PURPOSE: In order to obtain basic data for treatment plan in radiosurgery, we measured small fields of 6 MV X-rays and compared the measured data with our Monte Carlo simulations for the small fields. MATERIALS AND METHODS: The small fields of 1.0, 2.0 and 3.0 cm in diameter were used in this study. Percentage depth dose (PDD) and beam profiles of those fields were measured and calculated. A small semiconductor detector, water phantoms, and a remote control system were used for the measurement. Monte Carlo simulations were performed using the EGS4 code with the input data prepared for the energy distribution of 6 MV X-rays, beam divergence, circular fields and the geometry of the water phantoms. RESULTS: In the case of PDD values, the calculated values were lower than the measured values for all fields and depths, with the differences being 0.3 to 5.7% at the depths of 2.0 to 20.0 cm and 0.0 to 8.9% at the surface regions. As a result of the analysis of beam profiles for all field sizes at a depth of 10cm in water phantom, the measured 90% dose widths were in good agreement with the calculated values, however, the calculated penumbra radii were 0.1 cm shorter than measured values. CONCLUSION: The measured PDDs and beam profiles agreement with the Monte Carlo calculations approximately. However, it is different when it comes to calculations in the area of phantom surface and penumbra because the Monte Carlo calculations were performed under the simplified geometries. Therefore, we have to study how to include the actual geometries and more precise data for the field area in Monte Carlo calculations. The Monte Carlo calculations will be used as a useful tool for the very complicated conditions in measurement and verification.
Radiosurgery ; Semiconductors ; Water

PURPOSE: With the development of stereotactic immobilization systems capable of reliable serial repositioning, fractionated stereotactic radiation therapy (FSRT) offers the potential for an improved treatment outcome by excellent dose delivery, and dose distribution characteristics with the favorable radiobiological properties of fractionated irradiation. We describe our initial experience using FSRT for the treatment of intracranial benign tumor. MATERIALS AND METHODS: Between August 1995 and December 1996, 15 patients (7 males and 8 females aged 6-70 years) were treated with FSRT. The patients had the following diagnosis : pituitary adenoma (10) including one patient who previously had received radiotherapy, craniopharyngioma (2), acoustic neurinoma (1), meningioma (2). Using the Gill-Thomas-Cosman relocatable head frame and multiple non-coplanar therapy, the daily dose of 2Gy was irradiated at 90% to 100% isodose surface of the isocenter. The collimator sizes ranged from 26mm to 70mm. RESULTS: In all patients except one follow-up lost, disease was well- controlled. Acute complication was negligible and no patient experienced cranial nerve neuropathies and radiation necrosis. In overall patient setup with scalp measurements, reproducibility was found to have mean of 1.1+/-0.6mm from the baseline reading. CONCLUSION: Relocatable stereotactic system for FSRT is highly reproducible and comfortable. Although the follow-up period was relatively short, FSRT is considered to be a safe and effective radiation technique as the treatment of intracranial tumor. But the fractionation schedule (fraction size, overall treatment time and total dose) still remains to be solved by further clinical trials.
Adenoma ; Appointments and Schedules ; Cranial Nerves ; Craniopharyngioma ; Diagnosis ; Female ; Follow-Up Studies ; Head ; Humans ; Immobilization ; Male ; Meningioma ; Necrosis ; Neuroma, Acoustic ; Pituitary Neoplasms ; Radiotherapy ; Scalp ; Treatment Outcome

PURPOSE: Radiotherapy has been the mainstay of the treatment of brain metastases. We evaluated the response rate, survival and prognostic factors of patients with brain metastases treated with radiotherapy for palliative purpose. MATERIALS AND METHODS: From January 1994 through April 1997, in all 42 patients, a retrospective analysis was undertaken. Of these, 33 patients received whole brain irradiation with 30Gy in 10 daily fractions with or without a boost of 10Gy in 5 daily fractions to the site of solitary lesion. Nine patients failed to complete the planned treatment. RESULTS: Of 33 patients who finished radiotherapy, complete and partial response were observed in 4 (12%) patients and 22 (67%) ones, respectively. Overall response rate was 79% and median survival was 4 months. In univariate analysis, prognostic factors affecting survival were initial neurologic function class (p=0.0136), extracranial tumor activity (p=0.042), and response after radiotherapy (p=0.001). CONCLUSION: We confirmed that whole brain irradiation is the effective means for treating the patient with brain metastases. Initial neurologic function class, extracranial tumor activity, and response after radiotherapy were identified as prognostic factors affecting survival.
Brain* ; Humans ; Neoplasm Metastasis* ; Radiotherapy* ; Retrospective Studies ; Survival Rate

PURPOSE: To develop a dose calibration program for the IAEA TRS-277 and AAPM TG-21, based on the air kerma calibration factor (or the cavity-gas calibration factor), as well as for the IAEA TRS-398 and the AAPM TG-51, based on the absorbed dose to water calibration factor, so as to avoid the unwanted error associated with these calculation procedures. MATERIALS AND METHODS: Currently, the most widely used dosimetry protocols of high energy photon beams are the air kerma calibration factor based on the IAEA TRS-277 and the AAPM TG-21. However, this has somewhat complex formalism and limitations for the improvement of the accuracy due to uncertainties of the physical quantities. Recently, the IAEA and the AAPM published the absorbed dose to water calibration factor based, on the IAEA TRS-398 and the AAPM TG-51. The formalism and physical parameters were strictly applied to these four dose calibration programs. The tables and graphs of physical data and the information for ion chambers were numericalized for their incorporation into a database. These programs were developed user to be friendly, with the Visual C++ language for their ease of use in a Windows environment according to the recommendation of each protocols. RESULTS: The dose calibration programs for the high energy photon beams, developed for the four protocols, allow the input of informations about a dosimetry system, the characteristics of the beam quality, the measurement conditions and dosimetry results, to enable the minimization of any inter-user variations and errors, during the calculation procedure. Also, it was possible to compare the absorbed dose to water data of the four different protocols at a single reference points. CONCLUSION: Since this program expressed information in numerical and data-based forms for the physical parameter tables, graphs and of the ion chambers, the error associated with the procedures and different user could be solved. It was possible to analyze and compare the major difference for each dosimetry protocol, since the program was designed to be user friendly and to accurately calculate the correction factors and absorbed dose. It is expected that accurate dose calculations in high energy photon beams can be made by the users for selecting and performing the appropriate dosimetry protocol.
Calibration* ; Water

PURPOSE: To develop a practical film dosimetry system for routine Quality Assurance (QA). MATERIALS AND METHODS: An One Click Film (OCF) Dosimetry system was designed to perform swift routine QA with functions including automatic fog value elimination, angle adjustment, automatic symmetry calculation, and realtime profile generation with the ability to display realtime three-dimensional dose distributions. RESULTS: The most frequently used functions for routine QA, such as the elimination of the fog value, conversion into an H&D curve, symmetry, and isodose distribution, can be achieved with only one click. CONCLUSION: Reliable results were achieved with the OCF dosimetry with simpler steps than other commercially available film dosimetry systems for routine QA. More research on the refined user interface will make this system be clinically useful.
Film Dosimetry ; Weather

PURPOSE: To investigate the growth inhibitory effects, and the underlying mechanism of human colon cancer cell (HT-29) death, induced by a new synthetic bile acid derivative (HS-1200). MATERIALS AND METHODS: Human colon cancer cells (HT-29), in exponential growth phase, were treated with various concentrations of a new synthetic bile acid derivative (HS-1200). The growth inhibitory effects on HT-29 cells were examined using a trypan blue exclusion assay. The extent of apoptosis was determined using agarose gel electrophoresis, TUNEL assays and Hoechst staining. The apoptotic cell death was also confirmed by Western blotting of PARP, caspase-3 and DNA fragmentation factor (DFF) analysis. To investigate the involvement of mitochondria, we employed immunofluorescent staining of cytochrome c and mitochondrial membrane potential analyses. RESULTS: The dose required for the half maximal inhibition (IC50) of the HT-29 cell growth was 100~150 micro M of HS-1200. Several changes, associated with the apoptosis of the HT-29 cells, were reveal by the agarose gel eletrophoresis, TUNEL assays and Hoechst staining, following their treatment with 100 micro M of HS-1200. HS-1200 treatment also induced caspase-3, PARP and DFF degradations, and the western blotting showed the processed caspase-3 p20, PARP p85 and DFF p30 and p11 cleaved products. Mitochondrial events were also demonstrated. The cytochrome c staining indicated that cytochrome c had been released from the mitochondria in the HS-1200 treated cells. The mitochondrial membrane potential (deltaxm) was also prominently decreased in the HS-1200 treated cells. CONCLUSION: These findings suggest that the HS-1200 - induced apoptosis of human colon cancer cells (HT-29) is mediated via caspase and mitochondrial pathways.
Apoptosis* ; Bile ; Bile Acids and Salts ; Blotting, Western ; Caspase 3 ; Cell Death ; Colon* ; Colonic Neoplasms* ; Cytochromes c ; DNA Fragmentation ; Electrophoresis, Agar Gel ; HT29 Cells ; Humans* ; In Situ Nick-End Labeling ; Membrane Potential, Mitochondrial ; Mitochondria ; Sepharose ; Trypan Blue

PURPOSE: The purpose of the present study was to analyze and evaluate prior studies published in Korea on the cancer-related quality of life, in order to make recommendations for further research. MATERIALS AND METHODS: A total of 31 studies were selected from three different databases. The selected studies were analyzed according to 11 criteria, such as site of cancer, domain, independent variable, research design, self/proxy rating, single/battery instrument, translation/back translation, reliability, validity, scoring, and findings. RESULTS: Of the 31 studies, approximately half of them were conducted using a mixed cancer group of patients. Many of the studies asserted that the concept of quality of life had a multidimensional attribute. Approximately 30% were longitudinal design studies giving information about the changes in quality of life. In all studies, except one, patients directly rated their level of quality of life. With respect to the questionnaires used for measuring the quality of life, most studies did not consider whether or not their reliability and validity had been established. In addition, when using questionnaires developed in other languages, no studies employed a translation/ back-translation technique. All studies used sum or total scoring methods when calculating the level of quality of life. The types of variables tested for their influence on quality of life were quite limited. CONCLUSION: It is recommended that longitudinal design studies be performed, using methods of data collection whose validity and reliability has been confirmed, and that studies be conducted to identify new variables having an influence on the quality of life.
Data Collection ; Humans ; Korea* ; Quality of Life* ; Surveys and Questionnaires ; Reproducibility of Results ; Research Design

PURPOSE: To investigate the clinical usefulness of a follow-up examination using serum squamous cell carcinoma antigen (SCC) for the early detection of recurrence in patients treated for cervical squamous cell carcinoma. MATERIALS AND METHODS: 20 patients who were treated for recurrent cervical squamous cell carcinoma between 1997 and 1998, who had experienced a complete remission after radiotherapy and who underwent an SCC test around the time when recurrence was detected, were included in this study. The levels of SCC were measured from the serum of the patients by immunoassay and values less than 2 ng/mL were regarded as normal. The sensitivity of the SCC test for use in the detection of recurrence, the association between the SCC values and the recurrence patterns and the tumor size and stage, and the temporal relation between the SCC increment and recurrence detection were evaluated. RESULTS: The SCC values were above normal in 17 out of 20 patients, so the sensitivity of the SCC test for the detection of recurrence was 85%, and the mean and median of the SCC values were 15.2 and 9.5 ng/mL, respectively. No differences were observed in the SCC values according to the recurrence sites. For 11 patients, the SCC values were measured over a period of 6 months before recurrence was detected, and the mean and median values were 13.6 and 3.6 ng/mL, respectively. The SCC values of 7 patients were higher than the normal range, and the SCC values of the other 4 patients were normal but 3 among them were above 1.5 ng/mL. At the time of diagnosis, the SCC valuess were measured for 16 of the 20 recurrent patients, and the SCC values of the patients with a bulky tumor (> or =4 cm) or who were in stage IIb or III were higher than those of the patients with a non-bulky tumor or who were in stage Ib or IIa. CONCLUSION: The SCC test is thought to be useful for the early detection of recurrence during the follow up period in patients treated for cervical squamous cell carcinoma. When an effective salvage treatment is developed in the future, the benefit of this follow-up SCC test will be increased.
Carcinoma, Squamous Cell* ; Cervix Uteri* ; Diagnosis ; Female ; Follow-Up Studies* ; Humans ; Immunoassay ; Radiotherapy ; Recurrence ; Reference Values ; Uterine Cervical Neoplasms

PURPOSE: Radiotherapy is the main treatment modality for uterine cervix cancer. Since the rectum is in the radiation target volume, rectal bleeding is a common late side effect. This study evaluates the risk factors of radiation induced rectal bleeding and discusses its optimal management. MATERIALS AND METHODS: A total of 213 patients who completed external beam radiation therapy (EBRT) and intracavitary radiation (ICR) between September 1994 and December 1999 were included in this study. No patient had undergone concurrent chemo-radiotherapy. Ninety patients received radiotherapy according to a modified hyperfractionated schedule. A midline block was placed at a pelvic dose of between 30.6 Gy to 39.6 Gy. The total parametrial dose from the EBRT was 51 to 59 Gy depending on the extent of their disease. The point A dose from the HDR brachytherapy was 28 Gy to 30 Gy (4 Gyx7, or 5 Gyx6). The rectal point dose was calculated either by the ICRU 38 guideline, or by anterior rectal wall point seen on radiographs, with barium contrast. Rectal bleeding was scored by the LENT/SOMA criteria. For the management of rectal bleeding, we opted for observation, sucralfate enema or coagulation based on the frequency or amount of bleeding. The median follow-up period was 39 months (12~86 months). RESULTS: The incidence of rectal bleeding was 12.7% (27/213); graded as 1 in 9 patients, grade 2 in 16 and grade 3 in 2. The overall moderate and severe rectal complication rate was 8.5%. Most complications (92.6%) developed within 2 years following completion of radiotherapy (median 16 months). No patient progressed to rectal fistula or obstruction during the follow-up period. In the univariate analysis, three factors correlated with a high incidence of bleeding : an icruCRBED greater than 100 Gy (19.7% vs. 4.2%), an EBRT dose to the parametrium over 55 Gy (22.1% vs. 5.1%) and higher stages of III and IV (31.8% vs. 10.5%). In the multivariate analysis, the icruCRBED was the only significant factor (p>0.0432). The total parametrial dose from the EBRT had borderline significance (p=0.0546). Grade 1 bleeding was controlled without further management (3 patients), or with sucralfate enema 1 to 2 months after treatment. For grade 2 bleeding, sucralfate enema for 1 to 2 months reduced the frequency or amount of bleeding but for residual bleeding, additional coagulation was performed, where immediate cessation of bleeding was achieved (symptom duration of 3 to 10 months). Grade 3 bleeding lasted for 1 year even with multiple transfusions and coagulations. CONCLUSION: Moderate and severe rectal bleeding occurred in 8.5% of patients, which is comparable with other reports. The most significant risk factor for rectal bleeding was the accumulated dose to the rectum (icruCRBED), which corrected with consideration to biological equivalence. Prompt management of rectal bleeding, with a combination of sucralfate enema and coagulation, reduced the duration of the symptom, and minimized the anxiety/discomfort of patients.
Appointments and Schedules ; Barium ; Brachytherapy ; Cervix Uteri* ; Enema ; Female ; Follow-Up Studies ; Hemorrhage* ; Humans ; Incidence ; Multivariate Analysis ; Radiotherapy ; Rectal Fistula ; Rectum ; Risk Factors ; Sucralfate ; Uterine Cervical Neoplasms*

PURPOSE: The aim of this study was to determine if postoperative adjuvant chemotherapy (CT) alone and concurrent chemoradiation (CCRT), following radical surgery, improved the disease free survival (DFS) and overall survival (OS) in rectal cancer AJCC stage II and III patients. MATERIALS AND METHODS: A total of 144 patients with AJCC stage II and III rectal cancer who had had radical surgery between 1989 and 1999 were included in the study. Of these patients, 72 had been treated with postoperative CT, and the other 72 with postoperative CCRT. The chemotherapy regimen consisted of oral UFT on a daily basis for 1~12 months (median 12 months) or 5-FU (500 mg/m2 for 5 days) intravenous (IV) chemotherapy with 4 week intervals for 1~18 cycles (median 6 cycles). Radiation of 4,500 cGy was delivered to the surgical bed and regional pelvic lymph nodes area, followed by 540~1,440 cGy (median 540 cGy) boost to the surgical bed. The follow-up period ranged from 20 to 150 months, with a median of 44 months. RESULTS: The 5-year OS was 60.9% and 68.9% (p=0.0915), and the 5-year DFS was 56.1% and 63.8% (p=0.3510) for postoperative CT and postoperative CCRT, respectively. In the stage II patients, the 5-year OS was 71.1% and 92.2%, and the 5-year DFS was 57.3% and 85.4% for postoperative CT and CCRT, respectively. The OS was significantly improved (p=0.0379) but the DFS was not with postoperative CCRT compared to the postoperative CT (p=0.1482). In the stage III patients, the 5-year OS was 52.0% and 55.0%, and the 5-year DFS was 47.8% and 49.8% for postoperative CT and postoperative CCRT. There were no statistically significant differences between postoperative CT and CCRT (p=0.4280 and p=0.7891) in OS and DFS. The locoregional relapses were 16.7% and 12.5% for postoperative CT and CCRT, respectively. The distant relapses were 25.0% and 26.4% for postoperative CT and CCRT, respectively. CONCLUSION: These results showed that postoperative CCRT compared with CT alone improved OS in stage II patients. Although there was no statistical significance, the addition of postoperative RT to CT reduced locoregional relapses compared to CT alone.
Chemotherapy, Adjuvant* ; Disease-Free Survival ; Drug Therapy ; Fluorouracil ; Follow-Up Studies ; Humans ; Lymph Nodes ; Rectal Neoplasms* ; Recurrence