• Macromolecular Research
• /
• 제12권1호
• /
• pp.134-140
• /
• 2004

Semi-crystalline poly(ethylene terephthalate) (PET) film surfaces were modified with argon and oxygen plasmas by radio-frequency (RF) glow discharge at 240 mTorr/40 W; the changes in topography and surface structure were investigated by atomic force microscopy (AFM) in conjunction with specular reflectance of infrared microspectroscopy (IMS). Under our operating conditions, analysis of the AFM images revealed that longer plasma treatment results in significant ablation on the film surface with increasing roughness, regardless of the kind of plasma used. The basic topographies, however, were different depending upon the kind of gas used. The specular reflectance analysis showed that the ablative mechanisms of the argon and oxygen plasma treatments are entirely different with one another. For the Ar-plasma-treated PET surface, no observable difference in the chemical structure was observed before and after plasma treatment. On the other hand, the oxygen-plasma-treated PET surface displays a significant decrease in the number of aliphatic C-H groups. We conclude that a constant removal of material from the PET surface occurs when using the Ar-plasma, whereas preferential etching of aliphatic C-H groups, with respect to, e.g. , carbonyl and ether groups, occurs upon oxygen plasma.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권14호
• /
• pp.5799-5804
• /
• 2014

Background: Radiofrequency ablation (RFA) is the most widely used and studied method internationally for the local treatment of liver tumors. However, the extension of coagulation necrosis in one RFA procedure is limited and incomplete coverage of the damaged area can lead to a high local recurrence rate. Objective: In this study, we compared the effects of different solutions in enhancing hepatic radiofrequency by establishing a rabbit VX2 liver cancer model. We also determined the optimal solution to maximise effects on the extent of RFA-induced coagulation necrosis. Methods: Thirty VX2 tumor rabbits were randomly assigned to five groups: group A, RFA alone; group B, RFA with anhydrous ethanol injection; group C, RFA with 5% hypertonic saline injection; group D, RFA with lidocaine injection; and group E, RFA with a mixed solution. Routine ultrasound examinations and contrast-enhanced ultrasound (CEUS) of the ablation areas were performed after RFA. Then, we measured the major axis and transverse diameter and compared the areas of coagulation necrosis induced by RFA. Results: The mean ablation area range increased in groups B, C and especially E, and the scopes were greater compared with group A. Preoperative application of anhydrous ethanol, hypertonic saline, lidocaine and the mixed solution (groups B, C, D and E, respectively) resulted in larger coagulation necrosis areas than in group A (p<0.05). Among the groups, the coagulation necrosis areas in group E was largest, and the difference was statistically significant compared with other groups (p<0.05). Pathological findings were consistent with imaging results. Conclusions: A mixture of dehydrated alcohol, hypertonic saline and lidocaine injected with RFA increases the extent of coagulation necrosis in the liver with a single application, and the mixed solution is more effective than any other injection alone.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권14호
• /
• pp.6159-6162
• /
• 2015

Purpose: To evaluate efficacy of transarterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) in treatment of patients with hepatocellular carcinoma. Materials and Methods: During January 2009 to March 2012, 80 patients with hepatocellular carcinoma underwent TACE, with or without RFA. Alfafetoprotein (AFP) was checked before and after procedure. CT scans were obtained one month after TACE or RFA for all patients to evaluate tumor changes. Complete response+partial response+stable disease (CR+PR+SD)/n were used to assess the disease control rate (DCR). Survival at 3, 6 and 12 months was compared in both groups. Results: AFP levels in TACE + RFA group dropped rapidly, becoming obviously lower than that of the TACE group. In the TACE + RFA group DCR was 93.8%, while only 76.8% in the TACE group. The treatment effect between the two groups was statistically significant (P<0.05) by Ridit analysis. 1 year survival rate in the TACE + RFA group was 92.5%, significantly higher than that of the TACE group at 77.5% (P<0.05). Conclusions: TACE and RFA as combined therapy method for patients with middle and terminal stage HCC gives full play to synergy between the two and improves the therapeutic effect.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권5호
• /
• pp.2539-2543
• /
• 2016

Background: In the Barcelona Clinic Liver Cancer (BCLC) system, only sorafenib is suggested for HCC patients having performance status (PS) 1 or 2 even if they have treatable lesions. In the current study, we aimed to explore the outcome of using aggressive treatment for HCC patients with PS 1 and 2. Materials and Methods: Five hundred and twenty four patients with HCC were enrolled in this study and divided into 2 groups: 404 PS 1 and 120 PS 2. Of the included 524 patients, 136 recceived non-aggressive supportive treatment and sorafenib, while 388 patients were offered aggressive treatment in the form of surgical resection, transplantation, percutaneous ablation, trans-arterial chemoembolization and/or chemoperfusion. All the patients were followed up for a period of 2 years to determine their survival. Results: Most HCC patients were CHILD A and B grades (89.4% versus 85.0%, for PS1 and PS2, respectively). Patients with PS1 were significantly younger. Out of the enrolled 524 patients, 388 were offered aggressive treatment, 253 (65.2%) having their lesions fully ablated, 94 (24.2%) undergoing partial ablation and 41 patients with no ablation (10.6%). The median survival of the patients with PS 1 who were offered aggressive treatment was 20 months versus 9 months only for those who were offered supportive treatment and sorafenib (p<0.001). Regarding HCC patients with PS 2, the median survivals were similarly 19.7 months versus 8.7 months only (p<0.001). Conclusions: Aggressive treatment of HCC patients with PS 1 and 2 significantly improves their survival. Revising the BCLC guidelines regarding such patients is recommended.

• Archives of Plastic Surgery
• /
• 제42권1호
• /
• pp.52-58
• /
• 2015

Background The erbium:yttrium scandium gallium garnet (Er:YSGG) laser differs from other laser techniques by having a faster and higher cure rate. Since the Er:YSGG laser causes an appropriate proportion of ablation and coagulation, it has advantages over the conventional carbon dioxide ($CO_2$) laser and the erbium-doped yttrium aluminum garnet (Er:YAG) laser, including heating tendencies and explosive vaporization. This research was conducted to explore the effects and safety of the Er:YSGG laser. Methods Twenty patients participated in the pilot study of a resurfacing system using a 2,790-nm Er:YSGG laser. All patients received facial treatment by the 2,790-nm Er:YSGG laser system (Cutera) twice with a 4-week interval. Wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture were measured. Results Study subjects included 15 women and five men. Re-epithelization occurred in all subjects 3 to 4 days after treatment, and wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture within 6 months of treatment. Conclusions The 2,790-nm YSGG laser technique had fewer complications and was effective in the improvement of scars, pores, wrinkles, and skin tone and color with one or two treatments. We expect this method to be effective for people with acne scars, pore scars, deep wrinkles, and uneven skin texture and color.

• Journal of Chest Surgery
• /
• 제43권6호
• /
• pp.635-641
• /
• 2010

배경: 대복재 정맥의 역류로 인한 대퇴정맥 접합부 부전에 대한 치료로써 정맥내 시술인 고주파 열폐쇄술은 고전적 복재정맥 스트리핑과 비교해 부작용이 적고 우수한 방법이다. 기존의 대복재정맥에 대한 고주파 열폐쇄술의 단점은 시술 시간이 길다는 점이었으나 이를 보완한 2세대 고주파 열폐쇄술($VNUS^{\circledR}Colosure$ fast)은 분절 소작법을 채택하여 시술시간이 짧아지고 치료 방법 또한 더 간편해졌다. 이에 본 연구는 하지정맥류에 대한 2세대 고주파 열폐쇄술($VNUS^{\circledR}Colosure$ fast)을 이용한 치료 결과 및 합병증을 기존의 고주파 열폐쇄술($VNUS^{\circledR}Colosure$ plus)과 비교하고자 한다. 대상 및 방법: 2006년 6월부터 2009년 8월까지 대퇴 정맥 접합부의 역류가 있는 경우만을 골라 정맥내 고주파 열폐쇄술을 받은 환자를 대상으로 하였다. 기존의 고주파 열폐쇄술($VNUS^{\circledR}Colosure$ plus)를 시행 받은 총 4 명 (59족)의 환자(이후 1세대군)와 2세대 고주파 열폐쇄술($VNUS^{\circledR}Colosure$ fast) 시행 받은 67명 (76족)의 환자(이후 2세대군)를 대상으로 후향적으로 두 집단 사이의 환자의 성비, 평균 시술시간, 치료된 정맥직경, 동반한 치료방법, 시술 후 합병증을 비교하였다. 결과: 모든 환자는 하지정맥류로 인한 증상이 있었고 CEAP class 2 이상으로 초음파상 대퇴정맥접합부의 역류가 있었다. 치료된 대복재 정맥의 평균직경은 1세대군과 2세대군 사이에 양 군간의 통계학적 차이는 없었다($5.59{\pm}0.6mm$ vs.$5.65{\pm}0.6mm$, p=0.68). 평균 치료 시간은 2세대군이 유의하게 낮았다($17.0{\pm}6.5min$ vs. $62.7{\pm}9.8min$, p<0.001). 양 군에서 유의할 만한 합병증은 발생하지 않았다. 결론: 하지정맥류에 대한 치료로서 정맥내 시술인 고주파 열폐쇄술은 안전하며 효과적인 시술이며 2세대 열폐쇄술($VNUS^{\circledR}Colosure$ fast)은 시술시간의 단축과 조작의 용이함으로 의사 및 환자의 만족도가 높은 치료라 할 수 있겠고 향후 더 많은 수의 환자를 대상으로 장기적인 연구가 필요하다고 생각된다.

• 한국항공우주학회지
• /
• 제38권2호
• /
• pp.200-205
• /
• 2010

고온고압, 장시간 연소조건하에서 일정한 추력을 유지하는 로켓 추진기관 개발을 위해 W/$Y_2O_3$ 노즐목 삽입재를 평가하였다. 연소시간 증가에 따른 내열성능 변화를 검토하였으며, 비삭마 소재로 범용되고 있는 CIT의 내열성능과 비교하였다. 연소시간이 증가함에 따라 삭마율은 감소하는 경향을 보였으며, W/$Y_2O_3$의 삭마율은 CIT의 약 55 %이었다. 노즐목 삽입재의 육안검사와 미세조직검사에서 연소시간의 증가로 인한 특이 현상은 발견되지 않았으며, 진공 열처리는 균열 방지에 효과가 있음을 확인하였다.

• Nuclear Medicine and Molecular Imaging
• /
• 제43권4호
• /
• pp.259-279
• /
• 2009

Radioiodine ablation therapy has been considered to be a standard treatment for patient with differentiated thyroid cancer after total thyroidectomy. Patients may need to be hospitalized to reduce radiation exposure of other people and relatives from radioactive patients receiving radioiodine therapy. Medical staffs, nursing staffs and technologists sometimes hesitate to contact patients in radioiodine therapy ward. The purpose of this paper is to introduce radiation dosimetry, estimate radiation dose from patients and emphasize the safety of radiation exposure from patients treated with high dose radioiodine in therapy ward. The major component of radiation dose from patient is external exposure. However external radiation dose from these patients treated with typical therapeutic dose of 4 to 8 GBq have a very low risk of cancer induction compared with other various risks occurring in daily life. The typical annual radiation dose without shielding received by patient is estimated to be 5 to 10 mSv, which is comparable with 100 to 200 times effective dose received by chest PA examination. Therefore, when we should keep in mind the general principle of radiation protection, the risks of radiation exposure from patients are low and the medical personnel are considered to be safe from radiation exposure.

• Journal of Oral Medicine and Pain
• /
• 제45권2호
• /
• pp.44-47
• /
• 2020

The case of pseudo-aneurysm of internal maxillary artery (IMA) in oral and maxillofacial region is known to be very rare. The etiology of this case was regarded as IMA injury by radiofrequency ablation (RFA) and such incidence was not reported previously. One case of false aneurysm in the IMA was referred from local dental clinic to our department. Left facial swelling was observed with severe trismus immediately after radiofrequency procedure for masseteric nerve block in local dental clinic. Despite of medication and surgical intervention, the swelling did not subside and there was massive bleeding and pulsation on one of the follow ups. The traumatic vascular disorder was suspected and finally diagnosed with angiography and treated by embolization procedure. RFA targeting masseteric nerve or trigeminal ganglion may cause traumatic injury to adjacent anatomic structures such as IMA, resulting in pseudo-aneurysm. Clinicians must be aware of potential damages of RFA. Angiography enables the solid diagnosis for pseudo-aneurysm, and selective embolization can be optimum treatment method.

• Archives of Plastic Surgery
• /
• 제38권5호
• /
• pp.707-710
• /
• 2011

Purpose: Cardiac radiofrequency catheter ablation procedures using fluoroscopy were performed for the treatment of supraventricular and selected ventricular tachyarrhythmia. Fluoroscopy is used to localize the position of the intracardiac catheter. Fluoroscopically-guided procedures often involve high radiation doses to patient's skin, but the incidence of serious radiation injuries in these patients is rare. We reported two cases of severe postradiation skin injury on the back treated with the V-Y latissimus dorsi musculocutaneous flap. Methods: These two patients underwent radiofrequency catheter ablation under the diagnosis of Woff Parkinson White syndrome (WPW syndrome). They had radiation-induced skin injuries on the subscapular area and these lesions represented chronic ulceration, surrounding induration, hardness, and dyspigmentation. We treated these lesions with complete excision and coverage with V-Y latissimus dorsi musculocutaneous flap. Results: These two patients had no recurrence and no special complications during 20 months and 12 months follow-up periods and were satisfied aesthetically and functionally. Conclusion: V-Y latissimus dorsi musculocutaneous flap obtained better results functionally and aesthetically compared with conservative management and skin graft in severe radiation-induced skin injuries after cardiac radiofrequency catheter ablation procedure.