{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/10403"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/10403","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"Engineering Considerations for Treatment of Prosthetic Joint Infections Using Alternating Magnetic Fields (AMF)","abstract":"Treatment of infected orthopedic implants presents a major medical challenge, involving prolonged antibiotic therapy and revision surgery. This contributes to >1 billion USD in annual healthcare costs in the US alone. Exposure of metallic implants to alternating magnetic fields (AMF) generates heat that can provide a non-invasive means to target biofilm adhered to the surface. In this thesis, first an AMF system with a solenoid coil was constructed for targeting a metal plate surgically implanted in a sheep model. The system produced magnetic field strengths up to 12 mT and achieved plate temperatures of 65-80°C within 10-14 seconds. A tissue-mimicking phantom of the sheep leg was developed to evaluate heating with the system and to compare these results with numerical simulations. Single and intermittent AMF exposures of a tissue-mimicking phantom agreed with numerical simulations within ± 5%. Similar agreement between experimental measurements and simulations was also observed in the live sheep metal implant model. The simulations also predicted 2-3 mm of tissue damage using a CEM43 thermal dose model for 1-h AMF exposures targeting 65°C for pulse delays of 2.5 and 5 mins. This study confirmed that AMF technology can be scaled up to treat implants in a large animal model with the same rates of heating and peak temperature as observed in prior in vitro studies. After this, the thesis focused on designing a working prototype to target a clinical knee implant with AMF. For initial optimizations numerical simulations approximate interaction between AMF and metal implants were used to design AMF coils windings for heating clinical knee implant on horseshoe surface. These winding patters were engineered into a prototype, capable of running a total current upwards of 400 A, producing a magnetic field of 4 - 5 mT at 2000 W of input power. This coil was further characterized and calibrated to optimal AMF parameters. The AMF system was able cycle through this power for 60 s at each instance, producing uniform surface temperature on complex geometry of knee implant. This heating rate was equivalent of producing 70 - 80 °C on implant surface inside a simulated homogeneous tissue model. Equivalent simple Helmholtz coil was also designed to show its inability of producing a narrow temperature distribution on complex knee implant surface. This work will be further enhanced for the final design for clinical trials based on the findings presented in this thesis.","abstract_html":"Treatment of infected orthopedic implants presents a major medical challenge, involving prolonged antibiotic therapy and revision surgery. This contributes to >1 billion USD in annual healthcare costs in the US alone. Exposure of metallic implants to alternating magnetic fields (AMF) generates heat that can provide a non-invasive means to target biofilm adhered to the surface. In this thesis, first an AMF system with a solenoid coil was constructed for targeting a metal plate surgically implanted in a sheep model. The system produced magnetic field strengths up to 12 mT and achieved plate temperatures of 65-80°C within 10-14 seconds. A tissue-mimicking phantom of the sheep leg was developed to evaluate heating with the system and to compare these results with numerical simulations. Single and intermittent AMF exposures of a tissue-mimicking phantom agreed with numerical simulations within ± 5%. Similar agreement between experimental measurements and simulations was also observed in the live sheep metal implant model. The simulations also predicted 2-3 mm of tissue damage using a CEM43 thermal dose model for 1-h AMF exposures targeting 65°C for pulse delays of 2.5 and 5 mins. This study confirmed that AMF technology can be scaled up to treat implants in a large animal model with the same rates of heating and peak temperature as observed in prior in vitro studies. After this, the thesis focused on designing a working prototype to target a clinical knee implant with AMF. For initial optimizations numerical simulations approximate interaction between AMF and metal implants were used to design AMF coils windings for heating clinical knee implant on horseshoe surface. These winding patters were engineered into a prototype, capable of running a total current upwards of 400 A, producing a magnetic field of 4 - 5 mT at 2000 W of input power. This coil was further characterized and calibrated to optimal AMF parameters. The AMF system was able cycle through this power for 60 s at each instance, producing uniform surface temperature on complex geometry of knee implant. This heating rate was equivalent of producing 70 - 80 °C on implant surface inside a simulated homogeneous tissue model. Equivalent simple Helmholtz coil was also designed to show its inability of producing a narrow temperature distribution on complex knee implant surface. This work will be further enhanced for the final design for clinical trials based on the findings presented in this thesis.","abstract_has_math":false,"creators":["Sadaphal, Varun"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Madhuranthakam, Ananth","Chopra, Rajiv","Greenberg, David","Welch, Tre","Copley, Lawson A. B."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024-09-20T22:10:28Z","date_published":"2024-09-20T22:10:28Z","updated_at":"2026-07-24T05:52:15Z","subjects":["Biofilms","Heating","Magnetic Fields","Prostheses and Implants"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["1456721245"],"render_values":[{"text":"1456721245","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/10403","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Madhuranthakam, Ananth","Chopra, Rajiv","Greenberg, David","Welch, Tre","Copley, Lawson A. 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This contributes to >1 billion USD in annual healthcare costs in the US alone. Exposure of metallic implants to alternating magnetic fields (AMF) generates heat that can provide a non-invasive means to target biofilm adhered to the surface. In this thesis, first an AMF system with a solenoid coil was constructed for targeting a metal plate surgically implanted in a sheep model. The system produced magnetic field strengths up to 12 mT and achieved plate temperatures of 65-80°C within 10-14 seconds. A tissue-mimicking phantom of the sheep leg was developed to evaluate heating with the system and to compare these results with numerical simulations. Single and intermittent AMF exposures of a tissue-mimicking phantom agreed with numerical simulations within ± 5%. Similar agreement between experimental measurements and simulations was also observed in the live sheep metal implant model. The simulations also predicted 2-3 mm of tissue damage using a CEM43 thermal dose model for 1-h AMF exposures targeting 65°C for pulse delays of 2.5 and 5 mins. This study confirmed that AMF technology can be scaled up to treat implants in a large animal model with the same rates of heating and peak temperature as observed in prior in vitro studies. After this, the thesis focused on designing a working prototype to target a clinical knee implant with AMF. For initial optimizations numerical simulations approximate interaction between AMF and metal implants were used to design AMF coils windings for heating clinical knee implant on horseshoe surface. These winding patters were engineered into a prototype, capable of running a total current upwards of 400 A, producing a magnetic field of 4 - 5 mT at 2000 W of input power. This coil was further characterized and calibrated to optimal AMF parameters. The AMF system was able cycle through this power for 60 s at each instance, producing uniform surface temperature on complex geometry of knee implant. This heating rate was equivalent of producing 70 - 80 °C on implant surface inside a simulated homogeneous tissue model. Equivalent simple Helmholtz coil was also designed to show its inability of producing a narrow temperature distribution on complex knee implant surface. This work will be further enhanced for the final design for clinical trials based on the findings presented in this thesis."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Engineering Considerations for Treatment of Prosthetic Joint Infections Using Alternating Magnetic Fields (AMF)"]}]}],"canonical_facts":{"dc:contributor":["Madhuranthakam, Ananth","Chopra, Rajiv","Greenberg, David","Welch, Tre","Copley, Lawson A. B."],"dc:creator":["Sadaphal, Varun"],"dc:date":["2024-09-20T22:10:28Z","2022-08","August 2022"],"dc:description":["Treatment of infected orthopedic implants presents a major medical challenge, involving prolonged antibiotic therapy and revision surgery. This contributes to >1 billion USD in annual healthcare costs in the US alone. Exposure of metallic implants to alternating magnetic fields (AMF) generates heat that can provide a non-invasive means to target biofilm adhered to the surface. In this thesis, first an AMF system with a solenoid coil was constructed for targeting a metal plate surgically implanted in a sheep model. The system produced magnetic field strengths up to 12 mT and achieved plate temperatures of 65-80°C within 10-14 seconds. A tissue-mimicking phantom of the sheep leg was developed to evaluate heating with the system and to compare these results with numerical simulations. Single and intermittent AMF exposures of a tissue-mimicking phantom agreed with numerical simulations within ± 5%. Similar agreement between experimental measurements and simulations was also observed in the live sheep metal implant model. The simulations also predicted 2-3 mm of tissue damage using a CEM43 thermal dose model for 1-h AMF exposures targeting 65°C for pulse delays of 2.5 and 5 mins. This study confirmed that AMF technology can be scaled up to treat implants in a large animal model with the same rates of heating and peak temperature as observed in prior in vitro studies. After this, the thesis focused on designing a working prototype to target a clinical knee implant with AMF. For initial optimizations numerical simulations approximate interaction between AMF and metal implants were used to design AMF coils windings for heating clinical knee implant on horseshoe surface. These winding patters were engineered into a prototype, capable of running a total current upwards of 400 A, producing a magnetic field of 4 - 5 mT at 2000 W of input power. This coil was further characterized and calibrated to optimal AMF parameters. The AMF system was able cycle through this power for 60 s at each instance, producing uniform surface temperature on complex geometry of knee implant. This heating rate was equivalent of producing 70 - 80 °C on implant surface inside a simulated homogeneous tissue model. Equivalent simple Helmholtz coil was also designed to show its inability of producing a narrow temperature distribution on complex knee implant surface. This work will be further enhanced for the final design for clinical trials based on the findings presented in this thesis."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2152.5/10403","1456721245"],"dc:language":["en"],"dc:subject":["Biofilms","Heating","Magnetic Fields","Prostheses and Implants"],"dc:title":["Engineering Considerations for Treatment of Prosthetic Joint Infections Using Alternating Magnetic Fields (AMF)"],"dc:type":["Thesis","text"]},"updated_at":"2026-07-24T05:52:15Z"}