No abstract available.
Carcinoma, Papillary* ; Thyroid Gland* ; Tretinoin*

PURPOSE: We compared the first postoperative diagnostic and post-therapy scans of patients who received therapeutic doses of I-131, to investigate the difference in clinical outcomes between patients with concordant findings of diagnostic and post-therapy scans and patients with discrepant (more lesions in post-therapy scan) findings. MATERIALS AND METHODS: The first postoperative diagnostic and post-therapy radioiodine scans of one hundred forty three patients with well differentiated thyroid carcinoma were reviewed. Diagnostic scans were obtained following ingestion of 185 MBq of I-131 and post-therapy scans were obtained after therapeutic dose of 3.7~9.3 GBq of I-131. Successful ablation was defined as no radioiodine uptake on diagnostic radioiodine scan and normal range of serum thyroglobulin level (<10 ng/ml) during serum TSH elevation. RESULTS: Discrepant scan findings were noted in 25 (17.5%) patients. Twenty-two patients (15.4%) showed more lesions in post-therapy scan and 3 patients (2.1%) showed stunning effect. Nine (64.3%) of 14 patients with distant metastasis revealed metastatic lesion(s) only on post-therapy scan. Stunning effect was considered as sublethal damage in 1 patient and treatment by a diagnostic dose in 2 patients. Ablation was achieved in 52.4% (75/143) of all patients. Ablation rate and mean cumulative radioiodine dose were not different statistically between concordant and discrepant groups. CONCLUSION: There were 17.5% difference between diagnostic and post-therapy scan findings when using 185 MBq of I-131 as a diagnostic dose. However, 64.3% of distant metastases were revealed only on post-therapy scan. Ablation rate and mean cumulative radioiodine dose were not different statistically between concordant and discrepant groups. The stunning effect was considered as not only sublethal damage but also treatment by a small diagnostic dose of radioiodine.
Eating ; Humans ; Neoplasm Metastasis ; Reference Values ; Thyroglobulin ; Thyroid Gland* ; Thyroid Neoplasms*

No abstract available.
Spondylosis*

It is known that fixed source to skin distance (SSD) cannot be used when the treatment field is sloped or larger than the size of second collimator in electron beam irradiation and inverse square law using effective ssd should be adopted. Effective SSDs were measured in different field sizes in each 6, 9, 12, 15 and 18 MeV electron energy by suing NELAC 1018D linear accelerator of Kosin Medical Center. We found important parmeters of effective SSD. 1. Minimum effective SSD was 58.8 cm in small field size of 6x6 cm and maximum effective SSD was 94.9 cm in large field size of 25x25 cm, with 6 MeV energy. It's difference was 36.1 cm. The dose rate at measuring point was quite different even with a small difference of SSD in small field (6x6 cm) and low energy (6 MeV). 2. Effective SSD increased with field size in same electron energy. 3. Effective SSDs gradually increased with the electron energies and reached maximum at 12 or 15 MeV electron energy and decreased again at 18 MeV electron energy in each identical field size. And so the effective SSD should be measured in each energy and field size for practical radiotherapy.
Jurisprudence ; Particle Accelerators ; Radiotherapy ; Silver Sulfadiazine* ; Skin

Seventy-nine patients with carcinoma of maxillary antrum treated at the department of therapeutic radiology, Kosin Medical Center, between June 1980 and December 1986 were analyzed retrospectively for survival rate and treatment failure. Forty-three patients were treated with radiotherapy alone and thirty-six patients were treated with combination of surgery and radiotherapy. The overall 5 year survival rate was 32%, patients that were treated with radiotherapy alone had a 5-year survival rate of 23%, and patients who were treated with combination of surgery and radiotherapy had a 5-year survival rate of 42%. 54 patients(68.4%) failed to be cured. Among these 54 patients, 37 patients(68.5%) had only locoregional failure, 16 patients(29.6%) had locoregional failure and distant metastases and 1 patient had only distant metastasis. From above study combination of surgery and radiotherapy might be a better treatment modality for carcinoma of the maxillary antrum.
Humans ; Maxillary Sinus* ; Neoplasm Metastasis ; Radiation Oncology ; Radiotherapy* ; Retrospective Studies ; Survival Rate ; Treatment Failure

331 patients of stage IIb uterine cervix cancer treated by radiation alone at Kosin Medical Center between June 1980 and Dec. 1985 were analysed to determine parameters of radiotherapy associated to disease states. Survival rate was highest among the reported (82.8% for crude and 82.4% for disease free survival). Pelvic control rate in 6 weeks after the end of radiotherapy was 93.6% in the patients treated with ICR following total pelvic radiation and 71.6% with small field additional external irradiation. 5 year survival rate in those who achieved pelvic control was 98. 9% and 12.9% in those who had pelvic failure and/or metastasis after radiation. The survival rate figured maximal 88.5% with dosage of 7500~8500 cgy to point A with acceptable incidence of complications (4.9%) but without increasing survival above it and minimal 74.1% with dosage of less than 6500 cgy. The treatment failure was counted 18.7% (62 of 331 patients): Local failure 72. 6% ( 45 of 62 patients), locoregional failure 3.2% (2 of 62 patients) and distant failure 24% (15 of 62 patients). Late complications were found In 50 patients (15.1%) and 42% of them was rectal bleeding and stenosis. The dose of 8500 cgy to point A was found to be critical for complication and 70% of complications occurred above it and was more serious one such as fistula. Rectal complications were developed above rectal dose 6500 cgy and bladder complication above bladder dose 7500 cgy. Major cause of death was cachexia due to locoregional failure (73.7% of death), next was due to metastasis to lung, liver and bone, and only 3 patients died of complication of intestinal perforations and obstruction. In conclusion higher external radiation dose for a bulky uterine cervix and barrel shaped uterus was essential for local control.
Cachexia ; Cause of Death ; Cervix Uteri* ; Constriction, Pathologic ; Female ; Fistula ; Hemorrhage ; Humans ; Incidence ; Intestinal Perforation ; Liver ; Lung ; Neoplasm Metastasis ; Radiotherapy* ; Survival Rate ; Treatment Failure ; Urinary Bladder ; Uterus

PURPOSE: Secondary electrons generated by interaction between primary X-ray beam and block tray in megavoltage irradiation, result in excess soft radiation dose to the surface layer. To reduce the surface dose from the electron contamination, electron filters were attached under the tray when a customized block was used. MATERIALS AND METHODS: Cu, Al or Cu/Al combined plate with different thickness was used as a filter and the surface dose reduction was measured for each case. The measurement to find optimal filter was performed with 10cm x 10cm field size and 78.5cm source to surface distance. The measurement points are positioned with 2mm intervals from surface to maximum build-up point. To acquire the effect of field size dependence on optimal electron filter, the measurement was performed from 4cm x 4cm to 25cm x 25cm field sizes. RESULTS: The surface dose was slowly increased by increasing irradiation field but rapidly increased beyond 15cm x 15cm field size. Al plate was found to be inadequate filter because of the failure to have surface dose kept lowering than the dose of deep area. Cu 0.5mm plate and Cu/Al= 0.28mm/1.5mm combined plate were found to be optimal filters. By using these 2 filters, the absorbed dose to the surface layer was effectively reduced by 5.5%, 11.3%, and 22.3% for the field size 4cm x 4cm, 10cm x 10cm, and 25cm x 25cm, respectively. CONCLUSION: The surface dose attributable to electron contamination had a dependence on field size. The electron contamination was increased when tray was used. Specially the electron contamination in the surface layer was greater when the larger field was used. 0.5mm Cu plate and Cu/Al=0.28mm/1.5mm combined plates were selected as optimal electron filters. When the optimal electron filter was attached under the tray, excessive surface dose was decreased effectively. The effect of these electron filters was better when a larger field was used.

PURPOSE: This investigation was performed in order to improve the health care of radiation workers, to predict a risk, to minimize the radiation exposure hazard to them and for them to realize radiation exposure danger when they work in radiation area in hospital. METHODS AND MATERIALS: The documentations checked regularly for personal radiation exposure in four university hospitals in Pusan city in Korea between January 1, 1993 and December 31, 1997 were analyzed. There were 458 persons in this documented but 111 persons who worked less then one year were excluded and only 347 persons were included in this study. RESULTS: The average of yearly radiation exposure of 347 persons was 1.52+/-1.35 mSv. Though it was less than 50mSv, the limitaion of radiation in law but 125 (36%) people received higher radiation exposure than non-radiation workers. Radiation workers under 30 year old have received radiation exposure of mean 1.87+/-1.01 mSv/year, mean 1.22+/-0.69 mSv between 31 and 40 year old and mean 0.97+/-0.43 mSv/year over 41year old ( p<0.001). Men received mean 1.67+/-1.54 mSv/year were higher than women who received mean 1.13+/-0.61 mSv/year ( p<0.01). Radiation exposure in the department of nuclear medicine department in spite of low energy sources is higher than other departments that use radiations in hospital ( p<0.05). And the workers who received mean 3.69+/-1.81 mSv/year in parts of management of radiation sources and injection of sources to patient receive high radiation exposure in nuclear medicine department ( p<0.01). In department of diagnostic radiology high radiation exposure is in barium enema rooms where workers received mean 3.74+/-1.74 mSv/year and other parts where they all use fluoroscopy such as angiography room of mean 1.17+/-0.35 mSv/year and upper gastrointestinal room of mean 1.74+/-1.34 mSv/year represented higher radiation exposure than average radiation exposure in diagnostic radiology ( p<0.01). Doctors and radiation technologists received higher radiation exposure of each mean 1.75+/-1.17 mSv/year and mean 1.60+/-1.39 mSv/year than other people who work in radiation area in hospital ( p<0.05). Especially young doctors and technologists have the high opportunity to receive higher radiation exposure. CONCLUSION: The training and education of radiation workers for radiation exposure risks are important and it is necessary to rotate worker in short period in high risk area. The hospital management has to concern health of radiation workers more and to put an effort to reduce radiation exposure as low as possible in radiation areas in hospital.
Adult ; Angiography ; Barium ; Busan ; Delivery of Health Care ; Documentation ; Education ; Enema ; Female ; Fluoroscopy ; Hospitals, University ; Humans ; Jurisprudence ; Korea ; Male ; Nuclear Medicine

PURPOSE: To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam. MATERIALS AND METHODS: Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4X4cm2 - 15X15 cm2). RESULTS: At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4X4 cm2, 1.05 with 7X7 cm2, 1.048 with 10X10cm2, and 1.041 with 15X15cm2. Backscatter dose perturbation factor(BDPF) is about 0.99 with 4X4cm2, 0.981 with 7X7cm2, 0.956 with 10X10cm2 and 0.97 with 15X15cm2 . CONCLUSION: FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface.
Larynx

PURPOSE: To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam. MATERIALS AND METHODS: Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4X4cm2 - 15X15 cm2). RESULTS: At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4X4 cm2, 1.05 with 7X7 cm2, 1.048 with 10X10cm2, and 1.041 with 15X15cm2. Backscatter dose perturbation factor(BDPF) is about 0.99 with 4X4cm2, 0.981 with 7X7cm2, 0.956 with 10X10cm2 and 0.97 with 15X15cm2 . CONCLUSION: FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface.
Larynx