Tissue temperatures were measured by a thermistor-thermometer, at suprachoroid, inner retinal surface and intravitreous portion (1mm deep), during diathermy applications on the scleral surfaces of rabbit eyes. Castroviejo's Electro-surgical Ophthalmic unit Model S-5 was used and power intensity(current) was fixed to 2, and diathermy was applied on the sclera 3mm, 2mm, and 1mm from and above the measuring points. Measurements were performed in the following groups: Group 1: Spark gap power 2. duration of application 2 sec. Group 2: Spark gap power 2. duration of application 3 sec. Group 3: Spark gap power 3. duration of application 2 sec. Group 4: Spark gap power 3. duration of application 3 sec. Maximum rise of temperature was 20.0 degrees C at suprachoroid, 16.8 degrees C at inner retinal surface and 6.6 degrees C at vitreous in Group 4. Temperature rise in vitreous was much lower than that in suprachoroid and inner retinal surface (table II, which revealed percentage of average rise per tissue temperature before diathermy). Highest measuring temperature at inner retinal surface in this experiment was under 60 degrees C, at which vitreous collagen fibrils may coagulate.
Collagen ; Diathermy* ; Retinaldehyde ; Sclera

This study was performed to evaluate histopathologic and physical characteristics of anterior capsule during capsulorhexis with a new high-frequency diathermy.The authors investigated the histopathologic characteristics of anterior capsule according to coagulation time and anterior capsular diameter in diathermy capsulorhesxis(DC),comparing with those in continuous curvilinear capsulorhexis(CCC). Thermally induced histopathologic alter-ation was localized at anterior capsule with coagulation for 0.5 second, while it was extended into cortex with coagulation for 2 seconds.When capsulorhexis was performed with diameter of 6 mmand the margin was pulled with iris retractor,anterior capsular edge was fully extended both in CCC and DC.But with diameter of 3.5 mm,DC mostly led to tear of capsular edge on its extension,while CCC permitted full extension of anterior capsular edge.These results suggest that strength of anterior capsular edge in DC is inferior to that in CCC.However diathermy capsulorhexis is a useful alternative technique in cases,which CCC is difficult to perform,such ashypermature or congenital cataracts.
Capsulorhexis* ; Cataract ; Diathermy* ; Iris

The extensibility of the albino rabbit sclera was measured after cryoapplication and diathermy on the equator of sclera and these extensibilities were compared with normal control. For cryoapplication, 95% alcohol and solid carbon dioxide mixture was used and this cryoprobe was applied on the equator of rabbit sclera of right eye for 3 seconds. Castroviejo apparatus was used for diathermy and nonperforating surface diathermy was performed on the equator of rabbit sclera of left eye for one second with current of 30mA. Immediately after cryoapplication and diathermy, the extension rates of sclera were 2.556% and 6.039%, respectively. The extension rates of one week after cryoapplication and diathermy were 3.234 % and 4.127%, respectively. The extension rate of two weeks after diathermy was 3.489%. Normal control was 3.055%.
Carbon Dioxide ; Diathermy* ; Sclera*

As a tumor thermal ablation technology in cancer therapy, HIFU (High Intensity Focused Ultrasound) has been developed rapidly in recent years. With the technology becoming more and more mature, it's clinical application is becoming more and more widely. In HIFU therapy, the high-intensity ultrasound energy is focused in the target tumor tissue, generating heat within very short time, causing coagulation necrosis, so that the effect of the treatment is achieved. To ensure safe and therapeutic efficacy, HIFU therapy needs to be properly monitored by medical imaging, and temperature in the target has to be precisely measured, this article is based on the current domestic and foreign detection methods of the focal region temperature.
Diagnostic Imaging ; High-Intensity Focused Ultrasound Ablation ; Humans ; Neoplasms ; therapy ; Temperature ; Ultrasonic Therapy

BACKGROUNDIntravascular microbubble-enhanced acoustic cavitation is capable of disrupting the vascular walls of capillaries and small vessels. This study was designed to investigate the impact of microbubble-enhanced, pulsed and focused ultrasound (MEUS) on the blood perfusion of subcutaneous VX2 tumors in rabbits.

METHODSSubcutaneous VX2 cancers in twenty New Zealand rabbits were treated by combining high-pressure amplitude, pulsed and focused therapeutic ultrasound (TUS) and intravenous microbubble injections. The TUS transducer was operated with a peak negative pressure of 4.6 MPa and a duty cycle of 0.41%. Controls were subcutaneous VX2 cancers treated with TUS or microbubbles only. Contrast-enhanced ultrasound (CEUS) and intravenous Evans Blue (EB) perfusion were performed to assess the tumor circulation. The tumor microvascular disruption was assessed by histological examination.

RESULTSCEUS showed that the tumor circulation almost vanished after MEUS treatment. The average peak grayscale value (GSV) of tumor CEUS dropped significantly from 84.1±22.4 to 15.8±10.8 in the MEUS-treated tumors but no significant GSV changes were found in tumors in the two control groups. The mean tumor EB content of the MEUS-treated tumors was significantly lower than that of the controls. Histological examination found scattered tumor microvascular disruption with intercellular edema after MEUS treatment.

CONCLUSIONThe tumor circulation of VX2 cancers can be arrested or significantly reduced by MEUS due to microvascular disruption.

OBJECTIVETo study the efficacy of B1 field shimming technique and evaluate the specific absorption rate (SAR) in ultra-high field magnetic resonance imaging (MRI) for MRI-guided high-intensity focused ultrasound (HIFU).

METHODSAn electromagnetic model of the female pelvis with a temperature gradient was established. B1 field homogeneity and local SAR were simulated and calculated using regular and optimized B1 shimming coefficients.

RESULTSThe maximum local SAR reached 10.24 W/kg, which exceeded the safe threshold of 10 W/kg, as calculated using regular B1 shimming coefficients in the normal model. Using the optimized B1 shimming coefficients, the maximum local SAR of the tissue was 9.65 W/kg, which was below the safe threshold.

CONCLUSIONThe temperature distributions in the body generated by ultrasound energy need to be considered in ultra-high field MRI-guided HIFU surgery. The proposed optimized B1 shimming strategy based on the temperature gradient can be used to control the local SAR levels.

Artificial chorioretinal inflammation was produced by the application of the cryothermy, diathermy, or photocoagulation in man. The inflammatory reactions were followed-up by fluorescein angiography. Inflammatory lesion showed fluorescein leakage and pooling at the first postoperative day Cessation of leakage was seen niter the 10th postoperative dey regardless of method of inflammation production. Pigment stippling was seen at about 4-5 days after moderate to heavy cryo-application, but about 11-12 days after moderate intensity of photocoagulation and diathermy.
Diathermy ; Fluorescein Angiography ; Fluorescein* ; Inflammation* ; Light Coagulation

Endoscopic incision therapy was applied to two patients with postoperative anast-omotic stenosis. Radial diathermy incision was performed by needle knife papillot-ome using cutting current. Tne anastomotic stenosis was characteristic of short fibrotic segment and frequent restenosis after dilatation. An sufficient caliber and smooth, supple wall at the site of the stenosis was produced by incisional therapy by needle knife papillotome using cutting current. Clinical symptoms and endoscopic findings were improved after endoscopic incision. It is concluded that endoscopic incisional therapy seems to be safe and effective method for the treatment of anastomotic stenosis after gastrointestinal operation.
Constriction, Pathologic* ; Diathermy ; Dilatation ; Humans ; Needles*

Endoscopic incision therapy was applied to two patients with postoperative anast-omotic stenosis. Radial diathermy incision was performed by needle knife papillot-ome using cutting current. Tne anastomotic stenosis was characteristic of short fibrotic segment and frequent restenosis after dilatation. An sufficient caliber and smooth, supple wall at the site of the stenosis was produced by incisional therapy by needle knife papillotome using cutting current. Clinical symptoms and endoscopic findings were improved after endoscopic incision. It is concluded that endoscopic incisional therapy seems to be safe and effective method for the treatment of anastomotic stenosis after gastrointestinal operation.
Constriction, Pathologic* ; Diathermy ; Dilatation ; Humans ; Needles*

In order to investigate the effects of diathermy and cryosurgery on the scleral shrinkage, nonperforating surface diathermy and cryocautery were applied in rabbits eyes. The premarked scleral segments were measured by corneal microscope with micrometer, and the resultant elevation of the intraocular pressures was pressures was measured by Schiotz tonometer. In the eyes treated by 10 diathermy in 5 X 3mm area, average 20.1% of scleral shrinkage was observed. There was no significant difference between shrinkages in the meridional and latitudinal directions. In the eyes treated by cryopencil no significant changes were found. Diathermy applications in 3 X 10mm area in the sclera induced 36.9% increase in the intraocular pressure which lasted about 9 minutes. On the other hand, cryoapplication did not produce such an elevation in ocular tension.
Cryosurgery ; Diathermy* ; Hand ; Intraocular Pressure ; Rabbits* ; Sclera