1.Evaluating the Influence of Scan Timing on Dosimetric Accuracy in EBT3 and EBT4 Radiochromic Films
Jin Dong CHO ; Su Chul HAN ; Jason Joon Bock LEE ; Hyebin LEE ; Heerim NAM
Progress in Medical Physics 2024;35(4):135-144
Purpose:
This study compares the dosimetric properties of EBT3 and EBT4 GAFchromic films in transmission and reflection scanning modes, focusing on dose response, sensitivity, and postirradiation stability.
Methods:
The EBT3 and EBT4 films were irradiated at doses of 0–10 Gy using a Varian TrueBeam linear accelerator at 6 MV. The films were scanned at intervals between 1 and 336 hours after irradiation in both transmission and reflection modes. Net optical density (NetOD) values from each scan were used to evaluate dose response and sensitivity, with calibration curves created for each film and scan mode. Dose differences between calculated and delivered doses were assessed over time.
Results:
The EBT3 and EBT4 films exhibited similar dose–response curves and stable NetOD values across both scanning modes. However, EBT4 exhibited reduced sensitivity variability in response to dose changes. After irradiation, NetOD values increased up to 24 hours before stabilizing, suggesting that a 24-hour scan time is sufficient for consistent measurements. Dose differences between films and modes remained within ±4%.
Conclusions
EBT4 offers comparable dosimetric performance to EBT3, with additional benefits, such as improved dose–response linearity and reduced sensitivity fluctuations. The findings indicate that EBT4 can serve as a reliable successor to EBT3.
2.Evaluating the Influence of Scan Timing on Dosimetric Accuracy in EBT3 and EBT4 Radiochromic Films
Jin Dong CHO ; Su Chul HAN ; Jason Joon Bock LEE ; Hyebin LEE ; Heerim NAM
Progress in Medical Physics 2024;35(4):135-144
Purpose:
This study compares the dosimetric properties of EBT3 and EBT4 GAFchromic films in transmission and reflection scanning modes, focusing on dose response, sensitivity, and postirradiation stability.
Methods:
The EBT3 and EBT4 films were irradiated at doses of 0–10 Gy using a Varian TrueBeam linear accelerator at 6 MV. The films were scanned at intervals between 1 and 336 hours after irradiation in both transmission and reflection modes. Net optical density (NetOD) values from each scan were used to evaluate dose response and sensitivity, with calibration curves created for each film and scan mode. Dose differences between calculated and delivered doses were assessed over time.
Results:
The EBT3 and EBT4 films exhibited similar dose–response curves and stable NetOD values across both scanning modes. However, EBT4 exhibited reduced sensitivity variability in response to dose changes. After irradiation, NetOD values increased up to 24 hours before stabilizing, suggesting that a 24-hour scan time is sufficient for consistent measurements. Dose differences between films and modes remained within ±4%.
Conclusions
EBT4 offers comparable dosimetric performance to EBT3, with additional benefits, such as improved dose–response linearity and reduced sensitivity fluctuations. The findings indicate that EBT4 can serve as a reliable successor to EBT3.
3.Evaluating the Influence of Scan Timing on Dosimetric Accuracy in EBT3 and EBT4 Radiochromic Films
Jin Dong CHO ; Su Chul HAN ; Jason Joon Bock LEE ; Hyebin LEE ; Heerim NAM
Progress in Medical Physics 2024;35(4):135-144
Purpose:
This study compares the dosimetric properties of EBT3 and EBT4 GAFchromic films in transmission and reflection scanning modes, focusing on dose response, sensitivity, and postirradiation stability.
Methods:
The EBT3 and EBT4 films were irradiated at doses of 0–10 Gy using a Varian TrueBeam linear accelerator at 6 MV. The films were scanned at intervals between 1 and 336 hours after irradiation in both transmission and reflection modes. Net optical density (NetOD) values from each scan were used to evaluate dose response and sensitivity, with calibration curves created for each film and scan mode. Dose differences between calculated and delivered doses were assessed over time.
Results:
The EBT3 and EBT4 films exhibited similar dose–response curves and stable NetOD values across both scanning modes. However, EBT4 exhibited reduced sensitivity variability in response to dose changes. After irradiation, NetOD values increased up to 24 hours before stabilizing, suggesting that a 24-hour scan time is sufficient for consistent measurements. Dose differences between films and modes remained within ±4%.
Conclusions
EBT4 offers comparable dosimetric performance to EBT3, with additional benefits, such as improved dose–response linearity and reduced sensitivity fluctuations. The findings indicate that EBT4 can serve as a reliable successor to EBT3.
4.Postoperative Thoracic Cord Compression Induced by a Dural Sealant System (DuraSeal®): A Case Report and Literature Review
Dong Soon JANG ; Seung Hun SHEEN ; Inbo HAN ; Soo Hyun LEE ; Woo Seok CHOI ; Minsung BOCK ; Seil SOHN
The Nerve 2024;10(1):57-62
Cerebrospinal fluid (CSF) leakage is a rare complication that can occur due to dural defects during spinal surgery, hindering the improvement of the surgical site and increasing the possibility of infection. DuraSeal® is a dural sealing adhesive that prevents CSF leakage and is used as an adjunct to enable the watertight repair of dural defects when the dura is damaged during spinal surgery. In the present case, DuraSeal® was applied to repair a dural defect in the surgical area after thoracic spine surgery, and no neurological problems occurred immediately after surgery. However, a day later, the patient’s paraparesis worsened; therefore, reoperation was performed and the symptoms improved.
5.Evaluating the Influence of Scan Timing on Dosimetric Accuracy in EBT3 and EBT4 Radiochromic Films
Jin Dong CHO ; Su Chul HAN ; Jason Joon Bock LEE ; Hyebin LEE ; Heerim NAM
Progress in Medical Physics 2024;35(4):135-144
Purpose:
This study compares the dosimetric properties of EBT3 and EBT4 GAFchromic films in transmission and reflection scanning modes, focusing on dose response, sensitivity, and postirradiation stability.
Methods:
The EBT3 and EBT4 films were irradiated at doses of 0–10 Gy using a Varian TrueBeam linear accelerator at 6 MV. The films were scanned at intervals between 1 and 336 hours after irradiation in both transmission and reflection modes. Net optical density (NetOD) values from each scan were used to evaluate dose response and sensitivity, with calibration curves created for each film and scan mode. Dose differences between calculated and delivered doses were assessed over time.
Results:
The EBT3 and EBT4 films exhibited similar dose–response curves and stable NetOD values across both scanning modes. However, EBT4 exhibited reduced sensitivity variability in response to dose changes. After irradiation, NetOD values increased up to 24 hours before stabilizing, suggesting that a 24-hour scan time is sufficient for consistent measurements. Dose differences between films and modes remained within ±4%.
Conclusions
EBT4 offers comparable dosimetric performance to EBT3, with additional benefits, such as improved dose–response linearity and reduced sensitivity fluctuations. The findings indicate that EBT4 can serve as a reliable successor to EBT3.
6.Evaluating the Influence of Scan Timing on Dosimetric Accuracy in EBT3 and EBT4 Radiochromic Films
Jin Dong CHO ; Su Chul HAN ; Jason Joon Bock LEE ; Hyebin LEE ; Heerim NAM
Progress in Medical Physics 2024;35(4):135-144
Purpose:
This study compares the dosimetric properties of EBT3 and EBT4 GAFchromic films in transmission and reflection scanning modes, focusing on dose response, sensitivity, and postirradiation stability.
Methods:
The EBT3 and EBT4 films were irradiated at doses of 0–10 Gy using a Varian TrueBeam linear accelerator at 6 MV. The films were scanned at intervals between 1 and 336 hours after irradiation in both transmission and reflection modes. Net optical density (NetOD) values from each scan were used to evaluate dose response and sensitivity, with calibration curves created for each film and scan mode. Dose differences between calculated and delivered doses were assessed over time.
Results:
The EBT3 and EBT4 films exhibited similar dose–response curves and stable NetOD values across both scanning modes. However, EBT4 exhibited reduced sensitivity variability in response to dose changes. After irradiation, NetOD values increased up to 24 hours before stabilizing, suggesting that a 24-hour scan time is sufficient for consistent measurements. Dose differences between films and modes remained within ±4%.
Conclusions
EBT4 offers comparable dosimetric performance to EBT3, with additional benefits, such as improved dose–response linearity and reduced sensitivity fluctuations. The findings indicate that EBT4 can serve as a reliable successor to EBT3.
7.National Surgical Site Infection Surveillance System Results Report: July 2021 through June 2022
Jung Wan PARK ; Young Keun KIM ; Yoon-soo PARK ; Hong Bin KIM ; Jun Yong CHOI ; Hee Jung CHOI ; Chung Jong KIM ; Jeong Su PARK ; Shinwon LEE ; Yong Chan KIM ; Seong Jin CHOI ; Jongtak JUNG ; Sunggyun PARK ; Su Ha HAN ; Su Young KIM ; Su Hyun KIM ; Hee Jung SON ; Min Hee CHO ; Bock-Hui YOUN ; Jeong Hwa YEON ; Kyoung-Ho SONG
Korean Journal of healthcare-associated Infection Control and Prevention 2024;29(1):48-58
Background:
This report presents annual data from the surgical site infection (SSI) module of the Korean National Healthcare-associated Infections Surveillance System (KONIS) from July 2021 to June 2022.
Methods:
Surveillance of 20 surgeries (e.g., stomach, colon, rectal, gallbladder surgery, knee replacement, hip replacement, craniotomy, ventricular shunts, spinal fusion, laminectomy, cardiac artery bypass grafting - incision in the chest site only and incisions both the chest and donor site, cardiac, prostatectomy, abdominal hysterectomy, vaginal hysterectomy, appendectomy, thoracic, cesarean section, and head and neck surgeries) associated with SSI was performed between July 1, 2021, and June 30, 2022, according to the KONIS Manual 2020.
Results:
A total of 133,281 surgical cases were collected and 1,100 SSIs were identified, resulting in a SSI rate of 0.83%. The SSI rates for 30-day surveillance surgeries were 1.9% for stomach, 2.82% for colon, 1.88% for rectal, 0.29% for gallbladder, 0.25% for lumbar laminectomy, 0.33% for cesarean section, 0.67% for abdominal hysterectomy, 0.74% for vaginal hysterectomy, 0.23% for prostatectomy, 1.39% for appendectomy, and 0.06% for thoracic surgeries. Neck surgery could not be analyzed due to no reported cases. The SSI rates for the 90-day surveillance surgeries were 0.16% for knee replacement, 0.54% for hip replacement, 0.89% for spinal fusion, 0.70% for craniotomy, 0.92% for ventricular shunt, 1.13% for cardiac, 1.80% for cardiac artery bypass grafting (chest only incision), and 1.64% for cardiac artery bypass grafting (chest and leg incision) surgeries. In total, 608 strains were isolated and cultured from 1,286 infections.
Conclusion
Compared with the incidence of SSI (1.06%) in 2018, the overall incidence decreased, and most site-specific infection rates decreased or remained the same.
8.Increased Radiosensitivity of Solid Tumors Harboring ATM and BRCA1/2 Mutations
Kyung Hwan KIM ; Han Sang KIM ; Seung-seob KIM ; Hyo Sup SHIM ; Andrew Jihoon YANG ; Jason Joon Bock LEE ; Hong In YOON ; Joong Bae AHN ; Jee Suk CHANG
Cancer Research and Treatment 2022;54(1):54-64
Purpose:
Preclinical data indicate that response to radiotherapy (RT) depends on DNA damage repair. In this study, we investigated the role of mutations in genes related to DNA damage repair in treatment outcome after RT.
Materials and Methods:
Patients with solid tumor who participated in next generation sequencing panel screening using biopsied tumor tissue between October 2013 and February 2019 were reviewed and 97 patients that received RT were included in this study. Best response to RT and the cumulative local recurrence rate (LRR) were compared according to absence or presence of missense, nonsense, and frameshift mutations in ATM and/or BRCA1/2.
Results:
Of the 97 patients, five patients harbored mutation only in ATM, 22 in only BRCA1/2, and six in both ATM and BRCA1/2 (ATMmtBRCAmt). Propensity score matching was performed to select the control group without mutations (ATMwtBRCAwt, n=33). In total, 90 RT-treated target lesions were evaluated in 66 patients. Highest objective response rate of 80% was observed in ATMmtBRCAmt lesions (p=0.007), which was mostly durable. Furthermore, the cumulative 1-year LRR was the lowest in ATMmtBRCAmt lesions and the highest in ATMwtBRCAwt lesions (0% vs. 47.9%, p=0.008). RT-associated toxicities were observed in 10 treatments with no significant difference among the subgroups (p=0.680).
Conclusion
Tumors with ATM and BRCA1/2 mutations exhibited superior tumor response and local control after RT compared to tumors without these mutations. The results are hypothesis generating and suggest the need for integrating the tumor mutation profile of DNA repair genes during treatment planning.
9.Salivary microbiota in periodontal health and disease and their changes following nonsurgical periodontal treatment
Youngkyung KO ; Eun-Mi LEE ; Joo Cheol PARK ; Man Bock GU ; Seongmin BAK ; Suk JI
Journal of Periodontal & Implant Science 2020;50(3):171-182
Purpose:
The aims of this study were to examine the salivary microbiota in conditions of periodontal health and disease and to explore microbial changes following nonsurgical periodontal treatment.
Methods:
Non-stimulated saliva samples were collected from 4 periodontally healthy participants at baseline and from 8 patients with chronic periodontitis at baseline and 3 months following nonsurgical periodontal therapy. The V3 and V4 regions of the 16S rRNA gene from the DNA of saliva samples were amplified and sequenced. The salivary microbial compositions of the healthy participants and patients with periodontitis prior to and following nonsurgical treatment of periodontitis were compared based on the relative abundance of various taxa.
Results:
On average, 299 operational taxonomic units were identified in each sample. The phylogenetic diversity in patients with periodontitis was higher than that in healthy participants and decreased following treatment. The abundance of the phylum Spirochaetes and the genus Treponema in patients with periodontitis was 143- and 134-fold higher than in the healthy control group, respectively, but decreased significantly following treatment. The species that were overabundant in the saliva of patients with periodontitis included the Peptostreptococcus stomatis group, Porphyromonas gingivalis, the Fusobacterium nucleatum group, Parvimonas micra, Porphyromonas endodontalis, Filifactor alocis, and Tannerella forsythia. The phylum Actinobacteria, the genus Streptococcaceae_uc, and the species Streptococcus salivarius group were more abundant in healthy participants than in those with periodontitis. There was a trend toward a decrease in disease-associated taxa and an increase in health-associated taxa following treatment.
Conclusions
Our results revealed differences in the taxa of salivary microbiota between conditions of periodontal health and disease. The taxa found to be associated with health or disease have potential for use as salivary biomarkers for periodontal health or disease.
10.Predictive factors of symptomatic radiation pneumonitis in primary and metastatic lung tumors treated with stereotactic ablative body radiotherapy.
Kangpyo KIM ; Jeongshim LEE ; Yeona CHO ; Seung Yeun CHUNG ; Jason Joon Bock LEE ; Chang Geol LEE ; Jaeho CHO
Radiation Oncology Journal 2017;35(2):163-171
PURPOSE: Although stereotactic ablative body radiotherapy (SABR) is widely used therapeutic technique, predictive factors of radiation pneumonitis (RP) after SABR remain undefined. We aimed to investigate the predictive factors affecting RP in patients with primary or metastatic lung tumors who received SABR. MATERIALS AND METHODS: From 2012 to 2015, we reviewed 59 patients with 72 primary or metastatic lung tumors treated with SABR, and performed analyses of clinical and dosimetric variables related to symptomatic RP. SABR was delivered as 45–60 Gy in 3–4 fractions, which were over 100 Gy in BED when the α/β value was assumed to be 10. Tumor volume and other various dose volume factors were analyzed using median value as a cutoff value. RP was graded per the Common Terminology Criteria for Adverse Events v4.03. RESULTS: At the median follow-up period of 11 months, symptomatic RP was observed in 13 lesions (12 patients, 18.1%), including grade 2 RP in 11 lesions and grade 3 in 2 lesions. Patients with planning target volume (PTV) of ≤14.35 mL had significantly lower rates of symptomatic RP when compared to others (8.6% vs. 27%; p = 0.048). Rates of symptomatic RP in patients with internal gross tumor volume (iGTV) >4.21 mL were higher than with ≤4.21 mL (29.7% vs. 6.1%; p = 0.017). CONCLUSIONS: The incidence of symptomatic RP following treatment with SABR was acceptable with grade 2 RP being observed in most patients. iGTV over 4.21 mL and PTV of over 14.35 mL were significant predictive factors related to symptomatic RP.
Follow-Up Studies
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Humans
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Incidence
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Lung Neoplasms
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Lung*
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Radiation Pneumonitis*
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Radiotherapy*
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Risk Factors
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Tumor Burden

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