• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.910-917
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• 2000

Introduction : The management of chordomas and chondrosarcomas in the skull base is difficult due to the critical location, locally aggressive nature, and high recurrence rate. The authors present the effectiveness of surgical removal and radiation therapy on survival and tumor recurrence. Material and Methods : Thirty cranial base chordomas and chondrosarcomas from 23 patients(14 patients with chordomas and 9 patients with chondrosarcomas) were operated in our institution between 1985 and 1998. There were 15 men and 8 women, with a mean age of 40.7 years. The largest diameter of tumors ranged from 15 to 70mm (mean 41.5). The extent of surgical removal was subtotal or total in a half(15 operations). In nineteen operations, tumors were removed by conventional approaches and skull base approaches were applied in 11 operations. Postoperative radiation therapy was performed in 16(70%) patients. The mean duration of follow up is 50 months(1- 156 months). Results : The 3- and 5-year survival rates(YSR) of overall patient are 75% and 67%, respectively. The analysis showed that 1) skull base approach to chordomas and chondrosarcomas showed a tendency to remove more portion of the tumors(p＝0.058) but leave more frequent incidence of new deficits(p＝0.047) : 2) larger tumor diameter af-fected the extent of removal(p＝0.028) : 3) the extent of removal seemed to be the determining factor for overall survival and recurrence-free survival(the 5-YSR and RFSR of subtotal or total removal group are 92% and 80% vs. 40% of partial removal or biopsy group) : 4) conventional radiation therapy improved patient survival(5-YSR of patients who received RT is 76% whereas 5-YSR of those who didn't receive RT is 43%) but failed to prolong long-term recurrence-free survival. Conclusion : The extent of removal and postoperative radiation therapy are determining factors of patients' survival in skull base chordomas and chondrosarcomas. However, none of these factors significantly influenced the survival in multivariate analysis. Aggressive surgical removal of more than subtotal resection combined with postoperative radiation therapy seems to be the choice of therapy in the management of these tumors.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.587-593
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• 2016

We are evaluated the usefulness of radiation treatment planning applied respiration factor for stereotactic body radiation therapy in the lung cancer. Four dimensional computed tomography images were obtained in 10 patients with lung cancer. The radiation treatment plans were established total lung volume according to respiration images (new method) and conventional method. We was analyzed in the lung volume, radiation absorbed dose of lung and main organs (ribs, tracheobronchus, esophagus, spinal cord) around the tumor, respectively. We were confirmed that lung volume and radiation absorbed dose of lung and main organs around the tumor deference according to applied respiration. In conclusion, radiation treatment planning applied respiration factor seems to be useful for stereotactic body radiation therapy in the lung cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.17-28
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• 2008

This review focuses on the clinical use of $^{18}F-FDG$ PET to evaluate solitary pulmonary nodule (SPN) and non-small cell lung cancer (NSCLC). When SPN or mass without calcification is found on chest X-ray or CT, $^{18}F-FDG$ PET is an effective modality to differentiate benign from malignant lesions. For initial staging of NSCLC, $^{18}F-FDG$ PET is useful, and proved to be cost-effective in several countries. $^{18}F-FDG$ is useful for detecting recurrence, restaging and evaluating residual tumor after curative therapy in NSCLC. For therapy response assessment, $^{18}F-FDG$ PET may be effective after chemotherapy or radiation therapy. $^{18}F-FDG$ PET is useful to predict pathological response after neoadjuvant therapy in NSCLC. For radiation therapy planning, $^{18}F-FDG$ PET may be helpful, but requires further investigations. PET/CT is better for evaluating NSCLC than conventional PET.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.19-26
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• 2017

Objectives: In the Lung, the VMAT rotates continuously and examines radiation. That increases the low doses to normal lung. Due to that, the incidence of radiation pneumonia among radiation side effects may increase. The cause of radiation pneumonia is the lower dose area of the lungs. The H-VMAT was applied to patients who applied to reduce radiation in the lower doses of the lungs. We wanted to assess the usefulness of the H-VMAT by comparing the radiation doses to the low dose areas of the lungs and the normal organs. Materials and Methods: A total of 26 patients who applied for a H-VMAT procedure were applied to the patient. The prescription dose applied to total dose 44 Gy from 22 divisions. For each patient, a plan was implemented with Conventional RT, VMAT and H-VMAT. Conventional RT was carried out in four to five fields each, considering the size, location, shape, and location of the PTV. In the case of a VMAT plan, the two Half ARC, three Half ARC method and the two Full ARC were planned. The H-VMAT was planned by adding two Static fields in the VMAT, taking into account the dose of the lung and the tolerance dose of the organs. Results: In the NSCLC, the lung doses $V_5$ and $V_{10}$ of the lungs except for the treatment plan volume were the lowest with $55.40{\pm}13.39%$ and $32.05{\pm}11.37%$ of H-VMAT. And, in the SCLC, the lung doses of V5 and V10 were the lowest at $64.32{\pm}16.15%$ and $35.50{\pm}9.91%$, respectively. The spinal dose of VMAT in NSCLC was $21.15{\pm}4.02Gy$, which was 7.94 Gy lower than other treatment methods. The lowest spinal dose was delivered at $19.72{\pm}1.82Gy$ for SCLC. The mean dose delivered to the esophagus was also $17.44{\pm}2.04Gy$ and $17.84{\pm}9.20Gy$ in SCLC and NSCLC, respectively. Conclusion: When comparing the value of the surrounding normal organ dose, the VMAT showed that less doses were transmitted from the heart, esophagus and spinal cord than the rest of the treatment plan. However, it was similar to VMAT in normal organs except for the spinal cord. VMAT has increased doses of some normal organs but did not exceed the tolerance dose. It showed a low value in $V_5$, $V_{10}$. When comparing Conventional RT, VMAT, and H-VMAT, If the dose to the heart, esophagus and spinal cord is lower than the tolerance dose, it is thought to reduce the incidence of radiation pneumonia by applying H-VMAT that show the benefits of low doses of the lungs.

• Radiation Oncology Journal
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• v.24 no.1
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• pp.11-20
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• 2006

Puroose: In order to find out whether stereotactic radiation therapy (RT) using CyberKnife (CK) could improve survival rate and lower acute toxicity compared to conventional RT. Materials and Methods: From April 2003 through April 2004, 19 patients with Eastern Cooperative Oncology Group (ECOG) performance status ${\leq}3$ and locally advanced pancreas cancer without distant metastasis, evaluated by CT or PET/CT, were included. We administered stereotactic RT consisting of either 33 Gy, 36 Gy or 39 Gy in 3 fractions to 6, 4 and 9 patients, respectively, in an effort to increase the radiation dose step by step, and analyzed the survival rate and gastrointestinal toxicities by the acute radiation morbidity criteria of Radiation Therapeutic Oncology Group (RTOG). Prognostic factors of age, sex, ECOG performance score, chemotherapy, bypass surgery, radiation dose, CA 19-9, planning target volume (PTV), and adjacent organ and vessel invasion on CT scan were evaluated by Log Rank test. Results: The median survival time was 11 months with 1-year survival rate of 36.8%. During follow-up period (range $3{\sim}20$ months, median 10 months), no significant gastrointestinal acute toxicity (RTOG grade 3) was observed. In univariate analysis, age, sex, ECOG performance score, chemotherapy, bypass surgery, radiation dose, CA 19-9 level, and adjacent organ and vessel invasion did not show any significant changes of survival rate, however, patients with PTV (80 cc showed more favorable survival rate than those with PTV>80 cc (p-value<0.05). In multivariate analysis, age younger than 65 years and PTV>80 cc showed better survival rate. Conclusion: In terms of survival, the efficacy of stereotactic radiation therapy using CK was found to be superior or similar to other recent studies achieved with conventional RT with intensive chemotherapy, high dose conformal RT, intraoperative RT (IORT), or intensity modulated RT (IMRT). Furthermore, severe toxicity was not observed. Short treatment time in relation to the short life expectancy gave patients more convenience and, finally, quality of life would be increased. Consequently, this could be regarded as an effective novel treatment modality for locally advanced, unresectable pancreas cancer. PTV would be a helpful prognostic factor for CK.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.259-266
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• 1995

Purpose : The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. Materials and Methods : From January 1980 through December 1985, 227 patients with stage III uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients($317{\%}$) were stage IIIa, and 155 patients($68.3{\%}$) were stage IIIb according to FIGO classification. Age distribution was 32-71 years (median: 62 years). Sixty nine patients($95.8{\%}$) in stage IIIa and 150 patient ($96.8{\%}$) in stage IIIb were squamous cell carcinoma. pelvic lymph node metastasis at initial diagnosis was 8 patients($11.1{\%}$) in stage IIIa and 29 patients($18.7{\%}$) in stage IIIb, Among 72 patients with stage IIIa, 36 patients ($50{\%}$) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr.) and 36 patients($50{\%}$) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with $Cs^{137}$ sources, and among 155 patients with stage IIIb, 80 patients ($51.6{\%}$) were treated with external radiation therapy alone and 75 patients ($48.4{\%}$) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median: 78.5 Gy) and 65-125.5 Gy (median 83.5 Gy). Survival rate was calculated by life-table method. Results : Complete response rates were $58.3{\%}$(42 patients) in stage IIIa and $56.1{\%}$(87 patients) in stage IIIb. Overall 5 year survival rates were $57{\%}$ in stage IIIa and $40{\%}$ in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were $64{\%},\;40{\%}$ in the group treated in combination of external radiation and ICR, and $50\%,\;40\%$ in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were $90\%,\;66\%$ in responder group and $10\%,\;7\%$ in non-responder group (P<0.001) There were statistically no significant differences of 5 year survival rate by total radiation doses and external radiation doses(40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatment failures rates were $40.3\%$(29 patients) in stage IIla and $57.4\%$(89 patients) in stage IIIb. 17 patients ($23.6\%$) in stage IIIa and 46 patients ($29.7\%$) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa($50\%$) and IIIb($50\%$). Serious complication rates were higher in group received external radiation doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Serious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of death was cachexia due to locoregional failure in both stage IIIa($34.7\%$) and IIIb($43.9\%$). Conclusion : From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy to whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

• Journal of Radiation Protection and Research
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• v.45 no.4
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• pp.171-177
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• 2020

Background: This study aims to determine the effective atomic number (Zeff) from dual-energy image sets obtained using a conventional computed tomography (CT) simulator. The estimated Zeff can be used for deriving the stopping power and material decomposition of CT images, thereby improving dose calculations in radiation therapy. Materials and Methods: An electron-density phantom was scanned using Philips Brilliance CT Big Bore at 80 and 140 kVp. The estimated Zeff values were compared with those obtained using the calibration phantom by applying the Rutherford, Schneider, and Joshi methods. The fitting parameters were optimized using the nonlinear least squares regression algorithm. The fitting curve and mass attenuation data were obtained from the National Institute of Standards and Technology. The fitting parameters obtained from stopping power and material decomposition of CT images, were validated by estimating the residual errors between the reference and calculated Zeff values. Next, the calculation accuracy of Zeff was evaluated by comparing the calculated values with the reference Zeff values of insert plugs. The exposure levels of patients under additional CT scanning at 80, 120, and 140 kVp were evaluated by measuring the weighted CT dose index (CTDIw). Results and Discussion: The residual errors of the fitting parameters were lower than 2%. The best and worst Zeff values were obtained using the Schneider and Joshi methods, respectively. The maximum differences between the reference and calculated values were 11.3% (for lung during inhalation), 4.7% (for adipose tissue), and 9.8% (for lung during inhalation) when applying the Rutherford, Schneider, and Joshi methods, respectively. Under dual-energy scanning (80 and 140 kVp), the patient exposure level was approximately twice that in general single-energy scanning (120 kVp). Conclusion: Zeff was calculated from two image sets scanned by conventional single-energy CT simulator. The results obtained using three different methods were compared. The Zeff calculation based on single-energy exhibited appropriate feasibility.

• Radiation Oncology Journal
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• v.34 no.2
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• pp.145-155
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• 2016

Purpose: Radiation therapy targeting axilla and groin lymph nodes improves regional disease control in locally advanced and high-risk skin cancers. However, trials generally used conventional two-dimensional radiotherapy (2D-RT), contributing towards relatively high rates of side effects from treatment. The goal of this study is to determine if three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or volumetric-modulated arc therapy (VMAT) may improve radiation delivery to the target while avoiding organs at risk in the clinical context of skin cancer regional nodal irradiation. Materials and Methods: Twenty patients with locally advanced/high-risk skin cancers underwent computed tomography simulation. The relevant axilla or groin planning target volumes and organs at risk were delineated using standard definitions. Paired t-tests were used to compare the mean values of several dose-volumetric parameters for each of the 4 techniques. Results: In the axilla, the largest improvement for 3D-CRT compared to 2D-RT was for homogeneity index (13.9 vs. 54.3), at the expense of higher lung $V_{20}$ (28.0% vs. 12.6%). In the groin, the largest improvements for 3D-CRT compared to 2D-RT were for anorectum $D_{max}$ (13.6 vs. 38.9 Gy), bowel $D_{200cc}$ (7.3 vs. 23.1 Gy), femur $D_{50}$ (34.6 vs. 57.2 Gy), and genitalia $D_{max}$ (37.6 vs. 51.1 Gy). IMRT had further improvements compared to 3D-CRT for humerus $D_{mean}$ (16.9 vs. 22.4 Gy), brachial plexus $D_5$ (57.4 vs. 61.3 Gy), bladder $D_5$ (26.8 vs. 36.5 Gy), and femur $D_{50}$ (18.7 vs. 34.6 Gy). Fewer differences were observed between IMRT and VMAT. Conclusion: Compared to 2D-RT and 3D-CRT, IMRT and VMAT had dosimetric advantages in the treatment of nodal regions of skin cancer patients.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.25-32
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• 2004

Purpose : The simulator is used to determine patient field and ensure the treatment field, which encompasses the required anatomy during patient normal movement such as during breathing. The latest simulator provide real time display of still, flouroscopic and digitalized image, but conventional simulator is not yet. The purpose of this study is to introduce digital image capture system(DICS) using conventional simulator and clinical case using digital captured still and flouroscopic image. Methods and materials : We connect the video signal cable to the video terminal in the back up of simulator monitor, and connect the video jack to the A/D converter. After connection between the converter jack and computer, We can acquire still image and record flouroscopic image with operating image capture program. The data created with this system can be used in patient treatment, and modified for verification by using image processing software. (j.e. photoshop, paintshop) Result : DICS was able to establish easy and economical procedure. DCIS image was helpful for simulation. DICS imaging was powerful tool in the evaluation of the department specific patient positioning. Conclusion : Because the commercialized simulator based of digital capture is very expensive, it is not easily to establish DICS simulator in the most hospital. DICS using conventional simulator enable to utilize the practical use of image equal to high cost digitalized simulator and to research many clinical cases in case of using other software program.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.68-72
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• 2002

This study was done to implement intensity-modulated radiation therapy (IMRT) for the treatment of primary prostate cancer and to compare this technique with conventional treatment methods. A 72-year-old male patient with prostate cancer stage T2a was treated with IMRT delivered with dynamic multi-leaf collimation. Treatment was designed using an inverse planning algorithm, which accepts dose and dose-volume constraints for targets and normal structures. The IMRT plan was compared with a three-dimensional (3D) plan using the same 6 fields technique. Lower normal tissue doses and improved target coverage were achieved using IMRT at current dose levels, and facilitate dose escalation to further enhance locoregional control and organ movement during radiotherapy is an important issue of IMRT in prostate cancer.