Surgical Clips for Observation of Respiratory Motion of the Breast Via 2D Fluoroscopy and 3D CT Scans

이레나,서현숙 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.6

Many breathing techniques have been applied for an accurate treatment of the breast. A normal breathing technique that could provide an equally accurate treatment with less intervention and shorter treatment time is worth investigating by thoroughly observing the respiratory motion of the breast via 2D fluoroscopy and 3D CT scans with surgical clips for position verification of the tumor bed. A group of 22 patients with surgical clips implanted in the lumpectomy cavity during breast-conserving surgery as effective internal markers of the length, width, and depth of the tumor bed were involved. The group was divided into two subgroups according to data acquisition methods; namely, 2D fluoroscopy and 3D CT scan. Seven out of twenty two patients were involved in the 2D fluoroscopic study, and the rest were involved in the 3D CT study. No breathing control device was used in this study. To compensate for the sample size and to get a more favorable result for direct clinical application, we introduced the standard error of the mean (SEM), including 95% confidence interval based on t-distribution. The low-level in-house software for identifying the individual clip locations and setup adjustment was used to improve accuracy of the breast irradiation treatment. For the 2D fluoroscopic study, the average movement and standard deviation(SD) of the clip were 1.30 ± 0.65 (median: 1.23, 95% CI: 1.01 - 1.59), 0.77 ± 0.48 (median: 0.55, 95% CI: 0.56 - 0.98), and 1.20 ± 0.46 (median: 1.06, 95% CI: 1.03 - 1.37) for the anterior-posterior (AP), lateral, and tangential directions, respectively. Our results were compatible with those of Kinoshita et al.’s 3D study. In our 3D CT study, excursion lengths during a cycle of breathing were measured. The average excursion length and SD of the center-of-mass (COM) of the clips were 5.1 ± 3.5 (median: 4.7, 95% CI: 4.34 - 5.86), 0.8 ± 0.8 (median: 0.5, 95% CI: 0.62- 0.98), and 4.9 ± 4.3 (median: 3.1, 95% CI, 3.97 - 5.83) for the AP, lateral, and superior-inferior (SI) directions, respectively. Both the isocenter and the diaphragm movements were measured in the 3D CT study. The difference between the COM and the isocenter is considered to be not statistically significant (p > 0.7) for the three orthogonal directions. However, the p value for the difference between the clip and the lung is less than 0.001. We saw no strong correlation between the clip and the diaphragm movements. No immobilization devices or techniques were needed to control the movement of the breast tumor bed because our results suggest that the tumor bed is not significantly moved by breathing motion compared to the diaphragm during normal breathing. The motions of the breast in the AP and the SI directions were significantly greater than that in the lateral direction, which suggests that anisotropic and direction-dependent clinical margin may be more favorable in normal breathing clinical situations, although the reduction of internal margins should be performed with great care due to the individual tumor motion.

유방암 환자의 정상 호흡에서 종양에 삽입된 외과적 클립의 움직임 분석

이레나,정은아,서현숙,이경자,이지혜 대한방사선종양학회 2006 Radiation Oncology Journal Vol.24 No.3

국내 의료기관들의 광자 빔 데이터의 비교 분석 및 치료계획 시스템 정도관리자료

이레나,조병철,강세권,Lee, Re-Na,Cho, Byung-Chul,Kang, Sei-Kwon 한국의학물리학회 2006 의학물리 Vol.17 No.3

목적: 방사선 종양학과에서 사용되고 있는 선형가속기의 광자선 빔 데이터를 수집하여 비교 분석하였으며 치료계획용 시스템에 대한 간단한 정도관리 방법을 제시하였다. 대상 및 방법: 국내 26개 방사선 치료기관을 대상으로 출력교정 조건, 출력인자, 쐐기인자, 깊이 선량분포, 측방선량분포 및 선질에 대한 데이터를 수집하였다. 치료계획용 시스템의 선량계산의 정확성을 확인하기 위하여 10가지 광자선 치료 조건(정방형/직사각형/부정형 조사면, 쐐기필터 조사면, 축이탈 선량계산, SSD 변화)에 대한 선량계산을 치료계획용 시스템을 이용하여 시행하였으며 치료계획용 시스템을 이용하여 계산된 모니터 값과 수 계산에 의한 결과를 비교 분석하였다. 결과: 광자선 선질은 6 MV, 10 MV 및 15 MV에 대해 각각 $0.576{\pm}0.005,\;0.632{\pm}0.004$ 및 $0.647{\pm}0.006$이다. 최대선량 깊이에서 조사면의 크기에 따른 출력상수의 평균값은 6 MV 광자선의 경우 $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm$에 대해 $0.944{\pm}0.006,\;1.031{\pm}0.006,\;1.055{\pm}0.007$이다. 10 MV 광자의 경우는 조사면의 크기가 $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm$에 대해 각각 $0.935{\pm}0.006,\;1.031{\pm}0.007,\;1.054{\pm}0.0005$이다. 15 MV의 경우는 수집된 데이터의 수가 많지 않지만 $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm$에 대해 $0.941{\pm}0.008,\;1.032{\pm}0.004,\;1.049{\pm}0.014$이다. 치료 계획용 시스템과 수 계산에 의한 MU값의 계산 비교결과 7개 기관의 값이 허용오차 범위를 벗어났다. 쐐기를 제외한 8가지 조건에서 계산된 평균 MU값들은 SAD 조건으로 출력 교정된 장비가 SSD 조건으로 교정된 장비에 비해 6 MV 광자선은 3 MU, 10 MV 광자선은 5 MU 정도 더 높았다. 쐐기를 사용할 경우 MU값은 Varian사 장비와 Siemens사의 장비에 따라 다르고 동일 각의 쐐기를 사용할 경우 Siemens사의 쐐기를 사용할 때 MU값이 크다. 결론: 수집된 광자선 빔 데이터를 분석하여 빔데이터의 정확성과 치료계획용 시스템의 계산 정확성을 대략적으로 점검 할 수 있는 기준 값을 제시하였다. Purpose: Photon beam data of linear accelerators in Korea are collected, analyzed, and a simple method for checking and verifying the dose calculations in a TPS are suggested. Materials and Methods: Photon beam data such as output calibration condition, output factor, wedge factor, percent depth dose, beam profile, and beam quality were collected from 26 institutions in Korea. In order to verify the accuracy of dose calculation, ten sample planning tests were peformed. These Include square, elongated, and blocked fields, wedge fields, off-axis dose calculation, SSD variation. The planned data were compared to that of manual calculations. Results: The average and standard deviation of photon beam quality for 6, 10, and 15 MV were $0.576{\pm}0.005,\;0.632{\pm}0.004,\;and\;0.647{\pm}0.006$, respectively. The output factors of 6 MV photon beam measured at depth of dose maximum for $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm\;were\;0.944{\pm}0.006,\;1.031{\pm}0.006,\;and\;1.055{\pm}0.007$. For 10 MV photon beam, the values were $0.935{\pm}0.006,\;1.031{\pm}0.007,\;1.054{\pm}0.0005$. The collected data were not enough to calculate average, the output factors for 15MV photon beam with field size of $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm\;were\;0.941{\pm}0.008,\;1.032{\pm}0.004,\;1.049{\pm}0.014$. There was seven institutions $e{\times}ceeding$ tolerance when monitor unit values calculated from treatment planning system and manually were compared. The measured average MU values for the machines calibrated at SAD setup were 3 MU and 5 MU higher than the machines calibrated at SSD for 6 MV and 10 MV, respectively except the wedge case. When the wedges were inserted, the MU values to deliver 100 cGy to 5 cm depends on manufactures. When the same wedge angle was used, Siemens machine requires more MUs then Varian machine. Conclusion: In this study, photon beam data are collected and analyzed to provide a baseline value for chocking beam data and the accuracy of dose calculation for a treatment planning system.

Effectiveness of Bellyboard Device for Displacement of Small Bowel in Pelvic Irradiation

이레나,이경자,서현숙,Lee, Rena,Lee, Kyung-Ja,Suh, Hyunsuk Korean Society of Medical Physics 2007 의학물리 Vol.18 No.4

골반 방사선치료 시 방사선조사부위에서 소장을 제외하여 방사선에 의한 소장의 독성 감소에 가장 효율적인 방법을 알아보기 위하여 본 연구가 시행되었다. 연구대상은 자궁경부암, 자궁내막암, 직장암, S-결장암과 난소암으로 수술 후 골반에 방사선치료를 받은 환자 14명이다. 환자는 모의치료를 시행하기 1시간 30분 전에 150 ml의 바륨과 방광을 채우기 위해 물 500 ml를 마시고 환자의 자세변화와 벨리보드 사용 유무에 따라 5종류의 조영촬영을 하였다. 첫 번째는 방광을 채운 후 누운 자세로 전 후면과 측면을 촬영한다. 두 번째는 방광을 채운 상태에서 엎드린 자세로, 세 번째는 방광을 비운 후 누운 자세로, 네 번째는 방광을 비운 후 엎드린 자세로, 다섯 번째는 방광을 비운 후 벨리보드를 사용하여 엎드린 자세로 각각의 전 후면과 측면을 촬영한다. 모든 조영촬영 사진에서 방사선조사부위에 포함되는 소장의 용적을 측정하였다. 결과는 방광을 채우거나 비운상태 모두 엎드린 자세가 누운 자세보다 소장의 용적이 감소되었으며 특히 측면사진에서 더욱 감소되었다. 엎드린 자세에서는 방광을 채운 상태의 소장 용적이 방광을 비운상태에 비해 전후면 사진에서 13%, 측면 사진에서 26%가 감소되었다. 방광을 비운 후 벨리보드를 사용한 상태의 소장 용적이 벨리보드를 사용하지 않고 엎드린 자세에 비해 전 후면에서 $62.8{\pm}27.1%$, 측면에서 $63{\pm}32.9%$가 감소되었다. 결론적으로 골반에 방사선치료를 시행할 경우 방광을 비운 후 벨리보드를 사용함으로써 소장의 용적을 최소화시킬 수 있었다. Various techniques were evaluated to determine the best method for reducing small bowel involvement in pelvic irradiation. Fourteen patients receiving radiation in pelvic area were enrolled for this study. Five sets of small bowel images were obtained. Patients were positioned on a simulation couch with full bladder in prone and supine positions and 2 sets of images were taken. Then they were asked to empty their bladder and 2 sets of images were taken in prone and supine positions. A belly board device (BBD) was placed and one set of images was obtained. Using a software, the area of small bowel inside treatment field was contoured, measured, and analyzed. In both full and empty bladder cases, small bowel area reduction was observed in prone position as compared to supine position. Especially statistically significant reduction is noted in lateral film. An average decreases of 13% in PA and 26% in lateral direction were noted with bladder distention as compared to empty bladder. With the use of BBD for empty bladder, a significant reduction of $62.8{\pm}27.1%$ and $63.1{\pm}32.9%$ in PA and lateral directions were observed as compared to without BBD in prone position, respectively. In conclusion, the best sparing of small bowel concerning the area included in the treatment fields was achieved with BBD in prone position with empty bladder. However, further reduction is expected if the bladder was filled fully because the analysed data with empty vs full bladder study shows increased sparing of small bowel with distended bladder.

강내온열 치료를 위한 원통형 초음파 치료기 개발

이레나,서현숙 한국의학물리학회 2002 의학물리 Vol.13 No.2

Statistical Process Control Analysis for Patient Quality Assurance of Intensity Modulated Radiation Therapy

이레나,김규보,조삼주,임상욱,이석,심장보,허현도,이상훈,안소현 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.10

This study applied statistical process control to set and verify the quality assurances (QA) tolerance standard for our hospital’s characteristics with the criteria standards that are applied to all the treatment sites with this analysis. Gamma test factor of delivery quality assurances (DQA) was based on 3%/3 mm. Head and neck, breast, prostate cases of intensity modulated radiation therapy (IMRT) or volumetric arc radiation therapy (VMAT) were selected for the analysis of the QA treatment sites. The numbers of data used in the analysis were 73 and 68 for head and neck patients. Prostate and breast were 49 and 152 by MapCHECK and ArcCHECK respectively. Cp value of head and neck and prostate QA were above 1.0, Cpml is 1.53 and 1.71 respectively, which is close to the target value of 100%. Cpml value of breast (IMRT) was 1.67, data values are close to the target value of 95%. But value of was 0.90, which means that the data values are widely distributed. Cp and Cpml of breast VMAT QA were respectively 1.07 and 2.10. This suggests that the VMAT QA has better process capability than the IMRT QA. Consequently, we should pay more attention to planning and QA before treatment for breast Radiotherapy.

유방보존술 후 방사선치료에서 수술 흉터와 삽입된 클립을 이용한 전자선 추가 방사선 조사야 평가

이레나,정은아,이지혜,서현숙 대한방사선종양학회 2005 Radiation Oncology Journal Vol.23 No.4

Purpose: To evaluate the role of surgical clips and scars in determining electron boost field for early stage breast cancer undergoing conserving surgery and postoperative radiotherapy and to provide an optimal method in drawing the boost field. Materials and Methods: Twenty patients who had 4~7 surgical clips in the excision cavity were selected for this study. The depth informations were obtained to determine electron energy by measuring the distance from the skin to chest wall (SCD) and to the clip implanted in the most posterior area of tumor bed. Three different electron fields were outlined on a simulation film. The radiological tumor bed was determined by connecting all the clips implanted during surgery. Clinical field (CF) was drawn by adding 3 cm margin around surgical scar. Surgical field (SF) was drawn by adding 2 cm margin around surgical clips and an ideal field (IF) was outlined by adding 2 cm margin around both scar and clips. These fields were digitized into our planning system to measure the area of each separate field. The areas of the three different electron boost fields were compared. Finally, surgical clips were contoured on axial CT images and dose volume histogram was plotted to investigate 3-dimensional coverage of the clips. Results: The average depth difference between SCD and the maximal clip location was 0.7±0.56 cm. Greater difference of 5 mm or more was seen in 12 patients. The average shift between the borders of scar and clips were 1.7, 1.2, 1.2, and 0.9 cm in superior, inferior, medial, and lateral directions, respectively. The area of the CF was larger than SF and IF in 6/20 patients. In 15/20 patients, the area difference between SF and IF was less than 5%. One to three clips were seen outside the CF in 15/20 patients. In addition, dosimetrically inadequate coverage of clips (less than 80% of prescribed dose) were observed in 17/20 patients when CF was used as the boost field. Conclusion: The electron field determined from clinical scar underestimates the tumor bed in superior-inferior direction significantly and thereby underdosing the tissue at risk. The electron field obtained from surgical clips alone dose not cover the entire scar properly. As a consequence, our technique, which combines the surgical clips and clinical scars in determining electron boost field, was proved to be effective in minimizing the geographical miss as well as normal tissue complications.

유럽, 미국, 일본의 선형가속기 정도관리 비교

이레나,이수진,최진호 한국의학물리학회 2003 의학물리 Vol.14 No.1

컴퓨터에 의해 작동되는 선형가속기의 경우 모든 기기가 적절히 작동되는가를 확인하는 정도관리가 오작동으로 인한 환자 피해를 방지하기 위해 절대적으로 필요하다. 따라서 컴퓨터로직 및 마이크로 프로세서에 의해 작동되는 시스템의 안전을 고려하는 많은 보고서들이 발표되었다. 그 보고서에는 소프트웨어 및 하드웨어 고장으로 인해 발생하는 문제점들을 개선하기 위한 방법들이 제시하고 있다. 이와 관련하여 국내의 경우도 컴퓨터에 의해 작동되는 선형가속기의 수가 점차 적으로 증가하고 있는데 비해 체계적이고 일원화된 정도관리서가 없는 실정이다. 따라서 본 논문에서는 국내의 실정에 맞는 선형가속기 정도관리 기술을 개발하기 위한 기반으로 사용하기 위해 미국, 일본, 및 유럽에서 가장 일반적으로 사용되고 있는 정도관리서를 수집 및 요약하였다. 또한 각 나라간의 공통점 및 차이점이 비교분석 하였다. 국가별 정도관리를 비교한 결과 유럽의 경우 미국의 AAPM TG40을 참고자료로 주로 사용하였으며 중요한 정도관리의 항목은 점검주기에는 약간의 차이가 있으나 점검항목들은 거의 동일하다. For the treatment of cancer using computer controlled linear accelerator, it is important to ensure that all equipments are operated properly. Therefore, many studies were performed and published on the safe use of radiotherapy machine controlled by computer logic and microprocessor These studies provided methods of preventing accident from software and hardware failure. In Korea, the use of computer controlled linear accelerator has increased over the past 10 years. However, there are no standard protocols for quality assurance (QA) of linear accelerator. In this study, three QA protocols from America, Japan, and Europe were collected and summarized. In addition, agreement and disagreement among the protocols were analyzed. In conclusion, the QA items included in the protocols were similar among the various QA protocols although there were differences in performance frequencies.

전립선암 환자의 방사선 치료 시 방광 체적 변화

이레나,이지혜,이경자,지영훈 대한방사선방어학회 2008 방사선방어학회지 Vol.33 No.2

자궁암 치료용 다채널 초음파 온열치료기

이레나,Lee Rena 한국의학물리학회 2005 의학물리 Vol.16 No.1

본 연구에서는 자궁경부암 및 질암 치료 시 고선량률 강내 근접치료기와 병행하여 사용가능한 다채널 초음파 온열 치료 기구를 제작하였다. 텐덤형의 경우 자궁 내에 삽입이 용이하도록 외부직경 4 mm, 두께 0.7 mm, 길이 24.5 mm인 원통형 plezo-ceramic crystal transducer (PZT-5A) 물질이 초음파 발생원으로 사용되었다. 질벽 또는 질 천정치료에 이용될 치료기는 질에 삽입되어야 하므로 질의 크기와 비슷한 직경 24.5 mm, 두께 1.3 mm, 길이 15.2 mm인 원통형 PZT-8 물질이 이용되었다. 임피던스와 phase 측정결과에 따라 외부직경이 4 mm인 PZT-5A의 작동주파수는 3.2 MHz 로 결정되었고 외부직경이 24.5 mm인 PZT-8 물질의 작동 주파수는 1.7 MHz로 결정되었다. Radiation force 방법으로 측정된 초음파 발생효율은 텐덤형 초음파원은 33%이고 원통형 초음파원은 61%이다. 원통형 초음파 발생물질로부터 발생되는 초음파 분포도를 MATLAB을 이용하여 계산하였고 실제 물 팬텀 내에서 열전대를 이용하여 측정하였다. 계산을 통해 얻어진 radial 한 방향으로 방사된 초음파압은 자궁내로 삽입되는 텐덤형 트랜스듀서의 경우 표면에서 5 mm 되는 점을 기준으로 10 mm 에서는 58%이고 20 mm에서는 45%이다. 질 치료에 사용될 트랜스듀서의 세기는 표면으로부터 5 mm에서의 세기를 기준으로 15 mm 거리에서는 78%, 25 mm 거리에서는 66%로 감소하였다. 특성분석 결과 직경 4 mm인 PZT-5A 와 24.5 mm인 PZT8 물질은 온열치료의 초음파원으로 사용가능함이 입증되었다. 따라서 직경 4 mm인 PZT-5A 트랜스듀서 3개를 연결하여 치료길이가 75 mm인 텐덤형 온열치료기구를 제작하였고 직경 24.5 mm인 PZT-8 트랜스듀서 4개를 연결하여 치료길이가 61 mm인 질암 치료용 온열치료기구를 제작하였다. The objective of this study was to construct multi-element ultrasound applicators for the treatment of gynecologic cancer with high dose rate brachytherapy. For the treatment of uterus, piezo-ceramic crystal transducer (PZT -5A) with outer diameter of 4 mm, wall thickness of 1.3 mm, and length of 24.5 mm was selected. For the treatment of cervix or vagina, it should be possible to insert the applicator into the vagina. Thus, a cylindrical PZT -8 material with outer diameter of 24.5 mm, wall thickness of 1.3 mm, and length of 15.2 mm was selected. The operating frequencies determined by vector impedance measurement were 3.2 MHz for the PZT 5A cylinder (OD=4 mm) and 1.7 MHz for the PZT -8 cylinder (OD: 24.5 mm). The ratios of generated acoustic output power to applied electric power were 33% and 61% for the tandem type crystal and the cylinder type crystal, respectively. The radiated acoustic pressure fields from both transducers were calculated using a Matlab code and measured in water using hydrophone. There was good agreement between measured and calculated acoustic pressure field distribution. For a tandem type transducer, the calculated acoustic pressure field decreased from 0.023 MPa at 10 mm to 0.010 Mpa at 30 mm, the reduction of 57%. For the cylinder type transducer which will be used for the treatment of vagina showed 78% reduction at 15 mm and 66% at 25 mm as compared to values at 5 mm from the surface. Based on the characteristics of the transducers, this study demonstrated the possibility of using the crystals as a heating source. Finally, a 3-element and 4-element prototype applicators were constructed. The 3-element applicator is 75 mm long and 4 mm thick and will be used for the treatment of uterus. The 4-element applicator is 61 mm long and 24.5 mm thick and will be used for the treatment of vagina. Using these applicators, it is possible to generate enough power to increase temperature to therapeutic level.