• Radiation Oncology Journal
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• v.10 no.1
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• pp.59-67
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• 1992

From March 1979 through December 1986, 124 patients with early stage carcinoma of the uterine cervix received curative radiation therapy. According to FIGO classification, 35 patients were stage IB and 89 were stge II A. In stage IB, five year locoregional control, five year disease free survival, and five year overall survival was $79.0\%$, $76.4\%$ and $81.8\%$, respectively. In stage II A, five year locoregional control, five year disease free survival, and five year overall survival were $78.0\%$, $66.8\%$, and $72.1\%$, respectively. To identify prognostic factors, pretreatment parameters including age, ECOG performance status, number of pregnancies, history of diabetes mellitus and hypertension, histology, size and shape of primary tumor, CT findings and blood parameters were retrospectively analyzed in terms of locoregional control, disease free survival and overall survival using univariate analysis and multivariate analysis. In univariate analysis, tumor size on physicai examination and rectal invasion on CT significantly affected locoregional control, disease free survival and overall survival. Parametrial involvement on CT was a significant prognostic factor on locoregional control and disease free survival. Hemoglobin level affected disease free survival and overall survival. Histology and age were significant prognostic factors on locoregional control. In multivariate analysis excluding CT finding, tumor size on physical examination was a significant factor in terms of locoregioal control and overall survival. Hemoglobin level was significant in terms of disease free survival. In multivariate analysis including CT, histology was a prognostic factor on locoregional control and disease free survival. Hemoglobin level and rectal invasion on CT were significant factors on locoregional control.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.237-244
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• 2001

Purpose : To assess the tolerance, complete response rate, bladder preservation rate and survival rate in patients with muscle-invading bladder cancer treated with selective bladder preservation protocol. Method and Materials : From October 1990 to June 1998, twenty six patients with muscle-invading bladder cancer (clinical stage T2-4, N0-3, M0) were enrolled for the treatment protocol of bladder preservation. They were treated with maximal TURBT (transurethral resection of bladder tumor) and 2 cycles of MCV chemotherapy (methotrexate, crisplatin, and vinblastine) followed by $39.6\~45\;Gy$ pelvic irradiation with concomitant cisplatin. After complete urologic evaluation (biopsy or cytology), the patients who achieved complete response were planed for bladder preservation treatment and treated with consolidation cisplatin and radiotherapy (19.8 Gy). The patients who had incomplete response were planed to immediate radical cystectomy. If they refused radical cystectomy, they were treated either with TURBT followed by MCV or cisplatin chemotherapy and radiotherapy. The median follow-up duration is 49.5 months. Results : The Patients with stage T2-3a and T3b-4a underwent complete removal of tumor or gross tumor removal by TURBT, respectively. Twenty one out of 26 patients $(81\%)$ successfully completed the protocol of the planned chemo-radiotherapy. Seven patients had documented complete response. Six of them were treated with additional consolidation cisplatin and radiotherapy. One patient was treated with 2 cycles of MCV chemotherapy due to refusal of chemo-radiotherapy. Five of 7 complete responders had functioning tumor-free bladder. Fourteen patients of incomplete responders were further treated with one of the followings : radical cystectomy (1 patient), or TURBT and 2 cycles of MCV chemotherapy (3 patients), or cisplatin and radiotherapy (10 patients). Thirteen patients of them were not treated with planned radical cystectomy due to patients' refusal (9 patients) or underlying medical problems (4 patients). Among twenty one patients, 12 patients $(58\%)$ were alive with their preserved bladder, 8 patients died with the disease, 1 patient died of intercurrent disease. The 5 years actuarial survival rates according to CR and PR after MCV chemotherapy and cisplatin chemoradiotherapy were $80\%\;and\;14\%$, respectively (u=0.001). Conclusion : In selected patients with muscle-invading bladder cancer, the bladder preservation could be achieved by MCV chemotherapy and cisplatin chemo-radiotherapy. All patients tolerated well this bladder preservation protoco. The availability of complete TURBT and the responsibility of neoadjuvant chemotherapy and chemoradiotherapy were important predictors for bladder preservation and survival. The patients who had not achieved complete response after neoadjuvant chemotherapy and chemoradiotherapy should be immediate radical cystectomy. A randomized prospective trial might be essential to determine more accurate indications between cystectomy or bladder preservation.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.742-749
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• 2009

The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.169-176
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• 2018

Purpose : The purpose of this study is to evaluate clinical applicability of Co-60 ViewRay treatment plan to increase the skin dose in case of high skin dose is required such as Malignant Fungating Wound By measuring the presence / absence of Bolus application and skin dose by the treatment device and comparing it Materials and Methods : Nine inner measuring points of 2.5 cm lattice arrangement and all 13 measuring points including upper and lower left and right measuring points touching the chest and skin were marked. After CT was taken, each treatment plan was formulated through Eclipse and ViewRay-TPS, and a Fixed beam-IMRT treatment plan was formulated so that the left chest V2Gy=95 % is delivered. Before measurement QED detector was calibrated and the QED detector was positioned at the 13 measurement points displayed on Phantom and surface dose of each treatment planner was measured using 5 mm Bolus application using True-beam and View-ray before and after, measure three times and compare each before applying 5 mm Bolus. Results : The surface dose of the Co-60 ViewRay and the linear accelerator appeared at $76.8%{\pm}5.2%$ vs. $67.3{\pm}%7.5%$ and the surface dose after application of 5 mm Bolus was $87.6%{\pm}8.9%$ vs. $80.3%{\pm}10.2%$ It was measured at 10.2 % (p<0.001). Conclusion : As a result of the surface dose measurement of each treatment instrument, Co-60 ViewRay confirmed that the surface dose reached 95.6 % of 6 MV Linac with conventional 5 mm bolus, despite not using Bolus (p<0.001). Also, by utilizing magnetic resonance images for each treatment, it is possible to observe the change in the treatment site without the problem of exposure, it is easy to formulate an adaptive treatment plan and it is easy to secure the skin dose, so the size In the case of Malignant Fungating Wound patients who need fast skin changes and need high skin doses, Co-60 ViewRay is considered to be more useful than linear accelerators.

• Progress in Medical Physics
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• v.21 no.4
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• pp.332-339
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• 2010

We aimed to setup an adaptive radiation therapy platform using cone-beam CT (CBCT) and multileaf collimator (MLC) log data and also intended to analyze a trend of dose calculation errors during the procedure based on a phantom study. We took CT and CBCT images of Catphan-600 (The Phantom Laboratory, USA) phantom, and made a simple step-and-shoot intensity-modulated radiation therapy (IMRT) plan based on the CT. Original plan doses were recalculated based on the CT ($CT_{plan}$) and the CBCT ($CBCT_{plan}$). Delivered monitor unit weights and leaves-positions during beam delivery for each MLC segment were extracted from the MLC log data then we reconstructed delivered doses based on the CT ($CT_{recon}$) and CBCT ($CBCT_{recon}$) respectively using the extracted information. Dose calculation errors were evaluated by two-dimensional dose discrepancies ($CT_{plan}$ was the benchmark), gamma index and dose-volume histograms (DVHs). From the dose differences and DVHs, it was estimated that the delivered dose was slightly greater than the planned dose; however, it was insignificant. Gamma index result showed that dose calculation error on CBCT using planned or reconstructed data were relatively greater than CT based calculation. In addition, there were significant discrepancies on the edge of each beam while those were less than errors due to inconsistency of CT and CBCT. $CBCT_{recon}$ showed coupled effects of above two kinds of errors; however, total error was decreased even though overall uncertainty for the evaluation of delivered dose on the CBCT was increased. Therefore, it is necessary to evaluate dose calculation errors separately as a setup error, dose calculation error due to CBCT image quality and reconstructed dose error which is actually what we want to know.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.502-512
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• 1995

Background: One quarter to one third of patients with NSCLC present with primary tumors that although confined to the thorax are too extensive for surgical resection. Until resently standard treatment for these patients had been thoracic radiation, which produces tumor regression in most patients but few cures and dismal 5-year survival rate. The fact that death for most patients with stage III tumors is caused by distant metastases has promped a reevaluation of combined modality treatment approaches that include systemic chemotherapy. Therefore, we report the results observed in a study to evaluate the effect of multimodality treatment in locally advanced non-small cell lung cancer from 1/91 to 8/93 in CNUH. Method: We grouped the patients according to the treatment modalities and evaluated response rate, median survival and the effect of prognostic variables. Among 67 patients evaluated, twenty seven patients classified with group A, received cisplatin and etoposide containing combination chemotherapy alone, eighteen patients, classified with group B, received chemotherapy and radiotherapy, fifteen patients, group C, received neoadjuvant or adjuvant chemotherapy and surgery with/without radiation therapy, seven patients, group D, received only supportive care. Result: The major response rate for group A and B was 37% and 61% respectively. There was no statistically significant difference in response rate between A and B groups(p=0.97). The analysis of prognostic factors showed that differences of age, sex, pathology, blood type, smoking year, stage and ECOG performance did not related to improvement in survival. Median survival time was 8.6 months for group A, 13.4 months for group B, 19.2 months for group C, and 5.4 months for group D, respectively and there was statistically significant difference(p=0.003), suggesting that multimodality therapy was associated with signigicant improvement in survival. Subset survival analysis showed a significant therapeutic effect for earlier stage and good performance state(p=0.007, 0.009, respectively). A possible survival advantages were observed for major response groups. Conclusion: It was suggested that multimodality therapy for the management of patients who had stage III disease, has yielded good median survival and long survival for seleted patients. But, it is necessory to validate above result with further investigation in large scale and in prospective randomized trials.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.9-15
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• 1999

Purpose : This is a retrospective study to evaluate the response rate, acute toxicity, and survival rate of a combined chemotherapy and radiation therapy in limited disease small cell lung cancer, Materials and Methods : Firty-six patients with limited disease small-cell lung cancer who underwent combined chemotherapy and radiation therapy between October 1994 and April 1998 were evaluated. Six cycles of chemotherapy were planned either using a VIP regimen etoposide, ifosfamide, and cis-platin) or a EP regimen (etoposide and cis-platin). Thoracic radiation therapy was planned to deli- ver 44 Gy using 1 OMV X-ray, starting concurrently with chemotherapy. Response was evaluated 4 weeks after the completion of the planned chemotherapy and radiation therapy, and the prophylaetic cranial irradiation was planned only for the patients with complete responses. Acute toxicity was evaluated using the SWOG toxicity criteria, and the overall survival and disease-free survival were calculated using the Kaplan-Meier Method. Results : The median follow-up period was 16 months (range:2 to 41 months). Complete response was achieved En 30 (65$\%$) patients, of which 22 patients received prophylactic cranial irradiations. Acute toxicities over grade III were granulocytopenia in 23 (50$\%$), anemia in 17 (37$\%$), thrombo- cytopenia in nine (20$\%$), alopecia in nine (20$\%$), nausea/vomiting in five (11$\%$), and peripheral neuropathy in one (2$\%$). Chemotherapy was delayed in one patient, and the chemotherapy doses were reduced in 58 (24$\%$) out of the total 246 cycles. No radiation esophagitis over grade 111 was observed, while interruption during radiation therapy for a mean of 8.3 days occurred in 21 patients. The local recurrences were observed in 8 patients and local progressions were in 6 patients, and the distant metastases in 17 patients. Among these, four patients had both the local relapse and the distant metastasis. Brain was the most common metastatic site (10 patients), followed by the liver as the next common site (4 patients). The overall and progression-free survival rates were 79$\%$ and 55$\%$ in 1 year, and 45'/) and 32% in 2 years, respectively, and the median survival was 23 months. Conclusion : Relatively satisfactory local control and suwival rates were achieved after the combined chemotherapy and radiation therapy with mild to moderate acute morbidities in limited disease small cell lung cancer.

• Journal of Hospice and Palliative Care
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• v.11 no.2
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• pp.106-110
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• 2008

Palliative sedation has been used in patients who undergo intractable suffering at the end of life. Its implementation, however, may be complicated due to resistance of clinicians and barrier of bioethical issues. Here, we present 50-year-old man with stomach cancer and multiple bone metastasis who was treated with palliative chemotherapy and radiotherapy. He suffered from refractory pain on the whole body even after standard analgesics and multidisplinary effort to relieve. Upon shared decision for sedation, he was given midazolam until discharge. Literature reviews reveal cases similar to the present case.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.109-117
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• 2017

Objectives: The purpose of this study was to evaluate the change of body shape and the patient alignment state during image-guided volumetric modulated arc therapy in head and neck cancer patients, Materials and Methods: We performed a image-guided volumetric modulated arc therapy plan for 89 patients with head and neck cancer who underwent curative radiotherapy. Ten of them were evaluated for set up error. The landmarks of the ramus, chin, posterior neck, and clavicle were specified using ARIA software (Offline review), and the positional difference was analyzed. Results: The re-CT simulation therapy was performed in 60 men with $17{\pm}4$ cycles of treatment. The weight loss rate was $-6.47{\pm}3.5%$. 29 women performed re-CT simulation at $17{\pm}5$ cycles As a result, weight loss rate was $-5.73{\pm}2.7%$. The distance from skin to C1, C3, and C5 was measured, and both clavicle levels were observed to measure the skin shrinkage changes. The skin shrinkage standard deviations were C1 (${\pm}0.44cm$), C3 (${\pm}0.83cm$), and C5 (${\pm}1.35cm$), which is about 1 mm shrinkage per 0.5 kg reduction. Skin shrinkage according to the number of treatments was 1 ~ 4 fractions (no change), 5 ~ 13 fractions (-2 mm), 14 ~ 22 fractions (-4 mm) and 23 ~ 30 fractions (-6 mm). Conclusion: When the body shape changes about 5 mm, the central dose starts to differ about 3 % or more. Therefore, the CT simulation treatment for the adaptive therapy should be additionally performed. In addition, it is necessary to actively study the CT simulation therapy method and set up method of the lower neck and to examine the use of a new immobilization device.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.89-97
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• 1986

Using as assay for jejunal crypt stem cell survival, dose-response curves for the reproductive capacity of crypt stem cells of mouse jejunum exposed to multifractionated gamma-ray irradiation (single, 2, 3, 4, 5, 8, 10, 12, and 16 fractions) were analyzed and single-dose survival curve of these cells was constructed. The following conclusion were drawn: 1) Survival curves for higher numbers of dose fractions were displaced to higher dose, and characterized by increasingly shallower slopes. 2) The single-dose survival curve had broad shoulder, Dq=460 cGy, remaining near-exponential over initial dose range 0 to 300 cGy, with initial slope 1Do=474 cGy. 3) At fractionated dose En the range of 180 to 450 cGy, the average recovered dose per fraction interval was approximately $50\%$ of the dose per fraction. 4) The value of $\alpha/\beta$ ratio by using of linear regression analysis for the reciprocal dose plots was 8.3 Gy which lied in the range of 6-14 Gy for early-reacting tissues. 5) The linear-quadratic model for dose-response formula offers valid approximations for at 1 doses to be used in radiotherapy, only two parameters to be determined, and considerable convenience in practical applications.