A Study of Dosimetric Characteristics of a Diamond Detector for Small Field Photon Beams

John K. Loh,Sung Y. Park,Dong O. Shin,Soo I. Kwon,Kil D. Lee,Woo C. Kim,Young K. Cho 대한방사선방어학회 1999 방사선방어학회지 Vol.24 No.4

The Study of Shielding Effect on Ovoids of Three Different Gynecological Applicator Sets in microSelectron-HDR System

Loh,John J.K.,Kim,Woo C.,Cho,Young K.,Kim,Hung J.,Choi,Jin H.,Park,Sung Y.,Kim,Joo Y. 대한방사선 방어학회 1998 방사선방어학회지 Vol.23 No.4

Nucletron사의 microSelectron-High Dose-Rate(HDR) System에서 부인암의 강내 근접치료에 사용되는 standard shielded applicator set(SSAS)와 Fletcher-Williamson applicator set(FWAS)는 standard applicator set(SAS) 와 비교해서 다른 점이 ovoids 위와 아래 부분에 방광과 직장으로 가는 선량을 줄이기 위해 각각 스테인레스 강철(밀도 (밀도 ρ=8,000 ㎏/㎥)과 텅스텐 합금(밀도 ρ=14,000 ㎏/㎥)으로 차폐가 되어 있다. 이에 본 연구에서는 특별히 고안한 지지장치를 사용해서 국제방사선단위위원회(ICRU) 보고서 38에서 권고한 직장과 방광의 위치에 대하여 두 shielded ovoids의 차례효과가 어느 정도인가를 알아보고자 하였다. 지지장치를 PTW사의 전산화된 3차원 물팬톰에 부착하고 SAS의 ovoids를 지지장치에 고정하였다. Ovoids의 끝 부분을 전리함(PTW 0.125cc)의 측정점 높이와 일치시키고 전리함을 좌우로 이동시키면서 선량을 측정하여 두 ovoids의 중간 위치를 확인하였다. 직장에 미치는 선량은 ovoids의 중간에 위치한 선원 M5로부터 posterior방향으로 수직으로 위치한 점들인 20(R1), 25(R2), 30(R3), 40(R4), 50(R5), 60(R6) mm 에서 측정하였다. 방광에 미치는 선량은 M5로 부터 anterior방향으로 수직으로 위치한 점들인 20(B1), 30(B2), 40(B3), 50(B4), 60(B5) mm에서 측정하였다. 위와 같은 방법으로 SSAS와 FWAS의 ovoids에서도 각각의 점들에 대한 선량을 측정하였다. SAS와 SSAS의 직장에 미치는 선량차이는 실제 임상에서의 관심 점들과 가장 가까운 25 mm(R2) 30 mm(R3)거리에서 각각 8.0%, 6.0%였고 SAS와 FWAS의 직장에 미치는 선량차이는 25 mm(R2)와 30 mm(R3)거리에서 각각 25.0%, 23.0%로 나타났다. SAS와 SSAS의 방광에 미치는 선량차이는 20 mm(B1)와 30 mm(B2)거리에서 각각 8.0%, 3.0%였고 SAS와 FWAS의 방광에 미치는 선량차이는 20 mm(B1)와 30 mm(B2)거리에서 각각 23.0%, 17.0%로 나타났다. SAS를 SSAS나 FWAS가 SSAS보다 차폐효과가 더 좋은 것으로 나타났으며 이 두 종류의 shielded applicator set는 부인암의 근접치료시 직장과 방광으로 가는 선량을 감소시켜 환자치료의 최적화를 이룰 수 있을 것으로 생각된다. There are three different types of gynecological applicator sets available in microSelectron-high dose-rate(HDR) System by Nucletron; standard applicator set(SAS), standard shielded applicator set(SSAS), and Fletcher-Williamson applicator set(FWAS). Shielding effect of a SAS without shielding material was compared with that of a SSAS with shielding material made of stainless steel(density ρ=8,000 ㎏/㎥) at the top and bottom of each ovoid, and of a FWAS with shielding material made of tungsten alloy(density ρ=14,000 ㎏/㎥) at the top and bottom of each ovoid. The shielding effects to the rectum and bladder of these two shielded applicator sets were to be measured at reference points with an ion chamber and specially designed supporting system for applicator ovoids inside of the computerized 3-dimensional water phantom. To determine the middle point of two ovoids the measurement was performed with the reference tip of ion chamber placed at the same level and at the middle point from the two ovoids, while scanning the dose with the ion chamber on each side of ovoids. The doses to the reference points of rectum were measured at 20(R1), 25(R2), 30(R3), 40(R4), 50(R5), and 60(R6) mm located posteriorly on the vertical line drawn from M5(the middle dwell position of ovoid), and the doses to the bladder were measured at 20(B1), 30(B2), 40(B3), 50(B4), and 60(B5) mm located anteriorly on the vertical line drawn from M5. The same technique was employed to measure the doses on each reference point of both SSAS and FWAS. The differences of measured rectal doses at 25 mm(R2) and 30 mm(R3) between SAS and SSAS were 8.0 % and 6.0 %: 25.0% and 23.0% between SAS and FWAS. The differences of measured bladder doses at 20 mm(B1) and 30 mm(B2) between SAS and SSAS were 8.0% and 3.0%: 23.0% and 17.0% between SAS and FWAS. The maximum shielding effects to the rectum and bladder of SSAS were 8.0% and 8.0%, whereas those of FWAS were 26.0% and 23.0%, respectively. These results led to the conclusion that FWAS has much better shielding effect than SSAS does, nd when SSAS and FWAS were used for gynecological intracavitary brachytherapy in microSelectron-HDR system, the dose to the rectum and bladder was significantly reduced to optimize the treatment outcome and to lower the complication rates in the rectum and bladder.

Effect of Radiofrequency Induced Local Hyperthermia on Normal Canine Liver

Chang Ok Suh(서창옥) , John J.K.Loh(노준규) , Jin Sil Seong(성진실) , Sun Rock Moon(문성록) Hyung Sik Lee(이형식) , Hyun Soo Shin(신현수) , Sung Sil Chu(추성실) , Gwi Eon Kim(김귀언) , Chan Il Park(박찬일) ,Eun Kyung Han(한은경) 대한방사선종양학회 1991 Radiation Oncology Journal Vol.9 No.1

간조직에 온열치효를 시행시 출현하는 조직병리학적 소견 및 혈액의 생화학적 소견을 관찰하고자 13마리의 정상 간에 8MHz 라디오파를 이용한 온열치료를 시행하였다. 42.5±0.5°C로 30분간 온열치료를 받은 군 (제1군, n=5), 45±0.5°C로 30분간 온열치료를 받은 군 (제2군, n=5) 및 온열치료를 받지않은 대조군(n=3)으로 나누어 분석하였을때, 혈액의 SGOT의 SGPT는 온열치료를 시행한 두군 공히 증가된 소견을 보였고 제 1군에서는 간세포의 부종소견의 특이한 조직병리학적소견이 관찰되지않아 가역성 변화로 생각되었지만 제2군에서는 간 세포의 심한 괴사소견이 관찰되어 있는 불가역성의 가조직 손상으로 생각되었다. 이상의 결론으로 유추할 때 임상에서 행하여지는 간암의 온열치료시에 정상 가조직의 손상을 가능한 방지하기위하여는 정확한 종괴의 구역에 치료온도의 주의깊은 관찰이 요구된다. In order to assess the effects of radiofrequency-induced local hyperthermia on the normal liver, histopathologic findings and biochemical changes after localized hyperthermia in canine liver were studied. Hyperthemia was externally adminsitered using the Thermotron RF-8 (Yamamoto Vinyter Co., Japan; Capacitive type heating machine) with parallel opposed electrodes. Thirteen dogs were used and allocated into one control group (N=3) and two treatment groups according to the treatment temperature. Group I (N=5) was heated with 42.5±0.5°C for 30 minutes, and Group Ⅱ (N=5) was heated with 45±0.5°C for 15-30 minutes. Samples of liver tissue were obtained through a needle biopsy immediately after hyperthermia and 7, 14, and 28 days after treatment. Blood samples were obtained before treatment and 1, 3, 5, 7, 14 and 28 days after treatment and examined for SGOT, SGPT and alkaline phosphatase. Although SGOT and SGPT were elevated after hyperthermia in both groups (three of five in each group), there was no liver cell necrosis or hyperthermia related mortality in Group Ⅰ. A hydropic swelling of hepatocytes was prominent histologic finding. Hyperthermia with 45°C for 30 minutes was fatal and showed extensive liver cell necrosis. In conclusion, liver damage dy heat of 42.5±0.5°C for 30 minutes is reversible, and liver damage by heat of 45±0.5°C for 30 minutes can be fatal or irreversible. However, these results cannot be applied directly to human trial. Therefore, in order to apply hyperthermic treatment on human liver tumor safely, close observation of temperature with proper thermometry is mandatory. Hyperthermic treatment should be confined to the tumor area while sparing a normal liver as much as possible.

비인강암의 방사선 치료 성적

이종영(Jong Young Lee)·노준규(John J.K. Loh)·서창옥(Chang Ok Suh)·이연구(Yonu Goo Lee)·홍원표(Won Pyo Hong) 대한방사선종양학회 1988 Radiation Oncology Journal Vol.6 No.1

This study is the retrospective evaluation of ninety-six patients with biopsy-proven carcinoma of nasopharynx treated with radiotherapy at Yonsei University, College of Medicine Radiation Oncology from January 1971 to December 1985. Patient's age ranged from 15 to 71 years with a median age of 49 years. Fifty-two point five percent of local control and 47.5% of actuarial 5 year survival were achieved with radical radiotherapy. Five year survival rate for Stage I & II, III and IV were 75.0%, 74.6% and 41.4%, respectively. Distant metastasis rate was related with N stage (N1 12.5%, N1 0%, N2 23.5%, N3 32.1%) and histologic type (lymphoepithelioma 41.7% squamous cell carcinoma 6.5%) but not with T stage. Thirty-one of sixty-seven patient covered adequate radiation field received induction chemotherapy. However induction chemotherapy does not appear to improve over all survival.

Piezoelectric nanocomposite sensors assembled using zinc oxide nanoparticles and poly(vinylidene fluoride)

John S. Dodds,Kenneth J. Loh,Frederick N. Meyers 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.1

Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for sensing and damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory/field tests and possess significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and SHM applications. These films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. This study started with spin coating dispersed ZnO- and PVDF-TrFE-based solutions to fabricate the piezoelectric nanocomposites. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5 % increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled (at 50 MV-m-1) to permanently align their electrical domains and to enhance their bulk film piezoelectricity. Then, a series of hammer impact tests were conducted, and the voltage generated by poled ZnO-based thin films was compared to commercially poled PVDF copolymer thin films. The hammer impact tests showed comparable results between the prototype and commercial samples, and increasing ZnO content provided enhanced piezoelectric performance. Lastly, the films were further validated for sensing using different energy levels of hammer impact, different distances between the impact locations and the film electrodes, and cantilever free vibration testing for dynamic strain sensing.

Piezoelectric nanocomposite sensors assembled using zinc oxide nanoparticles and poly(vinylidene fluoride)

Dodds, John S.,Meyers, Frederick N.,Loh, Kenneth J. Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.1

Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for sensing and damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory/field tests and possess significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and SHM applications. These films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. This study started with spin coating dispersed ZnO- and PVDF-TrFE-based solutions to fabricate the piezoelectric nanocomposites. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5 % increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled (at 50 $MV-m^{-1}$) to permanently align their electrical domains and to enhance their bulk film piezoelectricity. Then, a series of hammer impact tests were conducted, and the voltage generated by poled ZnO-based thin films was compared to commercially poled PVDF copolymer thin films. The hammer impact tests showed comparable results between the prototype and commercial samples, and increasing ZnO content provided enhanced piezoelectric performance. Lastly, the films were further validated for sensing using different energy levels of hammer impact, different distances between the impact locations and the film electrodes, and cantilever free vibration testing for dynamic strain sensing.

A Study of Dosimetric Characteristics of a Diamond Detector for Small Field Photon Beams

Lee,Kil D.,Loh,John.k.,Park,Sung.Y.,Kwon,Soo I,Kim,Woo C.,Shin,Dong O.,Cho,Young K. 대한방사선 방어학회 2000 방사선방어학회지 Vol.24 No.4

고 에너지 광자선 소조사면에 대한 선량 특성은 조사면내의 급격한 선량 변화의 측면 전자 평형상태하의 측정이 어려우므로 정확하게 파악하기 어렵다. 다이아몬드 검출기를 이용하여 광자선 에너지 4, 6, 그리고 10 MeV에 대한 소조사면의 선량특성을 측정하였고 그 값들을 작은 용적의 원통형과 평행평판형 이온함의 선량특성과 비교하였다. 다이아몬드 검출기와 원통형 이온함 을 이용하여 의료용 선형가속기에서 방출되는 광자선 에너지 6 MeV X-선, 10 MeV X-선에 대한 소조사면(1x1, 1.5x1.5, 2x2, 3x3, 4x4 ㎠)에 대하여 심부선량백분율, 측면 선량분포를 측정하였다. 또한 다이아몬드 검출기, 원통형 이온함 및 평행평판형 이온함을 이용하여 광자선 에너지 4 MeV X-선, 6 MeV X-선 및 10 MeV X-선으로 소조사면의 크기를 1x1 ㎠에서 0.5 ㎠간격으로 4x4 ㎠까지 변화하면서 출력계수를 측정하였다. 세 가지 측정기에 대한 출력계수를 비교한 결과 광자선 에너지 4 MeV X-선은 조사면의 크기 2x2 ㎠, 6 MeV X-선은 2.5x2.5 ㎠ 그리고 10 MeV X-선은 3x3 ㎠이상에서 출력계수가 ±1.2% 내외로 잘 일치하였으나 원통형과 평행평판형 이온함에 대한 출력계수는 조사면의 크기가 작아질수록 다이아몬드의 검출기와 비교하여 낮게 평가 되었는데 이는 원통형과 평행평판형 이온함의 측면 전자평형상태가 이루어지지 않아 낮게 평가되었다. 광자선 에너지 6 MeV X-선과 10 MeV X-선에 대한 심부선량백분율은 다이아몬드 검출기와 원통형 이온함이 조사면의 크기 3x3 ㎠까지 ±1.5% 내외로 잘 일치하였으나 조사면의 크기가 작고 깊이가 깊어짐에 따라 다이아몬드이 심부선량백분율이 크게 평가되었다. 측면 선량분포는 원통형 이온함의 반음영의 크기가 측정된 소조사면에 대하여 다이아몬드 검출기보다 크게 나타났다. 측면 선량분포는 다이아몬드 검출기가 상대적으로 이온함에 비해 민감 용적이 작고 높은 분해능을 가지므로 반음영이 작은 것으로 사료된다. 따라서 고 에너지 광자선 소조사면에 대한 선량 측정시 검출기의 민감 용적이 작고 분해능이 우수하며 물과 등가인 다이아몬드 검출기는 이온함에 비해 상대적으로 우수한 것으로 생각된다. It is difficult to determine dosimetric characteristics for small field photon beams since such small fields do not achieve complete lateral electronic equilibrium and have steep dose gradients. Dosimetric characteristics of small field 4, 6, and 10 MeV photon beams have been measured in water with a diamond detector and compared to measurements using small volume cylindrical and plane parallel ionization chambers. Percent depth dose (PDD) and beam profiles for 6 and 10 MeV photon beams were measured with diamond detector and cylindrical ion chamber for small fields ranging from 1x1 to 4x4 ㎠. Total scatter factors(S) for 4, 6, and 10 MeV photon beams were measured with diamond detector, cylindrical and plane parallel ion chambers for small fields ranging from 1x1 to 4x4 ㎠. The S?? factors obtained with three detectors for 4, 6, and 10 MeV photon beams agreed well (±1.2%) for field sizes greater than 2x2, 2.5x2.5, and 3x3 ㎠, respectively. For smaller field size, the cylindrical and plane parallel ionization chambers measure a smaller S?? factor, as a result of the steep dose gradients across their sensitive volumes. The PDD values obtained with diamond detector and cylindrical ionization chamber for 6 and 10 MeV photon beams agreed well (±1.5%) for field sizes greater than 4x4 ㎠. For smaller field sizes, diamond detector produced a depth-dose curve which had a significantly shallower falloff than that obtained from the measurements of relative depth-dose with a cylindrical ionization chamber. For the measurements of beam profiles, a distortion in terms of broadened penumbra was observed with a cylindrical ionization chamber since diamond detector exhibited higher spatial resolution. The diamond detector with small sensitive volume, near water equivalent, and high spatial resolution is suitable detector compared to ionization chambers for the measurements of small field photon beams.

Dosimetry for Total Skin Electron Beam Therapy in Skin Cancer

추성실(Sung Sil Chu),노준규(John JK Loh),김귀언(Gwi Eon Kim) 대한방사선종양학회 1992 Radiation Oncology Journal Vol.10 No.1

4-5MeV의 전자선은 피부표면의 흡수선량을 증가시키고 표면하 10mm 내외에서 급속히 감소함으로 Mycosis fungoides, Kaposi's sarcoma등 전신피부암에 대한 가장 적당한 치료방사선으로 알려져왔다. 그러나 평면이 아니고 굴곡이 심한 인체표면에 균일한 선량을 계획하기는 많은 어려움이 있었다. 연세암센터에서는 1980년부터 시행하여왔던 6MeV 전자선의 마름모형, 네방향 조사방법을 개량하고 많은 문헌을 참고하여 상하 양방향의 조사면과 환자위치를 각각 여섯가지 자세로 나누어 조사(Six-Dual-Field)하는 방법을 사용하였으며 이에따른 전신피부표면의 선량과 선량분포를 측정하였다. 선형가속기에서 발생되는 6MeV 전자선을 0.5cm 두께의 아크릴판으로 감약시키고 콜리메터가 완전히 열린 조사면을 상하 19°씩 옮기므로서 타켓트에서 3m 거리에 약 2m×1m의 균일한선량의 조사면(평탄도 +3%)과 10mm 내외의 실효깊이(80% 선량지점) 및 산란선에 의한 피부표면선량을 증가시킬 수 있었다. 환자는 일부피부가 가려지지않도록 팔과 다리를 적당한 자세로 고정시키고 전자선을 여섯방향에서 각각 2회씩 상하로 조사시키므로서 피부표면에 균일한 선량분표(표준편차 5%)가 가능하였으며 80%의 심부률이 8~10mm에서 측정되었다. 모든 측정은 인체등가팬텀과 폴리스틸렌팬텀을 사용하였으며 필름, 평형전리측정기 및 표준전리측정기를 이용하였다. 특히 환자피부표면의 흡수선량분포를 확인하기 위하여 열형광측정기와 반도체측정기를 이용하였으며 6~20개의 소형 측정기를 환자 피부표면에 부착시킨후 전자선 치료과정 동안 피폭 시켜 측정하였고 그결과 차폐된 부위를 제외하고 평균 10%이내의 균일한 선량분포를 얻을 수 있었다. Increasing frequency of skin cancer, mycosis fungoides, kaposi's sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a 0.5cm×90cm×180cm acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. Instrumentation and techniques developed in determining the depth dose. dose distribution and bremsstrahlung dose are discussed.

Combined Radiotherapy and Hyperthermia for Nonresectable Hepatocellular Carcinoma

성진실(Jin Sil Seong),노준규(John Juhn Kyu Loh),서창옥(Chong Ok Suh)김귀언(Gwi Eon Kim),한광협(Kwong Hyub Han),이상인(Song In Lee),노재경(Joe Kyung Roh),김병수( Byung Soo Kim),최흥재(Heung Jai Choi) 대한방사선종양학회 1989 Radiation Oncology Journal Vol.7 No.2

절제 불가능한 원발성 간암은 여러 가지 다양한 치료법의 시도에도 불구하고 그 예후는 극히 불량하다. 이에 본 저자들은 온열요법에 대한 축적된 경험을 바탕으로 1988년 4월부터 7월까지 본과에 내원한 30명의 절제 불가능한 원발성간암 환자들에 대하여 온열 및 방사선 병용요법을 시행하였다. 방사선치료는 일일 조사량 180 cGy 씩 3.5주에 3060 cGy를 조사하였고 온열요법은 8MHz 유전형온열치료기(Thermotron RF-8, Cancermia)를 사용하여 주 2회씩 총 6회 시행하되 순서는 방사선 치료를 먼저 한 후 30분 이내에 온열요법이 30~60분간 시행되었다. 그 결과 부분반응이 12예에서 관찰되었고(40%), 증상의 호전이 28예중 22예에서 관찰되었다(78.6%). 종양의 반응을 예측할 수 있는 인자로서는 형태학적 유형이 가장 유의하게 나타났다(single massive: 10/14, 71.4%; diffuse infiltrative: 2/10, 20%; multinodular: 0/6, 0%; p<0.005). 치료로 인한 심각한 부작용은 관찰되지 않았다. 1년 생존율은 34%였고 정중앙 생존기간은 6.5개월이었다. 부분반응을 보인 환자군의 생존율 및 정중앙 생존 기간은 각각 50%, 11개월로서 반응을 보이지 않은 환자군의 22%, 5개월과 비교해 볼 때 정중앙 생존기간의 차이가 통계족으로 유의하였다(p<0.05). 결론적으로 온열 및 방사선 병용요법은 절제 불가능한 원발성 간암의 증상호전 및 국소적 치료에 효과가 있는 것으로 생각되며 생존율 및 부작용등에 관해서는 앞으로 연구가 더 진행되어야 할 것으로 생각된다. Thirty patients with nonresectable hepatocellular carcinoma (HOC) due to either locally advanced lesion of association with liver cirrhosis, treated with combined radiotherapy and hyperthermia between April 1988 and July 1988, at Dept. of Radiation Oncology, Yonsei university College of medicine, were analysed. External radiotherapy of a total dose of 3060 cGy/3.5 wks was given, Hyperthermia was given twice a week with a total of 6 treatment sessions using 8 MHz radiofrequency capacitive type heating device, i.e., Thermotron RF-8 and Cancermia. ln all cases hyperthermia was given within 30 minutes after radiotherapy for 30~60 min. Temperature was measured by inserting thermocouple into the tumor mass under the ultrasonographic guidance only for those who had not bleeding tendency. As a result, partial response (PR) was achieved in 12 patients (40%), and symptomatic improvement was observed in 22 patients (78.6%) among 28 patients who had suffered from abdominal pain. The most significant factor affecting the tumor response rate was the type or tumor (single massive: 10/14, 71.4%; diffuse infiltrative: 2/10, 20%: multinodular: 0/6, 0%; p<0.005). There were not any significant side effects relating to combined treatment. The overall 1 year survival rate was 34%, with 50% in the PR group and 22% in the no response group (NR), respectively. Median survival was 6.5 months and longer for those of PR than of NA (11 mos. vs 5, p<0.05). In conclusion, combined radiotherapy and hyperthermia appeared to be effective in local control and symptomatic palliation of HCC. Further study including a larger number of the patients to confirm its effect in survival and detrimental side effect should be urged.

유방암 환자의 삼문 조사 시 내외측 접면 조사야의 Posterior Edge의 어긋남의 교정

김헌정(Hun-Jung Kim),노준규(John JK Loh),김우철(Woo-Cheol Kim),박성용(Sung-Young Park) 대한방사선종양학회 2003 Radiation Oncology Journal Vol.21 No.2

목 적: 유방암 환자를 삼문으로 방사선 치료 할 경우 유방의 접면영역과 쇄골상 영역의 기하학적 일치를 이루기 위해 갠트리를 회전한 상태에서 테이블을 회전하는 방법이 사용되며, 이때 접면조사의 posterior edge에 발생 할 수 있는 어긋남을 필름 선량측정법과 삼차원 입체조영 치료계획을 통하여 확인하고, 그 어긋남의 해결방법으로 콜리메이터의 각도를 보정해주는 방법들을 연구하였다. 대상 및 방법: 어긋남의 보정을 위해 쇄골상영역과 유방의 접면영역을 반쪽 빔블록과 tangential field block을 사용하여 모의치료한 후 테이블 회전을 하지 않은 상태에서 환자의 몸에 접면 빔의 posterioredge에 선을 긋고, 테이블을 회전시킨 상태에서의 광조사야의 posterioredge와 테이블 회전이전에 환자의 몸에 그어놓은선과 일치되도록 콜리메이터를 회전시키는 방법과, 본 연구에서 고안한 방법인 삼각함수로부터 유도시킨 다음과 같은 공식에 따라 콜리메이터를 회전하여 posterior edge의 어긋남을 보정하고 두 방법을 비교하였다. Co=2sin-1{sinθsin(C/2)} (Co: collimator angle, θ: angle between tangential beam and table, C: couch angle) 결 과: 필름선량 측정법을 이용하여 콜리메이터를 보정하지않은 경우 내외측의접면 빔의 posterior edge가 어긋남을 확인할 수 있었으며, 콜리메이터를 보정함으로써 posterior edge의 일치함을 확인할 수 있었다.위 두 방법에서 콜리메이터의 회전 각도는 동일하였다.또한 전산화된 삼차원 입체조영 치료계획을 통하여,접면 빔의 posterioredge의 어긋남을 확인할 수 있었으며, 콜리메이터를 회전하여보정 함으로써 posterior edge의 일치를 확인할 수 있었다. 각각의 선량체적표를 비교할 경우, 콜리메이터를 보정하여 posterioredge의 일치를 이룬 경우가 더 적은 용적의 폐가 조사되는 것을 확인할 수 있었다. 결 론: 유방암 환자의 방사선 치료에서 삼문으로 치료할경우에 갠트리와 테이블을 동시에회전하여 쇄골위 영역의 아래면과 접면 빔의 윗면을 일치시킬때 각각의 접면빔의 posterioredge가 어긋남을 인지해야하며,약간의 콜리메이터를 회전시킴으로써 이 어긋남은 보정가능하고,폐에 조사되는 방사선 양도 줄일 수 있었다. Purpose: The target volume for the three field technique in breast cancer include the breast tangential and supraclavicular areas. The techniques rotating the gantry and couch angles, to match these two areas, will geometrically produce mismatching of the posterior edge between the medial and lateral tangential beams. This mismatch was confirmed by film dosimetry and three-dimensional computer planning. The correction methods of this mismatching were studied in this article. Materials and Methods: After the supraclavicular field was simulated using a halfbeamblockand the medial and lateral tangential fields, by the rotation of the couch and gantry, we compared the following two methods to correct the mismatch. The first method was the rotation of collimator until a line drawn on the posterior edge of tangential beams before the rotation of couch aligned the line drawn on the posterior edge after the rotation. The second method was the rotation of collimator according to the formula developed by the author as follows; Co=2sin-1{sinθ?sin (C/2)} (Co: collimator angle, θ: angle between tangential beam & table, C: couch angle) Results: The film dosimetry showed the mismatching of posterior edges of the medial and lateral tangential fields prior to the rotation of collimator, while the posterior edges matched well after the rotation of collimator according to the formula. The three-dimensional computer plan alsoshowed that the posterior edges matched well after the rotation of collimator accordingly. The DVH of the ipsilateral lung with the proper rotation of collimator angle was better than that without the rotation of collimator angle. Conclusion: The mismatching of the posterior edges of the medial and lateral tangential fields can be recognized on the three field technique in breast irradiation when the gantry and couch are simultaneously rotated and can be corrected with the proper rotation of the collimator angle. The radiation dose to the ipsilateral lung could be lowered with this technique.