Risk Factors for Distant Metastasis in Extrahepatic Bile Duct Cancer after Curative Resection (KROG 1814) / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Risk factors predicting distant metastasis (DM) in extrahepatic bile duct cancer (EHBDC) patients treated with curative resection were investigated. @*Materials and Methods@#Medical records of 1,418 EHBDC patients undergoing curative resection between Jan 2000 and Dec 2015 from 14 institutions were reviewed. After resection, 924 patients (67.6%) were surveilled without adjuvant therapy, 297 (21.7%) were treated with concurrent chemoradiotherapy (CCRT) and 148 (10.8%) with CCRT followed by chemotherapy. To exclude the treatment effect from innate confounders, patients not treated with adjuvant therapy were evaluated. @*Results@#After a median follow-up of 36.7 months (range, 2.7 to 213.2 months), the 5-year distant metastasis-free survival (DMFS) rate was 57.7%. On multivariate analysis, perihilar or diffuse tumor (hazard ratio [HR], 1.391; p=0.004), poorly differentiated histology (HR, 2.014; p < 0.001), presence of perineural invasion (HR, 1.768; p < 0.001), positive nodal metastasis (HR, 2.670; p < 0.001) and preoperative carbohydrate antigen (CA) 19-9 ≥ 37 U/mL (HR, 1.353; p < 0.001) were significantly associated with inferior DMFS. The DMFS rates significantly differed according to the number of these risk factors. For validation, patients who underwent adjuvant therapy were evaluated. In patients with ≥ 3 factors, additional chemotherapy after CCRT resulted in a superior DMFS compared with CCRT alone (5-year rate, 47.6% vs. 27.7%; p=0.001), but the benefit of additional chemotherapy was not observed in patients with 0-2 risk factors. @*Conclusion@#Tumor location, histologic differentiation, perineural invasion, lymph node metastasis, and preoperative CA 19-9 level predicted DM risk in resected EHBDC. These risk factors might help identifying a subset of patients who could benefit from additional chemotherapy after resection.

Implications of Radiotherapy Utilization in Korea from 2010 to 2019

Background@#This study was to assess the rate of radiotherapy (RT) utilization according to the modality in South Korea to identify the implications of contemporary RT patterns. @*Methods@#We collected information from claims and reimbursement records of the National Health Insurance Service from 2010 to 2019. We classified the location of each institution as capital (Seoul, Incheon, and Gyeonggi-do) and non-capital areas. @*Results@#The rate of RT utilization in total cancer patients nationwide was 24.5% in 2010, which consistently has increased to 36.1% in 2019 (annual increase estimate [AIE], 4.5%). There was an abrupt increase in patients receiving intensity-modulated RT (IMRT), with an AIE of 33.5%, and a steady decline in patients receiving three-dimensional conformal RT (3DCRT), with an AIE of −7.1%. The commonest RT modality was IMRT (44.5%), followed by 3DCRT and stereotactic RT (SRT) (37.2% and 13.5%) in 2019. An increasing trend of advanced RT (such as IMRT and SRT) utilization was observed regardless of the region, although the AIE in the capital areas was slightly higher than that in non-capital areas. @*Conclusion@#The utilization of overall RT application and especially of advanced modalities remarkably increased from 2010 to 2019. We also found gaps in their AIEs between capital and non-capital areas. We should ensure that advanced RT is accessible to all cancer patients across South Korea.

Implications of Radiotherapy Utilization in Korea from 2010 to 2019

Background@#This study was to assess the rate of radiotherapy (RT) utilization according to the modality in South Korea to identify the implications of contemporary RT patterns. @*Methods@#We collected information from claims and reimbursement records of the National Health Insurance Service from 2010 to 2019. We classified the location of each institution as capital (Seoul, Incheon, and Gyeonggi-do) and non-capital areas. @*Results@#The rate of RT utilization in total cancer patients nationwide was 24.5% in 2010, which consistently has increased to 36.1% in 2019 (annual increase estimate [AIE], 4.5%). There was an abrupt increase in patients receiving intensity-modulated RT (IMRT), with an AIE of 33.5%, and a steady decline in patients receiving three-dimensional conformal RT (3DCRT), with an AIE of −7.1%. The commonest RT modality was IMRT (44.5%), followed by 3DCRT and stereotactic RT (SRT) (37.2% and 13.5%) in 2019. An increasing trend of advanced RT (such as IMRT and SRT) utilization was observed regardless of the region, although the AIE in the capital areas was slightly higher than that in non-capital areas. @*Conclusion@#The utilization of overall RT application and especially of advanced modalities remarkably increased from 2010 to 2019. We also found gaps in their AIEs between capital and non-capital areas. We should ensure that advanced RT is accessible to all cancer patients across South Korea.

A Survey of Radiation Therapy Utilization in Korea from 2010 to 2016: Focusing on Use of Intensity-Modulated Radiation Therapy

BACKGROUND: This study aimed to assess the recent changes of radiation therapy (RT) modalities in Korea. In particular, we focused on intensity-modulated radiation therapy (IMRT) utilization as the main index, presenting the application status of advanced RT. METHODS: We collected information from the Korean Health and Insurance Review and Assessment Service data based on the National Health Insurance Service claims and reimbursements records by using treatment codes from 2010 to 2016. We classified locating region of each institution as capital vs. non-capital areas and metropolitan vs. non-metropolitan areas to assess the regional difference in IMRT utilization in Korea. RESULTS: IMRT use has been steadily increased in Korea, with an annual increase estimate (AIE) of 37.9% from 2011 to 2016 (P < 0.001) resulting in IMRT being the second most common RT modality following three-dimensional conformal radiotherapy. In general, an increasing trend of IMRT utilization was observed, regardless of the region. The rate of AIE in the capital areas or metropolitan areas was higher than that in non-capital areas or non-metropolitan areas (40.7% vs. 31.9%; P < 0.001 and 39.7% vs. 29.4%; P < 0.001, respectively). DISCUSSION: The result of our survey showed that IMRT has become one of the most common RT modalities. IMRT is becoming popular in both metropolitan and non-metropolitan areas, while metropolitan area has faster AIE possibly due to concentration of medical resources and movement of advanced patients.

Multicenter Planning Comparison of Stereotactic Body Radiotherapy for Hepatocellular Carcinoma with Major Portal Vein Tumor Thrombosis (KROG 16-17)

BACKGROUND/AIMS: To evaluate the technical feasibility of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) with the major portal vein tumor thrombosis (PVTT). METHODS: Ten institutions affiliated with the Korean Stereotactic Radiosurgery Group were provided the contours of four cases: the first case was the first branch PVTT with sufficient normal liver volume (NLV), the second was the first branch PVTT with insufficient NLV, the third was the main trunk PVTT at confluence level, and the fourth was the main trunk PVTT with entire length. The institutions were asked to make SBRT plans according to their current treatment protocols and to complete facility questionnaires. RESULTS: Based on institutional protocols, SBRT was feasible in nine institutions for the first case (32–60 Gy in 3–5 fractions), in eight institutions for the second case (32–50 Gy in 3–5 fractions), in seven institutions for the third case (35–60 Gy in 3–5 fractions), and in four institutions for the fourth case (35–42 Gy in 4–5 fractions). The other institutions recommended hypo- or conventional fractionation due to insufficient NLV or gastrointestinal organ proximity. With analysis of the SBRT dose to the central hepatobiliary tract, the major PVTT could theoretically be associated with a high risk of hepatobiliary toxicity. CONCLUSIONS: Although SBRT is a technically feasible option for HCC with the major PVTT, there was a variability among the participating institutions. Therefore, further studies will be necessary to standardize the practice of SBRT for the major PVTT.

Hypofractionated stereotactic body radiotherapy in low- and intermediate-risk prostate carcinoma

PURPOSE: Stereotactic body radiotherapy (SBRT) takes advantage of low α/β ratio of prostate cancer to deliver a large dose in few fractions. We examined clinical outcomes of SBRT using CyberKnife for the treatment of low- and intermediate-risk prostate cancer. MATERIALS AND METHODS: This study was based on a retrospective analysis of the 33 patients treated with SBRT using CyberKnife for localized prostate cancer (27.3% in low-risk and 72.7% in intermediate-risk). Total dose of 36.25 Gy in 5 fractions of 7.25 Gy were administered. The acute and late toxicities were recorded using the Radiation Therapy Oncology Group scale. Prostate-specific antigen (PSA) response was monitored. RESULTS: Thirty-three patients with a median 51 months (range, 6 to 71 months) follow-up were analyzed. There was no biochemical failure. Median PSA nadir was 0.27 ng/mL at median 33 months and PSA bounce occurred in 30.3% (n = 10) of patients at median at median 10.5 months after SBRT. No grade 3 acute toxicity was noted. The 18.2% of the patients had acute grade 2 genitourinary (GU) toxicities and 21.2% had acute grade 2 gastrointestinal (GI) toxicities. After follow-up of 2 months, most complications had returned to baseline. There was no grade 3 late GU and GI toxicity. CONCLUSION: Our experience with SBRT using CyberKnife in low- and intermediate-risk prostate cancer demonstrates favorable efficacy and toxicity. Further studies with more patients and longer follow-up duration are required.

The Efficacy of Intraluminal Brachytherapy as Palliative Therapy of Hilar Cholangiocarcinoma / 대한췌담도학회지

BACKGROUND/AIMS: The aim of this study is to assess the therapeutic benefits of a combination of external beam radiation therapy (EBRT) and intraluminal brachytherapy (ILBT) in hilar cholangiocarcinoma as palliative therapy. METHODS: A total of 21 patients with hilar cholangiocarcinoma were included. Only 12 patients were treated with EBRT (group 1), and only nine patients were treated with EBRT and ILBT (group 2). The survival data and stent patency period were measured in both groups and the results were compared. RESULTS: No statistically significant difference in patient survival was observed between the two groups. The median survival period of group 1 was 353 days and that of group 2 was 224 days. Also, stent patency did not differ significantly between groups. The period for group 1 was 250 days, and that of group 2 was 133 days. In addition, there were no other factors influencing patient survival and stent patency period. However, patient survival tended to increase with increase in the amount of irradiation dose (Spearman's correlation coefficient=0.65, p=0.065). CONCLUSIONS: EBRT with ILBT did not have a benefit when compared with the treatment effect of EBRT alone as palliative therapy for hilar cholangiocarcinoma.

Repair of type I endoleak by chimney technique after endovascular abdominal aortic aneurysm repair

Endovascular aneurysm repair is a minimally invasive, durable and effective alternative to open surgery for treatment of abdominal aortic aneurysms (AAA). However, in patients who do not have an adequate sealing zone, open surgical repair is required, which may increase mortality and morbidity. An alternative treatment in patients with challenging anatomy is the so-called "chimney graft" technique. Here, we describe a case using the chimney graft technique for treatment of juxtarenal type I endoleak followed by a previous conventional stent graft insertion to the AAA with good results.

The Analysis of the Outcome of Short- and Long-Segment Posterior Instrumentation for Thoracolumbar Bursting Fractures

STUDY DESIGN: A retrospective study. SUMMARY OF THE LITERATURE REVIEW: The reports comparing short- and long-segment instrumentation are insufficient. OBJECTIVES: To determine the postoperative results and to analyze relative factors affecting results between short- and long-segment instrumentation in thoracolumbar fractures. MATERIALS AND METHODS: From March 2006 to March 2012, 97 patients with thoracolumbar fracture were treated with posterior instrumentation. They were divided into 2 groups, the short- (Group I) and long-segment groups (Group II). To analyze factors affecting results, several factors including age, anterior column height (ACH), and the kyphotic angle were reviewed. For radiologic evaluation, postoperative and follow-up radiographs were evaluated by measuring the kyphotic angle and ACH. Additionally, the presence of complications was reviewed. RESULTS: Groups I and II consisted of 45, 52 cases and had mean ages of 50.3, 55.8 years, respectively. In Group I, the ACH increased from 44.2% to 75.3% postoperatively, and remained 72.8% at follow-up. The kyphotic angle decreased from 19.4degrees to 10.6degrees postoperatively, and remained at 12.8degrees at follow-up. In Group II, the ACH recovered from 41.6% to 76.4% postoperatively, and was 74.8% at follow-up. The kyphotic angle decreased from 21.6degrees to 12.6degrees postoperatively, and was 13.9degrees at follow-up. The canal compromise, age, and comminution were not directly related with results. However, the mean age of the 7 cases showing complications was 72 years, and the 7 cases had severe comminuted fractures. CONCLUSIONS: The short- and long-segment instrumentations of thoracolumbar fractures are not significantly different with respect to the results attained. However, in order to decrease complications, we should pay attention to age and fracture comminution.

Internal Iliac Artery Embolization during an Endovascular Aneurysm Repair with Detachable Interlock Microcoils

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of detachable interlock microcoils for an embolization of the internal iliac artery during an endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: A retrospective review was conducted on 40 patients with aortic aneurysms, who had undergone an EVAR between January 2010 and March 2012. Among them, 16 patients were referred for embolization of the internal iliac artery for the prevention of type II endoleaks. Among 16 patients, 13 patients underwent embolization using detachable interlock microcoils during an EVAR. Computed tomographic angiographies and clinical examinations were performed during the follow-up period. Technical success, clinical outcome, and complications were reviewed. RESULTS: Internal iliac artery embolizations using detachable interlock microcoils were technically successful in all 13 patients, with no occurrence of procedure-related complications. Follow-up imaging was accomplished in the 13 cases. In all cases, type II endoleak was not observed with computed tomographic angiography during the median follow-up of 3 months (range, 1-27 months) and the median clinical follow-up of 12 months (range, 1-27 months). Two of 13 (15%) patients had symptoms of buttock pain, and one patient died due to underlying stomach cancer. No significant clinical symptoms such as bowel ischemia were observed. CONCLUSION: Internal iliac artery embolization during an EVAR using detachable interlock microcoils to prevent type II endoleaks appears safe and effective, although this should be further proven in a larger population.

Combined Treatment of Murine Fibrosarcoma with Chemotherapy (Paclitaxel), Radiotherapy, and Intratumoral Injection of Dendritic Cells

BACKGROUND: New antitumor therapeutic strategies aim to combine different approaches that are able to induce tumor-specific effector and memory T cell responses that might control tumor growth. Dendritic cells (DCs) have the capacity to induce antigen-specific cytotoxic T lymphocytes. We have previously shown that the combined treatment of paclitaxel chemotherapy (Chemo) and injection of DCs led to complete tumor regression. OBJECTIVE: The goal of this study was to evaluate synergistic antitumor effect of a triple combination treatment comprising radiotherapy, paclitaxel Chemo and intratumoral injection of syngeneic bone marrow-derived DCs on murine fibrosarcoma, compared to other single or double combination treatments. METHODS: For the murine fibrosarcoma model, naive C57BL/6 mice were inoculated intradermally with 2x10(3) MCA102 cells in the right upper flank. Mice were assigned to five groups (untreatedcontrol, RT alone, RT+Chemo, RT+DC, and RT+Chemo+DC), with eight mice in each group. In vitro cytotoxicity assays were performed to assess the immune activity. The persistence of tumor-specific immunity was determined by second tumor challenge in mice with complete tumor regression. RESULTS: The triple combination treatment showed a significantly enhanced therapeutic efficacy by decreasing tumor size and inducing complete tumor regression, resulting in a cure of 50% of mice. The results of in vitro cytotoxicity assays and the second tumor challenge experiment strongly indicated the induction of a tumor-specific cytotoxic T lymphocyte response and acquisition of prolonged tumor immunity. CONCLUSION: These findings suggest that the triple combination treatment can be a promising strategy for the treatment of murine fibrosarcoma.

MR Images of Infarction of Wandering Spleen Associated with Intestinal Non-rotation

Wandering spleen is a rare clinical condition caused by lax splenic suspensory ligaments. The laxity of ligaments causes torsion of splenic vascular pedicle. CT scan of a 7-year-old girl with abdominal pain showed a non-enhancing lobular mass in lower abdomen. Small bowel loops were located at the right-sided abdomen and colonic loops at the left-sided abdomen. MRI scan showed non-enhancing heterogeneous mass with twisted vascular pedicle. To our knowledge, only a few cases have been reported about wandering spleen diagnosed on MRI.

The Result of Minimally Invasive Transforaminal Lumbar Interbody Fusion in Low Grade Spondylolisthesis - Minimum 2 Years Follow Up -

STUDY DESIGNS: A retrospective study. OBJECTIVES: To analyze the clinical and radiological outcomes of spontaneous reduction via minimally invasive transforaminal lumbar interbody fusion (Mini-TLIF) as the treatment for low-grade symptomatic spondylolisthesis. SUMMARY OF LITERATURE REVIEW: Although minimally invasive transforaminal lumbar interbody fusion is technically demanding, this procedure is an effective method for spontaneous reduction of low grade spondylolisthesis. MATERIALS AND METHODS: We analyzed consecutive series of 41 patients with low grade spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion, between April 2008 and July 2009. The minimum follow-up period was 2 years. Clinical evaluation was performed by an analysis of Visual Analogue Scale and Oswestry Disability Index. For the radiological evaluation, disc space height, slip percentage, and slip angle were analyzed. At the final follow-up, the fusion rate was analyzed according to the Bridwell's anterior fusion grade. RESULTS: For the evaluation of clinical outcomes, the Visual Analogue Scale for back pain decreased from 6.8+/-1.2 to 2.0+/-1.1, and that for radiating pain decreased from 7.9+/-1.3 to 1.7+/-1.1. Oswetry Disability Index decreased from 38.5+/-8.4 to 13.4+/-6.1. For the radiological evaluation, disc space height increased from 8.4+/-2.14mm to 11.8+/-1.54mm(P<0.05), slip percentage was reduced from 18.4+/-5.1% to 13.3+/-3.1%(P<0.05) and slip angle decreased from 10.6+/-4.5degrees to 6.2+/-3.4degrees (P<0.05). At the final follow-up, radiological union was obtained in 38 cases (92.7%). CONCLUSIONS: We conclude that minimally invasive transforaminal lumbar interbody fusion appears to be an effective method for spontaneous reduction of low grade spondylolisthesis if the surgeon becomes familiar with this method.

Relation Between Adjacent Superior Segmental Disease and Facet Joint Violations After Posterolateral Lumbar Fusion

STUDY DESIGN: To analyze the relationship between the adjacent superior segment disease and facet joint violations after lumbar fusion. OBJECTIVES: We retrospectively analyzed the relationship between the adjacent superior segment disease and facet joint violations after lumbar fusion. SUMMARY OF LITERATURE REVIEW: Among numerous literatures regarding adjacent superior segment disease, there is no analysis concerning the relationship between adjacent superior segment disease and facet joint violations after lumbar fusion. MATERIALS AND METHODS: We reviewed 2056 patients who underwent lumbar fusion, between March 2004 and April 2009. Analysis was performed for 79 (3.8%) of the 2056 patients with adjacent superior segment disease and needed a second operation. A facet joint was considered as 3 types of violations with computed tomography scans if any of the following situations were encountered: pedicle screw clearly within the facet joint; pedicle screw head clearly within the facet joint; and pedicle screw and/or screw head within 1mm from or abutting the facet joint, without clear joint involvement. RESULTS: The incidence of the violations was 45% (36/79) of all patients and 28% (44/158) of all screws. The incidence of L4-5 facet joint violations was 35% (28/79) of patients with adjacent superior segment disease, statistically. CONCLUSIONS: Facet joint violations were observed in patients with the adjacent superior segment disease after posterolateral lumbar fusion. Because L3-4 facet joint violations increased when L4-5 fusion was done, more care should be taken to avoid facet joint violations when the surgeon is considered for insertion of the pedicle screws at L4-5.

Comparison of TLICS & McAfee Classification in Thoracolumbar Injuries

STUDY DESIGN: A retrospective study. OBJECTIVES: We assessed the intraobserver and interobserver reliability of TLICS classification in the thoracolumbar injuries, which had been evaluated in our hospital. It was compared with that of the older, McAfee classification and discussed for clinical validation. SUMMARY OF LITERATURE REVIEW: Among the numerous literatures regarding the thoracolumbar injury, there is no consensus on the most useful classification, and there is nothing comparing the McAfee classification with the TLICS classification. MATERIALS AND METHODS: Among the 230 patients that were treated with conservative care or operation from January 1, 2005 to January 1, 2010 in our hospital, 185 patients with initial CT and MRI images were assessed. Five orthopedic surgeons reviewed histories, plain film, CT and MRI of the 185 thoracolumbar injury cases, respectively. Each case was classified and scored according to the McAfee classification and the TLICS classification. The case assessment was recorded and the orthopedic surgeons repeated the assessment 1 month later. Intraobserver and interobserver reliability were assessed by statistical analysis. The actual management of each case was compared with the treatment recommended by TLICS classification to calculate the validity of the indexes. RESULTS: Intraobserver and interobserver reliability in TLICS were higher than those in the McAfee classification. Agreement of the TLICS classification for treatment recommendation was 81.7%, comparing with the actual management of previous McAfee classification. Validity indexes were satisfactory in therapeutic decision making, especially specificity. CONCLUSIONS: TLICS classification has a relative high K-value, when compared with that of the McAfee classification for intraobserver and interobserver reliability. Through clinical studies, including prospective observational analysis, TLICS classification can be applied and adjusted more adequately.

Successful hybrid operation of an acute mobile thrombus in the abdominal aorta induced by chemotherapy / 대한외과학회지

Acute mobile thrombus of the abdominal aorta after chemotherapy is a very unusual finding, which can be a potential source of arterial embolism. We report here on a case of an acute mobile aortic thrombus with renal infarction. We successfully treated the patient with hybrid operation-open surgical and endovascular approach. Our case shows that hybrid treatment using wire-directed balloon catheter thrombectomy is a feasible, minimally-invasive treatment for a mobile aortic thrombus.

Clinical Value of Nerve Root Sedimentation Sign in Lumbar Spinal Stenosis

STUDY DESIGN: A retrospective study. OBJECTIVES: To assess the diagnostic value of the sedimentation sign seen on MRI with lumbar spinal stenosis and to compare postoperative clinical results. SUMMARY OF LITERATURE REVIEW: Nerve root sedimentation sign is an additional tool to diagnose lumbar spinal stenosis. MATERIALS AND METHODS: There were 302 patients enrolled that had been diagnosed with lumbar spinal stenosis by MRI, which were reviewed to identify a sedimentation sign and all underwent the operative treatment. There were 142 patients who could not have their spinal stenosis diagnosis confirmed by MRI, and thus were selected as the control group to estimate the diagnostic value of nerve root sedimentation sign. Correlation with the duration of preoperative symptoms and the number of involved segments were compared and analyzed between sedimentation sign positive (Group I) and negative (Group II). We estimated Million Visual Analogue Score (MVAS) and Korean Oswestry Disability Index (KODI) for the assessment of the pain and the functional disability. RESULTS: A positive sedimentation sign was found in 265 patients (87.7%) and diagnostic value was statistically significant (P<0.001). The involvement of 2 or more segments was significantly correlated with the sedimentation sign in the positive group (P<0.001). MVAS presented the improvement of 64.5+/-4.6%, KODI, 62.9+/-3.9% after surgical treatment in Group I. In Group II, each score showed improvement of 34.6+/-2.3% (MVAS), 37.1+/-1.8% (KODI). The improvement of these scores in Group I was better than in Group II. CONCLUSIONS: The nerve root sedimentation sign is an additional tool to diagnose lumbar spinal stenosis and the considerable factor to decide the operation.

A Study of Characteristics of MicroLion Liquid Ionization Chamber for 6 MV Photon Beam / 의학물리

Recently PTW developed a MicroLion liquid ionization chamber which is water_equivalent and has a small sensitive volume of 0.002 cm3. The aim of this work is to investigate such dosimetric characteristics as dose linearity, dose rate dependency, spatial resolution, and output factors of the chamber for the external radiotherapy photon beam. The results were compared to those of Semiflex chamber, Pinpoint chamber and Diode chamber with the sensitive volumes of 0.125 cm3, 0.03 cm3 and 0.0025 cm3, respectively and evaluated to be suitable for small fields. This study was performed in the 6MV photon energy from a Varian 2300 C/D linac accelerator and the MP3 water phantom (PTW, Freiburg) was used. Penumbras in the varios field sizes ranged from 0.5x0.5 cm2 to 10x10 cm2 were used to evaluate the spatial resolution. Output factors were measured in the field sizes of 0.5x0.5 to 40x40 cm2. Readings of the chamber was linearly proportional to dose. Dose rate dependency was measured from 100 MU/min to 600 MU/min, showed a maximum difference of 5.0%, and outputs decreased with dose rates. The spatial resolutions determined with comparing profiles for the field sizes of 0.5x0.5 cm2 to 10x10 cm2 agreed between every detector except the Semiflex chamber to within 2%. Outputs of detectors were compared to that of Semiflex chamber and showed good agreements within 2% for every chamber. This study shows that MicroLion chamber characterized by a high signal-to-noise ratio and water equivalence could be suitable for the small field dosimetry.

A Pilot Research for Real-Time Specific Patient Quality Assurance Using the Hybrid Optimized Vmat Phantom (Hovp) in Volume Modulated Arc Therapy / 의학물리

The purpose of this was to investigate the measurement of fluence dose map for the specific patient quality assurance. The measurement of fluence map was performed using 2D matrixx detector. The absorbed dose was measured by a glass detector, Gafchromic film and ion chamber in Hybrid Optimized VMAT Phantom (HOVP). For 2D Matrixx, the results of comparison were average passing rate 85.22%+/-1.7 (RT_Target), 89.96%+/-2.15 (LT_Target) and 95.14%+/-1.18 (G4). The dose difference was 11.72%+/-0.531, -11.47%+/-0.991, 7.81%+/-0.857, -4.14%+/-0.761 at the G1, G2, G3, G4. In HOVP, the results of comparison for film were average passing rate (3%, 3 mm) 93.64%+/-3.87, 90.82%+/-0.99. We were measured an absolute dose in steep gradient area G1, G2, G3, G4 using the glass detector. The difference between the measurement and calculation are 8.3% (G1), -5.4% (G2), 6.1% (G3), 7.2% (G4). The using an Ion-chamber were an average relative dose error -1.02%+/-0.222 (Rt_target), 0.96%+/-0.294 (Lt_target). Though we need a more study using a transmission detector. However, a measurement of real-time fluence map will be predicting a dose for real-time specific patient quality assurance in volume modulated arc therapy.

Concurrent Chemoradiation in a Patient with Unresectable Cholangiocarcinoma

Cholangiocarcinoma is a catastrophic tumor with a high mortality rate, for which surgery is the most reliable treatment. However, these tumors progress insidiously and are difficult to diagnose early. Most patients lack the opportunity to receive surgery due to the advanced disease stage at the time of the diagnosis, at which point only few alternative treatments are available. There is a need for more effective therapy to improve the survival or quality of life of these patients. The present case was a 73-year-old male who presented with jaundice and fatigue underwent CT imaging, in which a 3.5x4.0-cm low-attenuation mass was found in hepatic segment 4. Cholangiocarcinoma was diagnosed by cytological examination of the bile juice. A combination of CyberKnife radiosurgery and S-1 oral chemotherapy was performed. The patient was alive at a 8-month follow-up, and serial CT scans revealed a markedly regressed tumor. Therefore, we suggest that concurrent chemoradiation with the CyberKnife and S-1 is a treatment option for advanced cholangiocarcinoma.