20 cases of midline pineal tumors and 3 suprasellar germinomas received radiation therapy at Yonsei University Medical College, Severance hospital from 1971 to 1982 were reviewed. 12 cases were pathologically proved; 10 germinomas, 1 pineoblastoma, and 1 pineocytoma. 11 cases received radiotherapy without biopsy confirmation. Although treatment fields varied from small field to whole brain irradiation, but not to the spinal cord, most patients received 4000-000 rads irradiation to the primary tumor site. 17 patients are alive without evidence of disease and 5 year actuarial NED survival is 73.2%. 9 of 10 biopsy proved germinomas and all 6 presumed germinomas are alive and well. Optimum radiation dose, adequate irradiation field, tumor response to radiation observed in serial CT scan and role of radiation therapy in the management of pineal tumors are also discussed.
Biopsy ; Brain ; Germinoma* ; Humans ; Pinealoma* ; Radiotherapy ; Spinal Cord ; Tomography, X-Ray Computed

Two cases of primary malignant lymphoma of the brain and six cases of secondary CNS lymphoma seen at Yonsei cancer center, radiotherapy department for recent 4 years are presented. Primary lymphomas revealed single tumor mass on corpus callosum area and secondary lymphoma were intracranial (3 cases) or leptomeningeal type (3 cases). Histology of primary lymphoma were reticulum cell sarcoma and secondary lymphomas were either diffuse histiocytic or diffuse poorly differentiated lymphocytic lymphoma. All patients showed good response to radiation. Two patients with primary CNS lymphoma and two of six secondary CNS lymphoma are alive after radiotherapy (34, 31, 26, 12 months). But the prognosis of secondary CNS lymphoma is grave, because of progressive systemic disease. Incidence, risk factors, diagnosis and therapeutic management of CNS involvement are also discussed.
Brain ; Corpus Callosum ; Diagnosis ; Humans ; Incidence ; Leukemia, Lymphocytic, Chronic, B-Cell ; Lymphoma* ; Lymphoma, Non-Hodgkin ; Prognosis ; Radiotherapy ; Risk Factors

To evaluate the usefulness of computed tomography (CT) in radiotherapy treatment planning in malignant tumors of thoracic cage, the computer generated dose distributions were compared between plans based on conventional studies and those based on CT scan. 22 cases of thoracic malignancies, 15 lung cancers and 7 esophageal cancers, diagnosed and treated in Department of Therapeutic Radiology of Seoul National University Hospital from September, 1982 to April, 1983, were analyzed. In lung cancer, dose distribution in plans using AP, PA parallel opposing ports with posterior spinal cord block and in plans using box technique both based on conventional studies were compared with dose distribution using AP, PA and two oblique ports based on CT scan. On esophageal cancers, dose distribution in plans based on conventional studies and those based on CT scans, both using 3 port technique were compared. The results are as follows: 1. Parallel opposing field technique were inadequate in all cases of lung cancers, as portion of primary tumor in 13 of 15 cases and portion of mediastinum in all were out of high dose volume. 2. Box technique was inadequate in 5 of 15 lung cancers as portion of primary tumor was not covered and in every case the irradiated normal lung volume was quite large. 3. Plans based on CT scan were superior to those based on conventional studies as tumor was demarcated better with CT and so complete coverage of tumor and preservation of more normal lung volume could be made. 4. In 1 case of lung cancer, tumor localization was nearly impossible with conventional studies, but after CT scan tumor was more clearly defined and localized.
Esophageal Neoplasms ; Lung ; Lung Neoplasms ; Mediastinum ; Radiation Oncology ; Radiotherapy* ; Seoul ; Spinal Cord ; Tomography, X-Ray Computed

CT scans obtained on 15 patients of head and neck malignant tumors were evaluated for their utility in ratiotherapy treatment planning. To evaluate the advantage of incorporating CT scans in radiotherapy treatment planning of head and neck malignant tumors, the dose distributions of treatment plan with and without CT scan were compared in 15 patients. And then the dose distributions of the first and second treatment plan were compared. 1. Tumor extend and localization were clearly delineated on CT scan in 12 of 15 cases (80%), suggestive in 2 (13.3%), and not seen in only one (6.7%) which had been in the postoperative state. 2. Tumor coverage after CT scan was adequate in 14 of 15 cases (93.3%) and not in only one. In one case of inadequate tumor coverage the target volume lay inside the field but reached within 0.5cm of the field margin (marginal miss). 3. The volume of normal tissue irradiated was reduced after CT scan in 12 of 15 cases (80%), increased in 1 (6.7%) and not changed in 2 (13.3%). 4. We could maximize the local control of disease and minimize unnecessary morbidity by delineating the location and extent of tumor and normal tissue with CT for treatment plannings.
Head* ; Humans ; Neck* ; Radiotherapy* ; Tomography, X-Ray Computed

To obtain 7 MeV electron beam which is suitable for treatment of the chest wall after radical of modified radical mastectomy, the authors reduced the energy of electron beam by means by Lucite plate inserted in the beam. To determine the proper thickness of the Lucite plate necessary to reduce the energy of 9 MeV electron beam to 6 MeV, dosimetry was made by using a parallel plate ionization chamber in polystyrene phantom. Separation between two adjacent fields, 7 MeV for chest wall and 12 MeV for internal mammary region, was studied by means of film dosimetry in both polytyrene phantom and Humanoid phantom. The results were as follows. 1. The average energy of 9 MeV electron beam transmitted through the Lucite plate was reduced. Reduction was proportional to the thickness of the Lucite plate in the rate of 1.7 MeV/cm. 2. The proper thickness of the Lucite plate necessary to obtain 6 MeV electron beam from 9 MeV was 1.2 cm. 3. 7 MeV electron beam, 80% dose at 2cm depth, is adequate for treatment of the chest wall. 4. Proper separation between two adjacent electron fields, 7 MeV and 12 MeV, was 5mm on both flat surface and sloping surface to produce uniform dose distribution.
Film Dosimetry ; Mastectomy, Modified Radical ; Polymethyl Methacrylate ; Polystyrenes ; Thoracic Wall* ; Thorax*

Whole brain irradiation is one mode in the treatment of brain cancer and brain metastasis, but it might cause brain injury such as brain necrosis. It has been studied whether the dose distribution could be a cause of brain injury. The dose distribution in whole brain irradiated by Co-0 beam has been measured by means of calibrated TLD chips inserted in the brain of Humanoid phantom. The following results were obtained. 1. Dose distribution on each transverse section of the brain was uniform. 2. On the midsagital plane of the brain, the dose was highest in upper portion and lowest in lower portion, varying 8 from 104% to 90%. 3. When the radiation field includes free space of 2cm or more width out of the head, the dose distribution in the whole brain is almost independent of the field width. 4. It is important to determine adequate shielding area and to set shielding block exactly in repetition of treatment.
Brain Injuries ; Brain Neoplasms ; Brain* ; Head ; Necrosis ; Neoplasm Metastasis ; Radiotherapy*

Anterior and posterior parallel opposed field technique covering entire neck is desirable for elimination of junctional problems in treating upper neck with bilateral parallel opposed fields and lower neck with anterior one field. For good dose distribution in neck, dose in build-p region should be high for anterior field and should be low for posterior field. And so, with 10 MV X-ay, lead absorber was used for anterior field only. The adequate thickness of lead absorber, absorber-kin separation, width of central cord block for posterior field and anterior & posterior field weight were studied using film dosimery. The results are as follows. 1. As the thickness of the lead absorber increased the dose in build-p region increased. 2. As the absorber-kin separation decreased the dose in build-p region increased. 3. The adequate thickness of lead absorber was around 5.6mm. 4. The adequate absorber-kin separation was around 5cm. 5. The adequate posterior cord block width was 3cm. 6. 4:1 weighting for anterior and posterior field was adequate. And so with this technique, adequate dose distribution could be made as well as elimination junction problems.
Neck*

The thickness of the part being irradiated is finite. Percent depth dose tables being used routinely are generally obtained from dosimetry in a phantom much thickner than usual patient. At or close to exit surface, the dose should be less than that obtained from the percent depth dose tables, because of insufficient volume for backscattering. To know the difference between the true absorbed dose and the dose obtained from percent depth dose table, the doses at or close to the exit surface were measured with plate type ionization chamber with volume of 0.5ml. The results are as follows; 1. In the case of 60Co, percent depth dose at a given depth increases with underlying phantom thickness up to the 5cm. 2. In the case of 60Co, the dose correction factor at exit surface which is less than 1, increases with part thickness and decreases with field size. 3. Exposure time may not be corrected when the part above 10cm in thickness is treated by 60Co. 4. In the case of 10MV x-ay, the dose correction factor is nearly 1 and constant for the underlying phantom thickness and field size, so the correction of monitor unit is not necessary for part thickness.
Axis, Cervical Vertebra* ; Fibrinogen ; Humans

To evaluate late change of irradiated lung, a total of 60 rats was irradiated on right lungfield with a single dose of 2000 rads using Co-0 teletherapy unit. Follow-p roentgenographic and histopathologic study was performed three, six and twelve months after irradiation in each group of 20 rats. The results were as follows: 1.Chest roentgenographic findings in the order of frequency were pneumonic consolidation, atelectasis, and pleural effusion in 3-onth follow-p group; atelectasis, fibrostreaky infiltration, and pneumonic consolidation in 6-onth follow-p; and normal, and normal, and atelectasis in 12-onths follow-p group. 2. Main histopathological findings were alveolar and interstitial exudates, and diffuse infiltration of inflammatory cells in 3-onth follow-p group; thickening of interstitium and vascular wall in 6-onth follow-p group; and interstitial fibrosis in 12-onth follow-p group.
Animals ; Exudates and Transudates ; Fibrosis ; Lung* ; Pleural Effusion ; Pulmonary Atelectasis ; Rats

Experimental measurements of dose characteristics with pentagonal applicator at nominal energy of 4, 6, 9, 12 and 15 MeV electron beam were performed for intraoperative radiotherapy (IORT) in ML-15MDX linear accelerator. This paper presents the percent depth dose, surface dose, beam flatness and output factors of using the IORT applicator in different electron beam energy. The output factor showed as a 24 percent higher in IORT applicator than that of reference 10x10 cm? applicator. The surface dose of using the IORT applicator showed 7.7 and 2.7 percent higher than that of reference field in 4 and 15 MeV electron beam, respectively. In our experiments, the variation of percent depth dose was very small but the output factor and flatness at 0.5 cm depth have showed a large value in IORT applicator.
Particle Accelerators ; Radiotherapy