Microwave coagulation therapy (MCT) has been shown to be a reliable method for liver cancer. It can control local liver cancer especially less than 3 cm diameter. But the problems of conventional PMCT electrodes that the diameter of tissue coagulation achievable of with a single electrode insertion is limited, multiple electrode insertions were needed and related complications were occurred dose not resolved. We have recently investigated a newly devised PMCT electrode named PERCUPRO^®. It can elevate the forward power and decrease the reflecting power. It is coated with Teflon and cooled down system.
This article outlines laboratory experience and clinical experience of MCT using PERCUPRO^®. New PMCT electrodes can coagulate lager than previous electrodes in liver. Post-operative complications were not seen in the patients using new type of PMCT electrodes MCT for Liver cancer using PERCUPRO^® electrodes are more effective, useful and safe therapeutic modality for liver cancer compared with conventional PMCT electrodes.

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The possible use of percutaneous low output microwave tissue coagulation therapy (PLMCT) using ultra-sonography under local anesthesia for small solitary liver cancer was studied.
The subjects were 19 patients having primary or metastatic liver cancer with solitary liver tumor less than 4 cm in diameter. Consisting of 5 primary, 7 reccurent hepatocellular carcinoma and 7 metastatic liver cancers. PLMCT was performed continuously 3 times at the output of 30 watts for 30 seconds at a time. Tumors less than 3 cm in diameter were completely coagulated by irradiation from 2 to 6 times judged by enhanced CT.
No tumor recurrence was recognized in the coagulation area. Thus, the results suggest that PLMCT is a useful therapy for small solitary liver cancer especially, recurrence of hepatocellular carcinoma as a minimal invasive surgery.

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In order to increase the range of coagulation, we have developed multi-channel microwave coagulation therapy (MMCT) using numerous teflon-coated electrodes for hepatic cancer. In this study, the liver tissue of the adult mongrel dog was punctured and irradiated by 8 teflon-coated electrodes with microwave energy of 220-230 watts (55-57.5 watts per a electrode) for 10-15 minutes. We obtained the completely coagulated liver tissue and the specimens through sacrifices. The maximum diameters of the coagulated areas were 46 × 37 mm, 63 × 48 mm, 65 × 55 mm, 60 × 45 mm and 60 × 50 mm. HE-staining of cross sections showed necrotic and hemorrhagic changes. Further more, after coagulation, we could pull the teflon-coated electrode out of the liver tissue easily.
These results suggests that a hepatic cancer > 3 cm can be controlled by MMCT.

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Recently, microwave coagulation therapy (MCT) for liver tumor is expected as minimally invasive therapy. On the other hand, developing of open MR scanner, MR fluoroscopy technique and MR compatible instruments allows performing interventional MRI. The thermal imaging potential of MR was considered with regard to its temperature sensitivity. We tried MR guided and monitoring PMCT ex vivo using these techniques to safely and accurately perform this PMCT before clinical application. We evaluated artifact of microwave instruments and feasibility of MR temperature monitoring during PMCT. Causes of image artifact were known. MR temperature images correspond with temperature change. In future, MR guidance and temperature monitoring of PMCT appears feasible, clinically.

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We underwent percutaneous microwave coagulation therapy (PMCT) for 75 patients with 82 hepatocellular carcinoma (HCC) lesions (43 males/ 32 females ; average age 67.1 years ; number of nodules ≤ 3 ; 1.2 cm ≤ tumor size ≤ 5.3 cm in diameter).
Safety margin ≥ 4 mm and safety margin ≤ 3 mm in median disese free time (MDFT) were 12 months and 8 months respectively (p < 0.001). Tumor size < 2 cm in diameter and tumor size > 2 cm in diameter in MDFT were 12 months and 7 months respectively. Well and moderate differentiated HCC in MDFT were 8 months and 4 months respectively.
PMCT for HCC was effective treatment, but the recurrence rate was high. Therapeutic effects were correlated with safety margin, tumor size and tumor differentiation.

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MCT was employed for 11 nodules in 10 patients with HCC.
All of the patients have liver cirrhosis. Nodule size was ranging from 9 to 32 mm in diameter, and average size was 16.8 mm.
Average course of MCT was 2.6 times for the nodules less than 20 mm in diameter.
On subsequent CT to MCT, average safety margin of necrotic area in maximum diameter by MCT was 3.59 mm in length.
MCT alone was effective for the HCC nodules less than 20 mm in diameter, especially for the nodules with hypovascular nature. However, combined therapy such as Percutaneous Ethanol Injection Therapy (PEIT), Trans catheter Arterial Embolization (TAE), or Radio Frequency Ablation (RFA) was required in HCC nodules over 20 mm in diameter.

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We have performed percutaneous microwave coagulation therapy (PMCT) for hepatocellular carcinoma (HCC) of the size below 3 cm since 1994. In the present study, we examined the complication of 117 patients with HCC (including recurrent cases) having undergone PMCT. There was no severe complication with PMCT requiring a treatment except one patient with hemothorax (0.9%). Clinical results of the patients with single occurrence of HCC below 3 cm in size were examined by comparing the cumulative survival rate and cumulative nonrecurrent survival rate among the group of 16 patients having undergone PMCT as initial treatment, that of 38 patients given hepatectomy and that of 34 patients treated percutaneous ethanol injection therapy (PEIT) in the same period using Kaplan-Meier method. The 5-year cumulative survival rate was 93% in the group given PMCT, 72% in that given hepatectomy and 68% in that given PEIT, respectively. Similarly, the 4-year cumulative nonrecurrent survival rate was 29% in the group given PMCT, 38% in that given hepatectomy and 15% in that given PEIT, respectively. In conclusion, PMCT was a safe and less-invasive therapy similarly to PEIT. A therapeutic effect comparable to hepatectomy could be expected for PMCT in the patients with HCC below 3 cm in size.

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We treated 47 hepatocellular carcinomas (HCCs) of 42 patients by laparoscopic microwave coagulation (LMC) and treated 27 HCCs of 25 patients by percutaneous microwave coagulation (PMC). And we compared the efficacy of therapy between LMC and PMC. The mean diameter of HCCs was 18.3 mm in group of LMC and 17.0 mm in group of PMC. In follow-up observation, local recurrences were detected in 4 cases of LMC and in 2 cases of PMC. We think that HCC can be coagulated more exactly by LMC than by PMC, because we can coagulate the HCC under direct vision and puncture the needle into HCC several times with equal intervals by LMC. But no differences were observed in efficacy of therapy between LMC and PMC until now.

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In our department, laparoscopic microwave coagulation (LMC) had been performed under local anesthesia with venous anesthesia in the past. Then, because of abdominal adhesion, respiratory inhibition, and so forth, some patients could not undergone LMC under local anesthesia. It was investigated that whether LMC had been perfomed or not in 20 patients with hepatocellular carcinoma (27 nodules) undergoing laparoscopic therapy under general anesthesia. Six patients had undergone LMC after laparoscopic adhesiolysis and five patients had undergone LMC after insertion of other trocar at the appropriate position for laparosopic ultrasonography. All 20 patients had undergone LMC without complications. Under general anesthesia LMC was completely and safely performed compared with under local anesthesia. There is a tendency for local recurrence rate of HCC after LMC under general anesthesia to be smaller than that of LMC under local anesthesia.

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Surgical resection is the optimal treatment for hepatocellular carcinoma (HCC), however, in patients with liver cirrhosis, major hepatectomy is dangerous because of impaired liver function. We performed partial resection of the liver using microwave tissue coagulator (minimal invasive hepatectomy : MIH) in 14 cirrhotic patients with HCC smaller than 3 cm in diameter. Among 14 patients, 10 patients had hepatectomy with thoraco-abdominal approach. The blood loss during operation was 247 ± 95 ml, and only one patient had allogenic blood transfusion. We had not experienced postoperative major complications, and mean postoperative hospital stay was 18.5 ± 7.4 days. The serum interleukin-6 level at 1st postoperative day was 176 ± 48 pg/ml, which was significantly (p<0.05) lower than that in patients with major hepatectomy for HCC. Thus the partial resection of the liver using a microwave coagulator is considered to be less invasive, safe and useful method for cirrhotic patient with small HCC.

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In 39 patients with hepatocellural carcinoma (52 nodules) treated by percutaneous microwave coagulation therapy (PMCT), modality of recurrence was compared with regard to tumor size and treatments, to find the improvement of PMCT electrodes. Local recurrence occured in 4 (12%) of 35 patients with less than 30mm in diameter and less than 3 nodules, and in 2 (50%) of 4 patients with more than 31 mm in diameter.
In patients with less than 30 mm in diameter and less than 3 nodules, except for these 4 patients with recurrence, there is no difference at tha ratio of recurrence between patients treated by PMCT and hepatectomy.
To solve the recurrence at surgical margin is necessary for the enough diameter of tissue coagulation with a single insertion to be grown larger, and to be stronger and longer electrode.
If these problems are conquested, the indications for PMCT will be developed for the tumors with more than 31 mm in diameter.

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Microwave coagulo-necrotic therapy (MCT) have been realised ablation of hepatic tumor ensuring the tumor free margin without taking too many risks. It is the feature of MCT distinguished from any other minimal invasive therapy, including percutaneous ethanol injection therapy (PEIT) and transarterial chemoembolization (TACE) for hepatocellular carcinoma. But the lesions adjacent to the inferior vena cava (IVC) or the hepatic hilar portion are thought to be not good candidates for MCT on account of injuring these structures in ease.
We report a treated case of HCC adjacent to the IVC. Initially, TACE applied because of poor hepatic functional reserve, but TACE showed an insufficient effect, and MCT underwent secondary. After laparotomy, we performed 63 times punctures of the needle and coagulation to the tumor, and accomplished complete ablation to the tumor just front of the IVC. After 2 months from the open MCT, the lesions were enclosed within the coagulating area and no carcinoma recurence has been found for 2 years after these procedures.
This result from the case demonstrates that the MCT for the lesions neighboring the paracaval portion of the liver is one of useful procedures within the multidiscipliary approach to the hepatocellular caricinoma.

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Recently, laparoscopic procedures for liver resection have been established. Control of bleeding during resection of liver parenchyma is important in successful laparoscopic hepatectomy. The microwave tissue coagulator is useful for liver resection because of the strong hemostasis it yields. However, when handle space is limited, in certain regions coagulation is difficult to perform using the usual straight electrode pole. Using a flexible-neck microwave electrode pole (ENDO ANGLE PROBE), the authors performed laparoscopic partial liver resection for a large hemangioma in the lateral segment and report the usefulness of this instrument for laparoscopic hepatectomy.

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We performed transbronchoscopic microwave electrodes for two cases of respiratory tract tumors. One case had had a left complete atelectasis for bronchial tumor, after microwave electrodes had been carried out surgery. The otherhad had a right complete atelectasis for epidermoid carcinoma ; we performed transbronchial biopsy for diagnosis with using microwave electrodes for occasional bronchial bleeding.
We experienced less bleeding and smoke, a larger area could be coagulated in single procedure than high power laser ablation therapy. This method was effective in treating airway obstruction, especially in patients for administrating oxygen for respiratory failure because of less its ignitable.

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The purpose of this study was to investigate the clinical application of a microwave tissue coagulator at 2.45 GHz with a needle electrode specifically customized for endometrial ablation. Endometrial ablation was performed under intravenous thiopental anesthesia on three women suffering from hypermenorrhea caused by aplastic anemia (two), von Willebrand's disease (one) using a microwave tissue coagulator at 2.45 GHz. All patients were amenorrheic after endometrial ablation. No notable complications were observed during or after endometrial ablation. Endometrial ablation using a microwave tissue coagulator at 2.45 GHz is a simple and efficacious method for the treatment of hypermenorrhea.

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From January 1989 to December 1997, 170 patients underwent distal pancreatectomy with total gastrectomy for gastric cancer. We compared the incidences of postoperative pancreatic fistula in a group with use of a microwave tissue coagulator (132 cases : MW group) and a group without coagulator use it (38 cases : nMW group). Postoperative pancreatic fistula was observed in 15 patients (8.8%). Eleven cases of pancreatic fistula (8.3%) occurred postoperatively in the MW group. In the nMW group, 4 cases (10.5%) of pancreatic fistula occurred. These results suggest that use of a microwave tissue coagulator might be useful in preventing postoperative pacreatic fistula.

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We report two cases of hepatic infraction after percutaneous microwave coagulation therapy (PMCT) for hepatocellular carcinoma.
(Case 1) A 58-year-old man was diagnosed recurrence tumor 2.5 cm in diameter after right lobectomy. TAE was no effectiveness, and we performed PMCT under general anesthesia. After treatment, the patient had a high fever and a high AST/ALT level of 1779/1360 IU/L.
(Case 2) A 69-year-old man was diagnosed multiple recurrence tumor after right lobectomy. We performed TAE and PMCT under general anesthesia for 15 mm (S₄), 12 mm (S₃) and 11 mm (S₃) in diameter. After treatment, the patients had a high fever and a high AST/ALT level of 712/428 IU/L. In patients, CT scan revealed hepatic infraction in the proximal liver area.
The patients had a high fever and a high AST/ALT level, but discharged into the 10 days after PMCT.

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We experienced a rare case of hepatic artery aneurysm as a complication of microwave coagulation therapy. The patient was 79 years old man with gastric carcinoma and hepatocellular carcinoma. Hepatic tumors were located in S₅ and S₈. Totalgastrectomy and Microwave coagulation therapy (MCT) for hepatic tumor were performed simultaneously. On the 9th P, O, D and 19th P, O, D massive bleeding occurred with attendant hypovolemic shock. On the first episode, patient recovered by conservative therapy with blood transfusion. However, the emergency angiography carried out and revealed hepatic artery aneurysm, which ruptured into the abdominal cavity on the 19th P, O, D. Hemostasis was accomplished by transcatheter arterial embolization (TAE). Although, MCT is a effective treatment for hepatic tumor, the hepatic aneurysm is to be one of fatal complication.

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An experiment was conducted to investigate the changes in the thermocoagulation area induced by radiofrequency ablation (RFA) during interruption of the hepatic blood flow using the liver of a bovine. In a clinical case, the RFA was delivered percutaneously to hepatocellular carcinoma with a diameter of 25 mm during interruption of the hepatic blood flow. The RFA equipment used was 460-KHz Leveen needle electrode 26-207 (Boston Scientific, Tokyo, Japan). In the animal experiment, the radiofrequency electrode was introduced to a depth of 2 cm under the surface of the liver, and then eight umbrella-type needles were unfolded. Subsequently, RFA were of 40 W was delivered for 150 sec. The RFA delivery was carried out by the same procedure under the condition of hepatic blood flow interruption with a hemostatic tape. In the clinical application, a 6 F balloon catheter was inserted into the right hepatic vein, which was the dranage vein of the cancer-bearing area, and the artery was embolized with gel form the hepatic artery. Interruption of the portal blood flow in the cancer-bearing area was confirmed by CT scanning with portal venography. The animal experiment results showed that interruption of the hepatic arterial and portal blood flow provided more than twice the diameter of thermocoagulation by the non-interruption of the blood flow, and that the shape of the coagulation area was almost spherical. In conclusion, complete and spherical thermocoagulation was achieved by delivery of the RFA of 40 W, to hepatocellular carcinoma of 25 mm in diameter, for 4 minutes during interruption the hepatic blood flow.

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Upon the development of a customized magnetic resonance imaging (MRI)-compatible probe for the interstitial deposition of radiofrequency (RF) energy, we monitored ex vivo RF ablation (RFA) with MRI a 1.5T. We proposed to visualize the dynamics of the RFA with temperature mapping based on the temperature dependence of the water proton resonance frequency shift. The MR-compatible probe produced minimal artifact and allowed visualization and mapping of the tissue adjacent to the probe. Phase mapping obtained by calculation of phase differences provided clear visualization of the generated temperature gradients. Multi-slice images provided a 3-D appreciation of the heated volume. Dynamic quantitative thermal mapping derived from MRI obtained during RFA will be essential for the optimization of RFA in clinical applications.

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Forty three poor risk patients with liver malignant tumor ; 32 primary and 11 metastatic, were treated by ablation therapy. Twenty eight patients underwent microwave coagulation therapy (MCT); 15 patients experienced rediofrequency ablation therapy (RFA) according to tumor diameter, number and localization. One year survival rate of hepatocellular carcinoma (HCC) patients treated by RFA (90.9%, n = 13) was similar to that treated by MCT (91.7%, n = 19). Post opereative hospital days in RFA group was significantly shorter than that in MCT group because the later contained 2 cases of liver abcsses and 4 percutaneous cases of needle tract burn. Although RFA was acceptable as a mild and effective procedure, incomplete RFA followed by other treatments for early local recurrence was experimentted.
Attension should be taken to use the two ablation procedures properly with comprehesion of their features.

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Fifty-one year old man was treated with RITA (50 W, 100°C, 10 min) for his histologically proven HCC (25 × 17 mm). In series, ultrasound and histological study were performed before, 1 week after, and 5 months after the treatment. A fishing look like high-echoic lines, corresponding with the shape of the electrodes of the RITA needle, were observed in the center of the tumor by ultrasound immediately after the treatment, and was continued for 5 months. Histology showed this high-echoic line was coagulation necrosis around RITA needle. Though, basic finding of the HCC (low-echoic) had not been changed before and after the treatment, biopsy specimen revealed the tumor had after the treatment, biopsy specimen revealed the tumor had already been degenerated 1 week after, and had been entirely substituted with coagulation necrosis 5 months after the treatment.

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