  
Heating Process ◽  
Thermal Lesion ◽  
Feedback Information ◽  
Temperature Feedback ◽  
Heating Pattern

The purpose of this paper is to investigate the relationship between the formation of the thermal lesion and the major parameters of the external ultrasound heating systems, and to propose a useful thermal lesion determination procedure, which is capable of specifying the range of a thermal lesion by temperature feedback in external ultrasound thermal therapy. This work is based on an ideal ultrasound power deposition formed by an external ultrasound heating system and the temperature distribution is calculated by the transient bioheat transfer equation. A simplified model was employed to determine the heating pattern for four most important parameters. Through the simplified power expression, the property of a new parameter, T300, which is defined as the maximal temperature corresponding to the thermal dose of 300 minutes, is also investigated. When the target volume is large enough such that the thermal conduction effect becomes negligible, the T300 value is almost independent of the system parameters and the heating strategies, and is dominated by the blood perfusion rate with a monotonic correlation. The method enables us to use feedback information in the ultrasound heating process and to pre-determine the heating range of the thermal lesion, which will be very useful in ultrasound treatment planning.

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.

Tissue-Light Interaction During Monitoring of Thermal Lesion Using Quantum Dot Mediated Fluorescence Thermometry

2011 ◽  
Author(s):  
Willard Hanson ◽  
Najma Abdollahzadeh ◽  
Bumsoo Han
Keyword(s):  
Diffusion Approximation ◽  
Treatment Options ◽  
Thermal Therapy ◽  
Temperature Dependent ◽  
Thermal Lesion ◽  
Tissue Phantom ◽  
Localized Heating ◽  
Light Interaction

Thermal therapy, destroying tumor in situ by localized heating, is emerging as one of the treatment options for benign and localized tumors. Despite many advantages of thermal therapy, its clinical application is still limited due to the lack of a reliable intraoperative monitoring technique of the thermal lesion. To address this challenge, an intraoperative thermometry technique has been proposed using the temperature-dependent fluorescence of quantum dots (QDs). Its feasibility is recently demonstrated by monitoring the spatiotemporal temperature during gold nanoshell-mediated heating. In the present study, the effects of tissue-light interaction on the QD-mediated thermometry were investigated both experimentally and theoretically so that the technique can be extended to in vivo applications. As for experimental investigation, the QD fluorescence through tissue phantom was characterized with varying the thickness of the phantom over a temperature range relevant to thermal therapy. The results showed that the QD fluorescence through tissue phantom was still linearly correlated to the local temperature, but the slope of the correlations decreased with the phantom thickness. As for theoretical investigation, the radiative transfer equation was reduced to the diffusion approximation, and the QD fluorescence through tissue phantom was predicted by numerically solving the diffusion approximation. The results confirmed that the diffusion approximation could describe the tissue-light interaction for the QD-mediated thermometry but further research is still required to improve the accuracy of the prediction.

Spatiotemporal Temperature Measurement Using Quantum Dot Thermometry During Nanoshell Mediated Thermal Therapy

2008 ◽  
Author(s):  
Bumsoo Han ◽  
Willard L. Hanson ◽  
Karim Bensalah ◽  
Altug Tuncel ◽  
Joshua Stern ◽  
...  
Keyword(s):  
Surgical Techniques ◽  
Thermal Therapy ◽  
Thermal Lesion ◽  
Major Drawback ◽  
Thermal Lesions ◽  
Minimally Invasive Surgical ◽  
Thermal Therapies ◽  
Diagnostic Technologies ◽  
Widespread Dissemination

Due to advances and routine use of various diagnostic technologies, tumors are increasingly detected at very early stages. Thus, there is growing interest in employing minimally invasive surgical techniques for the management of tumors. Many of these procedures are thermal therapies, in which localized thermal lesions, either hyperthermic or cryogenic, are created to destroy malignant tissue in situ. However, the major drawback to the widespread dissemination and acceptance of thermal therapy is the lack of a reliable real-time intraoperative monitoring technique of the thermal lesion.

A unified approach to combine temperature estimation and elastography for thermal lesion determination in focused ultrasound thermal therapy

2010 ◽  
Vol 56 (1) ◽  
pp. 169-186 ◽  
Author(s):  
Hao-Li Liu ◽  
Meng-Lin Li ◽  
Po-Hsiang Tsui ◽  
Ming-Shi Lin ◽  
Sheng-Min Huang ◽  
...  
Keyword(s):  
Focused Ultrasound ◽  
Thermal Therapy ◽  
Unified Approach ◽  
Thermal Lesion ◽  
Temperature Estimation

High frequency induced thermal therapy (HITT) – four modalities, more possibilities. how and when to do it?

2008 ◽  
Vol 29 (S 1) ◽  
Author(s):  
H Stoyan ◽  
K Katzarov ◽  
Z Dunkov ◽  
D Takov ◽  
D Stoyanova ◽  
...  
Keyword(s):  
High Frequency ◽  
Thermal Therapy

Solid insulation drying of 110 kV paper-oil instrument transformers

2009 ◽  
Vol 25 (25) ◽  
pp. 35-38 ◽  
Author(s):  
Gerards Gavrilovs ◽  
Sandra Vītoliņa
Keyword(s):  
Temperature Regulation ◽  
Drying Method ◽  
Instrument Transformers ◽  
Conventional Drying ◽  
Solid Insulation

Solid insulation drying of 110 kV paper-oil instrument transformersInfluence of moisture on the instrument transformers' paper-oil insulation and its further maintenance is described in this paper. Improved insulation drying method using vacuum and temperature regulation with definite regulation algorithm of parameters is proposed and analyzed by comparing it with conventional drying method.

Spinal laser interstitial thermal therapy: single-center experience and outcomes in the first 120 cases

2020 ◽  
pp. 1-10
Author(s):  
Dhiego C. A. Bastos ◽  
Rafael A. Vega ◽  
Jeffrey I. Traylor ◽  
Amol J. Ghia ◽  
Jing Li ◽  
...  
Keyword(s):  
Local Recurrence ◽  
Local Control ◽  
Thoracic Spine ◽  
Adjuvant Radiotherapy ◽  
Neurological Complications ◽  
Thermal Therapy ◽  
External Beam Radiation ◽  
Beam Radiation ◽  
Laser Interstitial Thermal Therapy ◽  
Hazard Ratios

OBJECTIVEThe objective of this study was to present the results of a consecutive series of 120 cases treated with spinal laser interstitial thermal therapy (sLITT) to manage epidural spinal cord compression (ESCC) from metastatic tumors.METHODSThe electronic records of patients treated from 2013 to 2019 were analyzed retrospectively. Data collected included demographic, pathology, clinical, operative, and imaging findings; degree of epidural compression before and after sLITT; length of hospital stay; complications; and duration before subsequent oncological treatment. Independent-sample t-tests were used to compare means between pre- and post-sLITT treatments. Survival was estimated by the Kaplan-Meier method. Multivariate logistic regression was used to analyze predictive factors for local recurrence and neurological complications.RESULTSThere were 110 patients who underwent 120 sLITT procedures. Spinal levels treated included 5 cervical, 8 lumbar, and 107 thoracic. The pre-sLITT Frankel grades were E (91.7%), D (6.7%), and C (1.7%). The preoperative ESCC grade was 1c or higher in 92% of cases. Metastases were most common from renal cell carcinoma (39%), followed by non–small cell lung carcinoma (10.8%) and other tumors (35%). The most common location of ESCC was in the vertebral body (88.3%), followed by paraspinal/foraminal (7.5%) and posterior elements (4.2%). Adjuvant radiotherapy (spinal stereotactic radiosurgery or conventional external beam radiation therapy) was performed in 87 cases (72.5%), whereas 33 procedures (27.5%) were performed as salvage after radiotherapy options were exhausted. sLITT was performed without need for spinal stabilization in 87 cases (72.5%). Post-sLITT Frankel grades were E (85%), D (10%), C (4.2%), and B (0.8%); treatment was associated with a median decrease of 2 ESCC grades. The local control rate at 1 year was 81.7%. Local control failure occurred in 25 cases (20.8%). The median progression-free survival was not reached, and overall survival was 14 months. Tumor location in the paraspinal region and salvage treatment were independent predictors of local recurrence, with hazard ratios of 6.3 and 3.3, respectively (p = 0.01). Complications were observed in 22 cases (18.3%). sLITT procedures performed in the lumbar and cervical spine had hazard ratios for neurological complications of 15.4 and 17.1 (p < 0.01), respectively, relative to the thoracic spine.CONCLUSIONSsLITT is safe and provides effective local control for high-grade ESCC from vertebral metastases in the thoracic spine, particularly when combined with adjuvant radiotherapy. The authors propose considering sLITT as an alternative to open surgery in selected patients with spinal metastases.

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