Molecular Diagnosis of Recurrent Thyroid Cancer by Reverse Transcription-Polymerase Chain Reaction of Thyroglobulin Messenger Ribonucleic Acid in Peripheral Blood / 대한내분비학회지

BACKGROUND: Differentiated thyroid cancer is the most common endocrine malignancy. Despite advances in the treatment of thyroid cancer, disease recurrence and metastasis may occur in as many as 20% of patients, and so continues to pose major problems in its clinical management. Serum thyroglobulin (Tg) measurements, by immunoassay, are used to detect residual or recurrent thyroid cancer following thyroid ablation. However, the usefulness of immunoassay is limited by both the requirement for thyroid hormone withdrawal, to attain optimal test sensitivity, and interference by the antithyroglobulin antibody (Anti-Tg Ab). Recent studies have reported the clinical usefulness of reverse transcription-polymerase chain reaction (RT-PCR) detection of Tg mRNA in the peripheral blood of patients with differentiated thyroid carcinomas. We performed this study to evaluate the usefulness RT-PCR of Tg mRNA in peripheral blood of patients with thyroid carcinoma following a total thyroidectomy and radioiodine ablation therapy. METHODS: Forty cases that underwent a total thyroidectomy and radioiodine ablation therapy were included in this study. Of the 40 patients, 35 were papillary carcinomas and 5 were follicular carcinomas. Ten normal control subjects were also studied. Tg mRNA was extracted. Then RT-PCR, and nested RT-PCR, were run with specific Tg primers. Concurrently, DNA sequencing of the isolates was carried out to prove the isolates were identical to the nucleotide sequence of the Tg. RESULTS: The Tg was detected in 4 of 19 patients, with either a residual thyroid bed, or metastasis, on a 131I whole body scan and in 1 of 21 patients with a negative radioiodine scan. Surprisingly, the Tg mRNA was detected in all the patients and normal controls. CONCLUSION: From our results we can not recommend Tg mRNA, detected by RT-PCR in peripheral blood, as a tumor marker superior to that of the Tg serum level. We consider an intensive re-evaluation of the method is required before considering its clinical applications.

Results of Radiotherapy in Hypopharyngeal Cancer / 대한방사선종양학회지

PURPOSE: The aim of this study was to assess the effectiveness, survival rate and complications of radiation therapy and chemoradiation treatment in hypopharyngeal cancer. METHODS AND MATERIALS: From January 1984 to December 1999, 56 patients who had hypopharyngeal carcinoma treated with curative radiation therapy were retrospectively studied. Twenty four patients (42.9%) were treated with radiation therapy alone (Group I) and 32 (57.1%) treated with a combination of chemotherapy and radiation (Group II). Total radiation dose ranged from 40.5 to 83. 5 Gy (median 67.9 Gy). Radiotherapy was given with conventional technique in 9 patients (16.4%), with hyperfractionation I (1.15~1.2 Gy/fr., BID) in 26 (47.2%), hyperfractionation II (1.35 Gy/fr., BID) in 18 (32.7%), and accelerated fractionation (1.6 Gy/fr., BID) in 2 (3.6%). In chemotherapy, 5-FU (1,000 mg/m2 daily for 5 consecutive days) and cisplatin (100 mg/m2 on day 1) were administered in a cycle of 3 weeks interval, and a total of 1 to 3 cycles (average 2..3 cycles) were given prior to radiation therapy. Follow up duration was 1~195 months (median 28 months). RESULTS: Overall 2 and 5 year survival rates were 40.6% and 27.6%; 50.0% and 30.0% in Group I, and 36.4% and 26.3% in Group II, respectively. Complete local control rates in Group I and II were 70.0% and 67.7%, respectively. The response to radiotherapy and nodal stage were statistically significant prognostic factors. The complication rate was increased in Group II and was decreased in hyperfractionation. CONCLUSION: The response to radiotherapy and nodal stage were valid factors to indicate the degree of control over the hypopharyngeal cancer. The induction cisplatin, 5-Fu chemotherapy was not valid in terms of local control rate and survival rate, but did contribute to an increased complication rate. The use of hyperfractionation was valid to reduce the late radiation complications.

Retinoic Acid Redifferentiation Therapy for Papillary Carcinoma of Thyroid with Negative Radioiodine Uptake / 대한핵의학회잡지

No abstract available.

The Frequency of Chromosomal Aberrations of Peripheral Lymphocytes according to Radiation Dose and Dose Rate / 대한방사선종양학회지

PURPOSE: It was studied that the relationship between radiation dose, dose rate and the frequency of chromosomal aberrations in peripheral lymphocytes. METHODS AND MATERIALS: Peripheral lymphocytes were irradiated in vitro with 6 MeV X-ray at dose ranges from 50 cGy to 800 cGy. The variations of the frequency of chromosomal aberrations were observed according to different radiation dose rate from 20 cGy/min to 400 cGy/min at constant total dose of 400 cGy which it was considered as factor to correct biological radiation dose measurement. RESULTS: The yields of lymphocytes with chromosomal aberrations (dicentric chromosome, ring chromosome, acentric fragment pairs) are 0% at 50 cGy, 9% at 100 cGy, 20% at 200 cGy, 27% at 300 cGy, 55% at 400 cGy, 88% at 600 cGy, and 100% at 800 cGy. The value of Ydr is 0.000 at 50 cGy, 0.093 at 100 cGy, 0.200 at 200 cGy, 0.364 at 300 cGy, 0.612 at 400 cGy, 2.040 at 600 cGy, and 2.846 at 800 cGy. The relationship between radiation (D) and the frequency of dicentric chromosomes and ring chromosomes (Ydr) can be expressed as Ydr=0.188x10-2/GyxD+0.422x10-4/Gy2xD2. The value of Qdr is 0.000 at 50 cGy, 1.000 at 100 cGy, 1.000 at 200 cGy, 1.333 at 300 cGy, 1.118 at 400 cGy, 2.318 at 600 cGy, and 2.846 at 800 cGy. When 400 cGy is irradiated with different dose rate each of 20, 40, 60, 80, 100, 160, 240, 320, and 400 cGy/min, Ydr is each of 0.982, 0.837, 0.860, 0.732, 0.763, 0.966, 0.909, 1.006, and 0.806, and Qdr is each of 1.839, 1.565, 1.654, 1.333, 1.381, 1.750, 1.6000, 1.710, and 1.318. CONCLUSION: There are not the significant variations of Ydr and Qdr values according to different dose rate. And so radiation damage is influenced by total exposed radiation doses and is influenced least of all by different dose rate when it is acute single exposure.

The Analysis of Radiation Exposure of Hospital Radiation Workers / 대한방사선종양학회지

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.

Comparison of Diagnostic and Post-therapy Radioiodine Scan in Well-Differentiated Thyroid Cancer and the Clinical Outcome / 대한핵의학회잡지

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.

Comparison between Acetazolamide and Dipyridamole Activated SPECT for Cerebral Vascular Reserve Capacity Measurement

Object of this study was to make comparison between acetazolamide and dipyridamole activated SPECT for measurement of cerebral vascular reserve capacity. This study was also carried out to evaluate response in acetazolamide and dipyridamole activated SPECT in relation to clinical parameters, such as Glasgow Coma Scale, Hunt & Hess grade, Fisher grade and Glasgow Outcome Scale. It is concluded from study that. Acetazolamide and dipyridamole activated SPECT study proved to be valuable for cerebral vascular reserve capacity. Dipyridamole activated SPECT study was somewhat equivocal because of systemic vascular dilatation effect, but this problem could be resolved by Gamma Count Ratio. Although there were minimal transient side effect of dipyridamole such as dizziness, no complication.

Reduction of Electron ContaminationUsing a Filter for 6MV Photon Beam / 대한치료방사선과학회지

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.

Results of Radiotherapy in Nasopharyngeal Cancer / 대한치료방사선과학회지

PURPOSE: The aim of this study was to assess the effectiveness, survival rate and complication of radiation therapy in nasopharyngeal cancer. MATERIALS AND METHODS: From January 1980 to May 1989, Fifty Patients who had nasopharyngeal carcinoma treated with curative radiation therapy at Kosin Medical Center were retrospectively studied. Thirty seven patients(74%) were treated with radiation therapy alone(Group I) and 13 patients (26%) treated with combination fo chemotherapy and radiation(Group II). Age distribution was 16-75 years(median:45.8 years). In histologic type, squamous cell carcinoma was in 30 patients(60%), undifferentiated carcinoma in 17 patinets(34%), and lymphoepithelioma in 3 patients(6%). According to AJCC staging system, 4 patinets(8%) were in T1, 13 patients(2%) in T2, 20 patients(40%) in T3, 13 patients(26%) in T4 and 7 patients(14%) in N0, 6 patients(12%) in N1, 23 patients(46%) in N2, 14 patients (28%) in N3. Total radiaton dose ranges were 5250-9200 cGy(median : 7355 cGy) in Group I and 5360-8400 cGy(median :6758cGy) in Group II. Radiotherapy on 4-6MV linear accelerator and/or 6-12MeV electron in boost radiation was given with conventional thechnique to 26 patinets(52%), with hyperfractionation(115-120cGy/fr., 2times/day) to 16 patients(32%), with accelerated fractionation(160cGy/fr., 2 times/day) to 8 patients(16%). In Chemotherapy, 5 FU 1000mg daily for 5 consecutive days, pepleomycin 10mg on days 1 and 3, and cisplatin 100mg on day 1 were administered with 3 weeks interval, total 1 to 3 cycles(average 1.8cycles) prior to radiation therapy. Follow up duration was 6-140 months(mean:58 months). Statistics was calculated with Chi-square and Fisher's exact test. RESULTS: Complete local control rates in Group I and II were 75.7%, 69.2%. Overall 5 year survival rates in Group I and II were 56.8%, 30.8%. Five year survival rates by histologic type in Group I and II were 52.2, 14.3% in squamous cell carcinoma an d 54.5%, 50% in undifferentiated carcinoma. Survival rates in Group I were superior to those of Group II though there were not statistically significant. In both group, survival rates seem to be increased according to increasing total dose of radiation up to 7500cGy, but not increased beyond it. There were not statistically significant differences in survival rates by age, , stage, and radiation tehchniques in both group. Twenty four patients (48%) experienced treatment failures. Complications were found in 12 patients(24%). The most common one was osteomyelitis(4 patients, 33.3%) involving mandible (3 patients) and maxilla(1patient). CONCLUSION: Chemotherapy in combination with radiotherapy was found to be not effective to nasopharyngeal cancer and the survival rate was also inferior to that of radiation alone group though it was statistically not significant due to small population in chemotherapy combined group.

Results of Radiation Therapy in Stage III Uterine Cevical Cancer / 대한치료방사선과학회지

PURPOSE: The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. MATERIALS AND METHODS: From January 1980 through December 1985, 227 patients with stage II uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients(31.7%) were stage IIIa, and 155 patients(68.3%) were stage IIIb according to FIGO classification. Age distribution was 32-71 years(median: 62 years). Sixty nine patients(95.8%) in stage IIIa and 150 patients(96.8%) in stage IIIb were squamous cell carcinoma. Pelvic lymphnode metastasis at initial diagnosis was 8 patients (11.1%) in stage IIIa and 29 patients(18.7%) in stage IIIb. Among 72 patients with stage IIIa, 36 patients(50%) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr). And 36 patients(50%) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with Cs137 sources, and among 155 patients with stage IIIb, 80 patients(51.6%) were treated with external radiation therapy alone and 75 patients(48.4%) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median : 78.5 Gy) and 65-125.5 Gy (median :83.5 Gy). Survival rate was calculated by life-table method. RESULTS: Complete response rates were 58.3% (42 patients) in state IIIa and 56.1%(87 patients) in stage Iiib. Overall 5 year survival rates were 57% in stage IIIa and 40% in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were 64%, 40% in group treated in combination of external radiation and ICR, and 50%, 40% in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were 90%, 66% in responder group, and 10%, 7% in non-responder group (p<0.01). There were statistically no significances of 5 year survival rate by total radiation doses and external radiation doses (40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatement failures rates were 40.3%(29 patients) in stage IIIa and 57.4%(89 patients) in stage IIIb, 17 patients (23.6%) in stage IIIa and 46 patients (29.7%) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa(50%) and Iib(50%), Serious complicaton rates were higher in group received externl radiaton doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Seious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of deah was cachexia due to locoregional failure in both stage IIIa(34.7%) and IIIb(43.9%). CONCLUSION: From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy tho whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

Dosimetric Consideration of the Lung Block in the Mantle Field / 대한치료방사선과학회지

PURPOSE: To evaluate the dose under lung block as a function of depth and the effectiveness of a block as a function of block width. MATERIALS AND METHODS: Field size of mantle field was 22.8 x 32.4 cm2 . Dose distribution of the mantle field was measured with two dimensional water phantom system. To analyze the effectiveness of the lung block, central axis plane, 5cm off-axis plane, and 10cm off-axis plane were studied. RESULTS: The dose under the lung block was recorded with maximum at the depth between , 5cm and 10cm . In the central axis plane, dosimetric block width was 10-15% les than physical block width. In the 5cm off-axis plane. Dosimetric block width was 4-9% less than physical block width. In the 10cm off-axis plane, dosimetric block width was 2% less than physical block width. CONCLUSION: Depth dependence of the dose under the lung block was founded. Also, block width dependence of the lung block was founded. To induce the accurate relation between the physical block width and the "effective" block width, it needs more detailed understanding of the variables involved.

The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam / 대한치료방사선과학회지

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.

The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam / 대한치료방사선과학회지

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.

Radiotherapy of Carcinoma of Maxillary Antrum / 대한치료방사선과학회지

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.

A Trial of Hyperfractionated Radiotherapy in Supratentorial Gliomas

Fractionation dose and number have been known as radiation factor affecting the radiation complication and the effectiveness in radiotherapy for brain tumors. In this study hyperfractionation technique with 115cGy/fractioin 2 fractions daily 5days/wk, upto 5750-6900cGy to partial brain volume was compared with conventional fractionation technique with daily 200cGy/fraction 5 fraction/wk, upto 5400-6000cGy, in regarding to the effectiveness of hyperfractionated radiotherapy and eraly and later radiation reavtion. The survival period was longer in hyperfractionated irradiated group particularly if the tumors were located in the posterior portion of brain, however there was no singificant statistics due to small number of patients. Mean survival period for glioblastoma multiforme was 11.8 months in hyperfractionated group vs 8.7 months in conventional fractionated group and for high grade astrocytoma 36month in hyperfractionated group, but in conventional fractionated group all was died in 18 months. Acute radiation reaction occurred less frequently in hyperfractionated group, 15.8% vs 47.8% in conventional fractionated group(p<0.024). Alopeci was developed in 31.6% of the hyperfractionated group vs 82.6% of the conventional fractionated group(p<0.0031). One case of later radiation necrosis in cancer region was suspected in the hyperfractionated group but we has been in a dilemma for confirmatory diagnosis in present available diagnostic technique. The hyperfractionated irradiation technique was proven to be superior to conventional fractionated technique regarding the radiation reaction and the effectiveness of the treatment.

Analysis of Radiotherapy Associated Factors in Stage IIb Carcinoma of Uterine Cervix / 대한치료방사선과학회지

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.

Variation of Effective SSD According to Electron Energies and Irradiated Field Sizes / 대한치료방사선과학회지

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.