• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.365-371
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• 2012

The radiation therapy treatment technique is developed from 3D-CRT, IMRT to Tomotherapy. and these three technique was most widely using methods. We find out a comparison normal tissue doses and tumor dose of 3D-CRT, IMRT(Linac Based), and Tomotherapy on Head and Neck Cancer. We achieved radiological image used the Human model phantom (Anthropomorphic Phantom) and it was taken CT simulation (Slice Thickness : 3mm) and GTV was nasopharngeal region and PTV(including set-up margin) was GTV plus 2mm area. and transfer those images to the radiation planning system (3D-CRT - ADAC-Pinnacle3, Tomotherapy - Tomotherapy Hi-Art System). The prescription dose was 7020 cGy and measuring PTV's dose and nomal tissue (parotid gland, oral cavity, spinal cord). The PTV's doses was Tomotherapy, Linac Based - IMRT, 3D-CRT was 6923 cGy, 6901 cGy and 6718 cGy its dose value was meet TCP because its value was up to the 95% based on 7020 cGy, Nomal tissue (parotid gland, oral cavity, spinal cord) was 1966 cGy(Tomotherapy), 2405 cGy(IMRT), 2468 cGy(3D-CRT)[parotid gland], 2991 cGy(Tomotherapy), 3062 cGy(IMRT), 3684 cGy (3D-CRT)[oral cavity], 1768 cGy(Tomotherapy), 2151 cGy(IMRT), 4031 cGy(3D-CRT)[spinal cord] its value did not exceeded NTCP. All the treatment techniques are equated with tumor and nomal tissue doses. The 3D-CRT was worse than other techniques on dose distribution, but it is reasonable in terms of TCP and NTCP baseline Tomotherapy, IMRT -dose distribution was relatively superior- was hard to therapy to claustrophobic patients and patients with respiratory failure. Particularly, in case on Tomotherapy, it take MVCT before treatment so dose measurement will be unnecessary radiation exposure to patients. Conclusion, Tomotherapy was the best treatment technique and 2nd was IMRT, and 3rd 3D-CRT. But applicable differently depending on the the patient's condition even though dose not matter.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.413-419
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• 2011

Purpose: Reposition of the maxilla is a common technique for correction of midfacial deformities. To achieve the goal of the surgery, the maxilla should be repositioned based on the precisely planned position during surgery. The internal reference points (IRPs) and the external reference points (ERPs) are usually used to determine vertical dimension of maxilla, which is an important factor for confirming maxillary position. However, the IRPs are known to be inaccurate in determining the vertical dimension. In this study, we investigated the correlation of positional change of the modified IRPs with repositioned maxilla. Methods: The study group consisted of 26 patients with dentofacial deformities. For the simulation of the surgery, patient maxillary CT data and 3-D virtual surgery programs (V-$Works^{(R)}$ and V-$Surgery^{(R)}$) were used. IRPs of this study were set on both the lateral wall of piriform aperture, inferior margin of both infraorbital foramen, and the labial surfaces of the canine and first molar. The distance from the point on lateral wall of the piriform aperture to the point on the buccal surface of the canine was defined as IRP-C, and the distance from the point on the inferior margin of the infraorbital foramen to the point on the buccal surface of the $1^{st}$ molar was defined as IRP-M. After the virtual simulation of Le Fort I osteotomy, the changes in IRP-C and IRP-M were compared with the maxillary movement. All measures were analyzed statistically. Results: With respect to vertical movements, the IRP-C (approximately 98%) and the IRP-M (approximately 96%) represented the movement of the canine and the $1^{st}$ molar. Regarding rotating movement, the IRPs changed according to the movement of the canine and the $1^{st}$ molar. In particular, the IRP-C was changed in accordance with the canine. Conclusion: IRPs could be good indicators for predicting vertical movements of the maxilla during surgery.

• Progress in Medical Physics
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• v.28 no.4
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• pp.207-217
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• 2017

For effective patient treatment in proton therapy, it is therefore important to accurately measure the beam range. For measuring beam range, various researchers determine the beam range by measuring the prompt gammas generated during nuclear reactions of protons with materials. However, the accuracy of the beam range determination can be lowered in heterogeneous phantoms, because of the differences with respect to the prompt gamma production depending on the properties of the material. In this research, to improve the beam range determination in a heterogeneous phantom, we derived a formula to correct the prompt-gamma distribution using the ratio of the prompt gamma production, stopping power, and density obtained for each material. Then, the prompt-gamma distributions were acquired by a multi-slit prompt-gamma camera on various kinds of heterogeneous phantoms using a Geant4 Monte Carlo simulation, and the deduced formula was applied to the prompt-gamma distributions. For the case involving the phantom having bone-equivalent material in the soft tissue-equivalent material, it was confirmed that compared to the actual range, the determined ranges were relatively accurate both before and after correction. In the case of a phantom having the lung-equivalent material in the soft tissue-equivalent material, although the maximum error before correction was 18.7 mm, the difference was very large. However, when the correction method was applied, the accuracy was significantly improved by a maximum error of 4.1 mm. Moreover, for a phantom that was constructed based on CT data, after applying the calibration method, the beam range could be generally determined within an error of 2.5 mm. Simulation results confirmed the potential to determine the beam range with high accuracy in heterogeneous phantoms by applying the proposed correction method. In future, these methods will be verified by performing experiments using a therapeutic proton beam.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.137-147
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• 2014

Purpose : The purpose of this study is to verify the accuracy of dose delivery according to the patient's breathing cycle in Gated Volumetric Modulated Arc Therapy Materials and Methods : TrueBeam STxTM(Varian Medical System, Palo Alto, CA) was used in this experiment. The Computed tomography(CT) images that were acquired with RANDO Phantom(Alderson Research Laboratories Inc. Stamford. CT, USA), using Computerized treatment planning system(Eclipse 10.0, Varian, USA), were used to create VMAT plans using 10MV FFF with 1500 cGy/fx (case 1, 2, 3) and 220 cGy/fx(case 4, 5, 6) of doserate of 1200 MU/min. The regular respiratory period of 1.5, 2.5, 3.5 and 4.5 sec and the patients respiratory period of 2.2 and 3.5 sec were reproduced with the $QUASAR^{TM}$ Respiratory Motion Phantom(Modus Medical Devices Inc), and it was set up to deliver radiation at the phase mode between the ranges of 30 to 70%. The results were measured at respective respiratory conditions by a 2-Dimensional ion chamber array detector(I'mRT Matrixx, IBA Dosimetry, Germany) and a MultiCube Phantom(IBA Dosimetry, Germany), and the Gamma pass rate(3 mm, 3%) were compared by the IMRT analysis program(OmniPro I'mRT system software Version 1.7b, IBA Dosimetry, Germany) Results : The gamma pass rates of Case 1, 2, 3, 4, 5 and 6 were the results of 100.0, 97.6, 98.1, 96.3, 93.0, 94.8% at a regular respiratory period of 1.5 sec and 98.8, 99.5, 97.5, 99.5, 98.3, 99.6% at 2.5 sec, 99.6, 96.6, 97.5, 99.2, 97.8, 99.1% at 3.5 sec and 99.4, 96.3, 97.2, 99.0, 98.0, 99.3% at 4.5 sec, respectively. When a patient's respiration was reproduced, 97.7, 95.4, 96.2, 98.9, 96.2, 98.4% at average respiratory period of 2.2 sec, and 97.3, 97.5, 96.8, 100.0, 99.3, 99.8% at 3.5 sec, respectively. Conclusion : The experiment showed clinically reliable results of a Gamma pass rate of 95% or more when 2.5 sec or more of a regular breathing period and the patient's breathing were reproduced. While it showed the results of 93.0% and 94.8% at a regular breathing period of 1.5 sec of Case 5 and 6, it could be confirmed that the accurate dose delivery could be possible on the most respiratory conditions because based on the results of 100 patients's respiratory period analysis as no one sustained a respiration of 1.5 sec. But, pretreatment dose verification should be precede because we can't exclude the possibility of error occurrence due to extremely short respiratory period, also a training at the simulation and careful monitoring are necessary for a patient to maintain stable breathing. Consequently, more reliable and accurate treatments can be administered.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.100-106
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• 2003

Purpose : To develop a patients' setup verification tool (PSVT) to verify the alignment of the machine and the target isocenters, and the reproduclbility of patients' setup for three dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT). The utilization of this system is evaluated through phantom and patient case studies. Materials and methods : We developed and clinically tested a new method for patients' setup verification, using digitally reconstructed radiography (DRR), simulation, porial and digital images. The PSVT system was networked to a Pentium PC for the transmission of the acquired images to the PC for analysis. To verify the alignment of the machine and target isocenters, orthogonal pairs of simulation images were used as verification images. Errors in the isocenter alignment were measured by comparing the verification images with DRR of CT Images. Orthogonal films were taken of all the patients once a week. These verification films were compared with the DRR were used for the treatment setup. By performing this procedure every treatment, using humanoid phantom and patient cases, the errors of localization can be analyzed, with adjustments made from the translation. The reproducibility of the patients' setup was verified using portal and digital images. Results : The PSVT system was developed to verify the alignment of the machine and the target isocenters, and the reproducibility of the patients' setup for 3DCRT and IMRT. The results show that the localization errors are 0.8$\pm$0.2 mm (AP) and 1.0$\pm$0.3 mm (Lateral) in the cases relating to the brain and 1.1$\pm$0.5 mm (AP) and 1.0$\pm$0.6 mm (Lateral) in the cases relating to the pelvis. The reproducibility of the patients' setup was verified by visualization, using real-time image acquisition, leading to the practical utilization of our software Conclusions : A PSVT system was developed for the verification of the alignment between machine and the target isocenters, and the reproduclbility of the patients' setup in 3DCRT and IMRT. With adjustment of the completed GUI-based algorithm, and a good quality DRR image, our software may be used for clinical applications.

• Radiation Oncology Journal
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• v.24 no.2
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• pp.81-87
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• 2006

Purose: This study is to evaluate the xerostomia following 3-dimensional conformal radiation therapy (3D CRT) in nasopharynx cancer patients using the xerostomia questionnaire score (XQS). Materials and Methods: Questionnaire study was done on 51 patients with nasopharynx cancer who received 3D CRT from Dec. 2000 to Aug. 2005. 3D CRT technique is based on 'serial shrinking field' concept by 3 times of computed tomography (CT) simulation. Total target dose to the primary tumor was 72 Gy with 1.8 Gy daily fractions. Xerostomia was assessed with 4-questions XQS, and the associations between XQS and time elapsed after RT, age, sex, stage, concurrent chemotherapy, and parotid dose were analyzed. Results: Concurrent chemotherapy was given to 40 patients and RT alone was given to 11 patients. The median time elapsed after 3D CRT was 20 ($1{\sim}58$) months and the mean XQS of all 51 patients was $8.4{\pm}1.9\;(6{\sim}14)$. XQS continuously and significantly decreased over time after 3D CRT ($X^2$=-0.484, p<0.05). There was no significant difference in XQS according to sex, age, and stag. However, XQS of concurrent chemotherapy patients was significantly higher than RT alone patients (P=0.001). XQS of patients receiving total mean parotid dose ${\ge}35 Gy$ was significantly higher than <35 Gy (p=0.05). Decreasing tendency of XQS over time after 3D CRT was observed. Concurrent chemotherapy and total mean parotid dose ${\ge}35 Gy$ were suggested to adversely affect radiation-induced xerostomia.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.189-196
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• 2012

Purpose: The sufficiency of skin dose and the reemergence of patient set-up position to the success of skin cancer radiation treatment is a very important element. But the conventional methods to increase the skin dose were used to vacuum cushion, bolus and water tank have several weak points. For this reason, we producted Foxtail Millet Vacuum Cushion and evaluated the efficiency of the Foxtail Millet Vacuum Cushion in skin cancer Radiation treatment. Materials and Methods: We measured absolute dose for 3 materials (Foxtail Millet Vacuum Cushion, bolus and solid water phantom) and compared each dose distribution. We irradiated 6 MV 100 MU photon radiation to every material of 1 cm, 2 cm, 3 cm thickness at three times. We measured absolute dose and compared dose distribution. Finally we inspected the CT simulation and radiation therapy planing using the Foxtail Millet Vacuum Cushion. Results: Absolute dose of Foxtail Millet Vacuum Cushion was similar to absolute dose of bolus and solid water phantom's result in each thickness. it Showed only the difference of 0.1~0.2% between each material. Also the same result in dose distribution comparison. About 97% of the dose distribution was within the margin of error in the prescribed ranges ($100{\pm}3%$), and achieved the enough skin dose (Gross Tumor Volume dose : $100{\pm}5%$) in radiation therapy planing. Conclusion: We evaluated important fact that Foxtail Millet Vacuum Cushion is no shortage of time to replace the soft tissue equivalent material and normal vacuum cushion at the low energy radiation transmittance. Foxtail Millet Vacuum Cushion can simultaneously achieve the enough skin dose in radiation therapy planing with maintaining normal vacuum cushion' function. Therefore as above We think that Foxtail Millet Vacuum Cushion is very useful in skin cancer radiation treatment.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.25-29
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• 2008

Purpose: To monitor the changes of location of prostate gland using DIPS and to examine the adjustment and proton beam therapy depending on the movement of prostate gland in proton beam therapy for prostate gland in which a fiducial gold marker was inserted. Materials and Methods: This study was conducted in ten patients with prostate cancer who received proton beam therapy since April of 2008. To monitor the change of prostate location, three fiducial gold markers were inserted prior to the treatment. To minimize the movement of prostate gland, patients were recommended to urinate prior to the treatment, to intake a certain amount of water and to concomitantly undergo rectal balloon. In these patients, the set-up position was identical to that for a CT-simulation. The PA (posterior-anterior) and lateral images were obtained using both DIPS (digital image positioning system) and a plain radiography, and they were compared between the two imaging modalities. Thus, the changes of the location of fiducial gold marker were assessed based on three coordinates (x, y, z) and then adjusted. This was followed by proton beam therapy. Results: Images which were taken using a plain radiography were compared with those which were taken using DIPS. In ten patients, according to a reference bony marker, the mean changes of the location of fiducial gold marker based on an iso-center were X-axis: $\pm$0.116 cm, Y-axis: $\pm$0.19 cm and Z-axis: $\pm$0.176 cm. These ten patients showed a difference in the changes of location of prostate gland and it ranged between RT: 0.04 cm and RT: 0.24 cm on the X-axis; between Inf: 0.03 cm and Sup: 0.42 cm on the Y-axis; and Post: 0.05 cm and Ant: 0.35 cm on the Z-axis. Conclusion: To minimize the movement of prostate gland, as the pre-treatment prior to the treatment. In all the patients, however, three fiducial gold markers showed a daily variation which were inserted in the prostate gland. Based on the above data, Thus, the requirement of gold marker matching system depending on the daily variation in the proton beam therapy for which more accurate establishment of target was confirmed. It is assumed that an accurate effect of proton beam therapy would be enhanced by adjusting the target-center depending on the location change of prostate gland using DIPS which was used in the current study.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.149-159
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• 2016

Purpose : To evaluate the usefulness of the breathing exercise,we analyzed the change in the RPM signal and the diaphragm imagebefore 4D respiratory gated radiation therapy planning of lung cancer patients. Materials and Methods : The breathing training was enforced on 11 patients getting the 4D respiratory gated radiation therapy from April, 2016 until August. At the same time, RPM signal and diaphragm image was obtained respiration training total three steps in step 1 signal acquisition of free-breathing state, 2 steps respiratory signal acquisition through the guide of the respiratory signal, 3 steps, won the regular respiration signal to the description and repeat training. And then, acquired the minimum value, maximum value, average value, and a standard deviation of the inspiration and expiration in RPM signal and diaphragm image in each steps. Were normalized by the value of the step 1, to convert the 2,3 steps to the other distribution ratio (%), by evaluating the change in the interior of the respiratory motion of the patient, it was evaluated breathing exercise usefulness of each patient. Results : The mean value and the standard deviation of each step were obtained with the procedure 1 of the RPM signal and the diaphragm amplitude as a 100% reference. In the RPM signal, the amplitudes and standard deviations of four patients (36.4%, eleven) decreased by 18.1%, 27.6% on average in 3 steps, and 2 patients (18.2%, 11 people) had standard deviation, It decreased by an average of 36.5%. Meanwhile, the other four patients (36.4%, eleven) decreased by an average of only amplitude 13.1%. In Step 3, the amplitude of the diaphragm image decreased by 30% on average of 9 patients (81.8%, 11 people), and the average of 2 patients (18.2%, 11 people) increased by 7.3%. However, the amplitudes of RPM signals and diaphragm image in 3steps were reduced by 52.6% and 42.1% on average from all patients, respectively, compared to the 2 steps. Relationship between RPM signal and diaphragm image amplitude difference was consistent with patterns of movement 1, 2 and 3steps, respectively, except for No. 2 No. 10 patients. Conclusion : It is possible to induce an optimized respiratory cycle when respiratory training is done. By conducting respiratory training before treatment, it was possible to expect the effect of predicting the movement of the lung which could control the patient's respiration. Ultimately, it can be said that breathing exercises are useful because it is possible to minimize the systematic error of radiotherapy, expect more accurate treatment. In this study, it is limited to research analyzed based on data on respiratory training before treatment, and it will be necessary to verify with the actual CT plan and the data acquired during treatment in the future.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.44-65
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• 2003

Purpose : To conduct nationwide surgery on the principles In radiotherapy for rectal center, and develop the framework of a database of Korean Patterns of Care Study. Materials and Methods : A consensus committee was established to develop a tool for measuring the Patterns in radiotherapy Protocols for rectal cancer. The Panel was composed of radiation oncologists from 18 hospitals in Seoul Wetropolltan area. The committee developed a survey format to analyze radiation oncologist's treatment principles for rectal cancer. The survey items developed for measuring the treatment principles were composed of 1) 8 eliglblllty criteria, 2) 20 Items for staging work-ups and prognostic factors, 3) 7 Items for principles of combined surgery and chemotherapy, 4) 9 patient set-ups, 5) 19 determining radiation fields, 6) S radiotherapy treatment pians, 7) 4 physicalilaboratory examination to monitor a patient's condition during treatment, and 8) 10 follow-up evaluations. These items were sent to radiation oncoioglsts In charge of gastrolntestlnal malignancies in all hospitals (48 hospitals) In Korea to which 30 replies were received (63$\%$). Results : Most of the surrey Items were replied to without no major between the repliers, but with the fellowing items only 50$\%$ of repliers were in agreement : 1) Indications of preoperative radiation, 2) use of endorectal ultrasound, CT scan, and bone scan for staging work-ups, 3) principles of combining chemotherapy with radiotherapy, 4) use of contrast material for small bowel delineation during simulation, 5) determination of field margins, and 6) use of CEA and colonoscopy for follow-up evaluations. Conclusions : The Items where considerable disaggrement was shown among the radiation oncologists seemed to make no serious difference In the treatment outcome, but a practical and reasonable consensus should be reached by the committee, with logical processes of agreement. These Items can be used for a basic database for the Patterns of Care Study, which will survey the practical radiotherapy Patterns for rectal cancer in Korea.