1.Extraordinary radiation super-sensitivity accompanying with sorafenib combination therapy: what lies beneath?.
Jayoung LEE ; Ju Hye LEE ; Hanbin YOON ; Ho Jeong LEE ; Hosang JEON ; Jiho NAM
Radiation Oncology Journal 2017;35(2):185-188
Primary liver tumor, especially hepatocellular carcinoma (HCC), is a common cause of cancer death worldwide. The incidence is generally higher in Asian countries than in western countries. Carcinogenesis of HCC is often associated with hepatitis viral infections. Current standard treatment of HCC is surgical resection or transplantation in patients with early stage disease. However, the patient with advanced stage disease, surgical resection is often limited. Sorafenib or other treatment modalities are not so effective as well. We report a case of unusual radiation super-sensitivity in advanced stage HCC, and review the literature.
Asian Continental Ancestry Group
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Carcinogenesis
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Carcinoma, Hepatocellular
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Hepatitis
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Humans
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Incidence
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Liver
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Radiotherapy
2.Development of a Method to Measure the Radiation Isocenter Size of Linear Accelerators and Quantitative Analysis of the Radiation Isocenter Size for Clinac 21EX Linear Accelerator.
Hosang JEON ; Jiho NAM ; Dahl PARK ; Yong Ho KIM ; Wontaek KIM ; Dongwon KIM ; Yongkan KI ; Donghyun KIM
Korean Journal of Medical Physics 2011;22(3):131-139
A method to get a size of the radiation isocenter of linear accelerators using star-shot images was presented and a computer program was developed to automate the method. Accuracy of the method was verified. The developed program was used to measure sizes of the radiation isocenters for a Clinac 21EX (Varian, USA) using data of quality assurance (QA) performed from June 2008 to December 2010. To calculated the size of radiation isocenter, positions of two points on each central ray of the star-shot image were found and the equation of the central ray was determined using the positions of two points. Using the equations of central rays the radius of the minimum circle intersecting all the central rays, which is one half of the size of radiation isocenter, was calculated. The program measured X-intercepts and y-intercepts of the central rays within errors of 0.084 mm and sizes of radiation isocenters within 0.053 mm. All the errors were less than the spatial resolution of star-shot images 0.085 mm. The radiation isocenter sizes of Clinac 21EX were 0.33+/-0.27 mm, 0.71+/-0.36 mm, 0.50+/-0.16 mm for collimator, gantry and couch respectively. During the measurement period all the measured sizes were less than 2.0 mm and within tolerance. The developed program could calculate the size of radiation isocenters and it would be helpful to routine QA.
Particle Accelerators
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Radius
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Software
3.Prognostic value of the maximum standardized uptake value for the locoregional control in early glottic cancer
Donghyun KIM ; Yongkan KI ; Jihyeon JOO ; Hosang JEON ; Dahl PARK ; Jiho NAM ; Wontaek KIM
Radiation Oncology Journal 2021;39(4):297-303
Purpose:
To evaluate the prognostic value of the pretreatment maximum standardized uptake value (SUVmax) for locoregional control (LRC) of early glottic cancer treated with primary radiotherapy.
Materials and Methods:
We retrospectively reviewed the medical records of 101 patients with T1-T2N0 glottic cancer treated with helical tomotherapy between 2013 and 2016. The clinical T-stages were T1 in 87 (86.1%) and T2 in 14 (13.9%) patients. The median total dose was 63 Gy (63–67.5 Gy) in 2.25 Gy per fraction. The survival outcomes were plotted using Kaplan-Meier curves. Receiver operating characteristic curves were used to assess the optimal SUVmax cut-off value for predicting locoregional recurrence.
Results:
The median follow-up period was 58 months (range, 11 to 90 months). The 5-year overall survival (OS) and locoregional recurrence-free survival rates were 96.8% and 85.4%, respectively. The median pretreatment SUVmax of the primary tumor for all 101 patients was 2.3 (range, 1.1 to 9.1). The best cut-off value for SUVmax for predicting LRC was 3.3, with a sensitivity of 78.6% and specificity of 73.6%. Univariate analysis showed that T-stage, overall treatment time (≥43 days), and high SUVmax (≥3.3) were significant predictors of LRC. Multivariate analysis showed that LRC was independently affected by a high SUVmax (≥3.3) (hazard ratio = 5.505, p = 0.020).
Conclusion
High pretreatment SUVmax (≥3.3) is a negative prognostic factor for LRC in early glottic cancer patients treated with primary radiotherapy.
4.Analysis of risk factors for disease progression after salvage radiation therapy with androgen deprivation therapy in prostate cancer patients who have prostate-specific antigen persistence after radical prostatectomy
Kyeonghyo LEE ; Dongchan KIM ; Jiho NAM ; Dahl PARK ; Wontaek KIM ; Jihyeon JOO ; Hosang JEON ; Yongkan KI ; Donghyun KIM
Radiation Oncology Journal 2024;42(2):124-129
Purpose:
To assess risk factors of disease progression after salvage radiation therapy (SRT) with androgen deprivation therapy (ADT) in case of prostate-specific antigen (PSA) persistence after radical prostatectomy (RP).
Materials and Methods:
We analyzed 57 patients who received SRT with ADT between 2013 and 2019 due to PSA persistence after RP. The endpoint was disease progression defined by biochemical recurrence or clinical recurrence. Age, Pre-RP PSA level, Gleason score, pathologic stage, presence of pelvic lymph node dissection, surgical margins, and PSA at 6-8 weeks after RP were analyzed as predictive factors for disease progression. Kaplan-Meier method and Cox regression models were used for data analysis.
Results:
At a median follow-up of 38 months (interquartile range, 26–61), 17 patients had disease progression. Pathologic T stage (pT3b vs. pT3a or lower; hazard ratio [HR] = 9.20; p = 0.035) and PSA level at 6-8 weeks after RP (≥2.04 vs. <2.04 ng/mL; HR = 5.85; p = 0.002) were predictors of disease progression. The 5-year disease progression-free survival rate was 46.7% in pT3b group as compared to 92.9 % in pT3a or lower group, and 18.4% for PSA ≥2.04 ng/mL after RP as compared to 79.2% for PSA <2.04 ng/mL.
Conclusion
Pathological T stage (pT3b) and post RP PSA ≥2.04 ng/mL are independent risk factors of disease progression after SRT with ADT in patients with PSA persistence after RP.
5.Variants in the Gene EBF2 Are Associated with Kawasaki Disease in a Korean Population.
Yoonsun BAE ; Dongjik SHIN ; Jiho NAM ; Hye Rim LEE ; Jun Sung KIM ; Kyu Yeun KIM ; Dong Soo KIM ; Yeun Jun CHUNG
Yonsei Medical Journal 2018;59(4):519-523
PURPOSE: Kawasaki disease (KD) is a mucocutaneous lymph node syndrome. It is mainly seen in young children under the age of five. KD is a multifactorial disorder that includes genetic variants. The present study investigated the association between KD and single nucleotide polymorphisms (SNPs) in the candidate gene early B cell factor 2 (EBF2), which is associated with inflammation markers. MATERIALS AND METHODS: An SNP analysis was performed by whole exon sequencing of the EBF2 gene. Our study comprised a total of 495 subjects (295 KD patients and 200 unrelated normal controls) from a Korean population. Tag SNPs were discovered using the Haploview program. Genotyping of the EBF2 gene was performed with the TaqMan® assay with real-time PCR methods. RESULTS: Polymorphism of rs10866845 showed a significant difference in allele frequency between KD patients and controls (p=0.040). The EBF2 gene polymorphisms were significantly associated with KD on logistic regression analysis. CONCLUSION: EBF2 gene variants can contribute to KD in the Korean population.
Child
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Exons
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Gene Frequency
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Humans
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Inflammation
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Logistic Models
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Mucocutaneous Lymph Node Syndrome*
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Polymorphism, Single Nucleotide
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Real-Time Polymerase Chain Reaction
6.Adaptive Image Rescaling for Weakly Contrast-Enhanced Lesions in Dedicated Breast CT:A Phantom Study
Bitbyeol KIM ; Ho Kyung KIM ; Jinsung KIM ; Yongkan KI ; Ji Hyeon JOO ; Hosang JEON ; Dahl PARK ; Wontaek KIM ; Jiho NAM ; Dong Hyeon KIM
Journal of the Korean Radiological Society 2021;82(6):1477-1492
Purpose:
Dedicated breast CT is an emerging volumetric X-ray imaging modality for diagnosis that does not require any painful breast compression. To improve the detection rate of weakly enhanced lesions, an adaptive image rescaling (AIR) technique was proposed.
Materials and Methods:
Two disks containing five identical holes and five holes of different diameters were scanned using 60/100 kVp to obtain single-energy CT (SECT), dual-energy CT (DECT), and AIR images. A piece of pork was also scanned as a subclinical trial. The image quality was evaluated using image contrast and contrast-to-noise ratio (CNR). The difference of imaging performances was confirmed using student’s t test.
Results:
Total mean image contrast of AIR (0.70) reached 74.5% of that of DECT (0.94) and was higher than that of SECT (0.22) by 318.2%. Total mean CNR of AIR (5.08) was 35.5% of that of SECT (14.30) and was higher than that of DECT (2.28) by 222.8%. A similar trend was observed in the subclinical study.
Conclusion
The results demonstrated superior image contrast of AIR over SECT, and its higher overall image quality compared to DECT with half the exposure. Therefore, AIR seems to have the potential to improve the detectability of lesions with dedicated breast CT.
7.Adjuvant external beam radiation and brachytherapy for vaginal resection margin positive cervical cancer
Donghyun KIM ; Yongkan KI ; Wontaek KIM ; Dahl PARK ; Joohye LEE ; Jayoung LEE ; Hosang JEON ; Jiho NAM
Radiation Oncology Journal 2018;36(2):147-152
PURPOSE: To evaluate the treatment outcomes of adjuvant external beam radiation therapy (EBRT) and vaginal brachytherapy (VB) following radical hysterectomy in cervical cancer patients with involved vaginal resection margin (VRM). MATERIALS AND METHODS: We retrospectively reviewed the medical records of 21 patients treated with postoperative EBRT and VB for positive VRM FIGO stage IB–IIA cervical cancer between 2003 and 2015. Concurrent platinum-based chemotherapy was administered to all patients. RESULTS: The median whole pelvis EBRT dose was 50.4 Gy (range, 45 to 50.4 Gy). In the VB, the median dose per fraction, number of fractions, and total dose delivered were: 4 Gy (range, 3.0 to 4.0 Gy), 4 fractions (range, 3 to 5 fractions), and 16 Gy (range, 12 to 20 Gy), respectively. At a median follow-up of 46 months (range, 9 to 122 months), local recurrence was observed in 2 patients, and distant metastasis was present in 7 patients. All patients with local recurrence subsequently developed distant metastases. The 5-year local control, disease-free survival, and overall survival rates were 89.1%, 65.9%, and 62.9%, respectively. Of the 21 patients, 7 patients (33.3%) reported grade 2 acute toxicity; however, there were no grade 3 or higher acute adverse events. Grade 1–2 late toxicities were observed in 8 patients. Late grade 3 urinary toxicity was reported in 1 patient. CONCLUSIONS: Adjuvant EBRT and VB showed excellent local control and low toxicity in cervical cancer patients with positive VRM. Although limited by its retrospective nature, the findings from our study provide evidence supporting the use of additional VB in pathologically involved VRM.
Brachytherapy
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Disease-Free Survival
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Drug Therapy
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Follow-Up Studies
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Humans
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Hysterectomy
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Medical Records
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Neoplasm Metastasis
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Pelvis
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Recurrence
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Retrospective Studies
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Survival Rate
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Uterine Cervical Neoplasms
8.Simulating the Effect of Junction Setup Error in Dual-Isocentric Volumetric Modulated Arc Therapy for Pelvic Radiotherapy with a Large Target
Hojeong LEE ; Dong Woon KIM ; Ji Hyeon JOO ; Yongkan KI ; Wontaek KIM ; Dahl PARK ; Jiho NAM ; Dong Hyeon KIM ; Hosang JEON
Progress in Medical Physics 2024;35(2):52-57
Purpose:
The use of two adjacent radiation beams to treat a lesion that is larger than the maximum field of a machine may lead to higher or lower dose distribution at the junction than expected. Therefore, evaluation of the junction dose is crucial for radiotherapy. Volumetric modulated arc therapy (VMAT) can effectively protect surrounding normal tissues by implementing a complex dose distribution; therefore, two adjacent VMAT fields can effectively treat large lesions. However, VMAT can lead to significant errors in the junction dose between fields if setup errors occur due to its highly complex dose distributions.
Methods:
In this study, setup errors of ±1, ±3, and ±5 mm were assumed during radiotherapy for treating large lesions in the lower abdomen, and their effects on the treatment dose distribution and target coverage were analyzed using gamma pass rate (GP) and homogeneity index (HI). All studies were performed using a computational simulation method based on our radiation treatment planning software.
Results:
Consequently, when the setup error was more than ±3 mm, most GP values using a 3%/3-mm criterion decreased by <90%. GP was independent of the direction of the field gap (FG), whereas HI values were relatively more affected by negative values for FG.
Conclusions
Therefore, the size and direction of setup errors should be carefully managed when performing dual-isocentric VMATs for large targets.
9.Simulating the Effect of Junction Setup Error in Dual-Isocentric Volumetric Modulated Arc Therapy for Pelvic Radiotherapy with a Large Target
Hojeong LEE ; Dong Woon KIM ; Ji Hyeon JOO ; Yongkan KI ; Wontaek KIM ; Dahl PARK ; Jiho NAM ; Dong Hyeon KIM ; Hosang JEON
Progress in Medical Physics 2024;35(2):52-57
Purpose:
The use of two adjacent radiation beams to treat a lesion that is larger than the maximum field of a machine may lead to higher or lower dose distribution at the junction than expected. Therefore, evaluation of the junction dose is crucial for radiotherapy. Volumetric modulated arc therapy (VMAT) can effectively protect surrounding normal tissues by implementing a complex dose distribution; therefore, two adjacent VMAT fields can effectively treat large lesions. However, VMAT can lead to significant errors in the junction dose between fields if setup errors occur due to its highly complex dose distributions.
Methods:
In this study, setup errors of ±1, ±3, and ±5 mm were assumed during radiotherapy for treating large lesions in the lower abdomen, and their effects on the treatment dose distribution and target coverage were analyzed using gamma pass rate (GP) and homogeneity index (HI). All studies were performed using a computational simulation method based on our radiation treatment planning software.
Results:
Consequently, when the setup error was more than ±3 mm, most GP values using a 3%/3-mm criterion decreased by <90%. GP was independent of the direction of the field gap (FG), whereas HI values were relatively more affected by negative values for FG.
Conclusions
Therefore, the size and direction of setup errors should be carefully managed when performing dual-isocentric VMATs for large targets.
10.Simulating the Effect of Junction Setup Error in Dual-Isocentric Volumetric Modulated Arc Therapy for Pelvic Radiotherapy with a Large Target
Hojeong LEE ; Dong Woon KIM ; Ji Hyeon JOO ; Yongkan KI ; Wontaek KIM ; Dahl PARK ; Jiho NAM ; Dong Hyeon KIM ; Hosang JEON
Progress in Medical Physics 2024;35(2):52-57
Purpose:
The use of two adjacent radiation beams to treat a lesion that is larger than the maximum field of a machine may lead to higher or lower dose distribution at the junction than expected. Therefore, evaluation of the junction dose is crucial for radiotherapy. Volumetric modulated arc therapy (VMAT) can effectively protect surrounding normal tissues by implementing a complex dose distribution; therefore, two adjacent VMAT fields can effectively treat large lesions. However, VMAT can lead to significant errors in the junction dose between fields if setup errors occur due to its highly complex dose distributions.
Methods:
In this study, setup errors of ±1, ±3, and ±5 mm were assumed during radiotherapy for treating large lesions in the lower abdomen, and their effects on the treatment dose distribution and target coverage were analyzed using gamma pass rate (GP) and homogeneity index (HI). All studies were performed using a computational simulation method based on our radiation treatment planning software.
Results:
Consequently, when the setup error was more than ±3 mm, most GP values using a 3%/3-mm criterion decreased by <90%. GP was independent of the direction of the field gap (FG), whereas HI values were relatively more affected by negative values for FG.
Conclusions
Therefore, the size and direction of setup errors should be carefully managed when performing dual-isocentric VMATs for large targets.