Skin temperature increase during local exposure to high-power RF levels in humans

This work describes and presents results from a new three-dimensional whole-body model of human thermoregulation. The model has been implemented using a version of the “Brooks Man” anatomical data set, consisting of 1.3×108 cubic volume elements (voxels) measuring 0.2 cm/side. The model simulates thermoregulation through passive mechanisms (metabolism, blood flow, respiration, and transpiration) and active mechanisms (vasodilatation, vasoconstriction, sweating, and shivering). Compared with lumped or compartment models, a voxel model is capable of high spatial resolution and can capture a level of anatomical detail not achievable otherwise. A high spatial resolution model can predict detailed heating patterns from localized or nonuniform heating patterns, such as from some radio frequency sources. Exposures to warm and hot environments (ambient temperatures of 33–48°C) were simulated with the current voxel model and with a recent compartment model. Results from the two models (core temperature, skin temperature, metabolic rate, and evaporative cooling rate) were compared with published experimental results obtained under similar conditions. Under the most severe environmental conditions considered (47.8°C, 27% RH for 2 h), the voxel model predicted a rectal temperature increase of 0.56°C, compared with a core temperature increase of 0.45°C from the compartment model and an experimental mean rectal temperature increase of 0.6°C. Similar, good agreement was noted for other thermal variables and under other environmental conditions. Results suggest that the voxel model is capable of predicting temperature response (core temperature and skin temperature) to certain warm or hot environments, with accuracy comparable to that of a compartment model. In addition, the voxel model is able to predict internal tissue temperatures and surface temperatures, over time, with a level of specificity and spatial resolution not achievable with compartment models. The development of voxel models and related computational tools may be useful for thermal dosimetry applications involving mild temperature hyperthermia and for the assessment of safe exposure to certain nonionizing radiation sources.

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Temperature-Increase Characteristics in Bent Hole-Assisted Fiber Under High Power

Journal of Lightwave Technology ◽

10.1109/jlt.2007.894479 ◽

2007 ◽

Vol 25 (5) ◽

pp. 1231-1237 ◽

Cited By ~ 4

Author(s):

Takashi Matsui ◽

Kazuhide Nakajima ◽

Kenji Kurokawa ◽

Katsusuke Tajima ◽

Kazuyuki Shiraki ◽

...

Keyword(s):

High Power ◽

Temperature Increase

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Calculation of skin temperature increase caused by subcutaneous veins perpendicular to the skin surface

Physics in Medicine and Biology ◽

10.1088/0031-9155/25/1/008 ◽

1980 ◽

Vol 25 (1) ◽

pp. 85-91 ◽

Cited By ~ 5

Author(s):

L M Torell ◽

S K Nilsson

Keyword(s):

Skin Temperature ◽

Temperature Increase ◽

Skin Surface

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Permanent Lesion of the Lateral Femoral Cutaneous Nerve after Low-Volume Ethanol 96% Application on the Lumbar Sympathetic Chain

January 2018 - Pain Physician ◽

10.36076/ppj.2013/16/391 ◽

2013 ◽

Vol 4;16 (4;7) ◽

pp. 391-397

Author(s):

Dr. Werner Pennekamp

Keyword(s):

Skin Temperature ◽

Temperature Increase ◽

Pain Syndrome ◽

Cutaneous Nerve ◽

Lateral Femoral Cutaneous Nerve ◽

Sympathetically Maintained Pain ◽

Ct Guided ◽

Femoral Cutaneous Nerve ◽

Low Volume ◽

The Right

Lumbar sympathetic blocks and chemical sympathectomies are used for the pain treatment of peripheral arterial occlusive disease or sympathetically maintained pain syndrome after nerve injury or complex regional pain syndrome (CRPS). A 30-year-old patient was referred to the pain department with all the clinical signs and symptoms of a CRPS of the right foot one and a half years after being surgically treated for rupture of the achilles tendon. An inpatient admission was necessary due to insufficient pain reduction upon the current treatment, strong allodynia in the medial distal right lower leg and decreased load-bearing capacity of the right foot. A computed tomography (CT)-guided lumbar sympathetic block at the right L3 (Bupivacaine 0.5%, 4 mL) led to a skin temperature increase from 21°C before block to > 34°C for about 5 hours after the intervention. The patient experienced significant pain relief, indicating sympathetically maintained pain. Thus, we performed a CT-guided lumbar sympathetic neurolysis at the same level (ethanol 96%, 2 mL) 5 days later, achieving again a significant skin temperature increase of the right foot and a slight reduction of his pain intensity from numeric rating scale (NRS) 7 prior to the intervention to NRS 4 after 8 hours (NRS, 0 = no pain, 10 = strongest pain imaginable). Eight months later a repeated inpatient admission was necessary due to considerable pain relapse and decreased loadbearing capacity of his right foot. A CT-guided lumbar sympathetic neurolysis was repeated at the L4 level on the right side and was successful, inducing a significant skin temperature increase. Despite a temporary irritation of the genitofemoral nerve 8 hours after the intervention, a delayed irritation of the lateral femoral cutaneous nerve occurred. This was a long-lasting lesion of the lateral femoral cutaneous nerve following a CT-guided chemical sympathectomy with a low-volume ethanol 96% application - a complication which has not been described in literature until now. This is probably caused by broad dissemination of the neurolytic agent along the psoas muscle despite a correct needle position and spread of contrast agent. The development of this nerve injury even after injection of a small volume of ethanol (2 mL) may be delayed. Key words: Complex regional pain syndrome, CRPS; sympathetically maintained pain syndrome, sympathectomy, neurolysis, lateral femoral cutaneous nerve, ethanol, complication, genitofemoral nerve

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Are the Effects in Temperature and Current Flow Dependent on the Areas of Electrode Application of Capacitive-resistive Electric Transfer on the Shoulder? A Cadaveric Study

10.21203/rs.3.rs-103518/v1 ◽

2020 ◽

Author(s):

Jacobo Rodríguez-Sanz ◽

Carlos López-de-Celis ◽

César Hidalgo-García ◽

Max Canet-Vintró ◽

Pablo Fanlo-Mazas ◽

...

Keyword(s):

High Power ◽

Temperature Increase ◽

Current Flow ◽

In Vitro Study ◽

Supraspinatus Tendon ◽

Lateral Position ◽

Cross Sectional ◽

Significant Difference ◽

Glenohumeral Capsule

Abstract Background Impingement syndrome is currently estimated to represent 60% of all shoulder pain disorders. Capacitive-Resistive electric transfer therapy is aimed to provoke temperature and current flow changes in superficial and deep tissues. This in vitro study has evaluated the variation of temperature and current flow in the shoulder tissues during two different areas of application of the movable capacitive-resistive electric transfer electrode. Methods A cross-sectional study designed, five fresh cryopreserved cadavers (10 shoulders) were included in this study. Four interventions (capacitive and resistive modes; low- and high-power) were performed for 5 minutes each by a diathermy “T-Plus” device in two shoulder regions: postero-superior and antero-lateral. Supraspinatus tendon, glenohumeral capsule and superficial temperatures were recorded at 1-min intervals and 5 min after treatment. Results A statistically significant difference was found only for the superficial area and time interaction, with high power-resistive application at the postero-superior shoulder area (P < 0.035). All the applications showed a final temperature increase compared with the basal data, in all the application points. Superficial temperature in the high power-resistive application showed the greatest percent increase (42.93% ± 22.58), followed by the temperature in the tendon area with the same high power-resistive application (22.97% ± 14.70). The high power-resistive application showed the greatest percent of temperature increase in the applications, reaching 65.9% ± 22.96 at 5-min at the superficial level, and 32% ± 24.25 at 4-min at the level of the supraspinatus tendon. At the capsule level, high power-resistive was also the application that showed the greatest percent of increase, with 21.52% ± 16.16. The application with the lowest percent of temperature increase was the low power-capacitive, with a mean value of 4.86% at supraspinatus tendon level and 7.47% at capsular level. Conclusion The shoulder postero-superior or antero-lateral areas of application of capacitive-resistive electric transfer did not cause statistically significant differences in the temperature changes in either supraspinatus tendon or glenohumeral capsule tissues in cadaveric samples. The high power-resistive application in the postero-superior area significantly increased superficial temperature compared with the same application in the antero-lateral position area.

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Skin temperature increase mediated by wearable, long duration, low-intensity therapeutic ultrasound

10.1063/1.4977642 ◽

2017 ◽

Cited By ~ 1

Author(s):

Matthew D. Langer ◽

Wenyi Huang ◽

Angi Ghanem ◽

Yuan Guo ◽

George K. Lewis

Keyword(s):

Skin Temperature ◽

Temperature Increase ◽

Therapeutic Ultrasound ◽

Low Intensity ◽

Long Duration

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