No abstract available.
Fever* ; Microwaves*

OBJECTIVE: To study some thermal problems in invasive microwave coagulation (IMC) therapy. METHODS: Temperature fields predicts, limitation and remedy methods of the Pennes bioheat transfer equation during the temperature distribution analyses and how to kill a large anomalistic tumor for only once were discussed. RESULTS: The coagulation area between the simulations and actual measured results showed good correspondence. Blood flow influenced the rise in temperature significantly. CONCLUSIONS: Thermal distribution with computer simulation in invasive microwave coagulation therapy is an accurate and reliable method.
Computer Simulation ; Microwaves*

No abstract available.
Fever* ; Microwaves* ; Perfusion*

PURPOSE: To determine the effects of power and coagulation time on lesion size of ex-vivo bovine liver using microwaves. MATERIALS AND METHODS: Six bovine livers were divided into two groups(first group: 30W output, secondgroup: 60W output) and microwave coagulation was performed for 30, 60, and 120 sec. thermal injury site was thenobserved by means of sonography, and the maximal transverse diameter of the echo-change portion after microwave coagulation was measured. On the section of specimen, maximal transverse diameters of the thermal injury site weremeasured by gross inspection and compared with the result of sonographic measurement. RESULTS: Maximal transversediameters of hyperechoic lesions of the first group, as seen on sonography were 8.3 mm, 12.2mm, and 15.6mm, andthe maximal transverse diameters of thermal injury sites on gross specimens were 9.1mm, 12.0mm, and 15.1mm,respectively. Maximal transverse diameters of hyperechoic lesions of the second group, as seen on sonography, were12.1 mm, 17.4 mm, and 21.2 mm and maximal transverse diameters of thermal injury sites on gross specimens were13.2 mm, 16.0 mm, and 20.0 mm, respectively. Statistically maximal transverse diameters of hyperechoic lesions, asseen on sonography, correlated closely with the gross findings of maximal transverse diameters of thermal injurysites(p<0.05). CONCLUSION: Maximal transverse diameters of thermal injury sites were significantly increased asthe output of the microwave coagulator and the duration of coagulation time increased(p<0.05).
Animals ; Liver ; Microwaves* ; Ultrasonography

Endoscopic microwave coagulation therapy was applied to two cases of postoperative anastomotic stenosis. Clinical symptoms and endoscopic findings were improved by endoscopic microwave coagulation tberapy in both cases. It is concluded that this method will be a safe and sure method for the treatment of anastomotic stenosis after gastrointestinal operation
Constriction, Pathologic* ; Microwaves*

In this study, we tried to confirm clinically applicable applicability by comparing the difference in 3 point flexural strength and shade of the prosthesis depending on microwave sintering time of dental CAD / CAM zirconia. 3 Point flexural strength specimens (n=30) and shade measurement specimens (n=28) were prepared and sintered at different sintering times. 3 point flexural strength and shade were measured and analyzed by independent t-test (α=0.05). Measurement result of 3 point flexural strength the average of short-term sintering (STS) was 245.47±29.89 MPa, the average of long-term sintering (LTS) was 284.27±31.56 MPa, and there was a statistically significant difference (p < 0.05). The shade measurement result ⊿E*(ab) showed the average STS of 1.51±0.48 and the LTS of 1.52±0.41, but there was no statistically significant difference (p>0.05). The 3 point flexural strength of the zirconia restorations fabricated by short time and long time was high in long time sintering. However, other conditions may be required for clinical applications. Since the shade test did not show any significant color difference according to sintering time, it is considered to be sufficient for clinical application.
Microwaves ; Prostheses and Implants

No abstract available.
Bone Marrow* ; Microwaves* ; Plastics*

No abstract available.
Bone Marrow* ; Iron* ; Microwaves* ; Plastics*

PURPOSE: The purpose of this study was to evaluate the differences in the ablation effects of percutaneous ethanol injection therapy (PEIT), percutaneous microwave coagulation therapy (PMCT), and radiofrequency (RF) ablation therapy in extracted bovid livers, and to assess the appropriate therapeutic method for treating hepatic tumors according to their shape, size and location. MATERIALS AND METHODS: PEIT, PMCT and RF ablation were performed at 1 cm and 5 cm depth in bovid livers. PEIT was performed with 1, 2, 3 and 4 ml of ethanol, PMCT with 60 watt for a 30 th, 60 th and 120 th of a second, and RF ablation for 6, 8, 10, 12 and 14 minutes. Ultrasonography was used for the detection of the tissue necrosis that followed the different therapeutic modalities. RESULTS: For PEIT, the extent of the necrosis was smaller than that of the other modalities. For PMCT, the necrosis was elliptical and longer in length. For RF, the necrosis was oval and larger in size. At 1 cm depth for PMCT and RF ablation, the liver capsule was injured. CONCLUSION:We concluded that these different findings in tissue necrosis would aid in selecting the appropriate therapeutic method for hepatic tumors according to the tumors' shape, size and location.
Ethanol* ; Liver* ; Microwaves* ; Necrosis ; Ultrasonography

PURPOSE: This study was undertaken to determine the effect of the infusion rate on the temperature of the infusate reaching the distal end of an infusion tubing with active fluid warming. METHODS: One-liter bags of normal saline were warmed to 6 0 degrees C using a microwave oven and were then run through standard infusion tubing at rates of 200, 400, 600, 800, and 1,000 mL/hr. The temperatures at the distal end of the infusion tubing were measured every one minute for the first 10 minutes and then every ten minutes for 1 hour. Subsequently, normal saline and packed red blood cells, which were warmed using a fluid warmer, were infused at rates of 200, 400, 600, 800, and 1,000 mL/hr. Temperatures were recorded when the readings had stabilized within a range of +/-0.1 degrees C. RESULTS: Normal saline warmed by a microwave oven could be delivered through standard infusion tubing at a temperature of more than 37 degrees C if the normal saline had been preheated to 60 degrees C and infused through long tubing (210 cm) at rates of 800 and 1,000 mL/hr. Also, normal saline and packed red blood cells, warmed to 41 degrees C with a fluid warmer, could be delivered at a temperature of or near 3 7 degrees C through relatively short tubing (110 cm) at a rate of 1,000 mL/hr. The fluid composition influenced the infusate temperature (p < 0.05). CONCLUSION: When patients with hypothermia or major trauma are treated by infusing warmed normal saline or packed red blood cells, we should consider appropriate flow rates for the fluid so as to maintain a therapeutic delivery temperature when using practical infusion tubing in the ED setting.
Erythrocytes ; Humans ; Hypothermia ; Microwaves ; Reading