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

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*

Total 55 patients with nonsmall cell lung cancer treated with radiation therapy at Department of Therapeutic Radiology, Yeungnam University Hospital, between May-1 1986 and April-30 1993 were retrospectively analyzed by clinical characteristics, failure patterns follow up duration and survival ratio according to prognostic factors. Obtained results were as follows : 1. Male to female ratio was 17.3 2. Sixth and seventh decades were predominant age group. 3. The patients were 8 in stage I-II, 34 in stage IIIA, 13 in stage IIIb, respectively. 4. Forty five patients out of 55 were squamous cell carcinoma. 5. Primary tumor were originated from upper lobe bronchi predominantly. 6. The size of the primary tumor, lymph node involvement and the degree of differentiation were important in evaluation of prognosis. 7. In conclusion, for patients with poor prognostic factors systemic chemotherapy and multidisciplinary approach were recommended for better treatment outcome and improvement of survival.
Bronchi ; Carcinoma, Non-Small-Cell Lung ; Carcinoma, Squamous Cell ; Drug Therapy ; Female ; Follow-Up Studies ; Humans ; Lung Neoplasms* ; Lung* ; Lymph Nodes ; Male ; Prognosis ; Radiation Oncology ; Radiotherapy* ; Retrospective Studies ; Treatment Outcome

In recent years there has been a growing interest in all forms of rotational therapy, and many different types of therapy machines designed for this kind of treatment have become available. To the medical radiation physicist, the dosimetry of rotation therapy has presented a number of interesting problems, and much useful work has been published on the basic date of dose distribution and dosage calculation. The setting dose for ARC therapy were obtained by computer calculation and measurement with cylindrical phantom. Authors compared computer calculation with measured value. And in ARC therapy, the region of maximum dose in shifted from the tumor center. The extent of shift was analyzed by isodose distribution for ARC therapy techniques.
Particle Accelerators*

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

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*

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

Total 21 patients with airway obstruction from lung cancer treated with radiotherapy at Department of Therapeuctic Radiology, Yeungnam University College of Medicine, between April 1986 and December 1988 are retrospectively analyzed by means of roentgenologic findings. Obtained results are as follows. 1. 15 out of 21 patients (71%) showed complete or partial response. 2. Patients with small cell lung cancer showed 100% response in spite of low dose (30 GY/10 fractions.) 3. Patients with non-small cell lung cancer treated with 50 GY or over showed better response than below 45 GY or below. 4. There is no relationship between the response and site of airway obstruction. These date suggested that high dose irradiation is more effective in the management of airway obstruction from lung cancer and meticulous radiotherapy planning with appropriate protection of normal lung and critical organs should be investigated in order to maximize radiation effect and minimize side effect, complication or sequelae.
Airway Obstruction* ; Carcinoma, Non-Small-Cell Lung ; Humans ; Lung Neoplasms* ; Lung* ; Radiation Effects* ; Radiotherapy ; Retrospective Studies ; Small Cell Lung Carcinoma

In recent years there has been a growing interest in total body, hemibody, total lymphoid irradiation. For refractory leukemia or lymphoma patients, various techniques and dose regimens were introduced, including high dose total body irradiation for destruction of leukemic or bone marrow cells and immunosuppression prior to bone marrow transplantation, and low dose total body irradiation for treatment of lymphocytic leukemias or lymphomas. Accurate provision for specified dose and the desired homogeneity are essential before clinical total body irradiation. Purposes of this paper are to discuss calibrating Cobalt Unit in 3m distance using Rando Phantom, to compare calculated dose, calibrated dose, and compensating filters for homogeneous dose distribution in the head and neck, the lung and the pelvis. Results were following. 1. Measured dose on the lung was 6% higher than on the abdomen. Measured dose on the head (10%) and neck (18%) were higher than the abdomen because of thinness. Pelvic dose was measured 12% less than the abdomen. Those date suggest that compensating filter was essential. 2. Measured dose according to distance was 3% less than calculated dose which suggest that all doses in clinical use should be compared with calculated dose for minimizing error.
Abdomen ; Bone Marrow Cells ; Bone Marrow Transplantation ; Cobalt ; Head ; Humans ; Immunosuppression ; Leukemia ; Leukemia, Lymphoid ; Lung ; Lymphatic Irradiation ; Lymphoma ; Neck ; Pelvis ; Thinness ; Whole-Body Irradiation*