Chiyoung Jeong
University of Ulsan
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Publication
Featured researches published by Chiyoung Jeong.
Journal of Biomedical Optics | 2013
Kyoung Won Jang; Takahiro Yagi; Cheol Ho Pyeon; Wook Jae Yoo; Sang Hun Shin; Chiyoung Jeong; Byung Jun Min; Dongho Shin; Tsuyoshi Misawa; Bongsoo Lee
Abstract. A Cerenkov fiber-optic dosimeter (CFOD) is fabricated using plastic optical fibers to measure Cerenkov radiation induced by a therapeutic photon beam. We measured the Cerenkov radiation generated in optical fibers in various irradiation conditions to evaluate the usability of Cerenkov radiation for a photon beam therapy dosimetry. As a results, the spectral peak of Cerenkov radiation was measured at a wavelength of 515 nm, and the intensity of Cerenkov radiation increased linearly with increasing irradiated length of the optical fiber. Also, the intensity peak of Cerenkov radiation was measured in the irradiation angle range of 30 to 40 deg. In the results of Monte Carlo N-particle transport code simulations, the relationship between fluxes of electrons over Cerenkov threshold energy and energy deposition of a 6 MV photon beam had a nearly linear trend. Finally, percentage depth doses for the 6 MV photon beam could be obtained using the CFOD and the results were compared with those of an ionization chamber. Here, the mean dose difference was about 0.6%. It is anticipated that the novel and simple CFOD can be effectively used for measuring depth doses in radiotherapy dosimetry.
PLOS ONE | 2018
Hyekyun Chung; Jinhong Jung; Chiyoung Jeong; Jungwon Kwak; Jin-hong Park; Su Ssan Kim; Sang Min Yoon; Si Yeol Song; Jong Hoon Kim; Eun Kyung Choi; Seungryong Cho; Byungchul Cho
Purpose To develop a 4D dose reconstruction method and to evaluate the delivered dose in respiratory-gated volumetric modulated arc therapy (VMAT). Materials and methods A total 112 treatment sessions of gated VMAT for 30 stereotactic body radiotherapy (SBRT) patients (10 lung, 10 liver, and 10 pancreas) were evaluated. For respiratory-gated SBRT, 4DCT was acquired, and the CT data at the end-exhale phase was used for a VMAT plan. The delivered dose was reconstructed using a patient’s respiratory motion and machine motion acquired during the beam delivery. The machine motion was obtained from the treatment log file, while the target position was estimated from an external respiratory marker position. The target position was divided into 1-mm position bins, and sub-beams with beam isocenters corresponding to each position bin were created in a motion mimicking plan, reflecting motion data including MLC leaf positions and gantry angle and target position data during beam treatment. The reconstructed 4D dose was compared with the dose of the original plan using these dosimetric parameters; the maximum dose (Dmax) and mean dose (Dmean) of gross target volume (GTV) or organs at risk (spinal cord, esophagus, heart, duodenum, kidney, spinal cord, and stomach). The minimum dose (Dmin) to GTV was also calculated to verify cold spots in tumors. Results There was no significant difference of dose parameters regard to the GTV in all tumors. For the liver cases, there were significant differences in the Dmax of duodenum (-4.2 ± 1.4%), stomach (-3.5 ± 4.2%), left kidney (-4.1 ± 2.8%), and right kidney (-3.2 ± 1.3%), and in the Dmean of duodenum (-3.8 ± 1.4%), stomach (-3.9 ± 2.2%), left kidney (-3.1 ± 2.8%), and right kidney (-4.1 ± 2.6%). For the pancreas cases, there were significant differences in the Dmax of stomach (2.1 ± 3.0%), and in the Dmean of liver (1.5 ± 0.6%), duodenum (-1.0 ± 1.4%), stomach (2.1 ± 1.6%), and right kidney (-1.3 ± 0.9%). The average gamma pass rates were 97.6 ± 4.8% for lung cases, 99.6 ± 0.5% for liver cases, and 99.5 ± 0.5% for pancreas cases. Most cases showed insignificant dose variation, with gamma pass rates higher than 98%, except for two lung cases with gamma pass rates of 86.9% and 90.6%. The low gamma pass rates showed larger global motion ranges resulting from the baseline shift during beam delivery. Conclusion The actual delivered dose in thoracic and abdominal VMAT under breathing motion was verified by 4D dose reconstruction using typical treatment equipment and software. The proposed method provides a verification method for the actual delivered dose and could be a dosimetric verification QA tool for radiation treatment under various respiratory management techniques.
Journal of Applied Clinical Medical Physics | 2016
Ui-Jung Hwang; Kwanghyun Jo; Young Kyung Lim; Jung Won Kwak; Sang Hyoun Choi; Chiyoung Jeong; Mi Young Kim; Jong Hwi Jeong; Dongho Shin; Se Byeong Lee; Jeong-Hoon Park; Sung Yong Park; Siyong Kim
The aim of this study is to develop a new method to align the patient setup lasers in a radiation therapy treatment room and examine its validity and efficiency. The new laser alignment method is realized by a device composed of both a metallic base plate and a few acrylic transparent plates. Except one, every plate has either a crosshair line (CHL) or a single vertical line that is used for alignment. Two holders for radiochromic film insertion are prepared in the device to find a radiation isocenter. The right laser positions can be found optically by matching the shadows of all the CHLs in the gantry head and the device. The reproducibility, accuracy, and efficiency of laser alignment and the dependency on the position error of the light source were evaluated by comparing the means and the standard deviations of the measured laser positions. After the optical alignment of the lasers, the radiation isocenter was found by the gantry and collimator star shots, and then the lasers were translated parallel to the isocenter. In the laser position reproducibility test, the mean and standard deviation on the wall of treatment room were 32.3±0.93 mm for the new method whereas they were 33.4±1.49 mm for the conventional method. The mean alignment accuracy was 1.4 mm for the new method, and 2.1 mm for the conventional method on the walls. In the test of the dependency on the light source position error, the mean laser position was shifted just by a similar amount of the shift of the light source in the new method, but it was greatly magnified in the conventional method. In this study, a new laser alignment method was devised and evaluated successfully. The new method provided more accurate, more reproducible, and faster alignment of the lasers than the conventional method. PACS numbers: 87.56.Fc, 87.53.Bn, 87.53.Kn, 87.53.Ly, 87.55.GhThe aim of this study is to develop a new method to align the patient setup lasers in a radiation therapy treatment room and examine its validity and efficiency. The new laser alignment method is realized by a device composed of both a metallic base plate and a few acrylic transparent plates. Except one, every plate has either a crosshair line (CHL) or a single vertical line that is used for alignment. Two holders for radiochromic film insertion are prepared in the device to find a radiation isocenter. The right laser positions can be found optically by matching the shadows of all the CHLs in the gantry head and the device. The reproducibility, accuracy, and efficiency of laser alignment and the dependency on the position error of the light source were evaluated by comparing the means and the standard deviations of the measured laser positions. After the optical alignment of the lasers, the radiation isocenter was found by the gantry and collimator star shots, and then the lasers were translated parallel to the isocenter. In the laser position reproducibility test, the mean and standard deviation on the wall of treatment room were 32.3±0.93 mm for the new method whereas they were 33.4±1.49 mm for the conventional method. The mean alignment accuracy was 1.4 mm for the new method, and 2.1 mm for the conventional method on the walls. In the test of the dependency on the light source position error, the mean laser position was shifted just by a similar amount of the shift of the light source in the new method, but it was greatly magnified in the conventional method. In this study, a new laser alignment method was devised and evaluated successfully. The new method provided more accurate, more reproducible, and faster alignment of the lasers than the conventional method. PACS numbers: 87.56.Fc, 87.53.Bn, 87.53.Kn, 87.53.Ly, 87.55.Gh.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms | 2010
June-Dong Kim; C.H. Shin; Chiyoung Jeong; Yong-Jai Kwon; J.H. Park; Daeil Kim
Radiation Oncology | 2015
Ji Hyeon Joo; Su Ssan Kim; Seung Do Ahn; Jungwon Kwak; Chiyoung Jeong; Sei-Hyun Ahn; Bh Son; Jong Won Lee
Brachytherapy | 2017
Youngkyong Kim; Yeonjoo Kim; Joo-Young Kim; Young Kyung Lim; Chiyoung Jeong; Jonghwi Jeong; Meyoung Kim; Myong Cheol Lim; Sang-Soo Seo; Sang-Yoon Park
Strahlentherapie Und Onkologie | 2016
Yeonjoo Kim; Joo-Young Kim; Youngkyong Kim; Young Kyung Lim; Jonghwi Jeong; Chiyoung Jeong; Meyoung Kim; Myong Cheol Lim; Sang-Soo Seo; Sang-Yoon Park
Strahlentherapie Und Onkologie | 2016
Kim Yj; Joo-Young Kim; Y. Kim; Young Kyung Lim; Jonghwi Jeong; Chiyoung Jeong; Mi Kyung Kim; Myung-Chul Lim; Sang-Soo Seo; S.-Y. Park
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms | 2015
J.I. Shin; Seyjoon Park; Haksoo Kim; Meyoung Kim; Chiyoung Jeong; Sungkoo Cho; Young Kyung Lim; Dongho Shin; Se Byeong Lee; K. Morishima; N. Naganawa; O. Sato; Jungwon Kwak; Sung Hyun Kim; Jung Sook Cho; Jung Keun Ahn; Ji Hyun Kim; Chun Sil Yoon; S. Incerti
Physics in Medicine and Biology | 2013
Seyjoon Park; Chiyoung Jeong; Dong Yun Kang; Jae-ik Shin; Sungkoo Cho; Jeonghoon Park; Dongho Shin; Young Kyung Lim; Joo-Young Kim; Byung Jun Min; Jungwon Kwak; Jiseoc Lee; Seungryong Cho; Dae-Hyun Kim; Sung Yong Park; Se Byeong Lee