• Journal of the Korean Magnetics Society
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• v.25 no.6
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• pp.208-218
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• 2015

Recently, radiation therapy is used in the CT existing conventional two-dimensional radiation image, and set the size and location of the tumor in a manner that the image is going to change the treatment plan. After using the simulation using CT, radiation therapy it is four-dimensional or three-dimensional treatment made possible. and radiation therapy became the more effective ever before. High technology radiation therapy such as the treatment of SRS,IMRT, IGRT, SBRT, is a need to try contemplating the possibility to apply appropriate analysis and situation, so it has its own characteristics. and then it is believed that it is necessary to analyze and try it worries the proper applicability of the situation. The configuration of the various treatment that is applicable in many hospitals is necessary to try to determine how to practically apply the patients. Critical organs surrounding tumor give a small dose to avoid side effects and then the tumor has the therapeutic effect by providing a larger dose than before the radiation treatment.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.511-515
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• 2004

Purpose: The sodium-iodide symporter (NIS) expression is an important factor in determining the sensitivity of radioiodine therapy in well-differentiated thyroid cancers. Several previous studies for the expression of NIS in thyroid tissues show diverse results. To investigate whether there is difference between methods in determining the expression of NIS in thyroid tissues of patients with thyroid nodules, we measured the expression ot NIS using two different methods (RT-PCR and immunoshistochemical staining) and compared the results. Materials & Methods: We measured the expression of NIS by reverse transcriptase-polymerase chain reaction (RT-PCR) and also by immunohistochemical staining using anti-NIS antibody in thyroid cancers and other benign thyroid diseases. We compared the results of each method. We included 19 papillary carcinomas, 1 follicular carcinoma, 7 medullary carcinoma, 4 adenomas and 7 nodular hyperplasias. Results: By RT-PCR analysis, 10 of 19 papillary carcinomas expressed NIS, but 1 follicular cancer didn't express NIS. By immunohistochemical staining, 15 of 19 papaillary carcinomas express NIS, but 1 follicular lancer didn't express NIS. There was a significant correlation between the semiquautitative results of RT-PCR and immunohistochemical staining of NIS expression. (p<0.01) Conclusion: Our data demonstrated that the expression of NIS in thyroid cancers and other benign diseases investigated by RT-PCR and immunohistochemical staining correlated well each other. However, by immunohistochemical staining, more NIS expression was found.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.97-103
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• 2010

Purpose: Treating same region with different modalities there is a limit to evaluate the total absorbed dose of normal tissues. The reason is that it does not support to communication each modalities yet. In this article, it evaluates absorbed dose of the patients who had been treated same region by a tomotherapy and a linear accelerator. Materials and Methods: After reconstructing anatomic structure with a anthropomorphic phantom, administrate 45 Gy to a tumor in linac plan system as well as prescribe 15 Gy in tomotherapy plan system for make an ideal treatment plan. After the plan which made by tomoplan system transfers to the oncentra plan system for reproduce plan under the same condition and realize total treatment plan with summation 45 Gy linac treatment plan. To evaluate the absorbed dose of two different modalities, do a comparative study both a simple summation dose values and integration dose values. Then compare and analyze absorbed dose of normal tissues and a tumor with the patients who had been exposured radiation by above two differents modalities. Results: The result of compared data, in case of minimum dose, there are big different dose values in spleen (12.4%). On the other hand, in case of the maximum dose, it reports big different in a small bowel (10.2%) and a cord (5.8%) in head & neck cancer patients, there presents that oral (20.3%), right lens (7.7%) in minimum dose value. About maximum dose, it represents that spinal (22.5), brain stem (12%), optic chiasm (8.9%), Rt lens (11.5%), mandible (8.1%), pituitary gland (6.2%). In case of Rt abdominal cancer patients, there represents big different minimum dose as Lt kidney (20.3%), stomach (8.1%) about pelvic cancer patients, it reports there are big different in minimum dose as a bladder (15.2%) as well as big different value in maximum dose as a small bowel (5.6%), a bladder (5.5%) in addition, making treatment plan it is able us to get. Conclusion: In case of comparing both simple summation absorbed dose and integration absorbed dose, the minimum dose are represented higher as well as the maximum dose come out lower and the average dose are revealed similar with our expected values data. It is able to evaluate tumor & normal tissue absorbed dose which could had been not realized by treatment plan system. The DVH of interesting region are prescribed lower dose than expected. From now on, it needs to develop the new modality which are able to realize exact dose distribution as well as integration absorbed dose evaluation in same treatment region with different modalities.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.363-371
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• 2016

PURPOSE. On maxillofacial tumor patients, oral implant placement prior to postoperative radiotherapy can shorten the period of prosthetic reconstruction. There is still lack of research on effects of post-implant radiotherapy such as healing process or loading time, which is important for prosthodontic treatment planning. Therefore, this study evaluated the effects of post-implant local irradiation on the osseointegration of implants during different healing stages. MATERIALS AND METHODS. Custom-made implants were placed bilaterally on maxillary posterior edentulous area 4 weeks after extraction of the maxillary first molars in Forty-eight Sprague-Dawley rats. Experimental group (exp.) received radiation after implant surgery and the other group (control) didn't. Each group was divided into three sub-groups according to the healing time (2, 4, and 8 week) from implant placement. The exp. group 1, 2 received 15-Gy radiation 1 day after implant placement (immediate irradiation). The exp. group 3 received 15-Gy radiation 4 weeks after implant placement (delayed irradiation). RESULTS. The bone mineral density (BMD) was significantly lower in the immediate irradiation groups. BMD was similar in the delayed irradiation group and the control group. The irradiated groups exhibited a lower bone-to-implant contact ratio, although the difference was not statistically significant. The irradiated groups also exhibited a significantly lower bone volume and higher empty lacuna count than the control groups. No implant failure due to local irradiation was found in this study. CONCLUSION. Within the limits of this study, the timing of local irradiation critically influences the bone healing mechanism, which is related to loading time of prostheses.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.287-300
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• 2005

Squamous cell carcinoma (SCC) in head and neck show a variability in the response to chemotherapy, even when it present with similar histological tumor type, grade, and clinical stage. The purpose of present study it to identify predictive bio-marker for the sensitivity or resistance to conventional chemotherapeutic agents, 5-fluorouracil (5-FU) and Cisplatin Oral cancer cell lines were used in present study. MTT assay was performed to evaluate the sensitivity and/or resistance to 5-FU and Cisplatin. And RT-PCR was carried out for evaluation of the mRNA expressions of various genes associated with mutation, inflammation (COX pathway), cell cycle, senescence and extracellular matrix (ECM). The molecules which are correlated with the sensitivity to 5-FU are XPA, XPC, OGG, APEX, COX-2, PPAR, Cyclin E, Cyclin B1, CDC2, hTERT, hTR, TIMP-3, TIMP-4 and HSP47. And the molecules are correlated with the sensitivity to Cisplatin are COX-1, iNOS, eNOS, PCNA, collagen 1 and MMP-9. Taken together, when choosing the appropriate chemotherpeutic agents for patients, considering the molecules which are correlated or reversely correlated is helpful to choose the resonable agents for cancer patients.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.913-919
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• 2004

Mitochondrial DNA mutations have been reported in recent years in association with sensorineural hering loss. The purpose of this study is to identify the association between the noise-induced sensorineural hearing loss and the A to G mutation at nucleotide 3243, 1555, 7445 of mitochondrial DNA. Study subjects were established by history and chart review, and audiological and clinical data were obtained. Blood was sampled from 214 normal controls, 102 noise-induced hearing loss, and 28 sensorineural hearing loss. The DNA of these individuals were extracted, and mitochondrial DNA fragments were analyzed by polymerase chain reaction. Subsequently, the coding sequence of mitochondrial DNA 3243, 1555, 7445 were sequenced, and compared to the normal sequence, and all sequence variations were analyzed by restriction enzymes. Mitochondrial DNA mutations $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$ were not detected by polymerase chain reactions in any patients with noise-induced hearing loss, sensorineural hearing loss, and normal controls. The DNA sequencing of PCR products did not revealed an A to G substitution at nucleotide 3243, 1555, 7445 of mitochondrial DNA. The noise-induced sensorineural hearing loss was not associated with mitochondrial DNA mutation $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.465-484
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• 2004

Background : Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) inhibits the proliferation of non-small cell lung cancer (NSCLC) cells by inducing apoptosis. Methods : In this study, we investigated whether hypermethylation of IGFBP-3 promoter play an important role in the loss of IGFBP-3 expression in NSCLC. We also studied the mechanisms that mediate the silencing of IGFBP-3 expression in the cell lines which have hypermethylated IGFBP-3 promoter. Results : The IGFBP-3 promoter has hypermethylation in 7 of 15 (46.7%) NSCLC cell lines and 16 (69.7%) of 23, 7 (77.8%) of 9, 4 (80%) of 5, 4 (66.7 %) of 6, and 6 (100%) of 6 tumor specimens from patients with stage I, II, IIIA, IIIB, and IV NSCLC, respectively. The methylation status correlated with the level of protein and mRNA in NSCLC cell lines. Expression of IGFBP-3 was restored by the demethylating agent 5'-aza-2'-deoxycytidine (5'-aza-dC) in a subset of NSCLC cell lines. The Sp-1/ Sp-3 binding element in the IGFBP-3 promoter, important for promoter activity, was methylated in the NSCLC cell lines which have reduced IGFBP-3 expression and the methylation of this element suppressed the binding of the Sp-1 transcription factor. A ChIP assay showed that the methylation status of the IGFBP-3 promoter influenced the binding of Sp-1, methyl-CpG binding protein-2 (MeCP2), and histone deacetylase (HDAC) to Sp-1/Sp-3 binding element, which were reversed by by 5'-aza-dC. In vitro methylation of the IGFBP-3 promoter containing the Sp-1/Sp-3 binding element significantly reduced promoter activity, which was further suppressed by the overexpression of MeCP2. This reduction in activity was rescued by 5'-aza-dC. Conclusion : These findings indicate that hypermethylation of the IGFBP-3 promoter is one mechanism by which IGFBP-3 expression is silenced and MeCP2, with recruitment of HDAC, may play a role in silencing of IGFBP-3 expression. The frequency of this abnormality is also associated with advanced stages among the patients with NSCLC, suggesting that IGFBP-3 plays an important role in lung carcinogenesis/progression and that the promoter methylation status of IGFBP-3 may be a marker for early molecular detection and/or for monitoring chemoprevention efforts.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.1
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• pp.35-46
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• 2016

Purpose : BoS(Base of Skull) Frame, the fixation tool which is used for the proton of brain cancer increases the lateral penumbra by increasing the airgap (the distance between patient and beam jet), due to the collision of the beam of the posterior oblique direction. Thus, we manufactured the fixation tool per se for improving the limits of BoS frame, and we'd like to evaluate the utility of the manufactured fixation tool throughout this study. Materials and Methods : We've selected the 3 patients of brain cancer who have received the proton therapy from our hospital, and also selected the 6 beam angles; for this, we've selected the beam angle of the posterior oblique direction. We' ve measured the planned BoS frame and the distance of Snout for each beam which are planned for the treatment of the patient using the BoS frame. After this, we've proceeded with the set-up that is above the location which was recommended by the manufacturer of the BoS frame, at the same beam angle of the same patient, by using our in-house Bos frame fixation tool. The set-up was above 21 cm toward the superior direction, compared to the situation when the BoS frame was only used with the basic couch. After that, we've stacked the snout to the BoS frame as much as possible, and measured the distance of snout. We've also measured the airgap, based on the gap of that snout distance; and we've proceeded the normalization based on each dose (100% of each dose), after that, we've conducted the comparative analysis of lateral penumbra. Moreover, we've established the treatment plan according to the changed airgap which has been transformed to the Raystation 5.0 proton therapy planning system, and we've conducted the comparative analysis of DVH(Dose Volume Histogram). Results : When comparing the result before using the in-house Bos frame fixation tool which was manufactured for each beam angle with the result after using the fixation tool, we could figure out that airgap than when not used in accordance with the use of the in-house Bos frame fixation tool was reduced by 5.4 cm ~ 15.4 cm, respectively angle. The reduced snout distance means the airgap. Lateral Penumbra could reduce left, right, 0.1 cm ~ 0.4 cm by an angle in accordance with decreasing the airgap while using each beam angle in-house Bos frame fixation tool. Due to the reduced lateral penumbra, Lt.eyeball, Lt.lens, Lt. hippocampus, Lt. cochlea, Rt. eyeball, Rt. lens, Rt. cochlea, Rt. hippocampus, stem that can be seen that the dose is decreased by 0 CGE ~ 4.4 CGE. Conclusion : It was possible to reduced the airgap by using our in-house Bos frame fixation tool for the proton therapy; as a result, it was possible to figure out that the lateral penumbra reduced. Moreover, it was also possible to check through the comparative analysis of the treatment plan that when we reduce the lateral penumbra, the reduction of the unnecessary irradiation for the normal tissues. Therefore, Using the posterior oblique the Brain cancer proton therapy should be preceded by decreasing the airgap, by using our in-house Bos frame fixation tool; also, the continuous efforts for reducing the airgap as much as possible for the proton therapy of other area will be necessary as well.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.9-15
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• 2006

Purpose: Previous studies have not showed consistent results for the level of expression of sodium/iodide symporter (NIS) in thyroid diseases, especially malignant tumor. We undertook this study to evaluate the distribution of NIS expression in malignant thyroid diseases and compare with that in benign thyroid disease. Materials and Methods: Total patients were 119 cases (Men 15, $48{\pm}13$ yrs). Total number of samples were 205 pieces. In malignant thyroid disease, there were 153 samples: 90 in papillary carcinoma, 4 in follicular carcinoma, 2 in medullary carcinoma and 57 in metastatic lymph node. In benign thyroid disease, there were 52 samples: 36 in goiter/cyst, 11 in thyroiditis and 5 in follicular adenoma. Using immunohistochemical methods, we probed 205 samples with monoclonal anti-NIS Ab. Grading of staining was stored as 0 (negative or absent), 1 (weakly positive), 2 (moderately positive) or 3 (strongly positive). Expression rate (ER) of NIS positivity in individual disease entity was expressed as percentage of total number divided by number in 2 plus 3 grade. Results: ERs of malignant thyroid diseases were 63% in papillary carcinoma, 81% in metastatic lymph node, 71% in follicular carcinoma and 100% in medullary carcinoma. ERs of benign thyroid disease were 53% in goiter/cyst, 64% in thyroiditis and 40% in follicular adenoma. ER of malignant thyroid diseases was higher than benign thyroid diseases (71% vs 54%). Grading of NIS expression in papillary carcinoma or goiter/cyst was heterogeneously distributed in considerable cases. Normal tissue also showed heterogeneous distribution of NIS expression, which was not correlated with that of primary lesion. Conclusion: In papillary thyroid carcinoma, distribution of NIS expression was heterogeneous and increased, and not different compared with that of benign thyroid disease.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.7-12
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• 2022

Purpose: When it is difficult to secure the skin dose when treating Irregularly Shaped Skin Surface such as the nose where it is difficult to apply a bolus, increase the skin dose with a treatment plan that combines the IMRT (Intensity Modulated Radiation Therapy) delivery technique and FFF (Flattening Filter Free), It was tried to find out whether or not through the phantom experiment. Materials & Methods: Based on the 6MV-FF (Flattening Filter) and VMAT (Volumetric-Modulated Arc Therapy) treatment plans, which are the most commonly used treatment plans for head and neck cancer, A comparison group was created by combining VMAT and IMRT, FF and FFF, and the presence or absence of 5 mm bolus application. A virtual target was created on the Rando Phantom's nose, and a virtual bolus of 5 mm was applied assuming full contact on the Rando Phantom's nose. Five measurement points were determined based on the phantom's nose, and the absorbed dose was measured by irradiating each treatment plan 3 times per treatment plan according to the treatment technique and whether or not the bolus was applied. Result: The difference in skin dose in FF vs FFF increased in the case of FFF in VMAT bolus off, and there was no difference in case of IMRT bolus off. In VMAT bolus 5 mm and IMRT bolus 5 mm, it was confirmed that the skin dose was rather decreased in FFF. The difference in skin dose between VMAT and IMRT increased only in the case of FFF bolus off, and there was no statistical difference in the rest. For the difference in skin dose between bolus off vs bolus 5 mm, it was confirmed that the skin dose increased at bolus 5 mm, except for the case of using IMRT FFF. The treatment plan combining IMRT and FFF did not find any statistically significant difference as a result of analyzing the measured values of the treatment plan skin dose applied with a 5 mm bolus using the commonly used VMAT and FF. Therefore, it is thought that by using IMRT_FFF, it is possible to deliver a skin dose similar to that of applying a 5 mm bolus to VMAT_FF, which can be useful for patients who need a high skin dose but have difficulty applying a bolus. Conclusion: For patients who find it difficult to apply bolus, an increase in skin dose can be expected with a treatment plan that properly combines IMRT and FFF compared to VMAT and FF.