• Radiation Oncology Journal
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• v.4 no.1
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• pp.75-80
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• 1986

Heterotopic bone formation is a complication which occurs in 0.6 to $61.7\%$ of patients after total hip replacement arthroplasty. We reviewed 4 patients (8 hips) who received postoperative irradiation on their hi ps for prevention of heterotopic bone formation in the Department of Therapeutic of Therapeutic Radiology, Seoul National University versify Hospital from January 1981 through August 1985. Radiation therapy was started 6 to 10 days postoperatively with the dosage of 2,000 cGy given in 10 fractions. As a result, 7 hips had Grade 0 and 1 hip had Grade 1 heterotopic ossification according to modified Blocker system. Our result and review of the literatures strongly support that the postoperative radiotherapy is effective for prevention of heterotopic bone formation in high risk group.

• Radiation Oncology Journal
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• v.36 no.3
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• pp.227-234
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• 2018

Purpose: We compared how doses delivered via two-dimensional (2D) intracavitary brachytherapy (ICBT) and three-dimensional (3D) ICBT varied anatomically. Materials and Methods: A total of 50 patients who received 30 Gy of 3D ICBT after external radiotherapy (RT) were enrolled. We compared the doses of the actual 3D and 2D ICBT plans among patients grouped according to six anatomical variations: differences in a small-bowel V_2Gy, small bowel circumference, the direction of bladder distension, bladder volume, sigmoid V_3.5Gy, and sigmoid circumference. Seven dose parameters were measured in line with the EMBRACE recommendations. Results: In terms of bladder volume, the bladder and small-bowel D_2cc values were lower in the 150-250 mL bladder volume subgroup; and the rectum, sigmoid, and bladder D_2mL values were all lower in the >250 mL subgroup, for 3D vs. 2D ICBT. In the sigmoid V_3.5Gy >2 _mL subgroup, the sigmoid and bladder D_2mL values were significantly lower for 3D than 2D ICBT. The bladder D_2mL value was also significantly lower for 3D ICBT, as reflected by the sigmoid circumference. In patients with a small bowel V_2.0Gy >10 mL or small bowel circumference >15%, most dose parameters were significantly lower for 3D than 2D ICBT. The bladder distension direction did not significantly affect the doses. Conclusion: Compared to 2D ICBT, a greater bladder volume can reduce the internal 3D ICBT organ dose without affecting the target dose.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.109-121
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• 2016

To verify the accuracy of the image guided radiotherapy using ExacTrac 6D couch, the error values in six directions are randomly assigned and corrected and then the corrected values were compared with CBCT image to check the accurateness of ExacTrac. The therapy coordination values in the Rando head Phantom were moved in the directions of X, Y and Z as the translation group and they were moved in the directions of pitch, roll and yaw as the rotation group. The corrected values were moved in 6 directions with the combined and mutual reactions. The Z corrected value ranges from 1mm to 23mm. In the analysis of errors between CBCT image of the phantom which is corrected with therapy coordinate and 3D/3D matching error value, the rotation group showed higher error value than the translation group. In the distribution of dose for the error value of the therapy coordinate corrected with CBCT, the restricted value of dosage for the normal organs in two groups meet the prescription dose. In terms of PHI and PCI values which are the dose homogeneity of the cancerous tissue, the rotation group showed a little higher in the low dose distribution range. This study is designed to verify the accuracy of ExacTrac 6D couch using CBCT. It showed that in terms of the error value in the simple movement, it showed the comparatively accurate correction capability but in the movement when the angle is put in the couch, it showed the inaccurate correction values. So, if the body of the patient is likely to have a lot of changes in the direction of rotation or there is a lot of errors in the pitch, roll and yaw in ExacTrac correction, it is better to conduct the CBCT guided image to correct the therapy coordinate in order to minimize any side effects.

• Korean Journal of Head & Neck Oncology
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• v.27 no.2
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• pp.190-197
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• 2011

Background and Objective : Radiation resistance(RR) is one of main determinants of treatment outcome in oral squamous cell carcinoma(OSCC), but accurate prediction of RR is difficult. We aim to establish RR OSCC cell lines and identify genes related with RR by a measurement of altered gene expression after inducing RR. Material and Methods : OSCC cell lines, SCC15, SCC25 and QLL1, were treated with 2Gy radiation per session, and parts of them were alive in finally accumulated dosage of 60Gy through 30 times repetition of radiotherapy for inducing RR cell lines. We compared results of cDNA array and proteomics in non-radiated cell lines and RR cell lines to detect changes of gene expression. Western blot was used for the validation of results. Results : cDNA array revealed 265 commonly up-regulated genes and 268 commonly down-regulated genes in 3 RR cell lines comparing their non-radiated counterpart. Among them, 30 cancer related genes were obtained. Proteomics showed 51 commonly altered protein expressions in 3 RR cell lines and 18 cancer related proteins were obtained. Among the detected genes, we found NM23-H1 and PA2G4 were over-expressed in both cDNA array and proteomics. Western blot showed increased expression of NME1 in RR cell lines but not in PA2G4. Conclusion: We concluded that NM23-H1 may be a candidate of RR related gene and over-expression of NM23-H1 could be a biomarker to predict RR in OSCC.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.99-106
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• 2007

Purpose: The patient's position and anatomy during the treatment course little bit varies to some extend due to setup uncertainties and organ motions. These factors could affected to not only the dose coverage of the gross tumor but over dosage of normal tissue. Setup uncertainties and organ motions can be minimized by precise patient positioning and rigid immobilization device but some anatomical site such as prostate, the internal organ motion due to physiological processes are challenge. In planning procedure, the clinical target volume is a little bit enlarged to create a planning target volume that accounts for setup uncertainties and organ motion as well. These uncertainties lead to differences between the calculated dose by treatment planning system and the actually delivered dose. The purpose of this study was to evaluate the differences of interfractional displacement of organ and GTV based on the tomoimages. Materials and Methods: Over the course of 3 months, 3 patients, those who has applied rectal balloon, treated for prostatic cancer patient's tomoimage were studied. During the treatment sessions 26 tomoimages per patient, Total 76 tomoimages were collected. Tomoimage had been taken everyday after initial setup with lead marker attached on the patient's skin center to comparing with C-T simulation images. Tomoimage was taken after rectal balloon inflated with 60 cc of air for prostate gland immobilization for daily treatment just before treatment and it was used routinely in each case. The intrarectal balloon was inserted to a depth of 6 cm from the anal verge. MVCT image was taken with 5 mm slice thickness after the intrarectal balloon in place and inflated. For this study, lead balls are used to guide the registration between the MVCT and CT simulation images. There are three image fusion methods in the tomotherapy, bone technique, bone/tissue technique, and full image technique. We used all this 3 methods to analysis the setup errors. Initially, image fusions were based on the visual alignment of lead ball, CT anatomy and CT simulation contours and then the radiation therapist registered the MVCT images with the CT simulation images based on the bone based, rectal balloon based and GTV based respectively and registered image was compared with each others. The average and standard deviation of each X, Y, Z and rotation from the initial planning center was calculated for each patient. The image fusions were based on the visual alignment of lead ball, CT anatomy and CT simulation contours. Results: There was a significant difference in the mean variations of the rectal balloon among the methods. Statistical results based on the bone fusion shows that maximum x-direction shift was 8 mm and 4.2 mm to the y-direction. It was statistically significant (P=<0.0001) in balloon based fusion, maximum X and Y shift was 6 mm, 16mm respectively. One patient's result was more than 16 mm shift and that was derived from the rectal expansions due to the bowl gas and stool. GTV based fusion results ranging from 2.7 to 6.6 mm to the x-direction and 4.3$\sim$7.8 mm to the y-direction respectively. We have checked rotational error in this study but there are no significant differences among fusion methods and the result was 0.37$\pm$0.36 in bone based fusion and 0.34$\pm$0.38 in GTV based fusion.