• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1157-1164
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• 2023

This study measures the additional dose for each treatment area using kV X-ray based OBI (On-Board Imager) and CBCT (Cone-Beam CT), which have excellent spatial resolution and contrast, and evaluates the adequacy and stability of radiation management aspects of IGRT. The subjects of the experiment were examined with OBI and CBCT attached to a linear accelerator (Clinac IX), and ring-shaped Halcyon CBCT under imaging conditions for each treatment area, and the dose at the center was measured using an ion chamber. OBI single fraction dose was measured as 0.77 mGy in the head area, 3.04 mGy in the chest area, and 7.19 mGy in the pelvic area. The absorbed doses from the two devices, Clinac IX CBCT and Halcyon CBCT, were measured to be similar in the pelvic area, at 70.04 mGy and 70.45 mGy. and in chest CBCT, the Clinac IX absorbed dose (70.05 mGy) was higher than the Halcyon absorbed dose (21.01 mGy). The absorbed dose to the head area was also higher than that of Clinac IX (9.08 mGy) and Halcyon (5.44 mGy). In kV X-ray-based IGRT, additional radiation exposure due to photoelectric absorption may affect the overall volume of the treatment area, and caution is required.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.243-252
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• 1995

Purpose : Intraluminal high dose rate brachytherapy is an accepted treatment for the tumors of GI tract. However, there is only some limited clinical data for intraluminal high dose rate brachytherapy for the tumors of GI tract. Materials and Methods : Between February 1991 and July 1993, 18 Patients who have the tumors of GI tract (esophageal cancer-8 cases, rectal cancer-10 cases) were treated with high dose rate Iridium-192 afterloading system (Microselectron-HDR, Nucletron CO, Netherland) at the department of therapeutic radiology, St. Mary's hospital, Catholic university medical college. Age range was 47-87 years with a mean a9e 71 years. All patients were treated with intraluminal high dose rate brachytherapy within two weeks after conventional external radiation therapy and received 3-5 Gy/fraction 3-4 times per week to a total dose 12-20 Gy (mean 17 Gy). Standard fractionation and conventional dose were delivered for external radiation therapy. Total dose of external radiation therapy ranged 41.4-59.4 Gy (mean 49.6 Gy). Median follow up was 19 months Results : The analysis was based on 18 patients, The complete response and partial response in esophageal cancer was similar (38%). Two year rates for survival and median survival were 13% and 10 months, respectively. Among 10 patients of rectal cancers, partial response was obtained in 6 patients (60%). There was no complete response in the patients with rectal cancer, but good palliative results were achieved in all patients. Conclusion : Although the number of patients was not large and the follow-up period was relatively short, these findings suggested that intraluminal high dose rate brachytherapy could be useful in the treatment of the patients with advanced tumors of GI tract.

• Radiation Oncology Journal
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• v.26 no.3
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• pp.173-180
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• 2008

Purpose: The modification of radiation-induced apoptosis by EGCG, known as antioxidants or oxidants, was studied in mice spleens irradiated with a lethal dose. Materials and Methods: Male C57BL/6 mice were divided into control, irradiation-only, and EGCG (100 mg/kg i.p. 1 h before irradiation) pretreatment groups. The mice were irradiated with a single whole-body dose of 7 Gy. The apoptosis in the spleens after irradiation of the lethal dose were analyzed by TUNEL assay. In addition, the expression levels of the Bax and Bcl-2 proteins were quantified using a Western blotting method. Results: The induction of apoptosis was detected in the splenic white pulp. The highest level of apoptosis was detected at 8 hours after irradiation. No significant difference was identified by the apoptotic index (53.9% vs. 52.1%, p=0.328) and relative Bax protein expression (0.86 vs. 0.81, p=0.335), between the irradiation-only and EGCG pretreatment group, respectively. However, a lower Bax/Bcl-2 ratio (1.64 vs. 0.97, p=0.037) and higher relative expression level of Bcl-2 protein (0.57 vs. 0.82, p=0.037) was measured in the EGCG pretreatment group. Conclusion: The EGCG pretreatment neither decreased the radiation-induced apoptosis in mice splenocytes, nor induced additional apoptosis.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.121-126
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• 2011

The author reports a bile duct cancer patient whose stent shifted significantly from right to left over the course of radiotherapy. The 80-year-old female patient had a short stature with thoracic kyphosis and mutiple spinal compression fractures. She was also emaciated and very lean. By comparing the weekly scanned computed tomography images, the author found her stent to have shifted by more than 4 cm from right to left over the course of external beam radiotherapy. The results of this case study suggest that for a very lean and emaciated kyphotic bile duct cancer patient, the possibility of large interfractional movement of the bile duct or stent during radiotherapy should be considered.

• the MEAT Journal
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• s.36 summer
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• pp.72-86
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• 2009

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beef patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation. the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed somewhat higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.437-444
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• 2008

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beer patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation, the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed some-what higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.339-348
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• 1997

Purpose : To evaluate the role of postoperative radiation therapy after curative resection of sigmoid colon cancer Materials and Methods : From 1988 to 1993, a total of 93 Patients with curative resectable sigmoid colon cancer of modified Astler-Coiler (MAC) stage B2, B3, C2, C3 was divided into two groups on the basis of those who received radiation treatment and those who did not. Forty-three patients who treated by surgery alone were classified as postop RT (-) group The remaining 50 patients who underwent postoperative radiotherapy were classified as postop RT (+) group. In all patients in Postop RT (+) group. radiation therapy was delivered using 4 or 10 MV linear accelerators to treat the tumor bed with approximately 5cm margin to a total dose 50.4-61Gy(median 54Gy) in 1.8Gy per fraction. Thirty-two patients were treated. with 5-Fluorouracil based adjuvant chemotherapy at least 3 cycles. but these was no significant difference between two groups. Treatment failure Pattern, 5-year local failure-free survival rates (LFFS), and 5-year disease-free survival rates (DFS) were compared between two groups. Result : Five year LFFS and DFS were $85.1\%,\;68.5\%$, respectively, In Postop RT (-) group, LFFS was $76.2\%$ compared with $91.7\%$ in Postop RT (+) group. Improved LFFS and DFS were seen for patients with stage C3 sigmoid colon carcinoma with postoperative radiation therapy compared with postop RT (-) group (P=0.01, p=0.06 respectively), in stage B3, LFFS washigher in postop RT (+) group than that in Postop RT (-) group. although itwas not significant. Especially, local control was higher in stage 74 inpostop RT (+) group than that in postop RT (-) group, Conclusion : This studv showed significantly improved LFFS and DFS in MAC Stage C3 and improved tendency of LFFS and DFS in MAC Stage B3 disease. Large scale prospective study is required to verify the role of adjuvant radiation therapy in resectable sigmoid colon cancer.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.539-543
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• 2016

In this research, The way to decrease a patient's exposure dose by reducing the scattered radiation dosage outside a radiation field with an diagnosis X-ray was examined. The scattered radiation dosage reaching other parts outside the radiation field was to be reduced by attaching a self-produced $150{\times}190mm^2$ lead plate to the lower part of a collimator. When a lead plate was inserted additionally and the scattered radiation dosage of the X axis was measured in the direction of the central X-ray axis, It was found out to have been decreased by 26 to 36%, and in the direction of Y axis, which was vertical direction from the central axis, The scattered radiation dosage depending on whether a lead plate was used or not displayed no large differences. These results shows that the impact of the scattered radiation by the off focus X-ray that was generated around the focus was bigger than that generated by the shutter of the collimator. Therefore it has been concluded that installing an additional lead plate in the lower part of the existing collimator can decrease the scattered radiation dosage outside a radiation field.

• Progress in Medical Physics
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• v.13 no.1
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• pp.32-36
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• 2002

For Intensity Modulated Radiation Therapy(IMRT), the spatial resolution of intensity map(IM) is limited by the width of multi-leaf collimator, which would make an effect on the conformity of the target, as well as organs at risk. Several Methods are suggested to increase the spatial resolution, which can be categorized by the hardware-dependent technique and the software-based technique. However the best solution might be to make the width of MLC finer. it has several obstacles in the respects of technical difficulty and cost. This preliminary study is designed to investigate the clinical effectiveness of the virtual-micro IMRT(VMIMRT) technique, one of the software-based technique. A particular intensity map was created, which has 42$\times$54 pixel dimension ,0.5cm pixel size and 15 intensity levels. Using this intensity map, segment fields of IMRT were generated with 1$\times$lcm, 0.5$\times$1cm, 0.5$\times$0.5cm(VMIM) beamlet size, respectively As results, we found that there was no evidence of improvement for VMIMRT, compared with the 0.5$\times$lcm beamlet size which can be delivered by 1cm width MLC. The reason seems to be due to the constraint of VMIMRT. Further study is required to prove the benefit of the VIMRT in clinical case like head and neck cancer, where is expected that higher resolution than 1cm is necessary.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.11-16
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• 2004

Purpose: To evaluate the survival rate, local failure rate and patterns of failure, and analyze the prognostic factors affecting local relapse of ductal carcinoma in situ treated with breast conserving surgery and radiotherapy Materials and Methods: From June 1995 to December 2001, 96 patients with ductal carcinoma in situ treated with breast conserving surgery and radiotherapy were retrospectively analyzed. The operations were either local or wide excision in all patients, with an axillary lymph node dissection performed in some patients. Radiation dose to the whole breast was 50.4 Gy, over 5 weeks, with 1.8 Gy daily fractions, with additional doses ($10\~14$ Gy) administered to the primary tumor bed in some patients with close ($\leq$2 mm) or positive resection margin. The median follow-up period was 43 months (range $10\~102$ months). Results: The 5-year local relapse free survival and overall survival rates were 91 and $100\%$ respectively. Local relapse occurred in 6 patients ($6.3\%$). Of the 6 recurrences, one was invasive ductal cell carcinoma. With the exception of one, all patients recurred 2 years after surgery. There was no regional recurrence or distant metastasis. Five patients with local recurrence were salvaged with total mastectomy, and are alive with no evidence of disease. One patient with recurrent invasive ductal cell carcinoma will receive salvage treatment. On analysis of the prognostic factors affecting local relapse, none of the factors among the age, status of resection margin, comedo type and nuclear grade affected local relapse. Operation extent also did not affect local control (p=0.30). In the patients with close resection margin, boost irradiation to the primary tumor bed did not affect local control (p=1.0). Conclusions: The survival rate and local control of the patients with ductal carcinoma in situ treated with breast conserving surgery and radiotherapy were excellent. Close resection margin and boost irradiation to the primary tumor bed did not affect local relapse, but further follow-up with much more patients is needed.