PURPOSE: An investigation has been carried out on the factors which affect the response reading of thermoluminescent dosimeters (TLD-100) loaded with thin material in high energy photon. The aim of the study was to assess the energy response of TLD-100 to the therapeutic ranges of photon beam. MATERIALS AND METHODS: In this technique, TLD-100 (abbreviated as TLD) chips and three different thin material (Tin, Gold, and Tissue equivalent plastic plate) which mounted on the TLD chip were used in the clinical photon beam. The thickness of each metal plates was 0.1 mm and TE plastic plate was 1 mm thick. These compared with the photon energy dependence of the sensitivities of TLD (normal chip), TLD loaded with Tin or Gold plate, for the photon energy range 6 MV to 15 MV, which was of interest in radiotherapy. RESULTS: The enhancement of surface dose in the TLD with metal plate was clearly detected. The TLD chips with a Gold plate was found to larger response by a factor of 1.83 in 10 MV photon beam with respect to normal chip. The sensitivity of TLD loaded with Tin was less than that for normal TLD and TLD loaded with Gold. The relative sensitivity of TLD loaded with metal has little energy dependence. CONCLUSION: The good stability and linearity with respect to monitor units of TLD loaded with metal were demonstrated by relative measurements in high energy photon (6~15 MV) beams. The TLD laminated with metals embedded system in solid water phantom is a suitable detector for relative dose measurements in a small beam size and surface dose.
Metals ; Plastics ; Radiotherapy ; Tin ; Water

PURPOSE: LiF TLD has a problem to be used in vivo dosimetry because of the toxic property of LiF. The aim of this study is to develop new dosimeter with LiF TLD to be used in vivo dosimetry. MATERIALS AND METHODS: We designed and manufactured the teflon box(here after TLD holder) to put TLD in. The external size of TLD holder is 4x4x1 mm3. To estimate the effect of TLD holder on TLD response for radiation, the linearity of TLD response to nominal dose were measured for TLD in TLD holder. Measurement were performed in the 10 MV x-ray beam with LiF TLD using a solid water phantom at SSD of 100 cm. Percent Depth Dose (PDD) and Tissue-Maximum Ratio (TMR) with varying phantom thickness on TLD were measured to find the effect of TLD holder on the dose coefficient used for dose calculation in radiation therapy. RESULTS: The linearity of response of TLD in TLD holder to the nominal dose was improved than TLD only used as dosimeter. And in various measurement conditions, it makes a marginnal difference between TLD in TLD holder and TLD only in their responses. CONCLUSION: It was proven that the TLD in TLD holder as a new dosimetry could be used in vivo dosimetry.
Polytetrafluoroethylene ; Silver Sulfadiazine ; Water

BACKGROUND/AIMS: Despite the potent suppression of the hepatitis B virus with modern antiviral agents, only a minority of HBeAg-positive patients achieve hepatitis B e antigen seroconversion. We aimed to explore the potential efficacy of combination therapy consisting of pegylated interferon (p-IFN) and an oral antiviral agent in patients with HBeAg-positive chronic hepatitis B. METHODS: The treatment protocol consisted of p-IFN-α-2a at 180 μg/wk for 48 weeks, with either entecavir or tenofovir added 8 weeks after the initiation of p-IFN and continued for at least 6 months after HBe seroconversion was achieved. RESULTS: To date, 10 patients have been treated under the protocol (eight adults, mean age 36±8 years; two adolescents, aged 12 and 16 years). All eight adult patients experienced loss of HBeAg at a mean of 72.3±66.9 weeks, including six patients who also developed anti-HBe and one patient who had HBs seroconversion. Although both adolescents remain on therapy, one adolescent had HBs seroconversion without HBe seroconversion. A total of nine of our 10 patients experienced a favorable serological transition. CONCLUSIONS: The combination of p-IFN and a modern oral antiviral agent may be more effective than monotherapy with either class of agent in the treatment of HBeAg-positive chronic hepatitis B patients.
Adolescent ; Adult ; Antiviral Agents ; Clinical Protocols ; Hepatitis B ; Hepatitis B e Antigens ; Hepatitis B virus ; Hepatitis B, Chronic* ; Hepatitis, Chronic* ; Humans ; Interferons ; Seroconversion ; Tenofovir

A docking intraoperative electron beam applicator system, which is easily docking in the collimator for a linear accelerator after setting a sterilized transparent cone on the tumor bearing area in the operation room, has been designed to optimize dose distribution and to improve the efficiency of radiation treatment method with linear accelerator. This applicator system consisted of collimator holder with shielded metals and docking cone with transparent acrylic cylinder. A number of technical innovations have been used in the design of this system, this docking cone gives a improving latral dose coverage at therapeutic volume. The position of 90% isodose curve under surface of 8 cm diameter cone was extended 4~7 mm at 12 MeV electron and the isodose measurements beneath the cone wall showed hot spots as great as 106% for acrylic cone. The leakage radiation dose to tissues outside the cone wall was reduced as 3~5% of output dose. A comprehensive set of dosimetric characteristics of the intraoperative radiation therapy applicator system is presented.
Metals ; Particle Accelerators

Increasing frequency of skin cancer, mycosis fungoides, Kaposi's sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a 0.5cm x90cm x180cm acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. Instrumentation and techniques developed in determining the depth dose, dose distribution and bremsstrahlung dose are discussed.
Foot ; Head ; Humans ; Mycosis Fungoides ; Particle Accelerators ; Sarcoma, Kaposi ; Skin Neoplasms* ; Skin* ; Toes

From May 1979 through December 1981 a total of 524 patients with carcinoma of the uterine cervix were treated by radiation therapy with curative intent. Among the 524 patients, 356 were treated with a high-dose-rate (HDR), remote-controlled, afterloading intracavitary irradiation (ICR) system using a cobalt source (Ralstron), and 168 patients received a low-dose-rate (LER) ICR using a radium source. External beam irradiation with a total dose of 40-50 gy to the whole pelvis followed by intracavitary irradiation with a total dose or 30-39 gy in 10-13 fractions to point A was the treatment protocol ICR was given three times a week with a dose of 3 gy per fraction. Five-year actuarial survival rates in the HER-ICR group were 77.6% in stage IB (N=20), 68.2% in stage II (N=182), and 50.9% in stage III (N=148). In LDR-ICR group, 5-year survival rates were 87.5% in stage IB (N=22), 66.3% in stage II (N=91), and 55.4% in stage III (N-52). Survival rates showed a statistically significant difference by stage, but there was no significant difference between the two ICR groups. Late bowel complications after radiotherapy were noted in 3.7% of the HDR-ICR group and 8.4% of the LDR-ICR group. There was no severe complication requiring surgical management. The incidence of bladder complications was 1.4% in the HDR-ICR group and 2.4% in the LDR-ICR group. The application of HDR-ICR was technically simple and easily performed on an outpatient basis without anesthesia, and the patients tolerated it very well. Radiation exposure to personnel was virtually nil in contrast to that of LDR-ICR. Within a given period of time, more patients can be treated with HDR-ICR because of the short treatment time. Therefore, the HDR-ICR system is highly recommended for a cancer center, particularly one with a large number of patients to be treated. In order to tachieve an improved outcome, however, the optimum dose-fractionation schedule of HDR-ICRand optimum combination of intracavitary irradiation with external beam irradiation should be determined through an extensive protocol study with different treatment regimens.
Anesthesia ; Appointments and Schedules ; Cervix Uteri* ; Clinical Protocols ; Cobalt ; Female ; Humans ; Incidence ; Outpatients ; Pelvis ; Radiotherapy ; Radium ; Survival Rate ; Urinary Bladder

PURPOSE: The objective of our study was to evaluate the immunohistochemical expression of p53 and bax proteins as prognostic markers in FIGO stage IIb invasive squamous cell carcinoma of the uterine cervix. MATERIALS AND METHODS: Sixty-five cases of squamous cell carcinoma of the cervix (stage IIb) that were diagnosed from October 1996 to December 2003 were analyzed retrospectively for the bax and p53 expression. These expressions were determined immunohistochemically and they were correlated to the patients' overall survival and disease-free survival. RESULTS: The overall 5-year survival (OS) rate and the disease-free survival (DFS) rate were 65.1% and 62.9%, respectively. p53 and bax immunoreactivity was seen in 26.2% and 52.3% of cases, respectively, with variable levels of expression. On the univariate analysis, only p53 positivity correlated with poor survival in DFS (log-rank test p=0.027), but this significance was not maintained on multivariated analysis by Cox's regression. The nine cases with the immunophenotype p53+/bax- had the poorest survival. CONCLUSION: Neither p53 nor bax expression are independent predictors of the prognosis for stage IIb cervical squamous cancers. Evaluation of p53 and bax co-expression may affect the clinical outcome and further investigation is needed.
bcl-2-Associated X Protein ; Carcinoma, Squamous Cell ; Cervix Uteri ; Disease-Free Survival ; Female ; Humans ; Prognosis ; Retrospective Studies

PURPOSE: To evaluate possible acute toxicity and early response of concurrent radiation therapy and low dose daily cisplatin as a radiosensitizer in patients with locally advanced uterine cervical carcinomas. MATERIALS AND METHODS: From December 1996 to January 1999, 38 previously untreated patients with locally advanced squamous cell carcinoma of the uterine cervix (from stage IIB to stage IIIB) were treated at Inha University Hospital. All patients underwent standard pretreatment staging procedures after the initial evaluation by gynecologists and radiation oncologists. Sixteen patients with huge cervical mass (>4 cm) were submitted to the group treated with concurrent radiation therapy and low dose daily cisplatin while the remainder was treated with radiation therapy alone. Radiation therapy consisted of 4500 cGy external beam irradiation to whole pelvis (midline block after 3060 cGy), 900~1000 cGy boost to involved parametrium, and high dose-rate intracavitary brachytherapy (a total dose of 3000~3500 cGy/500 cGy per fraction to point A, twice per week). In the group treated with low dose cisplatin concurrently, 10 mg of daily intravenous cisplatin was given from the 1st day of radiation therapy to the 20th day of radiation therapy. Acute toxicity was measured according to expanded common toxicity criteria of the NCI (C) Clinical Trials. Early response data were analyzed at minimum 4 weeks' follow-up after completion of the treatment protocol. RESULTS: Hematolgic toxicity was more prominent in patients treated with radiation therapy and cisplatin. Six of 16 patients (37.5%) treated with radiation therapy and cisplatin and one of 22 patients (4.5%) treated with radiation therapy alone experienced grade 3 leukopenia. In Fisher's exact test, there was statistically significant difference between two groups regarding leukopenia (P=0.030). There was no apparent difference in the frequency of gastrointestinal and genitourinary toxicity between two groups (P=0.066). Three of 16 patients (18.7%) treated with radiation therapy and cisplatin and two of 22 patients (9.1%) treated with radiation therapy alone experienced more than 5 kg weight loss during the treatment. There was no statistically significant difference on weight loss between two groups (P=0.63). Two patients on each group were not evaluable for the early response because of incomplete treatment. The complete response rate at four weeks' follow-up was 80% (16/20) for the radiation therapy alone group and 78% (11/14) for the radiation therapy and cisplatin group. There was no statistically significant difference in early response between two treatment groups (P=0.126). CONCLUSION: This study led to the conclusion that the hematologic toxicity from the treatment with concurrent radiation therapy and low dose daily cisplatin seems to be more prominent than that from the treatment of radiation therapy alone. There was no grade 4 hematologic toxicity or mortality in both groups. The hematologic toxicity in both treatment groups seems to be well managable medically. Since the risk factors were not balanced between two treatment groups, the direct comparison of early response of both groups was not possible. However, preliminary results regarding early response for patients with bulky cervical tumor mass treated with radiation therapy and low dose daily cisplatin was encouraging. Longer follow-up is necessary to evaluate the survival data. A phase III study is needed to evaluate the efficacy of concurrent daily low dose cisplatin with radiation therapy in bulky cervical cancer.
Brachytherapy ; Carcinoma, Squamous Cell* ; Cervix Uteri* ; Chemoradiotherapy ; Cisplatin* ; Clinical Protocols ; Female ; Follow-Up Studies ; Humans ; Leukopenia ; Mortality ; Pelvis ; Risk Factors ; Uterine Cervical Neoplasms ; Weight Loss

A total of 20 patients(male : female=10:10, adult : children=8:12) with brainstem tumors had been received radiation therapy in the Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine between 1980 and 1990. Thirteen of 20 patients were treated with conventional radiation therapy (before 1989, 180~200 cGy per fraction, 5 days a week, total dose 4680~5400 cGy), and seven patients were treated with hypefractionated radiation therapy(in 1990, 100 cGy per fraction, twice daily 10 fractions a week, total dose 7200 cGy). Median follow up periods for conventional radiation therapy group and hyperfractionated radiation therapy group were 39 months and 10 months, respectively. Four of 20 Patients had histopathologic diagnosis prior to treatment ; 3 cases were low grade astrocytoma and 1 case was high grade astrocytoma. Overall 2-year actuarial survival rate was 30%. The prognosis of patients with a longer duration of symptom and sign was better(60% vs 12%), and the adult(52%) was better than children(14%). There was no significant difference between the focal(29%) and diffuse(20%) type. The initial clinical response was better in the hyperfractionated radiation therapy group. Because of the relatively small number of Patients and short follow up Period in hyPerFractionated radiation therapy group, there was no comparison between two group.
Adult ; Astrocytoma ; Brain Stem Neoplasms* ; Brain Stem* ; Diagnosis ; Follow-Up Studies ; Humans ; Prognosis ; Radiation Oncology ; Survival Rate

Sixty patients, treated with postoperative radiation therapy following radical hysterectomy and pelvic lymphadenectomy for stage lb carcinoma of the uterine cervix between Jan. 1980 and Dec. 1984 at Department of Radiation Oncology, Yonsei University College of Medicine, were retrospectively analysed. The minimum follow-up period was 5 years. The indications for postoperative radiotherapy were positive pelvic lymph node (34 pts), a large tumor size more than 3 cm in longest diameter (18 pts), positive surgical margin (10 pts), deep stromal invasion (10 pts), and lymphatic permeation (9 pts). The overall 5-year survival rate was 81.8%. The univariate analysis of prognostic factors disclosed tumor size (less than 3cm, greater than or equal to 3cm) and the status of the surgical margin (positive, negative) as significant factors (tumor size; 88.1% vs 6.3%, surgical margin; 85.5% vs 60%, p less than 0.05). Age (less than or equal to 40, greater than 40 yrs) was marginally significant (90.2% vs 73.1%, p less than 0.1). Multivariate analysis clarified two independent prognostic factors; tumor size (p = 0.010) and surgical margin (p = 0.004). Analysis of the tumor factors with the radiation dose disclosed a better survival rate for patients with a positive surgical margin who were given over 50 Gy than for those who were given below 50 Gy in patients (4/4, 100% vs 2/6, 33.4%; p = 0.06). Significant complications requiring surgical correction were not observed. In conclusion, it is believed that the status of the surgical margin and tumor size both have important prognostic significance, and that a radiation dose over 50 Gy is advisable for patients with a positive surgical margin.
Adult ; Carcinoma/mortality/*radiotherapy/surgery ; Cervix Neoplasms/mortality/*radiotherapy/surgery ; Combined Modality Therapy ; Female ; Human ; Hysterectomy ; Lymph Node Excision ; Lymphatic Metastasis ; Prognosis ; Retrospective Studies ; Support, Non-U.S. Gov't