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Biomedical Engineering and Bioengineering Commons™
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Articles 1 - 5 of 5
Full-Text Articles in Biomedical Engineering and Bioengineering
Design And Evaluation Of Closed-Loop Feedback Control Of Minimum Temperatures In Human Intracranial Tumors Treated With Interstitial Hyperthermia, J A. Deford, Charles F. Babbs, U H. Patel, N E. Fearnot, J A. Marchosky, C J. Moran
Design And Evaluation Of Closed-Loop Feedback Control Of Minimum Temperatures In Human Intracranial Tumors Treated With Interstitial Hyperthermia, J A. Deford, Charles F. Babbs, U H. Patel, N E. Fearnot, J A. Marchosky, C J. Moran
Weldon School of Biomedical Engineering Faculty Publications
The dynamic nature of blood flow during hyperthermia therapy has made the control of minimum tumor temperature a difficult task. This paper presents initial studies of a novel approach to closed-loop control of local minimum tissue temperatures utilizing a newly developed estimation algorithm for use with conductive interstitial heating systems. The local minimum tumor temperature is explicitly estimated from the power required to maintain each member of an array of electrically heated catheters at a known temperature, in conjunction with a new bioheat equation-based algorithm to predict the ‘droop’ or fractional decline in tissue temperature between heated catheters. A closed …
A Predictive-Adaptive, Multipoint Feedback Controller For Local Heat Therapy Of Solid Tumors, Charles F. Babbs, V A. Vanguine, J T. Jones
A Predictive-Adaptive, Multipoint Feedback Controller For Local Heat Therapy Of Solid Tumors, Charles F. Babbs, V A. Vanguine, J T. Jones
Weldon School of Biomedical Engineering Faculty Publications
Uniform heating of tumor tissue to therapeutic temperatures without damaging surrounding normal tissue is required for optimal local heat therapy of cancer. This paper describes an algorithm for online computer control that will allow the therapist to minimize the standard deviation of measured intratumoral temperatures. The method is applicable to systems incorporating multiple surface and/or interstitial applicators delivering microwave, radiofrequency, or ultrasonic power and operating under the control of a small computer. The essential element is a novel predictive-adaptive control algorithm that infers relevant thermal parameters from the responses of multiple temperature sensors, as each of the power applicators is …
Use Of Combined Systemic Hypothermia And Local Heat Treatment To Enhance Temperature Differences Between Tumor And Normal Tissues, Charles F. Babbs, William D. Voorhees Iii, Robert R. Clark, David P. Dewitt
Use Of Combined Systemic Hypothermia And Local Heat Treatment To Enhance Temperature Differences Between Tumor And Normal Tissues, Charles F. Babbs, William D. Voorhees Iii, Robert R. Clark, David P. Dewitt
Weldon School of Biomedical Engineering Faculty Publications
The feasibility of combining local heat treatment with wholebody hypothermia in an effort to improve therapeutic gain was assessed. Superficial, non perfused phantom tumors were fashioned in eight anesthetized mongrel dogs by transplantation of the spleen from the abdomen to a subcutaneous site on the hind limb. After pretreatment of the animal with the vasodilator hydralazine (0.5 mg/kg, IV) to enhance normal tissue perfusion, the spleen implant was heated with a 2450-MHz microwave diathermy apparatus, first with the animal's core body temperature in the normal range (39°C) and then after the animal had been packed in ice to reduce core …
Hydralazine-Enhanced Selective Heating Of Transmissible Venereal Tumor Implants In Dogs, William D. Voorhees Iii, Charles F. Babbs
Hydralazine-Enhanced Selective Heating Of Transmissible Venereal Tumor Implants In Dogs, William D. Voorhees Iii, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
This study was designed to test the hypothesis that vasodilator drugs can enhance selective heating of solid tumors by producing a favorable redistribution of blood flow between tumor and normal tissues. Subcutaneous transmissible venereal tumor implants were heated by inductive diathermy using Helmholtz coils in 8 dogs. The temperature rise in tumor and adjacent muscle was measured before and after giving hydralazine (0.5 mg/kg i.v.). Blood flow to the tumors and underlying muscle was measured with radioactive tracer microspheres. Before hydralazine treatment mean muscle blood flow was about one-third tumor blood flow (0.11 0.02 vs. 0.28 0.09 ml/min/g), …
Theoretical Feasibility Of Vasodilator-Enhanced Local Tumor Heating, Charles F. Babbs, David P. Dewitt, William D. Voorhees, Janet S. Mccaw, Rosanna C. Chan
Theoretical Feasibility Of Vasodilator-Enhanced Local Tumor Heating, Charles F. Babbs, David P. Dewitt, William D. Voorhees, Janet S. Mccaw, Rosanna C. Chan
Weldon School of Biomedical Engineering Faculty Publications
Normal arterioles, in contrast to the abnormal microvasculature of many solid tumors, provide a target for selective drug action that can enhance local heat treatment of the tumors. Measurements of tissue blood flow with radioactive microspheres and estimates of changes in blood flow with thermal clearance methods revealed that vasodilator drugs either decreased or did not alter blood flow in hamster melanoma, rat hepatoma, and canine transmissible venereal tumor, while increasing perfusion in adjacent normal tissues 2 to 4-fold. Solutions of the bio-heat transfer equation, which take into account such selective effects of vasodilators on blood flow in normal tissues, …