• Progress in Medical Physics
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• v.25 no.4
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• pp.298-303
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• 2014

In this study, we examine the trends and types of incidents frequently occur during radiation therapy by using the data from the radiation oncology safety information system (ROSIS), according to discovery method explores the development direction of future research accident cause factor control method. This study was carried out analysis of incident data in ROSIS nearly 1163 cases in last 11 years from 2003 to 2013. We categorized into treatment methods, found the time, discoverer of occupations and finding ways to analyze the data. Then, we calculate the percentage and the classification for each item. About 1163 cases of incident cases including the near miss cases, external radiation therapy, brachytherapy and other were 97%, 2% and 1%. In the case was improperly planned dose delivery was 44% (497 cases) which 429 cases (86%) was found before 3 fractions and 13 cases were found after 11 fractions. The investigation was found to be distributed in various a found times. Approximately 42% of found time was during treatment and 29% of patients were found the problem during inspection chart. Occupation to discover the most radiation accidents was the radiation therapist (53%) who works in treatment room. Among 1163 incidence cases, 24% cases were found the accident before the treatment, therefore most of accident were found after of during the treatment (70%, 813 cases). This trend is acquired through ROSIS analysis, is expected to be not significantly different in the case of Korea, so it is necessary more diverse and systematic research for the prevention and early detection by using the ROSIS data.

• Journal of Gastric Cancer
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• v.14 no.2
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• pp.87-104
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• 2014

Although gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to those in western countries. However, there are currently no Korean multidisciplinary guidelines for gastric cancer. Experts from related societies developed guidelines de novo to meet Korean circumstances and requirements, including 23 recommendation statements for diagnosis (n=9) and treatment (n=14) based on relevant key questions. The quality of the evidence was rated according to the GRADE evidence evaluation framework: the evidence levels were based on a systematic review of the literature, and the recommendation grades were classified as either strong or weak. The applicability of the guidelines was considered to meet patients' view and preferences in the context of Korea. The topics of the guidelines cover diagnostic modalities (endoscopy, endoscopic ultrasound, and radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, and radiotherapy), and pathologic evaluation. An external review of the guidelines was conducted during the finalization phase.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.63-63
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• 2003

Purpose: Planning target volume (PTV) for tumors in abdomen or thorax includes enough margin for breathing-related movement of tumor volumes during treatment. We developed a simple and handy method, which can reduce PTV margins in patients with moving tumors, respiratory motion reduction device system (RMRDs). Materials and Methods: The patients clinical database was structured for moving tumor patients and patient setup error measurement and immobilization device effects were investigated. The system is composed of the respiratory motion reduction device utilized in prone position and abdominal presser (strip device) utilized in the supine position, moving phantom and the analysis program, which enables the analysis on patients setup reproducibility. It was tested for analyzing the diaphragm movement and CT volume differences from patients with RMRDs, the magnitude of PTV margin was determined and dose volume histogram (DVH) was computed using a treatment planning software. Dose to normal tissue between patients with RMRDs and without RMRDs was analyzed by comparing the fraction of the normal liver receiving to 50% of the isocenter dose(TD50). Results: In case of utilizing RMRDs, which was personally developed in our hospital, the value was reduced to $5pm1.4 mm$, and in case of which the belt immobilization device was utilized, the value was reduced to 3$pm$0.9 mm. Also in case of which the strip device was utilized, the value was proven to reduce to $4pm.3 mm$0. As a result of analyzing the TD50 is irradiated in DVH according to the radiation treatment planning, the usage of the respiratory motion reduction device can create the reduce of 30% to the maximum. Also by obtaining the digital image, the function of comparison between the standard image, automated external contour subtraction, and etc were utilized to develop patients setup reproducibility analysis program that can evaluate the change in the patients setup. Conclusion: Internal organ motion due to breathing can be reduced using RMRDs, which is simple and easy to use in clinical setting. It can reduce the organ motion-related PTV margin, thereby decrease volume of the irradiated normal tissue.

• Progress in Medical Physics
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• v.19 no.4
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• pp.241-246
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• 2008

Patient's respiration can have an effect on movement of tumor range and peripheral organs. Therefore, the respiratory signal was acquired by relation between external markers and movement of patient's abdomen during radiational therapy in order to minimize the effect of respiration. Based on this technique, many studies of rational therapy to irradiate at particular part of stable respiratory signals have executed and they have been clinically applied. Nevertheless, the phase-based method is preferred to the amplitude-based method for the rational therapy related to respiration. Because stabilization of the respiratory signal are limited. In this study, a in-house respiratory signal analysis program was developed for the phase reassignment and the analysis of the irregular respiratory signals. Various irregular respiratory patterns was obtained from clinical experimental volunteers. After then, the in-house program analyzed the factors affecting to phase assignment which is directly related to irradiated sector. Subsequently, accuracy of phase assignment was improved with removement of irregular signals by self-developed algorithm. This study is considered to be useful for not only image reconstruction and elevation of irradiating accuracy through phase assignment of RPM system but also analysis of respiratory signals. Moreover, development of 4D CT image is planed with phantom researches or clinical experiments based on this program.

• Progress in Medical Physics
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• v.18 no.4
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• pp.226-232
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• 2007

We studied a Monte Carlo simulation of the proton beam delivery system at the National Cancer Center (NCC) using the Geant4 Monte Carlo toolkit and tested its feasibility as a dose verification framework. The Monte Carlo technique for dose calculation methodology has been recognized as the most accurate way for understanding the dose distribution in given materials. In order to take advantage of this methodology for application to external-beam radiotherapy, a precise modeling of the nozzle elements along with the beam delivery path and correct initial beam characteristics are mandatory. Among three different treatment modes, double/single-scattering, uniform scanning and pencil beam scanning, we have modeled and simulated the double-scattering mode for the nozzle elements, including all components and varying the time and space with the Geant4.8.2 Monte Carlo code. We have obtained simulation data that showed an excellent correlation to the measured dose distributions at a specific treatment depth. We successfully set up the Monte Carlo simulation platform for the NCC proton therapy facility. It can be adapted to the precise dosimetry for therapeutic proton beam use at the NCC. Additional Monte Carlo work for the full proton beam energy range can be performed.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.240-248
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• 2009

Purpose: To provide a simple research tool that may be used to analyze a dose volume histogram from different radiation therapy planning systems for NTCP (Normal Tissue Complication Probability), OED (Organ Equivalent Dose) and so on. Materials and Metohds: A high-level computing language was chosen to implement Niemierko's EUD, Lyman-Kutcher-Burman model's NTCP, and OED. The requirements for treatment planning analysis were defined and the procedure, using a developed GUI based program, was described with figures. The calculated data, including volume at a dose, dose at a volume, EUD, and NTCP were evaluated by a commercial radiation therapy planning system, Pinnacle (Philips, Madison, WI, USA) for comparison. Results: The volume at a special dose and a dose absorbed in a volume on a dose volume histogram were successfully extracted using DVH data of several radiation planning systems. EUD, NTCP and OED were successfully calculated using DVH data and some required parameters in the literature. Conclusion: A simple DVH analyzer program was developed and has proven to be a useful research tool for radiation therapy.

• Korean Journal of Head & Neck Oncology
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• v.25 no.2
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• pp.138-142
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• 2009

Introduction : Although bilateral exploration has been thought to be the standard therapeutic modality for primary hyperparathyroidism(pHPT) due to the admirable cure rate, questions have remained as to whether bilateral neck exploration for all patients with pHPT is needed because 80-85% of patients with pHPT have a single parathyroid adenoma. If the diseased parathyroid can be determined preoperatively, a directed and minimal operation is appropriate using the recent innovations of preoperative diagnosis and operation techniques for parathyroid diseases, the radio-guided parathyroid surgery(RGPS) is one of the standards. In especial, RGPS has been reported beneficial in special circumstances, such as in recurrent disease, ectopic parathyroid, and in mediastinal parathyroid. It can be also useful for the parathyroid disease in previously explored or irradiated neck. Material and Methods : We experienced 2 cases of pHPT successfully treated by RGPS in who previously underwent extensive neck dissection and concomitant external or internal radiotherapy. We adopted and modified the technique described by Dr. James Norman at the University of South Florida-the minimally invasive parathyroidectomy using intraoperative nuclear mapping with 99mTc-sestamibi scanning and radioactivity detection probe. Results : We acquired the successful results for these patients. Conclusion : RGPS is thought to be the alternative technique for the patients with prior central neck exploration and irradiation.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.218-224
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• 1994

Soft tissue sarcoma of the head and neck is not frequent neoplasm, accounting for less than 1% of all malignant neoplasm in the region. The histological varieties include osteogenic sarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma, fibrosarcoma, tenosynovial sarcoma, angiosarcoma and chondrosarcoma. Rhabdomyosarcomas of the head and neck usually occur in children under the age of 10 years (over 70%) and rarely develop in adults over the age of 20 years. The prevalent sites of involvement include the orbit, nasal cavity, external ear, paranasal sinus and soft tissue of mouth and the primary location of tumor is considered to be one of the important prognostic factors. Before the 1960s, when surgical resection was the only method of treatment, the 5-year survival rate was less than 20%, but recently it has been greatly improved by the multimodality treatment, combining surgery with chemotherapy and radiation therapy. Here we treated a rhabdomyosarcoma woman with three cycles of high dose chemotherapy followed by radiation therapy. After the, completion of preoperative treatments, successful result of more than partial response was achieved. Three months later total maxillectomy and radical neck dissection was performed. There was no evidence of tumor infiltration in the resected tumor and regional lymphnodes but metastasized tumor cells in cervical lymphnodes were detected. Tumor cell infiltration was also found on the bone marrow biopsy to evaluate the pancytopenia which occurred during postoperative recovery. Two months later she died of secondary bone marrow failure. We think that this multimodality treatment combining pre-operative chemotherapy, radiotherapy and surgery might play an important role in curative resection and eyeball preservation in patients with rhabdomyosarcoma involving the eyeball.

• Journal of Life Science
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• v.26 no.9
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• pp.1088-1096
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• 2016

Despite that moderate hyperthermia can exert various antitumor activities such as direct cytotoxic effects on tumor cells, effects on tumor vasculatures and immunological effects, hyperthermia has been usually combined with radiotherapy or chemotherapy due to its limited efficacy in cancer treatment, showing some positive clinical benefits with generally well-tolerated side effects. Since heat shock responses itself can interfere with the anti-tumor effects of hyperthermia, not all of these studies might have demonstrated positive clinical outcomes in cancer patients. Therefore, the negative anti-tumor effect of hyperthermia should be reduced to enhance the effectiveness of hyperthermia. Although the responses to heat stress of tumor tissues containing vessels, immune cells, connective tissues as well as cancer cells, are very complicated, it is needed to study in the near future if some clinically available drugs, which can modulate heat stress responses, can improve the efficacy of hyperthermia in patients with cancer. In this review, the effect of clinical hyperthermia centered on non-invasive external hyperthermia using radiofrequency at moderate temperature will be discussed, since it is the state-of-the-art technology in the current clinical practice of hyperthermia, and a moderate operational temperature is used to increase the therapeutic effectiveness of conventional therapy without additional toxicity to normal tissues.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.7-14
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• 1992

Between August 1988 and December 1991, 24 patients with intracranial tumors were treated with stereotactic radiosurgery(RS) using a 10 MV linear accelerator at Severance Hospital, Yonsei University College of Medicine. There were 5 meningiomas, 3 craniopharyngiomas, 9 glial tumors, 2 solitary metastases, 2 acoustic neurinomas, 2 pineal tumors, and 1 non-Hodgkin's lymphoma. Ten patients were treated as primary treatment after diagnosis with stereotactic biopsy or neuroimaging study. Nine patients underwent RS for post-op. residual tumors and three patients as a salvage treatment for recurrence after external irradiation. Two patients received RS as a boost followed by fractionated conventional radiotherapy. Among sixteen patients who were followed more than 6 months with neuroimage, seven patients (2 meningiomas, 4 benign glial tumors, one non-Hodgkin's lymphoma) showed complete response on neuroimage after RS and nine patients showed decreased tumor size. There was no acute treatment related side reaction. Late complications include three patients with symptomatic peritumoral brain edema and one craniopharyngioma with optic chiasmal injury. Through this early experience, we conclude that stereotactically directed single high doses of irradiation to the small intracranial tumors is effective for tumor control. However, in order to define the role of radiosurgery in the management of intracraniai tumors, we should get the long-term results available to demonstrate the benefits versus potential complications of this therapeutic modality.