A non-invasive system to assess tissue temperature distribution (Conference Presentation)

Assessment on reproduction physiological parameters of ruminant caused by thermal stress usually uses invasive methods. However, these methods are less accurate because they are subjective, require a significant time and resources, and there are problems in animal welfare. Infrared thermography is one alternative solution that can be used. Infrared thermography is a modern, non-invasive, non-destructive, and safe technique to visualize thermal profile and surface temperature. This paper describes the application of infrared thermography in monitoring reproduction physiology status of ruminant. This method does not require physical contact and allows direct visualisation of temperature distribution so that it can be used as a reference in understanding and evaluating several parameters in livestock.

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Effect of the SAR Distribution of a Radio Frequency (RF) Coil on the Temperature Field Within a Human Leg: Numerical Studies

10.1115/imece1999-0570 ◽

1999 ◽

Author(s):

J. X. Ling ◽

Jeffrey W. Hand ◽

Ian R. Young

Keyword(s):

Temperature Distribution ◽

Temperature Change ◽

Absorption Rate ◽

Specific Absorption Rate ◽

Source Term ◽

Fdtd Method ◽

Tissue Temperature ◽

Maximum Temperature ◽

Rf Coil ◽

Specific Absorption

Abstract This paper presents a three dimensional Finite Element Model for studying the effect of the specific absorption rate (SAR) distribution of a RF coil on the temperature distribution within a human leg due to the energy deposit. The model consists of fat, muscle, and bone, and has 21,158 uniform elements. The 3-D leg model was derived from the tissue maps that are obtained from the 79 sequential MR images of a volunteer’s leg. The specific absorption rate (SAR) data are from the solution to the fundamental Maxwell’s electromagnetic equations of the leg with RF coil in place using finite difference time domain (FDTD) method. The blood perfusion term, which is a function of the local tissue temperature, along with the metabolic heat as well as the SAR term, are treated as one heat source term in the classical bio-heat transfer equation. A commercial FEA code, ANSYS, was used to solve the 3-D heat conduction equation with an additional iteration method to deal with the temperature dependent source term. The 3-D temperature fields without and with the SAR term were computed, as well as the changes in temperature. They predict that the maximum temperature change occurs in approximately the same location as the maximum local SAR. The map of the temperature change clearly shows how the presence of the RF coil affect the temperature distribution within the leg. With 2 watts absorbed in the leg, about 8.8 w/kg of peak SAR value, the maximum change in temperature of the leg is about 1.74° C.

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Abstract 4648: Mechanism of Tissue Cooling With Cryoenergy Delivery to Pulmonary Veins: Tissue Temperature Distribution and Chonic Esophageal Effects

Circulation ◽

10.1161/circ.118.suppl_18.s_924-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Charles Dalegrave ◽

Benhur D Henz ◽

Yasuo Okumura ◽

Mark Kolasa ◽

Dylan V Miller ◽

...

Keyword(s):

Temperature Distribution ◽

Pulmonary Veins ◽

Tissue Temperature ◽

Esophageal Injury ◽

Energy Sources ◽

Esophageal Wall ◽

Potential Complication ◽

Internal Temperature ◽

Chronic Effects ◽

New Energy

Background: Although pulmonary vein (PV) isolation has been used to treat AF, complications create important limitations. New energy sources, including cryothermal, have been developed to minimize these complications. The purpose of this study was to evaluate the effect of PV cryoablation on esophageal (ESO) temperatures acutely and correlate them with chronic effects on the esophageal wall. Methods: A 23 mm cryoballoon was placed in the LA of 10 dogs through a 12 Fr deflectable sheath. PV and ESO temperatures (TEMP) were recorded using 7–9 thermocouples (TC) outside the PVs and on the external and internal ESO surfaces during 2 cryoablations of 4 min duration. Results : Cryoablation of 15 PV (10 RIPV and 5 LIPV) during 1.7±0.6 ablations yielded a total of 168 TC time-TEMP profiles (6.4±2.4/PV). Minimum tissue TEMP was inversely dependent on the distance of the TC from the balloon surface (Table 1 ). All PVs were isolated acutely and 14/15 (93%) chronically. Minimum TEMP achieved at the PV surface and external ESO were similar (−32±8 and −37±9 at targets within 2.5 mm from the balloon respectively [P=NS]). A TEMP decrease at the internal ESO was seen during 15 of 25 (60%) ablations, but was significantly less pronounced than the external TEMP (17.9°C±13.3 and 6.1°C±24.8 [p<0.05]) resulting in a minimum recorded internal TEMP of −6.2°C. The ESO histological examination in 5 dogs showed very limited external lesions in these dogs (depth= 2.2±1.1, width3 18.6±7.4 and length= 12±5.7 mm), but no transmural or internal ulceration, fibrosis or scarring seen. Conclusion: Although PV cryoablation decreases external ESO temperature and produces minor lesions, significant chronic disruptive tissue damage was not seen. Esophageal injury is an unlikely, but potential complication of cryoablation, with internal temperature proving unhelpful in predict negative outcome.

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Non-invasive tissue temperature evaluation during application of therapeutic ultrasound: precise time-spatial non-linear modelling

World Congress on Medical Physics and Biomedical Engineering 2006 - IFMBE Proceedings ◽

10.1007/978-3-540-36841-0_25 ◽

2007 ◽

pp. 69-72

Author(s):

C. A. Teixeira ◽

M. Graça Ruano ◽

A. E. Ruano ◽

W. C. A. Pereira

Keyword(s):

Therapeutic Ultrasound ◽

Tissue Temperature ◽

Non Invasive ◽

Linear Modelling ◽

Non Linear ◽

Precise Time

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Development of Body-Tissue Temperature-Control Transducer

Sensors ◽

10.3390/s19010014 ◽

2018 ◽

Vol 19 (1) ◽

pp. 14

Author(s):

Audrone Dumciene ◽

Saule Sipaviciene

Keyword(s):

Temperature Field ◽

Temperature Measurement ◽

Field Distribution ◽

Temperature Control ◽

Material Properties ◽

Tissue Temperature ◽

Human Tissues ◽

Temperature Field Distribution ◽

Non Invasive ◽

Simulation Results

The aim of this study was to develop a transducer for non-invasive temperature measurement in deeper tissue layers during tissue cooling. Simulation of the temperature field distribution in human tissues and the transducer were done, and the influence of transducer structure and material properties were studied. Using simulation results, the experimental transducer was designed for temperature measurement in deeper tissue layers during cooling. The temperature measurements with the needle thermometer and the transducer were well correlated at both before tissue cooling r = 0.723 and after cooling r = 0.945, and the temperature difference was no more than ±0.2 °C.

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USE OF THERMAL IMAGING TESTS IN THE STEEL INDUSTRY

Journal of Metallic Materials ◽

10.32730/imz.2657-747.20.1.3 ◽

2020 ◽

Vol 72 (1) ◽

pp. 39-47

Keyword(s):

Temperature Distribution ◽

Steel Industry ◽

Thermal Imaging ◽

Imaging Technique ◽

Steel Production ◽

Metallurgical Industry ◽

Production Cycle ◽

Charge Preparation ◽

Non Invasive ◽

Testing Method

The paper presents the possibilities and selected examples of practical use of the thermal imaging technique in the metallurgical industry as a non-invasive testing method for measuring temperature distribution on the surface of the examined object. This method can be used in all stages of steel production, from charge preparation to finished product, as well as diagnostics of technical devices. The paper emphasises the non-invasive nature of the examination, which does not disturb the production cycle.

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