PURPOSE: To get an acute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic tranmultiarc beam mode based on linear accelerator photon beam. METHODS AND MATERIALS: This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. RESULTS: In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. CONCLUSION: 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery.This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs.It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles.In our experiments. the absorbed dose has been decreased to 27 % /mm in maximum at the interval of 50% to 80% of isodose line.
Brain ; Follow-Up Studies ; Humans ; Particle Accelerators* ; Prognosis ; Radiosurgery* ; Tomography, X-Ray Computed

PURPOSE: This report is the result of retrospective analysis for children who received prophyactic cranial irradiation combined with intrathecal chemotherapy. METHODS AND MATERIALS: Ninety children with ALL who had got bone marrow remission after induction chemotherapy received PCI. All but 3 children were treated with a dose of 1800 cGy as a standard regimen. While the PCI was given, all patients received intrathecal chemotherapy. RESULTS: Nine of 90 patients experienced CNS relapse during the duration of follow-up ranged from 36 to 96 months (median 60 months). Three children experienced BM relapse prior to CNS relapse. Therefore, CNS relapse rate as the first adverse event was 6.7%. Median time interval of CNS relapse was 16 months from the first day of hematologic complete remission. Eighty-nine percent of patients who had CNS relapse occurred during maintenance chemotherapy (on-therapy relapse). The CNS RFS at 2 and 5 years are 68 % and 42 %, respectively with median of 43 months. The prognostic factors affecting CNS RFS are initial WBC count (cut-off point of 50,000/mul), FAB subtype and CALGB risk WBC count (cut-off point of 50,000/mul), FAB subtype, POG and CALGB risk criteria. CONCLUSION: In our study, 6.7% of CNS relapse rate as a first adverse event was comparable with other studies. Various risk criteria was based on age at diagnosis and initial WBC count such as POG and CALGB criteria, had prognostic significance for CNS RFS and DFS. Prospective randomized trial according to prognostic subgroup based on risk criteria and systematic study about neuropsychologic function for long term survivors, are essential to determine the most effective and least toxic form of CNS prophylaxis.
Bone Marrow ; Child ; Cranial Irradiation* ; Diagnosis ; Drug Therapy ; Follow-Up Studies ; Humans ; Induction Chemotherapy ; Maintenance Chemotherapy ; Precursor Cell Lymphoblastic Leukemia-Lymphoma* ; Recurrence ; Retrospective Studies ; Survivors

PURPOSE: To evaluate the effectiveness and tolerance of patients ofexternal beam radiotherapy ofr carcinoma of the extrahepatic biliary system (EHBS) including gall bladder (GB) and extrahepatic bile ducts (EHBD) and to define the role of radiotherapy for these tumors. METHODS AND MATERIALS: We retrospectively analyzed the records of 43 patients with carcinoma of the EHBS treated with external beam radiotherapy at our institution between April, 1986 and July, 1994. Twenty three patients had GB cancers and remaining 20 patients did EHBD cancers. Of those 23 GB cancers, 2 had Stage II, 12 did Stage III and 9 did Stage IV disease, respectively. Male to female ratio was 11 to 12. Fifteen patients underwent radical surgery with curative intent and 8 patients did biopsy and bypass surgery alone. Postoperatively 16 patients were irradiated with 4500 cGy or higher doses and 4 patients with 3180 to 4140 cGy. Follow up periods ranged from 8 to 34 months. RESULTS: overall median survival time of patients with GB cancer was 11 months. Median survival time for patients with Stage III and IV disease were 14 months and 5 months, respectively. Corresponding two year survival rates were 36%(4/11) and 13%(1/8), respectively. Those who underwent surgery with curative intent showed significantly better survival at 12 months than those who underwent bypass surgery alone(67% vs 13%). None of the patients died of treatment related complications. Median survival time for entire group of 20 EHBD patients was 10 months. Median survivals of 10 Stage III and 7 Stage IV disease were 10 and 8 months, respectively. Two patients who underwent Whipple's procedure had 11 and 14 month survival and those treated with resection and drainage showed median survival of 10 month. CONCLUSION: Postoperative external beam radiotherapy for carcinoma of the extrahepatic billary system is well tolerated and might improve survival of patients. especially those with respectable lesions with microscopic or gross residual disease after surgery.
Bile Duct Neoplasms ; Bile Ducts, Extrahepatic* ; Biopsy ; Drainage ; Female ; Follow-Up Studies ; Gallbladder Neoplasms ; Humans ; Male ; Radiotherapy* ; Retrospective Studies ; Survival Rate ; Urinary Bladder

PURPOSE: This is a retrospective study to compare the palliation rates, survival rates and complications of low dose rate and high dose rate endobronchial brachytherapy in the management of malignant airway obstruction. METHODS AND MATERIALS: Forty three consecutive patients with malignant airway compromise from primary or metastatic lung tumors were treated with low dose rate(LDR) endobronchial Iridium-192 insertion (21 patients) between October 1988 and June 1992, and high dose rate(HDR) endobronchial brachytherapy(22 patients) between August 1992 and April 1994 with palliative aim. Flexible fiberoptic bronchoscopy under fluoroscopic control was utilized in all 91 provedures. Twenty seven LDR provedures delivereda dose of 5-7.5 Gy to a 1.0 cm radius respectively. RESULTS: Subjective and objective responses to treatments were evaluated on follow-up examinations by clinical examination, chest x-rays and CT scan of the chest had been demonstrated on 8 LDR patients and 10 HDR patients. CONCLUSION: The technique of LDR and HDR endobronchial brachytherapy is simple and well tolerated procedure with minimal morbidity. It provides excellent palliation by keeping airway patent in these short life-spanned patients.
Airway Obstruction ; Brachytherapy* ; Bronchoscopy ; Follow-Up Studies ; Humans ; Lung ; Radius ; Retrospective Studies ; Survival Rate ; Thorax ; Tomography, X-Ray Computed

PURPOSE: To improve the treatment results of locally advanced nonsmallcell lung cancer (NSCLC) patient, we treated those paients with regional hyperthermia combined with radiotherapy. And we conducted a retrospective analysis of the results. METHODS AND MATERIALS: Thirty two nonsmall cell lung cancer patients treated at the Department of Radiation Oncology, St. Mary's hospital. Catholic University Medical College were the base of this analysis. Fourteen patients of above them were treated with hyperthermia and radiotherapy of more than 3000 cGy in radiation dose. Radiofrequency capacitive hyperthermia was administered twice weekly, immediately after radiotherapy. Total sessions of hyperthermia ranged from 3 to 13 times (mean 7,8). Eighteen patient received an external radiation therapy alone. Median radiation dose was 5580 cGy (range, 3000-7000 cGy) in fraction of 180-300 cGy, 5 fractions per week. RESULTS: The results of themoradiotherapy group (HTRT group) were compared with radiation alone group (RT group). There were no complete response (CR) and 12 partial responses (PR) (CR rate 0%, response rate 85.7%) in HTRT group, whereas there were 2 CRs, 8 PRs and 8 no responses (CR rate 11.1%, response rate 55.6%) in RT group. There was significant differece in local response rate of the tumors between RT group and HTRT group (p<0.05). Overall 2 year survival rate and mean survival were 7.1% and 10.5 months for HTRT group, and 0% 8.1 months for RT group. However, by the number of hyperthermia, in cases with more than or equal to 10 sessions of hyperthermia, there were significant improvement in 2 year survival rate and mean survival (40.0% and 18.2 months) compared with those in cases with less than 10 sessions of hyperhtemia (7.4% and 7.4 months) (p<0.05). CONCLUSION: Thermoradiotherapy in locally advanced NSCLC patients increased their response rate but not 2 year survival and mean survival, therefore thermoradiotherpy with enough number of hyperthermia is suggested that may be one of the effective palliative treatments of those patients. And in cases with more than 10 sessions of hyperthermai, there showed improved 2 year survival rate and mean survival. But the number of the cases was small, further study in this aspect is required.
Carcinoma, Non-Small-Cell Lung* ; Fever ; Humans ; Lung Neoplasms ; Palliative Care ; Radiation Oncology ; Radiotherapy ; Retrospective Studies ; Survival Rate

PURPOSE: To improve treatment modality and results by analysis of clinical characteristics. local control, survival and resurrence rate in limited stage small cell lung cancer. METHODS AND MATERIALS : 26 patients with limited stage small cell lung cancer were treated with combined radiation and chemotherapy from Feb. 1986 to Dec. 1992 at the National Medical Center. We followed up on 21 patients (81%) , who were mostly irradiated with 4,000-5,000cGy (75% of all patients) in the results by the analysis retrospectively. Survival rate was evaluated by the Kaplan-Meier method. RESULTS: Mean survival of irradiated patients with limited small cell lung cancer was 12 months. 1-year and 2-year survival rate were 65.3% and 15.4%. Tumor response rate and median survival after combined chemotherapy and irradiation were the following ; 50% and 15 months of complete response, and 23% and 11 months of partial response respectively. Response rates by radiation dose were 66% for below 4,000cGy. 69% for between 4,000-5,000cGy and 86% for above 5,000cGy. 21 of all patients showed treatment failure(81%), which as appeared 9 of local failure.9 of distant failure and 3 of local and distant failure. CONCLUSION: Local response rate after induction chemotherapy alone in limited stage of small cell lung cancer was 54%. Furthermore it was increased to 73% after adding of radiation. We have to increase radiation dose above 5,000cGy and need to try new effective chemotherapy agents for the improvement of local control and survival rate and also will try concurrent chemoradiotherapy in near time.
Chemoradiotherapy ; Drug Therapy ; Humans ; Induction Chemotherapy ; Retrospective Studies ; Small Cell Lung Carcinoma* ; Survival Rate*

PURPOSE: A retrospective analysis for patients with oropharyngeal carcinoma who were treated with radiation was performed to assess the results of treatment and patterns of failure, and to identify the factors that might influence survival. METHODS AND MATERIALS: From March 1985 through June 1993, 53 patients with oropharyngeal carcinoma were treated with either radiation therapy alone or combination of neoadjuvant chemotherapy and radiation therapy at the Department of Radiation Oncology, Kyungpook National University Hospital. Patients' ages ranged from 31 to 73 years with a median age of 54 years. There were 47 men and 6 women. Forty-two patients (79.2%) had squamous cell carcinoma, 10 patients (18.9%) had undifferentiated carcinoma and 1 patient (1.9%) had adenoid cystic carcinoma. There were 2 patients with stage I 12 patients with stage II, 12 patients with stage III and 27 patients with stage IV. According to the TNM classification, patients were distributed as follows: T1 7, T2 2, T3 10, T4 7, TX 1, and N0 17, N1 13, N2 21, N3 2. The primary tumor sites were tonsillar region in 36 patients (67.9%) base of the tongue in 12 patients (22.6%), and soft palate in 5 patients (9.4%). Twenty-five patients were treated with radiation therapy alone and twenty-eight patients were treated with one to three courses of chemotherapy followed by radiation therapy. Chemotherapeutic regimens used were either CF (cisplatin and 5-fluorouracil) or CVB (cisplatin, vincristine and bleomycin), Radiation therapy was delivered 180-200 cGy daily,five times a week using 6 MV X-ray with or without 8-10 MeV electron beams. A tumor dose ranged from 4500 cGy to 7740 cGy with a median dose of 7100 cGy. The follow-up time ranged from 4months to 99 months with a median of 21 months. RESULTS: Thrity-seven patients (69.8%) achieved a CR (complete response) and PR (partial response) in 16 patients (30.2%) after radiation therapy. The overall survival rates were 47% at 2 years and 42% at 3 years, respectively. The median survival time was 23 months. Overall stage (p=0.02) and response to radiation therapy (p=0.004) were significant prognostic factors for overall survival. The 2-year disease-free survival rate was 45.5%. T-stage (p=0.03), N-stage (p=0.04) and overall stage (p=0.04) were significant prognostic factors for disease-free survival. Age, sex, histology, primary site of the tumor, radiation dose, combination of chemotherapy were not significantly associated with disease-free survival. Among evaluable 32 patients with CR to radiation therapy, 12 patients were considered to have failed. Among these, 8 patientsfailed locoregionally and 4 patients failed distantly. CONCLUSION: T-stage, N-stage and overall stage were significant prognostic factors for disease-free survival in the treatment of oropharyngeal cancer. Since locoregional failure was the predominant pattern of relapse, potential methods to improve locoregional control with radiation therapy should be attempted. More controlled clinical trials should be completed before acceptance of chemotherapy as a part of treatment of oropharyngeal carcinoma.
Carcinoma ; Carcinoma, Adenoid Cystic ; Carcinoma, Squamous Cell ; Classification ; Disease-Free Survival ; Drug Therapy ; Female ; Follow-Up Studies ; Gyeongsangbuk-do ; Humans ; Male ; Oropharyngeal Neoplasms ; Oropharynx* ; Palate, Soft ; Radiation Oncology ; Recurrence ; Retrospective Studies ; Survival Rate ; Tongue ; Vincristine

No abstract available.
Astrocytoma* ; Epidermal Growth Factor* ; Receptor, Epidermal Growth Factor*

PURPOSE: To collect beam data for dynamic wedge fields using conventional measurement tools without the multi-detector system, such as the linear diode detectors or ionization chambers. MATERIALS AND METHODS: The accelerator CL 2100 C/D has two photon energies of 6MV and 15MV with dynamic wedge angles of 15o, 30o, 45o and 60o. Wedge transmission factors, percentage depth doses(PDD's) and dose profiles were measured. The measurements for wedge transmission factors are performed for field sizes ranging from 4x4cm2 to 20x20cm2 in 1-2cm steps. Various rectangular field sizes are also measured for each photon energy of 6MV and 15MV, with the combination of each dynamic wedge angle of 15o, 30o, 45o and 60o. These factors are compared to the calculated wedge factors using STT(Segmented Treatment Table) value. PDD's are measured with the film and the chamber in water phantom for fixed square field. Converting parameters for film data to chamber data could be obtained from this procedure. The PDD's for dynamic wedged fields could be obtained from film dosimetry by using the converting parameters without using ionization chamber. Dose profiles are obtained from interpolation and STT weighted superposition of data through selected asymmetric static field measurement using ionization chamber. RESULTS: The measured values of wedge transmission factors show good agreement to the calculated values. The wedge factors of rectangular fields for constant Y-field were equal to those of square fields. The differences between open fields' PDDs and those from dynamic fields are insignificant. Dose profiles from superposition method showed acceptable range of accuracy(maximum 2% error) when we compare to those from film dosimetry. CONCLUSION: The results from this superposition method showed that commissionning of dynamic wedge could be done with conventional dosimetric tools such as point detector system and film dosimetry winthin maximum 2% error range of accuracy.
Film Dosimetry ; Water

PURPOSE: To obtain the actual dose distribution from measured data by deconvolution method using the measured ion chamber response function. MATERIALS AND METHODS: The chamber response functions for 2 ionization chambers (diameter 5mm, 6.4mm) were measured, and dose profiles were measured for 10X20cm2 field size using two different detectors. The deconvolution of chamber response function from the measured data were performed for these profiles. The same procedures were repeated for 4MV, 6MV and 15MV photon energies. RESULTS: Different dose profiles were obtained for the same field with the chambers which have the different response functions. Nearly the same results could be obtained with deconvolution for the profiles from various detectors. CONCLUSION: The effect of the chamber response function can be extracted by deconvolution method. Deconvolved dose profile using various ionization chambers gave better dose distributions. Technical improvements are needed for practical application.