• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.469-473
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• 2010

본 논문에서는 조각 병리 영상을 강체 정합을 통해 하나의 영상으로 자동 스티칭하는 방법을 제안한다. 제안 방법은 영상의 위치 초기화, 위치 보정, 강체 정합의 세 단계로 이루어진다. 첫째, 영상의 위치 초기화 단계에서는 순서 없이 흩어진 부분 영상을 탬플릿 매칭 기법을 사용한 영상 내 문자 인식을 통해 위치를 초기화한다. 둘째, 강체 정합의 정확성을 높이기 위해 코너점을 이용해 부분 영상의 위치를 보정한다. 셋째, 조각 영상 간 거리를 최소화하는 강체 정합을 수행한다. 실험 결과, 부분 영상 간 간격이 최소화되어 하나의 영상으로 스티칭되는 것을 확인하였고, 최적화 반복 횟수와 변환 벡터에 따른 정확성, 견고성 평가를 통해 거리 차의 제곱 합이 최소화되어 수렴됨을 알 수 있었다. 본 논문의 제안 방법은 조각 영상을 하나의 영상으로 스티칭함으로써 병리 조직의 전체적인 구조 파악과 이를 이용한 전립선암 확진에 사용될 수 있다.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.91-98
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• 2011

Purpose: To assess the usefulness of implanted fiducial markers in the setup of hypofractionated radiotherapy for prostate cancer patients by comparing a fiducial marker matched setup with a pelvic bone match. Materials and Methods: Four prostate cancer patients treated with definitive hypofractionated radiotherapy between September 2009 and August 2010 were enrolled in this study. Three gold fiducial markers were implanted into the prostate and through the rectum under ultrasound guidance around a week before radiotherapy. Glycerin enemas were given prior to each radiotherapy planning CT and every radiotherapy session. Hypofractionated radiotherapy was planned for a total dose of 59.5 Gy in daily 3.5 Gy with using the Novalis system. Orthogonal kV X-rays were taken before radiotherapy. Treatment positions were adjusted according to the results from the fusion of the fiducial markers on digitally reconstructed radiographs of a radiotherapy plan with those on orthogonal kV X-rays. When the difference in the coordinates from the fiducial marker fusion was less than 1 mm, the patient position was approved for radiotherapy. A virtual bone matching was carried out at the fiducial marker matched position, and then a setup difference between the fiducial marker matching and bone matching was evaluated. Results: Three patients received a planned 17-fractionated radiotherapy and the rest underwent 16 fractionations. The setup error of the fiducial marker matching was $0.94{\pm}0.62$ mm (range, 0.09 to 3.01 mm; median, 0.81 mm), and the means of the lateral, craniocaudal, and anteroposterior errors were $0.39{\pm}0.34$ mm, $0.46{\pm}0.34$ mm, and $0.57{\pm}0.59$ mm, respectively. The setup error of the pelvic bony matching was $3.15{\pm}2.03$ mm (range, 0.25 to 8.23 mm; median, 2.95 mm), and the error of craniocaudal direction ($2.29{\pm}1.95$ mm) was significantly larger than those of anteroposterior ($1.73{\pm}1.31$ mm) and lateral directions ($0.45{\pm}0.37$ mm), respectively (p<0.05). Incidences of over 3 mm and 5 mm in setup difference among the fractionations were 1.5% and 0% in the fiducial marker matching, respectively, and 49.3% and 17.9% in the pelvic bone matching, respectively. Conclusion: The more precise setup of hypofractionated radiotherapy for prostate cancer patients is feasible with the implanted fiducial marker matching compared with the pelvic bony matching. Therefore, a less marginal expansion of planning target volume produces less radiation exposure to adjacent normal tissues, which could ultimately make hypofractionated radiotherapy safer.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.2
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• pp.145-156
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• 2015

Purpose : The purpose of this study is to evaluate the efficiency of Split VMAT planning(Contouring rectum divided into an upper and a lower for reduce rectum dose) compare to Conventional VMAT planning(Contouring whole rectum) for prostate cancer radiotherapy involving pelvic lymph nodes. Materials and Methods : A total of 9 cases were enrolled. Each case received radiotherapy with Split VMAT planning to the prostate involving pelvic lymph nodes. Treatment was delivered using TrueBeam STX(Varian Medical Systems, USA) and planned on Eclipse(Ver. 10.0.42, Varian, USA), PRO3(Progressive Resolution Optimizer 10.0.28), AAA(Anisotropic Analytic Algorithm Ver. 10.0.28). Lower rectum contour was defined as starting 1cm superior and ending 1cm inferior to the prostate PTV, upper rectum is a part, except lower rectum from the whole rectum. Split VMAT plan parameters consisted of 10MV coplanar $360^{\circ}$ arcs. Each arc had $30^{\circ}$ and $30^{\circ}$ collimator angle, respectively. An SIB(Simultaneous Integrated Boost) treatment prescription was employed delivering 50.4Gy to pelvic lymph nodes and 63~70Gy to the prostate in 28 fractions. $D_{mean}$ of whole rectum on Split VMAT plan was applied for DVC(Dose Volume Constraint) of the whole rectum for Conventional VMAT plan. In addition, all parameters were set to be the same of existing treatment plans. To minimize the dose difference that shows up randomly on optimizing, all plans were optimized and calculated twice respectively using a 0.2cm grid. All plans were normalized to the prostate $PTV_{100%}$ = 90% or 95%. A comparison of $D_{mean}$ of whole rectum, upperr ectum, lower rectum, and bladder, $V_{50%}$ of upper rectum, total MU and H.I.(Homogeneity Index) and C.I.(Conformity Index) of the PTV was used for technique evaluation. All Split VMAT plans were verified by gamma test with portal dosimetry using EPID. Results : Using DVH analysis, a difference between the Conventional and the Split VMAT plans was demonstrated. The Split VMAT plan demonstrated better in the $D_{mean}$ of whole rectum, Up to 134.4 cGy, at least 43.5 cGy, the average difference was 75.6 cGy and in the $D_{mean}$ of upper rectum, Up to 1113.5 cGy, at least 87.2 cGy, the average difference was 550.5 cGy and in the $D_{mean}$ of lower rectum, Up to 100.5 cGy, at least -34.6 cGy, the average difference was 34.3 cGy and in the $D_{mean}$ of bladder, Up to 271 cGy, at least -55.5 cGy, the average difference was 117.8 cGy and in $V_{50%}$ of upper rectum, Up to 63.4%, at least 3.2%, the average difference was 23.2%. There was no significant difference on H.I., and C.I. of the PTV among two plans. The Split VMAT plan is average 77 MU more than another. All IMRT verification gamma test results for the Split VMAT plan passed over 90.0% at 2 mm / 2%. Conclusion : As a result, the Split VMAT plan appeared to be more favorable in most cases than the Conventional VMAT plan for prostate cancer radiotherapy involving pelvic lymph nodes. By using the split VMAT planning technique it was possible to reduce the upper rectum dose, thus reducing whole rectal dose when compared to conventional VMAT planning. Also using the split VMAT planning technique increase the treatment efficiency.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.23-29
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• 1999

Purpose : To evaluate the efficacy of radiation therapy and extrafascial hysterectomy in bulky stage IB, IIA-B uterine cervix cancers. Methods and Materials : Twenty four patients with bulky stage IB and IIA-B carcinoma of the uterine cervix were treated with extrafascial hysterectomy following radiation therapy due to doubts of residual disease at Department of therapeutic radiology, Keimyung University, Dongsan Hospital, from April 1986 to December 1997 According to FIGO staging system, there were 7 patients with stage IB, 9 patients with IIA and 8 patients with IIB stage whose median age was 45. Pathologic distribution showed 16 patients with squamous cell carcinoma and 8 patients with adenocarcinoma. Seven patients had tumors that are less than 5cm in size and 17 patients had tumors with larger than 5cm. The mean interval between radiation therapy and extrafascial hysterectomy was 57 days. The radiation therapy consisted of external irradition to the whole pelvis (180 cGy/fraction, mean 4100 cGy) and parametrial boost (for a mean total dose of 5000 cGy) with midline shield (4H 10 cm), followed by intracavitary irradiation up to 7500 cGy to point A (maximum 8500 cGy). The maximum follow up duration was 107 months and mean follow up duration was 42 months. Results :Ten out of 24 patients (41.7%) had residual disease found at the time of extrafascial hysterectomies. Five year overall survival rate (5Y OSR) and five year disease free survival rate (5Y DFSR) were 63.6% and 62.5% respectively. Five year overall survival rate for stage IB and IIA was 71.4% and 50% for stage IIB. There was a significant difference in 5Y OSR and 5Y DFSR between patients with and those without residual disease (negative vs positive, 83.3% vs. 40% (P=0.01), 83.3% vs 36% (P=0.01) respectively). There was a notable tendency of better survival with adenocarcinoma than with squamous cell carcinoma (adenocarcinoma vs squamous cell carcinoma, 85.7% vs. 53.3% (P=0.1), 85.7% vs. 50.9% (P=0.1) of 5Y OSR and 5Y DFS respectivey). Total dose to A point did not make a significant difference in survival rate or the existence of residual lesion (< 7500 cGy, ${\geq}$ 7500 cOy). It was also noted that significantly more frequent local failures have occurred in patients with positive residual disease compared with negative residual disease (5/10 vs. 0/14, p=0.003), There was no death related to the treatment. Conclusion : There was no improvement of residual disease and to the overall survival rate in spite of increased total dose to point A. We conclude that there is a possible beneficial effect of radiation therapy followed by extrafaseial hysterectomy in survival for adenocarcinoma of bulky stage IB and IIA-B uterine cervix. We need to confirm this with longer follow up and with large number of patients.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.428-437
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• 2000

Background : Five year survival rate of postoperative stage I non-small cell lung cancer(NSCLC) reaches to 66%. In the remaining one third of patients, however, cancer recurs and the overall survival of NSCLC remains dismal. To evaluate clinical and pathologic characteristics of recurred NSCLC, the patterns and factors for postoperative recurrence in patients with staged I and II NSCLC were studied. Method : A retrospective analysis was performed in 234 patients who underwent radical resection for pathologic stage I and II NSCLC. All patients who were followed up for at least one year were included in this study. Results : 1) There were 177 men and 57 women The median age was 63. The median duration of the follow up period was 732 days (range 365~1,695 days). The overall recurrence rate was 26.5%, and the recurrence occurred $358.8{\pm}239.8$ days after operation. 2) The ages of recurred NSCLC patients were higher ($63.2{\pm}8.8$ years) than those of non-recurred patients ($60.3{\pm}9.8$ years)(p=0.043). The recurrence rate was higher in stage II (46.9%) than in stage I (18.8%) NSCLC p<0.001. The size of primary lung mass was larger in recurred ($5.45{\pm}3.22\;cm$) than that of non-recurred NSCLC ($3.74{\pm}1.75\;cm$, p<0.001). Interestingly, there were no recurrent cases when the resected primary tumor was less than 2cm. 3) Distant recurrence was more frequent than locoregional recurrence (66.1% vs. 33.9%). Distant recurrence rate was higher in females and in cases of adenocarcinoma. Brain metastasis was more frequent in patients with adenocarcinoma than in those with squamous cell carcinoma (p=0.024). Conclusion: The tumor size and stage were two important factors for determining the possibility of a recurrence. Because distant brain metastasis was more frequent in patients with adenocarinoma, a prospective study should be conducted to evaluate the effectiveness of preoperative brain imaging.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.275-282
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• 1998

Purpose : The effect of hyperfractionated radiotherapy on locally advanced non-small lung cancer was studied by a retrospective analysis. Materials & Methods : We analyzed sixty one patients of biopsy-confirmed, IIIA and IIIB non-small cell lung cancer. Using the ECOG performance scale, all the patients were scored less than 2. They were treated by curative hyperfractionated radiotherapy alone from Oct. 1992 to Oct. 1995 at the Department of Radiation Oncology. All the patients received 120cGy b.i.d with more than 6 hours interval between each fraction. The total dose of radiation was reached up to 6400-7080 cGy with a mean dose of 6934 cGy. The results were analyzed retrospectively. Results : The overall survival rate was 53 1$\%$ in 1 year, 9.9$\%$ in 2 years with a median survival time (MST) of 13.9 months. The progression free survival (PFS) rate was 37.0$\%$ in 1 year, 8.9$\%$ in 2 years. Twenty two Patients were classified as complete responders to this treatment and their MST was 19.5 months When this was compared with that of partial responders (MST: 11 7months), it was statistically significant (p=0.0003). Twenty nine patients of stage IIIA showed a better overall survival rate (1yr 63.3$\%$, 2yr 16.8$\%$) than IIIB patients (1yr 43.3$\%$, 2yr 3.6$\%$), which was also statistically significant (p=0.003). Patients with adenocarcinoma showed a better survival rate (1yr 64.3$\%$, 2yr 21.4$\%$) than that of squamous cell counterpart (1yr 49.4$\%$, 2yr 7.4$\%$), although this was not significant statistically (p=0.61). Two patients developed fatal radiation-induced pneumonia right after the completion of the treatment which progressed rapidly and they all died within 2 months. One patient developed radiation-induced fibrosis after 13 months. He refused further treatment and died soon after the development of fibrosis. Conclusion : Among locally advanced NSCLC, hyperfractionated radiotherapy was effective on stage IIIA patients by increasing MST with acceptable toxicities. Acute radiation-induced pneumonia should be carefully monitored and must be avoided during or after this treatment.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.625-634
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• 2003

More than a decade after its initial proposal, deployment of IP Multicast has been limited due to the problem of traffic control in multicast routing, multicast address allocation in global internet, reliable multicast transport techniques etc. Lately, according to increase of multicast application service such as internet broadcast, real time security information service etc., overlay multicast is developed as a new internet multicast technology. In this paper, we describe an overlay multicast protocol and propose fast join mechanism that considers switching of the tree. To find a potential parent, an existing search algorithm descends the tree from the root by one level at a time, and it causes long joining latency. Also, it is try to select the nearest node as a potential parent. However, it can't select the nearest node by the degree limit of the node. As a result, the generated tree has low efficiency. To reduce long joining latency and improve the efficiency of the tree, we propose searching two levels of the tree at a time. This method forwards joining request message to own children node. So, at ordinary times, there is no overhead to keep the tree. But the joining request came, the increasing number of searching messages will reduce a long joining latency. Also searching more nodes will be helpful to construct more efficient trees. In order to evaluate the performance of our fast join mechanism, we measure the metrics such as the search latency and the number of searched node and the number of switching by the number of members and degree limit. The simulation results show that the performance of our mechanism is superior to that of the existing mechanism.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.289-295
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• 2014

Purpose : Cone Beam Computed Tomography(CBCT) in Image Guided Radiation Therapy(IGRT), Set-up error can be reduced but exposure dose of the patient due to CBCT will increase. Through this study, we are to evaluate by making a scenario with the implementation period of CBCT as every other day. Materials and Methods : Of prostate cancer patients, 9 patients who got a Intensity Modulated Radiation Therapy(IMRT) with CBCT in IGRT were analyzed. Based on values corrected by analyzing set-up error by using CBCT every day during actual treatment, we created a scenario that conducts CBCT every other day. After applying set-up error values of the day not performing CBCT in the scenario to the treatment planning system(Pinnacle 9.2, Philips, USA) by moving them from the treatment iso-center during actual treatment, we established re-treatment plan under the same conditions as actual treatment. Based on this, the dose distribution of normal organs and Planning Target Volume(PTV) was compared and analyzed. Results : In the scenario that performs CBCT every other day based on set-up error values when conducting CBCT every day, average X-axis : $0.2{\pm}0.73mm$, Y-axis : $0.1{\pm}0.58mm$, Z-axis : $-1.3{\pm}1.17mm$ difference was shown. This was applied to the treatment planning to establish re-treatment plan and dose distribution was evaluated and as a result, Dmean : -0.17 Gy, D99% : -0.71 Gy of PTV difference was shown in comparison with the result obtained when carrying out CBCT every day. As for normal organs, V66 : 1.55% of rectal wall, V66 : -0.76% of bladder difference was shown. Conclusion : In case of a CBCT perform every other day could reduce exposure dose and additional treatment time. And it is thought to be able to consider the application depending on the condition of the patient because the difference in the dose distribution of normal organs, PTV is not large.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.2
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• pp.9-13
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• 2016

Purpose PET-CT examinations using $^{18}F-FDG$ to treat urinary system cancer are limited in terms of anatomical structure and excretion route of $^{18}F-FDG$. But one of the ongoing examinations utilizing $^{11}C-Acetate$ can compensate for such defects. We would like to introduce a clinical application of $^{11}C-Acetate$ PET-CT in urinary cancer patients. Materials and Methods We conducted a clinical survey of 22 patients diagnosed with urinary cancer at our hospital, 10 prostate cancer patients, 10 renal cell carcinoma patients, and 2 bladder cancer patients. All patients were performed $^{18}F-FDG$ PET-CT examinations, $^{11}C-Acetate$ examinations were performed after two weeks on average. The equipment used to D-710 PET-CT in GE Company and we performed PET-CT procedures 15 minutes after injecting $^{11}C-Acetate$, and a medical doctor from the department of nuclear medicine appraised and compared images between $^{18}F-FDG$ and $^{11}C-Acetate$. Results According to our survey, prostate cancer patients generally had lower uptake of $^{18}F-FDG$ than other cancer patients did. In 2 out of 10 prostate cancer patients, metastasized cancer showed greater uptake in $^{11}C-Acetate$ than $^{18}F-FDG$. In renal cell carcinoma cases, 8 out of 10 patients displayed evidently greater uptake in $^{11}C-Acetate$ than $^{18}F-FDG$. We excluded bladder cancer cases in this study because uptake of $^{18}F-FDG$ in the bladder was too hot, the number of patients was insufficient, and the cases did not meet criteria such as the use of diuretics. Conclusion It is too premature to draw solid conclusions from the survey, since it involved only a small number of participants. However, there are a number of studies conducted abroad that prove the effectiveness of the $^{11}C-Acetate$ PET-CT examinations in treating urinary system cancer, and this study is still ongoing at our hospital. If the tests were to be conducted on a larger number of participants, this study could lead to numerous other potential research topics, such as the correlation between Prostatic specific antigen (PSA) values and $^{11}C-Acetate$ PET-CT, Gleason sum values from biopsy before surgery, Specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV) between $^{18}F-FDG$ PET-CT examinations and $^{11}C-Acetate$ PET-CT examinations in other urinary system cancers.

• Progress in Medical Physics
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• v.21 no.3
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• pp.298-303
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• 2010

The aim of this study was to compare the dose distribution of intensity modulated radiation therapy (IMRT) with 3 dimensional conformal radiation therapy (3DCRT) in prostate cancer. The IMRT plan and the 3DCRT plan used the 9 fields technique, respectively. In IMRT, tumor dose was a total dose of 66 Gy at 2.0 Gy per day, 5 days a week for 5 weeks. All cases were following the dose volume histogram (DVH) constraints. The maximum and minimum tumor dose constraints were 6,700 cGy and 6,500 cGy, respectively. The rectum dose constraints were <35% over 50 Gy. The bladder dose constraints were <35% over 40 Gy. The femur head dose constraints were <15% over 20 Gy. Tumor dose in the 3DCRT were 66 Gy. In IMRT, the maximum dose of PTV was 104.4% and minimum dose was 89.5% for given dose. In 3DCRT, the maximum dose of PTV was 105.3% and minimum dose was 85.5% for given dose. The rectum dose was 34.0% over 50 Gy in IMRT compared with 63.3% in 3DCRT. The bladder dose was 30.1% over 40 Gy in IMRT compared with 30.6% in 3DCRT. The right femur head dose was 9.5% over 20 Gy in IMRT compared with 17.5% in 3DCRT. The left femur head dose was 10.6% over 20 Gy in IMRT compared with 18.3% in 3 DCRT. The dose of critical organs (rectum, bladder, and femur head) in IMRT showed to reduce than dose of 3DCRT. The rectum dose over 50 Gy in IMRT was reduced 29.3% than 3DCRT. The bladder dose over 40 Gy in IMRT was similar to 3DCRT. The femur head dose over 20 Gy in IMRT was reduced about 7~8% than 3DCRT.