• Radiation Oncology Journal
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• v.12 no.3
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• pp.387-392
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• 1994

Purpose : This study was done to confirm the reference point variation according to variation in applicator configuration in each fractioation of HDR ICR. Materials and Methods : We analyzed the treatment planning of HDRICR for 33 uterine cervical cancer patients treated in department of therapeutic radiology from January 1992 to February 1992. Analysis was done with respect to three view points-Interfractionation A point variation, interfractionation bladder and rectum dose ratio variation, interfractionation treatment volume variation. Interfractionation A point variation was defined as difference between maximum and minimum distance from fixed rectal point to A point in each patient. Interfractionation bladder and rectum dose ratio variation was defined as difference between maximum and minimum dose ratio of bladder or rectum to A point dose in each patient, Interfractionation treatment volume variation was defined as difference between miximum and minimum treatment volume which absorbed over the described dose-that is, 350 cGy or 400 cGy-in each patient. Results The mean of distance from rectum to A point was 4.44cm, and the mean of interfractionation distance variation was 1.14 cm in right side,1.09 cm in left side. The mean of bladder and rectum dose ratio was $63.8\%$ and $63.1\%$ and the mean of interfractionation variation was $14.9\%$ and $15.8\%$ respectively. With fixed planning administration of same planning to all fractionations as in first fractionation planning-mean of bladder and rectum dose ratio was $64.9\%$ and $72.3\%$.and the mean of interfraction variation was $28.1\%$ and $48.1\%$ reapectively. The mean of treatment volume was $84.15cm^3$ and the interfractionation variation was $21.47cm^2$. Conclusion : From these data, it was confirmed that there should be adapted planning for every fractionation ,and that confirmation device installed in ICR room would reduce the interfractionation variation due to more stable applicator configuration.

• Radiation Oncology Journal
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• v.37 no.2
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• pp.127-133
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• 2019

Purpose: The aim of this study was to identify volume changes and dose variations of rectum and bladder during radiation therapy in prostate cancer (PC) patients. Materials and Methods: We analyzed 20 patients with PC treated with helical tomotherapy. Daily image guidance was performed. We re-contoured the entire bladder and rectum including its contents as well as the organ walls on megavoltage computed tomography once a week. Dose variations were analyzed by means of Dmedian, Dmean, Dmax, V₁₀ to V₇₅, as well as the organs at risk (OAR) volume. Further, we investigated the correlation between volume changes and changes in Dmean of OAR. Results: During treatment, the rectal volume ranged from 62% to 223% of its initial volume, the bladder volume from 22% to 375%. The average Dmean ranged from 87% to 118% for the rectum and 58% to 160% for the bladder. The Pearson correlation coefficients between volume changes and corresponding changes in Dmean were -0.82 for the bladder and 0.52 for the rectum. The comparison of the dose wall histogram (DWH) and the dose volume histogram (DVH) showed that the DVH underestimates the percentage of the rectal and bladder volume exposed to the high dose region. Conclusion: Relevant variations in the volume of OAR and corresponding dose variations can be observed. For the bladder, an increase in the volume generally leads to lower doses; for the rectum, the correlation is weaker. Having demonstrated remarkable differences in the dose distribution of the DWH and the DVH, the use of DWHs should be considered.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1414-1420
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• 2022

High dose rate (HDR) brachytherapy treatment planning usually involves optimization methods to deliver uniform dose to the target volume and minimize dose to the healthy tissues. Four optimizations were used to evaluate the high-risk clinical target volume (HRCTV) coverage and organ at risk (OAR). Dose-volume histogram (DVH) and dosimetric parameters were analyzed and evaluated. Better coverage was achieved with PGO (mean CI = 0.95), but there were no significant mean CI differences than GrO (p = 0.03322). Mean EQD₂ doses to HRCTV (D₉₀) were also superior for PGO with no significant mean EQD₂ doses than GrO (p = 0.9410). The mean EQD₂ doses to bladder, rectum, and sigmoid were significantly higher for NO plan than PO, GrO, and PGO. PO significantly reduced the mean EQD₂ doses to bladder, rectum, and sigmoid but compromising the conformity index to HRCTV. PGO was superior in conformity index (CI) and mean EQD₂ doses to HRCTV compared with the GrO plan but not statistically significant. The mean EQD₂ doses to the rectum by PGO plan slightly exceeded the limit from ABS recommendation (mean EQD₂ dose = 78.08 Gy EQD₂). However, PGO can shorten the treatment planning process without compromising the CI and keeping the OARs dose below the tolerance limit.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.179-186
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• 2016

Purpose : To figure out if the treatment plan for rectum, bladder and prostate that have a lot of interfraction errors satisfies dosimetric limits without adaptive plan by analyzing MR image. Materials and Methods : This study was based on 5 prostate cancer patients who had IMRT(total dose: 70Gy) Using ViewRay MRIdian System(ViewRay, ViewRay Inc., Cleveland, OH, USA) The treatment plans were made on the same CT images to compare with the plan quality according to adaptive plan, and the Eclipse(Ver 10.0.42, Varian, USA) was used. After registrate the 5 treatment MR images to the CT images for treatment plan to analyze the interfraction changes of organ, we measured the dose volume histogram and the changes of the absolute volume for each organ by appling the first treatment plan to each image. Over 5 fractions, the total dose for PTV was $V_{36.25}$ Gy $${\geq_-}$$ 95%. To confirm that the prescription dose satisfies the SBRT dose limit for prostate, we measured $V_{100%}$, $V_{95%}$, $V_{90%}$ for CTV and $V_{100%}$, $V_{90%}$, $V_{80%}$ $V_{50%}$ of rectum and bladder. Results : All dose average value of CTV, rectum and bladder satisfied dose limit, but there was a case that exceeded dose limit more than one after analyzing the each image of treatment. After measuring the changes of absolute volume comparing the MR image of the first treatment plan with the one of the interfraction treatment, the difference values were maximum 1.72 times at rectum and maximum 2.0 times at bladder. In case of rectum, the expected values were planned under the dose limit, on average, $V_{100%}=0.32%$, $V_{90%}=3.33%$, $V_{80%}=7.71%$, $V_{50%}=23.55%$ in the first treatment plan. In case of rectum, the average of absolute volume in first plan was 117.9 cc. However, the average of really treated volume was 79.2 cc. In case of CTV, the 100% prescription dose area didn't satisfy even though the margin for PTV was 5 mm because of the variation of rectal and bladder volume. Conclusion : There was no case that the value from average of five fractions is over the dosimetric limits. However, dosimetric errors of rectum and bladder in each fraction was significant. Therefore, the precise delivery is needed in case of prostate SBRT. The real-time tracking and adaptive plan is necessary to meet the precision delivery.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.161-169
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• 2016

Purpose : To quantify the inter-fractional variation in prostate displacement and their dosimetric effects for prostate cancer treatment. Materials and Methods : A total of 176 daily cone-beam CT (CBCT) sets acquired for 6 prostate cancer patients treated with volumetric-modulated arc therapy (VMAT) were retrospectively reviewed. For each patient, the planning CT (pCT) was registered to each daily CBCT by aligning the bony anatomy. The prostate, rectum, and bladder were delineated on daily CBCT, and the contours of these organs in the pCT were copied to the daily CBCT. The concordance of prostate displacement, deformation, and size variation between pCT and daily CBCT was evaluated using the Dice similarity coefficient (DSC). Results : The mean volume of prostate was 37.2 cm3 in the initial pCT, and the variation was around ${\pm}5%$ during the entire course of treatment for all patients. The mean DSC was 89.9%, ranging from 70% to 100% for prostate displacement. Although the volume change of bladder and rectum per treatment fraction did not show any correlation with the value of DSC (r=-0.084, p=0.268 and r=-0.162, p=0.032, respectively), a decrease in the DSC value was observed with increasing volume change of the bladder and rectum (r=-0.230,p=0.049 and r=-0.240,p=0.020, respectively). Conclusion : Consistency of the volume of the bladder and rectum cannot guarantee the accuracy of the treatment. Our results suggest that patient setup with the registration between the pCT and daily CBCT should be considered aligning soft tissue.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.223-229
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• 2005

Purpose: In this work we designed and made MPBP(Multi Purpose Brachytherapy Phantom). The MPBP enables one to reproduce the same patient set-up in MPBP as the treatment of the patient and we tried to get an exact analysis of rectal doses in the phantom without need of in-vivo dosimetry. Materials and Methods: Dose measurements were tried at a point of rectum 1, the reference point of rectum, with a diode detector for 4 patients treated with tandem and ovoid for a brachytherapy of a cervix cancer. Total 20 times of rectal dose measurements were made with 5 times a patient. The set-up variation of the diode detector was analyzed. The same patient set-ups were reproduced in self-made MPBP and then rectal doses were measured with TLD. Results: The measurement results of the diode detector showed that the set-up variation of the diode detector was the maximum $11.25{\pm}0.95mm$ in the y-direction for Patient 1 and the maximum $9.90{\pm}4.50mm,\;20.85{\pm}4.50mm,\;and\;19.15{\pm}3.33mm$ in the z-direction for Patient 2, 3, and 4, respectively. Un analyzing the degree of variation in 3 directions the more variation was showed in the z-direction than x- and y-direction except Patient 1. The results of TLD measurements in MPBP showed the relative maximum error of 8.6% and 7.7% at a point of rectum 1 for Patient 1 and 4, respectively and 1.7% and 1.2% for Patient 2 and 3, respectively. The doses measured at R1 and R2 were higher than those calculated except R point of Patient 2. this can be thought to related to the algorithm of dose calculation, whcih corrects for air and water but is guessed not to consider the correction for the scattered rays, but by considering the self-error (${\pm}5%$) TLD has the relative error of values measured and calculated was analyzed to be in a good agreement within 15%. Conclusion: The reproducibility of dose measurements under the same condition as the treatment could be achieved owing to the self-made MPMP and the dose at the point of interest could be analyzed accurately. If a treatment is peformed after achieving dose optimization using the data obtained in the phantom, dose will be able to be minimized to important organs.

• Korean Journal of Veterinary Research
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• v.11 no.1
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• pp.55-58
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• 1971

At the Seoul first slaughter house, 2,964 heads of swine were examined for the infection and distribution of Cysticercus tenuicollis. The results were summarized as follows. 1. The Cysticercus tenuicollis were detected from 106 heads of swine and the infection rate were 3.58 percent. 2. Incidence at each province were 5.7% in Jeon-ra-puk Do, 4.4% in Chung-cheong-nam Do, 3.83% in Kyong-sang-nam Do, 3.57% in Jeon-ra-nam Do, 2.52% in Kang-won Do, 1.75% in Kyong-sang-puk Do, and Kyong-gi Do and Seoul City were not recognized. 3. The monthly variation of the infection of Cysticercus tenuicollis were not found nearly through a year. 4. The usual habitat of Cysticercus tenuicollis were recognized the omentum and liver, but unusually one case was found around the rectum.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.53-60
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• 2015

Purpose : The purpose of this study is to evaluate the usefulness of a 3D printed phantom for in-vivo dosimetry of a prostate cancer patient. Materials and Methods : The phantom is produced to equally describe prostate and rectum based on a 3D volume contour of an actual prostate cancer patient who is treated in Asan Medical Center by using a 3D printer (3D EDISON+, Lokit, Korea). CT(Computed tomography) images of phantom are aquired by computed tomography (Lightspeed CT, GE, USA). By using treatment planning system (Eclipse version 10.0, Varian, USA), treatment planning is established after volume of a prostate cancer patient is compared with volume of the phantom. MOSFET(Metal OXIDE Silicon Field Effect Transistor) is estimated to identify precision and is located in 4 measuring points (bladder, prostate, rectal anterior wall and rectal posterior wall) to analyzed treatment planning and measured value. Results : Prostate volume and rectum volume of prostate cancer patient represent 30.61 cc and 51.19 cc respectively. In case of a phantom, prostate volume and rectum volume represent 31.12 cc and 53.52 cc respectively. A variation of volume between a prostate cancer patient and a phantom is less than 3%. Precision of MOSFET represents less than 3%. It indicates linearity and correlation coefficient indicates from 0.99 ~ 1.00 depending on dose variation. Each accuracy of bladder, prostate, rectal anterior wall and rectal posterior wall represent 1.4%, 2.6%, 3.7% and 1.5% respectively. In- vivo dosimetry represents entirely less than 5% considering precision of MOSFET. Conclusion : By using a 3D printer, possibility of phantom production based on prostate is verified precision within 3%. effectiveness of In-vivo dosimetry is confirmed from a phantom which is produced by a 3D printer. In-vivo dosimetry is evaluated entirely less than 5% considering precision of MOSFET. Therefore, This study is confirmed the usefulness of a 3D printed phantom for in-vivo dosimetry of a prostate cancer patient. It is necessary to additional phantom production by a 3D printer and In-vivo dosimetry for other organs of patient.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1389-1393
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• 2012

Objective: To discuss the significance of DOG1, CD117 and PDGFRA in the diagnosis of gastrointestinal stromal tumors (GISTs), and analyze their correlations with clinicopathological features and risk ranking. Method: DOG1, CD117 and PDGFRA were detected with IHC Envision ldpe-g-nvp in 63 GISTs and 43 cases of non-GISTs, and analyzed for relations with clinicopathological factors (gender, age, location, tumor size, mitotic phase, histology) and risk degree. Results: The positive expression rate of DOG1, CD117 and PDGFRA in GISTs was 84.1% (53/63), 90.5% (57/63), 53.2% (33/63), respectively. Among the 6 CD117 negative cases, all were DOG1 positive and 5 were PDGFRA positive. Rates in patients with non-GISTs was 11.6%, 16.3%, 6.98%, respectively. Expression of DOG1 and PDGFRA demonstrated no significant variation with gender, age, position, tumor size, mitotic phase, histology, and risk rank. However, CD117 was related with position and histology (P=0.008 and P=0.045), those in the mesentery having a higher positive rate than those derived from stomach, small intestine, colon and rectum (50.0% vs 94.7%, P=0.008). Furthermore CD117 was also highly expressed in spindle and epithele types. Conclusions: DOG1 had a good sensitivity and specificity as a kind of newly discovered marker, especially for KIT negative GISTs. However, DOG1, CD117 and PDGFRA cannot be used for assessing the rish of patients.

• Journal of Biomedical Engineering Research
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• v.30 no.6
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• pp.482-488
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• 2009

Conventional devices for transanal endoscopic microsurgery that are currently used clinically for intestine or rectal cancer patients have 40 mm external diameter of rectoscope tube - induces anal damage and long-term postoperative pain for small-sized patients. In this paper, we designed rectum and rectoscope models and calculated the changing trends of operation area of the surgical tools in accordance with the step-by-step variation of design parameters of the rectoscope tube - external diameter, axial length, and distal angle. Using the results of computer simulation, we suggested an optimal set of design parameters that minimizes external diameter of the rectoscope tube and at the same time, maintains similar operation area of the surgical tools compared with commercialized devices (${\geq}\;4274.7mm^2$). The results of the simulation showed that the optimal design parameters were 35 mm external diameter, 100 mm axial length, and $45^{\circ}$ distal angle of the rectoscope tube. This result can be applied to the development of endoscopic microsurgery device that can minimize side effects to the intestine or rectal cancer patients.