Feasibility Study of Vertical Multileaf Collimator for Determination of Irradiation Size / 의학물리

The purpose of this study was to evaluate feasibility of Vertical Multileaf Collimator for determination of irradiation size using Vertical Multileaf Collimator and lead block to determine 4 different irradiation shape in case of Co-60 gamma-ray and 6 MV X-ray. We chose ion chamber, glass dosimeter and EBT chromic film to compare with Vertical Multileaf Collimator results and lead block results. In case of Co-60 gamma-ray and 6 MV X-ray, the central axis point dose normalized at reference field of lead block with ion chamber results for Vertical Multileaf Collimator were estimated higher than lead block about 5.1%, 4.2%. In case of Co-60 gamma-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 2.2%, 7.8%, 7.2%, 4.0% for reference, circle, triangle, cross field, respectively. In case of 6 MV X-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 6.7%, 6.2%, 3.8%, 6.2% for reference, circle, triangle, cross field, respectively. The results of EBT chromic film, Vertical Multileaf Collimator of penumbra size for all irradiation shape was smaller than lead block of those size that 2.0~3.5 mm for Co-60 gamma-ray, 0.5~1.0 mm for 6 MV X-ray. The results from this study, radiation treatment volume that results in shielding block can be minimized. In addition, during radiation treatment for 2, 3-dimensional radiation therapy using a Vertical Multileaf Collimator of this survey can be used to determine variety of irradiation fields.

The Radioprotective Effect and Mechanism of Captopril on Radiation Induced Lung Damage in Rat / 대한방사선종양학회지

PURPOSE: It was reported that Captopril (angiotensin converting enzyme inhibitor) had an effect to reduce the pneumonitis and pulmonary fibrosis induced by radiation in rat. We performed this study to investigate the radioprotective effect and mechanism of Captopril. METHODS AND MATERIALS: The comparison was made between the radiation only group and the combined Captopril and radiation group by examining histopathologic findings and immunohistochemical stains (TNFalpha and TGFbeta1) at 2 and 8 weeks after irradiation. Each group has 8 to 10 rats (Sprague-Dawley). 12.5 Gy of X-ray was irradiated to the left hemithorax in a single fraction. Captopril (50 mg/kg/d) mixed with water was given per oral and continuously from 1 week prior to irradiation up to 8th week of the experiment. RESULT: In the combined Captopril and radiation group, the histopathologic changes which were hemorrhage into alveolar space, changes of alveolar epithelium, bronchial epithelium and blood vessels, and perivascular edema were less severe than in the radisation only group at 2 weeks. At 8 weeks, the alveolar epithelial changes and perivascular edema were less prominant in the combined Captopril and radiation group. At 2 weeks, the TNFalpha expression of the combined Captopril and radiation group was markedly decreased at the alveolar epithelium (p<0.01), lymphoid tissue (p=0.06) and the macrophage of alveolar space (p<0.01) compared with the radiation only group. Furthermore the TGFbeta1 expression was significantly prominant at the alveolar epithelium (p<0.02) and the macrophage in alveolar space (p< 0.02). At 8 weeks, the expression of TNFalpha and TGFbeta1 of most sites, except TGFbeta1 of the macrophage of alveolar space (p=0.09), showed no significant difference between 2 groups. CONCLUSION: This study revealed that early lung damage induced by irradiation was reduced with the addition of Captopril in the latent and early pneumonitis phase. The expression of TNFalpha and TGFbeta1 at 2 weeks and TGFbeta1 at 8 weeks was further decreased in the combined Captopril and radiation group than the radiation only group. From these results, it may be concluded that the proinflammatoy cytokine (TNFalpha) and fibrogenic cytokine (TGFbeta1) probably play the role of the radioprotective mechanism in Captopril.

Local Control and Survival in Radiation Treatment of Locally Advanced Non-Small Cell Lung Cancer / 대한치료방사선과학회지

The retrospective analysis was performed on 37 patients with stage III non small cell lung cancer who received the radiotherapy from Feb. 1986 to Dec. 1990 at the Dept. of Radiation Oncology, National Medical Center. This analysis, with 29 patients (78.4%) having been followed from 10 to 60 months, was done to know the survival rate and significant prognostic factor. The actuarial 2, 5-year survival rates were 20.6%, 6.9% in our all patients and Median survival time was 10 months. Of patients with KPS(Karnofsky performance status) greater than 80%, the 2, 5 year survival rate and median survival time were 29.2%, 9.7% and 13 months, respectively. The 2-year survival rate and median survival time of patients with KPS less than 80% were 13.7% and 7 months, respectively. The survival difference according to performance status was statistically significant(29.2% vs. 13.7%)(p0.1). Of the prognostic factors, the difference of survival rate by initial performance status was statistically significant (p<0.05). But the difference of survival rates by pathologic cell type, stage, total radiation dose, radiotherapy response, and combination with chemotherapy were not statistically significant.

Radiation Treatment for Malignant Small Cell Tumor of the Thoracopulmonary RegionPrimitive Pluripotent Histogenesis and Differential Diagnosis: A Case Report and Review of Literatures / 대한치료방사선과학회지

Malignant small round cell tumor (SRCT) of the thoracopulmonary region appears to originate in the soft tissues of the chest wall or the peripheral lung. A differential diagnosis of poorly differentiated small round cell tumors which include Ewing's sarcoma of bone and soft tissue, embryonal rhabdomyosarcoma, Askin tumor, neuroblastoma, peripheral neuroectodermal tumor, small cell osteogenic sarcoma and lymphoma are after difficult by light microscopy alone. In recent, by the extensive studies electron microscopic examination, histochemical study, immunochemical study, cytogenetics and gene analysis, these tumors may be derived from the primitive and pluripotential cells, differentiating into mesenchymal, epithelial and neural features in variable proportions. Treatment for SRCT of thoracopulmonary regin is not determined because of massive involvement of the lung, pleura or soft tissues of the chest wall resulted in a dismal outcome despite aggressive surgery, irradiation and chemotherapy.

Radical Radiotherapy with Lympectomy (Wide excisional biopsy) for Early Breast Cancer: A Case Report and Review of Literature / 대한치료방사선과학회지

However, long-term results of retrospective studies suggest that, for the great majority of individuals, mastectomy or conservative surgery with radiation therapy were be equally effective. The results at 5 and 10 years from prospective randomized trials indicate that survival following primary radiation therapy for early breast cancer is equivalent to that following mastectomy. When competently performed, primary radiation therapy gives highly satisfactory cosmetic results and acceptably low rates of local tumor recurrence. A number of controversial issues remain concerning patient evaluation and selection and the optimal techniques of treatment, both surgical and radiotherapeutic. In addition, further work is needed to clearity the best way to integrate primary radiotherapy with adjuvant systemic treatment. And further follow-up these patients with primary radiation therapy for early breast cancer will be required for ultimate proof of the relative merits. A case which was conservative surgery and radical irradiation of early breast cancer with review of literatures will be done.