Biomaterial Database

Effect of frequency on entrance and propagation pattern of high-frequency (radiofrequency) electrical currents in biologic tissues. 2015

A Taheri, and P Mansoori, and K E Huang, and S R Feldman

Center for Dermatology Research, Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, NC, USA.

BACKGROUND Radiofrequency electrical currents have a tendency to move toward the center of the bulk of biologic tissues. OBJECTIVE To evaluate the effect of the frequency of currents on their entrance and propagation pattern in biologic tissues. METHODS Three electrosurgical generators with 0.4, 1.5, and 3 MHz frequency outputs were studied. Current was applied using a metallic needle introduced into a piece of cow liver, with different amounts of energy delivered at multiple points. Cross-sections of the liver were then studied for tissue effect. The diameters of the coagulated areas at the deepest and most superficial parts were measured. The tendency of the currents for penetration in the deeper layers of tissue rather than in the superficial layers was assessed using the superficial diameter/deep diameter ratio. RESULTS Diameter of coagulated area was larger around deeper parts than around superficial parts of the electrode. No correlation between frequency of current and the superficial/deep diameter ratio of the coagulation zone was found. CONCLUSIONS Radiofrequency currents have a tendency to move toward the center of the tissue. Frequency of current over the range of 0.4-3 MHz did not show any effect on this tendency.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D011846	Radio Waves	Electromagnetic waves with frequencies between about 3 kilohertz (very low frequency - VLF) and 300,000 megahertz (extremely high frequency - EHF). They are used in television and radio broadcasting, land and satellite communications systems, radionavigation, radiolocation, and DIATHERMY. The highest frequency radio waves are MICROWAVES.	Hertzian Waves,High Frequency Waves,Radiowave,Radiowaves,Short Waves,Very High Frequency Waves,Frequency Wave, High,Frequency Waves, High,High Frequency Wave,Radio Wave,Short Wave,Wave, High Frequency,Wave, Radio,Wave, Short,Waves, Hertzian,Waves, High Frequency,Waves, Radio,Waves, Short
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D006498	Hepatectomy	Excision of all or part of the liver. (Dorland, 28th ed)	Hepatectomies
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D017115	Catheter Ablation	Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.	Ablation, Transvenous Electric,Catheter Ablation, Electric,Catheter Ablation, Percutaneous,Catheter Ablation, Radiofrequency,Catheter Ablation, Transvenous,Ablation, Catheter,Ablation, Transvenous Electrical,Catheter Ablation, Electrical,Electric Catheter Ablation,Electrical Catheter Ablation,Percutaneous Catheter Ablation,Radiofrequency Catheter Ablation,Transvenous Catheter Ablation,Ablation, Electric Catheter,Ablation, Electrical Catheter,Ablation, Percutaneous Catheter,Ablation, Radiofrequency Catheter,Ablation, Transvenous Catheter,Electric Ablation, Transvenous,Electrical Ablation, Transvenous,Transvenous Electric Ablation,Transvenous Electrical Ablation
D065638	Absorption, Radiation	The uptake or transfer of energy from RADIATION.	Radiation Absorption
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In