Clinical estimation of bladder and rectal doses from high dose rate intracavitary irradiation in carcinoma of the cervix uteri has been initiated on a routine basis in an effort to obtain the optimum radiotherapeutic dose. Simulation films with contrast media are used to image the bladder and rectum, and dose rates are estimated at various interesting points with the aid of treatment planning computer, NEC Therac-2300. Fifty-three patients have been reviewed in order to ascertain the correlation between radiation dose at interesting points in the bladder and rectum and the dose at Point A and B. The dose ratio between doses at Point A and interesting points in an important clinical factor in evaluating the treatment planning. This also serves as documentation of the dose to normal structures within the treatment volume. Authors conclude that obtained data are within acceptable ranges and routine simulation films of the bladder and rectum after administration of contrast media with dose calculations at interesting points provide important information for optimizing radiotherapy planning in the treatment of cervical carcinoma without increased time and effort or patient's discomfort.
Cervix Uteri ; Contrast Media ; Female ; Humans ; Radiotherapy ; Rectum ; Urinary Bladder ; Uterine Cervical Neoplasms*

In electron therapy, low melting point alloy is used for shaping of the field. Electron field shaping material affect the output factor as well as the collimator system. The output factors of electron beams for shaped fields from NELAC-1018 were measured using ionization chamber of Farmer type in water phantom. The output factors of electron beams depend on the incident energy, inherent collimator system and the size of shaped field. Obtained results were followings. 1. In the smaller applicator, output varied extremely according to extent of collimator opening. 2. The higher energy, the output is less varied according to treatment field at small field.
Alloys ; Farmers ; Freezing ; Water

Uterine cervical cancer is the most common malignancy in Korean women. In spite of recent development of early diagnostic and therapeutic modalities, about 40% of treated patient will develop relapse. So more aggressive local treatment such as more extensive surgery and higher radiation dose and administration of systemic chemotherapy will promote the curability but treatment related complications cannot be avoidable. We used 22 cases of early cervical cancer, treated with surgery and post-operative radiotherapy, clinical data of these patients were analyzed to determine relationship between clinical parameters and final outcome. Three out of 22 cases revealed relapse and one patient showed rectovaginal fistula and another patient showed small bowel obstruction and the other patient showed rectal obstruction. Two out of three recurrence were stage IIa and the other one case was stage Ib adenocarcinoma with lymphovascular involvement. Nineteen out of 22 cases were followed without remarkable side effect or treatment related complication or sequelae. We concluded that out treatment policy was safe and effective to eradicate high risk postoperative cervical cancer with acceptable side effects or complication.
Adenocarcinoma ; Drug Therapy ; Female ; Humans ; Radiotherapy* ; Rectovaginal Fistula ; Recurrence ; Uterine Cervical Neoplasms*

PURPOSE: To evaluate the role of MRI in the management of cervical cancer treated by conventional four-field whole pelvic irradiation. METHOD AND MATERIAL: Between 1993-march and 1994-february, 20 patients(4 Stage I B, 3 Stage U A, 13 Stage U B) with invasive cervical cancer were eligible for evaluation of accuracy of conventionally designed lateral treatment field without MRI determination. RESULTS: 5 out of 20 Patients had inadequate margin without MRI. The position of uterine fundus was more important than cervix in correction of field size and the center of treatment field. CONCLUSION: This Preliminary date show MRI determination of uterine position prior to radiotherapy planning is essential in the case of four-field whole pelvic irradiation technique.
Cervix Uteri ; Female ; Humans ; Magnetic Resonance Imaging* ; Radiotherapy* ; Uterine Cervical Neoplasms*

An analytic expression for equivalent square fields and a table are derived using the empirical representations obtained from the measured field size dependence of output for square field in a phantom. The expression is applicable to radiation fields that consistent with the following two assumptions imposed on these representations. 1) It is a linear function of the logarithm of the field area. 2) It is approximately the same function for both square and circular field of similar areas. In this paper, the derived tables and BJR table were consulted.

Since discovery of X-rays, radiotherapy has evolved into one of the most scientific branches of medicine and has established its role as the primary line or the secondary line of attack, after surgery,. in the treatment of malignant cancers. Nowadays its importance is illustrated by the fact that as many as 70 per cent of all pastients with cancer will receive radiation therapy at sometime during their disease process. Biologic effects-of X-rays began to be apparant soon after the discovery by Roentgen in 1895. In clinical radiotherapy, the biologic endpoint of most importance is loss of cellular reproductive ability or clonogenicity. One of the commonest ;nays to assess cell survival is to use an in vitro plating assay. We analyzed radiation effect on colony formation of HaLa. S3(SC) cell line and obtained results are as follows The plating efficiency is 0.464. The shape of cell survival curve is similar to multi-target plus single hit component model. Estimated values of Do, Dq, and extrapolation number are 150 cGy, 80 cGy and 1.7 respectively. We reported these experimental data with review of literature.
Cell Line* ; Cell Survival ; Radiation Effects ; Radiotherapy

Scatter-air ratios are used for the purpose of calculating scattered dose in the medium. The computation of the primary and the scattered dose separately is particularly useful in the dosimetry of irregular fields with shielding block in radiation field, dose distribution of scattered radiation using 18MeV Linear accelerator and Co-60 teletherapy measured. The effect of scattered radiation dose by protecting block was been ignored in radiation therapy, 2-3% of scattered radiation may be 90-200cGy which could be influence vital complication such as cataract, oligospermia or sterility. So that exact calculate scattered radiation by protecting block exactly for irregular field c small protection of vital organ is very important. The purpose of this article is to calculate scattered radiation by protecting block exactly for irregular field c Linac or Co-60 irradiation and to applicate these data in clinical radiation field. Authors could obtain following results. 1. The lesser angle between shielding block showed more scattered radiation. 2. With decreasing distance between shielding blocks, the dependent of scattered radiation were increased. 3. Output of 18 MeV Linear accelerator and Co-60 was related linear proportion on field size, but independent according to the size of shielding block in 18 MeV Linear accelerator.
Cataract ; Infertility ; Male ; Oligospermia ; Particle Accelerators

The basic strategy of irradiation is to deliver a dose to the cancer that is high enough to make cancer cells incapable of reproduction, while keeping the doses to the various healthy tissues below tolerable levels. In order to improve local control and survival, as a boost therapy after external radiotherapy, high dose rate transcatheteric irradiation using remote control after loading system (RALSTRON-20B) was used for twelve patients with head and neck cancers. Present results showed complete remission of cancer in 9 out of 112 patients without treatment related complications. Although this procedure is easy to operate, well trained skillful hand in essential for good results. Furthermore out experience suggested that meticulous treatment planning should be developed for better results.
Hand ; Head and Neck Neoplasms* ; Head* ; Humans ; Neck ; Radiotherapy ; Reproduction

The stereotactic radiosurgery using ionizing radiation of high energy is a technique for exadicating intracranial small tumors, which are inaccessible or unsuitable for open surgical technique. For such a small field radiosurgery, TLD or film dosimetry is essential. The three dimensional dose planning of radiosurgery was performed with dose planning computer system (Therac 2300). The target dose distribution and its error according to patient position were discussed. And were measured of circular cone which specially designed in our Hospital. The position error of Rando Phantom compared with CT were 0.4 mm in the AP-LAT section and in the AP-VERT section, 1.0 mm in the AP-VERT 45°section. The ratio of accuracy of the gantry and couch rotation were 1.5 mm diameter for central axis of 18MeV linear accelerator. Our study suggested that radiosurgery of small field in out department will be appropriate for clinical application.
Computer Systems ; Film Dosimetry ; Humans ; Particle Accelerators ; Radiation, Ionizing ; Radiosurgery*

Radiotherapeutically, nasopharyngeal caner is an important disease in Korea. Because of its blind anatomic location, early detection is relatively uncommon. Clinically, most of cases are locally advanced and nodal involvements are common. Recently better understanding of nature of the disease and improvement of radio – therapy technique permit better treatment result, including locoregional control and survival rate, and minimal normal tissue damages comparing with previously published date. We analyzed 31 patients of pathologically proven and previously untreated naso – pharyngeal carcinoma with different treatment techniques, retrospectively. Minimal and maximal follow up period of the survivor is 6 months and 68 months, respectively. Thirteen patients with squamous cell carcinoma are included in this analysis. The median age is 49 years (range from 20 to 64 years). Twenty two patients are stage III. Eleven patients are treated with radiotherapy alone and 20 are treated with combined modalities treatment. The degree of response after radiotherapy are categorized by 3-classes, i,e. complete response, partial response. In spite of similarities of complete response rate and 1-year survival rate between two different treatment techniques, those patients with undifferentiated carcinoma appear to benefit from the adjuvant chemotherapy. In addition, systemic failure is more suggest that adjuvant therapy in the radiotherapeutic management of nasopharyngeal cancer needs additional research according to histologic types and future extensive clinical trials.
Carcinoma ; Carcinoma, Squamous Cell ; Chemotherapy, Adjuvant ; Follow-Up Studies ; Humans ; Korea ; Nasopharyngeal Neoplasms* ; Radiotherapy ; Retrospective Studies ; Survival Rate ; Survivors