Intracellular ions which have a major role in cellular function have been reported to affect repair of radiation damage. Recently it has been reported that ouabain sensitizes A549 tumor cells hut not CCL-120 normal cells to radiation. Ouabain inhibits the Na+-K+-pump rapidly thus it increases intracellular Na concentration. Vanadate which is distributed extensively in almost all living organisms in known to be a Na+-K+-ATPase inhibitors. This study was performed to see any change in radiosensitivity of tumor cell by vanadate and any role of Na+-K+-ATPase in radiosensitization. Experiments have been carried out by pretreatment with vanadate in human cell line(A549, JMG) and mouse cell line(L1210, spleen). For the cell survival MTT assay was performed for A549 and JMG cell and trypan blue dye exclusion test for L120, and spleen cells. Measurements of Na+-K+-ATPase activity in control, vanadate treated cell, radiation treated cell (9 Gy for A549 and JMG, 2 Gy for L1201, spleen), and combined 10-6 M vanadate and radiation treated cells were done. The results were summarized as follows. 1. L1210 cell was most radiosensitive, and spleen cell and JMG cell were intermediate, and A549 cell was least radiosensitive. 2. Minimum or cytotoxicity was seen with vanadate below concentration of 10-6 M. 3. In A549 cells there was a little change in radiosensitivity with treatment of vanadate. However radiation sensitization was shown in low dose level of radiation i. E. 2-Gy. In JMG cells no change in radiosensitivity was noted. Both L1210 and spleen cell had radiosensitization but change was greater in tumor cell. 4. Na+-K+-ATPase activity was inhibited significantly in tumor cell by treatment of vanadate. 5. Radiation itself inhibited Na+-K+-ATPase activity of tumor cell with high Na+- K+-ATPase concention. Increase in radiosensitivity by vanadate was closely associated with original Na+-K+-ATPase contents. From the above results vanadate had little cytotoxicity and it sensitized tumor cells to radiation. Inhibitory effect of vanadate on Na+-K+-ATPase activity might be one of the contributing factors for radiosensitization to tumor cells which has greater enzyme activity than that of normal cell. It was suggested vanadate could be used as a potential radiosensitizer for tumor cells.
Animals ; Cell Survival ; Humans ; Ions ; Mice ; Ouabain ; Radiation Tolerance* ; Spleen ; Trypan Blue ; Vanadates*

PURPOSE: To evaluate the results of radiation management on recurrence, survival and prognostic factors of patients with nasopharyngeal cancer. MATERIALS AND METHODS: Forty-nine patients, treated for nasopharyngeal cancer by radiotherapy between January 1984 and June 2000, were retrospectively studied. All patients were followed up for at least 2.5 years. Their median age was 52 years (range 17~78). The histological types were 21 squamous cell carcinoma, 25 undifferentiated carcinoma, and 3 adenoid cystic carcinoma. The tumor stages were as follows: T1 in 14 patients, T2 in 24, T3 in 3, and T4 in 8, and N0 in 17 patients, N1 in 15, N2 in 4 and N3 in 13. Stages I, IIa, IIb ,III, IV and IVb were 4, 7, 12, 5, 8, and 13 patients respectively. Radiation doses of 58~70 Gy (median 68.7 Gy) were given to the nasopahryngeal and involved lymphatic areas and of 46~50 Gy to the uninvolved neck areas. RESULTS: The overall 5 and 10-year actuarial and disease free survival rates were 54.53% and 47%, and 55.7% and 45.3%, respectively. The overall five-year survival rates were 100% in stage I , 80% in stage IIa, 59.5% in stage IIIb, 40% in stage III, and 42.2% in stage IV tumors. Twenty-three patients failed either loco-regionally or distantly. Incidences of local failure, regional failure and distant metastasis for the first failure were 20.4%, 8.2% and 20.4%, respectively. Local recurrences were 4.3% in T1, 12.5% in T2, 0% in T3, and 62.5% in T4 lesions. Distant metastasis was seen in 41.2% of N2-3 lesions. Fifty percent of local recurrence appeared within 2 years of treatment at the primary lesion, whereas 70% of distant metastasis appeared within 2 years following treatment. Young age, female, early T stage, N0 stage, and poorly differentiated carcinoma were all related with good survival. However only stage showed statistically significance. CONCLUSION: Based on the results of this study, radiation therapy to nasopharyngeal cancer showed high local recurrence in T4 and increased metastasis in N2-3 lesions. To improve local failure, further radiation doses, such as stereotactic radiation or IMRT radiation, are necessary especially in T4 lesions. The high incidence of distant metastasis in positive lymph node patients, indicates that combined radiation and effective chemotherapeutic agents with appropriated schedule are necessary.
Appointments and Schedules ; Carcinoma ; Carcinoma, Adenoid Cystic ; Carcinoma, Squamous Cell ; Disease-Free Survival ; Female ; Humans ; Incidence ; Lymph Nodes ; Nasopharyngeal Neoplasms ; Neck ; Neoplasm Metastasis ; Radiotherapy* ; Recurrence ; Retrospective Studies ; Survival Rate

PURPOSE: To evaluate effect and tolerance of external beam radiotherapy for carcinoma of the prostate and define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: We retrospectively analyzed the records of 60 patients with prostate cancer who were treated with external beam radiotherapy with curative intent in our institution between September, 1987 and March, 2000. Histologic diagnosis was established by transurethral resection or ultrasonography guided biopsy. The major presenting symptoms were a nodule at routine prostatic examination and frequency and urgency of urination, along with dysuria. The median age was 63 years with range of 51 to 87 years. There were 6 patients in Stage A, 20 in Stage B, 26 in Stage C, and 8 in Stage D1. All patients were treated with megavoltage equipment producing 10 MV photons. The 4 field pelvic brick technique was used to a dose of 45 Gy or 50.4 Gy at 1.8 Gy per day in 5 to 6 weeks, after which a small boost field was delivered 2.0 Gy per day to a total dose of 66 to 70 Gy. The follow-up period ranged from 1 to 8 years. RESULTS: Actuarial 5-year and 7-year survival rates for Stage A, B, C, and D1 were 100% and 84%, 83% and 72%, 67% and 54%, and 40% and 30%, respectively. The corresponding 5-year and 7-year relapse free survival rates were 84% and 84%, 77% and 67%, 48% and 40%, and 33% and 25%, respectively. Relapse free 5-year survival rates for Stage B were 80%, 80%, and 50% for well, moderately, and poorly differentiated tumors, respectively. These were 64%, 44%, and 33% for Stage C, respectively. The local control rates at 5 years were 84%, 85%, 78%, and 60% for Stage A, B, C, and D1, respectively. Mild to moderate complications were observed in 22% of patients. Severe complications requiring surgical procedures were documented in only 3% of patients. CONCLUSION: This study confirms that external beam irradiation is an effective and safe treatment for prostatic cancer, providing long-term local control and good survival with acceptable complications.
Biopsy ; Diagnosis ; Dysuria ; Follow-Up Studies ; Humans ; Photons ; Prostate* ; Prostatic Neoplasms ; Radiotherapy* ; Recurrence ; Retrospective Studies ; Survival Rate ; Ultrasonography ; Urination

PURPOSE: To evaluate the effectiveness and tolerance of the postoperative radiation therapy for patients with Stage III thymoma and to define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: We retrospectively analyzed the records of 24 patients with Stage III thymoma who were referred for postoperative radiation therapy in our institution from June, 1987 to May, 1999. Surgical therapy consisted of total resection in one patient, subtotal resection in seventeen, and biopsy alone in six patients. Age of the patients was ranged from 20 to 62 years with mean age of 47 years. Male to female ratio was 14 to 10. Radiation therapy was delivered with linear accelerator producing either 6 MeV or 10 MeV photons. The irradiated volume included anterior mediastinum and known residual disease. The supraclavicular fossae were not irradiated. The delivered total dose was ranged from 30 to 56 Gy. One patient received 30 Gy and eighteen patients received minimum of 50 Gy. Follow up period was ranged from 12 months to 8 years with median follow up of 40 months. RESULTS: The overall local control rate for entire group of patients was 67% at 5 years. The cumulative local failure rates at one, three and five year were 18%, 28% and 33%, respectively. In patients treated with subtotal resection and biopsy alone, local control rate was 76% and 33%, respectively. The actuarial observed survival rate at 5 years was 57%, and actuarial adjusted survival at 5 years was 72%. The difference between 5 year survival rates for patients treated with subtotal resection and biopsy alone was not statistically significant (62% vs 30%). CONCLUSION: We might conclude that postoperative radiation therapy was safe and effective treatment for patients with Stage III thymoma. Postoperative radiation therapy is recommended in cases where tumor margin is close or incomplete resection is accomplished.
Biopsy ; Female ; Follow-Up Studies ; Humans ; Male ; Mediastinum ; Particle Accelerators ; Photons ; Retrospective Studies ; Survival Rate ; Thymoma*

Twenty five patients with unresectable non-small cell carcinoma of the lung have been treated with hyperfractionated radiotherapy with concomitant boost technique since September, 1989. Those patients with history of previous surgery or chemotherapy, pleural effusion or significant weight loss (greater than 10% of body weight) were excluded from the study. Initially, 27 Gy were delivered in 15 fractions in 3 weeks to the large field. Thereafter, large field received 1.8 Gy and cone downboost field received 1.4Gy with twice a day fractinations up to 49.4Gy. After 49.4Gy, only boost field was treated twice a day with 1.8 and 1.4 Gy. Total tumor doses were 62.2Gy for 12 patients and 65.4Gy for remaining 13 patients. Follow up period was ranged from 6 to 24 month. Actuarial survival rates at 6, 12, and 18 month were 88%, 62%, and 38%, respectively. Corresponding disease free survival rates were 88%, 41%, and 21%, respectively. Actuarial cumulative local failure rates at 9,12 and 15 month were 36%, 42%, and 59%, respectively. No significant increase of acute or late complications including radiation pneumonitis was noted with maximum follow up of 24 month. Although the longer follow up is needed, it is worthwhile to try the prospective randomized study to evaluate the efficacy of hyperfractionated radiotherapy with concomitant boost technique for unresectable non-small cell lung cancers in view of excellent tolerance of this treatment. In the future, further increase of total radiation dose might be necessary to improve local control for non-small cell lung cancer.
Carcinoma, Non-Small-Cell Lung ; Disease-Free Survival ; Drug Therapy ; Follow-Up Studies ; Humans ; Lung Neoplasms ; Lung* ; Pleural Effusion ; Radiation Pneumonitis ; Radiotherapy* ; Survival Rate ; Weight Loss

PURPOSE: To evaluate the effectiveness and tolerance of postoperative external radiotherapy for patients with intracranial meningiomas. MATERIALS AND METHODS: The records of thirty three patients with intracranial meningiomas who were treated with postoperative external irradiation at our institution between Feb, 1988 and Nov, 1999 were retrospectively analyzed. Median age of patients at diagnosis was 53 years with range of 17 to 68 years. Sites of involvement were parasagital, cerebral convexity, sphenoid ridge, parasellar and tentorium cerebelli. Of 33 evaluated patients, 15 transitional, 10 meningotheliomatous, 4 hemangiopericytic, 3 atypical and 1 malignant meningioma were identified. Four patients underwent biopsy alone and remaining 29 patients underwent total tumor resection. A dose of 50 to 60 Gy was delivered in 28-35 daily fractions over a period of 5 to 7 weeks. Follow-up period ranged from 12 months to 8 years. RESULTS: The actuarial survival rates at 5 and 7 years for entire group of patients were 78% and 67%, respectively. The corresponding disease free survival rates were 73% and 61%, respectively. The overall local control rate at 5 years was 83%. One out of 25 patients in benign group developed local failure, while 4 out of 8 patients in malignant group did local failure (p<0.05). Of 4 patients who underwent biopsy alone, 2 developed local failure. There was no significant difference in 5 year actuarial survival between patients who underwent total tumor resection and those who did biopsy alone. Patients whose age is under 60 showed slightly better survival than those whose age is 60 or older, although this was not statistically significant. There was no documented late complications in any patients. CONCLUSION: Based on our study, we might conclude that postoperative external beam radiotherapy tends to improve survival of patients with intracranial meningiomas comparing with surgery alone.
Biopsy ; Diagnosis ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Meningioma* ; Radiotherapy* ; Retrospective Studies ; Survival Rate

The beam characteristics and dosimetric measurements of the 10 MV X-ray beam from a Mevatron KD linear accelerator are examined. The Percent Depth Dose (PDD) table and the Tissue Maximum Ratio (TMR) table are taken from measurement as a function of the field size and the depth. The calculated TMR table from PDD table is compared with those from measurement. Other beam characteristics such as output factor, beam profile (including flatness, symmetry and penumbra), wedge, and the variation of Dmax are presented.
Particle Accelerators*

Some modern accerelators provide a dual energy for photon beam treatment. The main advantages of dual energy in the treatment of rectosigmoid or rectal cancer are as follows. Dose in the critical organ such as small intestine, bladder and genital organ are reduced. Presacral and perineal area is fully covered. Dose distribution analysis such as calculation of dose in a target volume, isocenter, Dmax and dose spectrum in any region of interest are possible. Examples of plan are given and results are discussed.
Genitalia ; Intestine, Small ; Rectal Neoplasms ; Urinary Bladder

From Jan. 1984 to Dec. 1986, 90 patients with lung cancer were treated t the Department of Radiation Therapy in Hanyang University Hospital. Histopathologically, 67 cases of them were the squamous cell carcinoma, 7 cases were the adenocarcinoma, 4 cases were the large cell undifferentiated carcinoma and 12 cases were the small cell carcinoma. Among the 78 patients with non small cell carcinoma, 50 patients had received radiation dosage above 4000 cgy. 40 patient had follow up from 17 months to 53 months. The complete response rate was 7.3% and partial response rate was 68.3%. Overall survival at 1,2 and 3 years were 47.5%, 23.5% and 6.3% respectively. None was survived longer than 38 months. Median survival was 12.2 month for 40 patient and 9 month for stage III, M1 group and 9.5 month for stage III, M0 group. In M1 patient no survival was seen after 2 years while in M0 patient 23.3% survival was seen.
Adenocarcinoma ; Carcinoma ; Carcinoma, Non-Small-Cell Lung* ; Carcinoma, Small Cell ; Carcinoma, Squamous Cell ; Follow-Up Studies ; Humans ; Lung Neoplasms ; Radiation Dosage ; Radiotherapy

Computation of three dimensional dose distribution using CT image and RT plan was applied to a case of pituitary adenoma. Algorithm was based on two dimensional Tissue Maximum Ratio model extended to the third dimension. The resulting isodose curve of transeverse, coronal and sagittal section was demonstrated. This RT plan allows computation of dose distribution in any arbitarily defined plane in addition to conventional cross sectional view.
Pituitary Neoplasms*