Publications by authors named "Jae Won Jung"

47 Publications

Fetal dose from proton pencil beam scanning craniospinal irradiation during pregnancy: a Monte Carlo study.

Phys Med Biol 2022 Jan 13. Epub 2022 Jan 13.

Radiation Epidemiology Branch, National Cancer Institute, 9609 Medical Center Dr, Bethesda, Maryland, 20850 , UNITED STATES.

Objective: We conducted a Monte Carlo study to comprehensively investigate the fetal dose resulting from proton pencil beam scanning (PBS) craniospinal irradiation (CSI) during pregnancy.

Approach: The gestational-age dependent pregnant phantom series developed at the University of Florida (UF) were converted into DICOM-RT format (CT images and structures) and imported into a treatment planning system (TPS) (Eclipse v15.6) commissioned to a IBA PBS nozzle. A proton PBS CSI plan (prescribed dose: 36 Gy) was created on the phantoms. The TOPAS MC code was used to simulate the proton PBS CSI on the phantoms, for which MC beam properties at the nozzle exit (spot size, spot divergence, mean energy, and energy spread) were matched to IBA PBS nozzle beam measurement data. We calculated mean absorbed doses for 28 organs and tissues and whole body of the fetus at eight gestational ages (8, 10, 15, 20, 25, 30, 35, and 38 weeks). For contextual purposes, the fetal organ/tissue doses from the treatment planning CT scan of the mother's head and torso were estimated using the National Cancer Institute dosimetry system for CT (NCICT, Version 3) considering a low-dose CT protocol (CTDIvol: 8.97 mGy).

Main Results: The majority of the fetal organ/tissue doses from the proton PBS CSI treatment fell within a range of 3 to 6 mGy. The fetal organ/tissue doses for the 38-week phantom showed the largest variation with the doses ranging from 2.9 mGy (adrenals) to 8.2 mGy (eye lenses) while the smallest variation ranging from 3.2 mGy (oesophagus) to 4.4 mGy (brain) was observed for the doses for the 20-week phantom. The fetal whole-body dose ranged from 3.7 mGy (25 weeks) to 5.8 mGy (8 weeks). Most of the fetal doses from the planning CT scan fell within a range of 7 to 13 mGy, approximately 2-to-9 times lower than the fetal dose equivalents of the proton PBS CSI treatment (assuming a quality factor of 7).

Significance: The fetal organ/tissue doses observed in the present work will be useful for one of the first clinically informative predictions on the magnitude of fetal dose during proton PBS CSI during pregnancy.
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http://dx.doi.org/10.1088/1361-6560/ac4b38DOI Listing
January 2022

Application of an automatic segmentation method for evaluating cardiac structure doses received by breast radiotherapy patients.

Phys Imaging Radiat Oncol 2021 Jul 23;19:138-144. Epub 2021 Aug 23.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States.

Background And Purpose: Quantifying radiation dose to cardiac substructures is important for research on the etiology and prevention of complications following radiotherapy; however, segmentation of substructures is challenging. In this study we demonstrate the application of our atlas-based automatic segmentation method to breast cancer radiotherapy plans for generating radiation doses in support of late effects research.

Material And Methods: We applied our segmentation method to contour heart substructures on the computed tomography (CT) images of 70 breast cancer patients who received external photon radiotherapy. Two cardiologists provided manual segmentation of the whole heart (WH), left/right atria, left/right ventricles, and left anterior descending artery (LAD). The automatically contours were compared with manual delineations to evaluate similarity in terms of geometry and dose.

Results: The mean Dice similarity coefficient between manual and automatic segmentations was 0.96 for the WH, 0.65 to 0.82 for the atria and ventricles, and 0.06 for the LAD. The mean average surface distance was 1.2 mm for the WH, 3.4 to 4.1 mm for the atria and ventricles, and 6.4 mm for the LAD. We found the dose to the cardiac substructures based on our automatic segmentation agrees with manual segmentation within expected observer variability. For left breast patients, the mean absolute difference in mean dose was 0.1 Gy for the WH, 0.2 to 0.7 Gy for the atria and ventricles, and 1.8 Gy for the LAD. For right breast patients, these values were 0.0 Gy, 0.1 to 0.4 Gy, and 0.4 Gy, respectively.

Conclusion: Our automatic segmentation method will facilitate the development of radiotherapy prescriptive criteria for mitigating cardiovascular complications.
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http://dx.doi.org/10.1016/j.phro.2021.08.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397890PMC
July 2021

A dose voxel kernel method for rapid reconstruction of out-of-field neutron dose of patients in pencil beam scanning (PBS) proton therapy.

Phys Med Biol 2020 08 27;65(17):175015. Epub 2020 Aug 27.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States of America.

Monte Carlo (MC) radiation transport methods are used for dose calculation as 'gold standard.' However, the method is computationally time-consuming and thus impractical for normal tissue dose reconstructions for the large number of proton therapy patients required for epidemiologic investigations of late health effects. In the present study, we developed a new dose calculation method for the rapid reconstruction of out-of-field neutron dose to patients undergoing pencil beam scanning (PBS) proton therapy. The new dose calculation method is based on neutron dose voxel kernels (DVKs) generated by MC simulations of a proton pencil beam irradiating a water phantom (60 × 60 × 300 cm), which was conducted using a MC proton therapy simulation code, TOPAS. The DVKs were generated for 19 beam energies (from 70 to 250 MeV with the 10 MeV interval) and three range shifter thicknesses (1, 3, and 5 cm). An in-house program was written in C++ to superimpose the DVKs onto a patient CT images according to proton beam characteristics (energy, position, and direction) available in treatment plans. The DVK dose calculation method was tested by calculating organ/tissue-specific neutron doses of 1- and 5-year-old whole-body computational phantoms where intracranial and craniospinal irradiations were simulated. The DVK-based doses generally showed reasonable agreement with those calculated by direct MC simulations with a detailed PBS model that were previously published, with differences mostly less than 30% and 10% for the intracranial and craniospinal irradiations, respectively. The computation time of the DVK method for one patient ranged from 1 to 30 min on a single CPU core of a personal computer, demonstrating significant improvement over the direct MC dose calculation requiring several days on high-performance computing servers. Our DVK-based dose calculation method will be useful when dosimetry is needed for the large number of patients such as for epidemiologic or clinical research.
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http://dx.doi.org/10.1088/1361-6560/abaa5fDOI Listing
August 2020

Analytical and Potential Clinical Performance of Oncomine Myeloid Research Assay for Myeloid Neoplasms.

Mol Diagn Ther 2020 10;24(5):579-592

Department of Laboratory Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.

Introduction: Next-generation sequencing (NGS) panels have recently been introduced to efficiently detect genetic variations in hematologic malignancies.

Objectives: Our aim was to evaluate the performance of the commercialized Oncomine™ myeloid research assay (OMA) for myeloid neoplasms.

Methods: Certified reference materials and clinical research samples were used, including 60 genomic DNA and 56 RNA samples. NGS was performed using OMA, which enables the interrogation of 40 target genes, 29 gene fusions, and five expression target genes with five expression control genes by the Ion S5 XL Sequencer. The analyzed data were compared with clinical data using karyotyping, reverse transcription polymerase chain reaction (PCR), fluorescence in situ hybridization, Sanger sequencing, customized NGS panel, and fragment analysis.

Results: All targets of reference materials were detected except three (two ASXL1 and one CEBPA) mutations, which we had not expected OMA to detect. In clinical search samples, OMA satisfactorily identified DNA variants, including 90 single nucleotide variants (SNVs), 48 small insertions and deletions (indels), and eight FLT3 internal tandem duplications (ITDs) (Kappa agreement 0.938). The variant allele frequencies of SNVs and indels measured by OMA correlated well with clinical data, whereas those of FLT3-ITDs were significantly lower than with fragment analysis (P = 0.008). Together, OMA showed strong ability to identify RNA gene fusions (Kappa agreement 0.961), except one RUNX1-MECOM. The MECOM gene was highly expressed in all five samples with MECOM-associated rearrangements, including inv(3), t(3;3), and t(3;21).

Conclusion: OMA revealed excellent analytical and potential clinical performance and could be a good replacement for conventional molecular tests.
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http://dx.doi.org/10.1007/s40291-020-00484-5DOI Listing
October 2020

On-beam computed tomography reconstruction for radiotherapy verification from projection image differences caused by motion during treatment.

Phys Med Biol 2020 02 28;65(5):055001. Epub 2020 Feb 28.

Department of Nuclear and Quantum Engineering, KAIST, Daejeon, 34141, Republic of Korea.

The purpose of this study is to propose a reconstruction method of a target and its neighborhood, representative of the moment of radiotherapy delivery, based on differences in its transit images between the time of planning computed tomography (pCT) and the time of treatment beam delivery. To validate the method, a lung phantom with a target object was constructed, and CT-scanned before and after making a shift of the target. The latter scan was intended to simulate a potential organ movement at the time of treatment, and to serve as ground-truth images. Treatment planning using arc-beam delivery was done on the first pCT images. The planned beams were irradiated to the phantom after the shift, while cine transit images were acquired. Cine transit images were also calculated through the pCT images before the shift. From the ratio of the measured and calculated transit images, the amount of image changes due to the organ movement between the time of pCT and that of treatment was three-dimensionally reconstructed. By adding the reconstructed images to the pCT images before the shift, the CT images of the phantom at the time of the beam delivery were generated and compared with the ground truth images. The phantom after the shift was also scanned by on-board cone-beam computer tomography (CBCT) and reconstructed from the measured transit images (MVCT) for comparison. The proposed method reconstructed images that are very close to the ground-truth images in the volume and HU values of the target and the dose-volume coverage of the target and lung. Similar agreement was not found in the CBCT and MVCT images. The method may be used for 4D target image reconstruction, and, combined with the reconstructed image of un-irradiated areas, may offer clinically useful images of the entire region of interest.
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http://dx.doi.org/10.1088/1361-6560/ab6eb9DOI Listing
February 2020

Automatic segmentation of cardiac structures for breast cancer radiotherapy.

Phys Imaging Radiat Oncol 2019 Oct 5;12:44-48. Epub 2019 Dec 5.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA.

Background And Purpose: We developed an automatic method to segment cardiac substructures given a radiotherapy planning CT images to support epidemiological studies or clinical trials looking at cardiac disease endpoints after radiotherapy.

Material And Methods: We used a most-similar atlas selection algorithm and 3D deformation combined with 30 detailed cardiac atlases. We cross-validated our method within the atlas library by evaluating geometric comparison metrics and by comparing cardiac doses for simulated breast radiotherapy between manual and automatic contours. We analyzed the impact of the number of cardiac atlas in the library and the use of manual guide points on the performance of our method.

Results: The Dice Similarity Coefficients from the cross-validation reached up to 97% (whole heart) and 80% (chambers). The Average Surface Distance for the coronary arteries was less than 10.3 mm on average, with the best agreement (7.3 mm) in the left anterior descending artery (LAD). The dose comparison for simulated breast radiotherapy showed differences less than 0.06 Gy for the whole heart and atria, and 0.3 Gy for the ventricles. For the coronary arteries, the dose differences were 2.3 Gy (LAD) and 0.3 Gy (other arteries). The sensitivity analysis showed no notable improvement beyond ten atlases and the manual guide points does not significantly improve performance.

Conclusion: We developed an automated method to contour cardiac substructures for radiotherapy CTs. When combined with accurate dose calculation techniques, our method should be useful for cardiac dose reconstruction of a large number of patients in epidemiological studies or clinical trials.
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http://dx.doi.org/10.1016/j.phro.2019.11.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7807574PMC
October 2019

Is Acromial Fracture after Reverse Total Shoulder Arthroplasty a Negligible Complication?: A Systematic Review.

Clin Orthop Surg 2019 Dec 12;11(4):427-435. Epub 2019 Nov 12.

Department of Orthopedic Surgery, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.

Background: The purpose of this study was to investigate the incidence of acromial fracture after reverse total shoulder arthroplasty (RTSA) and clinical and radiological outcomes of treatment of the fracture.

Methods: A systematic review was performed to identify studies that reported the results of treatment of acromial fractures after RTSA. A literature search was conducted by two investigators using four databases (PubMed, Embase, Cochrane, and Ovid Medline).

Results: Fifteen studies (2,857 shoulders) satisfied our inclusion criteria. The incidence of acromial fracture after RTSA was 4.0% (114 / 2,857). The mean age of the patients at the time of fracture was 72.9 years (range, 51 to 91 years). The mean time from RTSA to diagnosis of acromial fracture was 9.4 months (range, 1 to 94 months). One hundred shoulders (87.7%) were treated conservatively and 14 shoulders (12.3%) were treated surgically. The mean follow-up period after acromial fracture was 33.8 months. The overall union rate was 50.0% (43.8% for conservative treatment and 87.5% for operative treatment). The fracture incidence was significantly different among the medial glenoid and medial humerus prosthesis design (8.4%), the lateral glenoid and medial humerus design (4.0%), and the medial glenoid and lateral humerus design (2.8%). The mean values at final follow-up were as follows: visual analog scale score, 2.2; American Shoulder and Elbow Surgeons score, 59.1; Constant score, 59.7; and Simple Shoulder Test, 5.8. The mean forward flexion, abduction, and external rotation were 102.3°, 92.3°, and 25.8°, respectively.

Conclusions: Acromial fractures after RTSA are a complication neither uncommon nor negligible. In the absence of studies with high-level evidence, there is a controversy on the outcomes after treatment. Further well-designed prospective randomized controlled studies with a long-term follow-up should be performed to ascertain the diagnosis, treatment, and prognosis of acromial fractures after RTSA.
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http://dx.doi.org/10.4055/cios.2019.11.4.427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6867909PMC
December 2019

A Monte Carlo model for organ dose reconstruction of patients in pencil beam scanning (PBS) proton therapy for epidemiologic studies of late effects.

J Radiol Prot 2020 Mar 11;40(1):225-242. Epub 2019 Sep 11.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States of America.

Significant efforts such as the Pediatric Proton/Photon Consortium Registry (PPCR) involving multiple proton therapy centers have been made to conduct collaborative studies evaluating outcomes following proton therapy. As a groundwork dosimetry effort for the late effect investigation, we developed a Monte Carlo (MC) model of proton pencil beam scanning (PBS) to estimate organ/tissue doses of pediatric patients at the Maryland Proton Treatment Center (MPTC), one of the proton centers involved in the PPCR. The MC beam modeling was performed using the TOPAS (TOol for PArticle Simulation) MC code and commissioned to match measurement data within 1% for range, and 0.3 mm for spot sizes. The established MC model was then tested by calculating organ/tissue doses for sample intracranial and craniospinal irradiations on whole-body pediatric computational human phantoms. The simulated dose distributions were compared with the treatment planning system dose distributions, showing the 3 mm/3% gamma index passing rates of 94%-99%, validating our simulations with the MC model. The calculated organ/tissue doses per prescribed doses for the craniospinal irradiations (1 mGy Gy to 1 Gy Gy) were generally much higher than those for the intracranial irradiations (2.1 μGy Gy to 0.1 Gy Gy), which is due to the larger field coverage of the craniospinal irradiations. The largest difference was observed at the adrenal dose, i.e. ∼3000 times. In addition, the calculated organ/tissue doses were compared with those calculated with a simplified MC model, showing that the beam properties (i.e. spot size, spot divergence, mean energy, and energy spread) do not significantly influence dose calculations despite the limited irradiation cases. This implies that the use of the MC model commissioned to the MPTC measurement data might be dosimetrically acceptable for patient dose reconstructions at other proton centers particularly when their measurement data are unavailable. The developed MC model will be used to reconstruct organ/tissue doses for MPTC pediatric patients collected in the PPCR.
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http://dx.doi.org/10.1088/1361-6498/ab437dDOI Listing
March 2020

Conversion of computational human phantoms into DICOM-RT for normal tissue dose assessment in radiotherapy patients.

Phys Med Biol 2019 07 5;64(13):13NT02. Epub 2019 Jul 5.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States of America.

Radiotherapy (RT) treatment planning systems (TPS) are designed for the fast calculation of dose to the tumor bed and nearby organs at risk using x-ray computed tomography (CT) images. However, CT images for a patient are typically available for only a small portion of the body, and in some cases, such as for retrospective epidemiological studies, no images may be available at all. When dose to organs that lie out-of-scan must be estimated, a convenient alternative for the unknown patient anatomy is to use a matching whole-body computational phantom as a surrogate. The purpose of the current work is to connect such computational phantoms to commercial RT TPS for retrospective organ dose estimation. A custom software with graphical user interface (GUI), called the DICOM-RT Generator, was developed in MATLAB to convert voxel computational phantoms into the digital imaging and communications in medicine radiotherapy (DICOM-RT) format, compatible with commercial TPS. DICOM CT image sets for the phantoms are created via a density-to-Hounsfield unit (HU) conversion curve. Accompanying structure sets containing the organ contours are automatically generated by tracing binary masks of user-specified organs on each phantom CT slice. The software was tested on a library of body size-dependent phantoms, the International Commission on Radiological Protection reference phantoms, and a canine voxel phantom, taking only a few minutes per conversion. The resulting DICOM-RT files were tested on several commercial TPS. As an example application, a library of converted phantoms was used to estimate organ doses for members of the National Wilms Tumor Study (NWTS) cohort. The converted phantom library, in DICOM format, and a standalone MATLAB-compiled executable of the DICOM-RT Generator are available for others to use for research purposes (http://ncidose.cancer.gov).
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http://dx.doi.org/10.1088/1361-6560/ab2670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6612588PMC
July 2019

Acute Displaced Fracture of Lateral Acromion after Reverse Shoulder Arthroplasty: A Case Report and Surgical Technique.

Clin Shoulder Elb 2019 Jun 1;22(2):106-109. Epub 2019 Jun 1.

Department of Orthopedic Surgery, Dongsan Medical Center, School of Medicine, Keimyung University, Daegu, Korea.

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle pre-contoured plate.
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http://dx.doi.org/10.5397/cise.2019.22.2.106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7714300PMC
June 2019

Utilization of Archived Plasma to Detect Epidermal Growth Factor Receptor Mutation in Non-Small Cell Lung Cancer Patients.

Biopreserv Biobank 2019 Aug 19;17(4):319-325. Epub 2019 Mar 19.

1Department of Laboratory Medicine, Korea Cancer Center Hospital, Seoul, Republic of Korea.

Precision medicine has received increased attention as an effective approach for the treatment of cancer patients. Because of challenges associated with the availability of archived tissue, liquid biopsies are often performed to detect cancer-specific mutations. One of the major advantages of the liquid biopsy is that the treatment can be monitored longitudinally, even after the tumor tissue is no longer available. In a clinical setting, one component of precision medicine is the detection of cancer-specific mutations using archived samples. In this study, we evaluated the epidermal growth factor receptor (EGFR) mutation status of samples of lung cancer patients stored before introduction of the plasma EGFR test at our institution. The aim of this study was to validate the utility of archived plasma samples for detection of the EGFR mutation in nonsmall cell lung cancer (NSCLC) patients. The Cobas EGFR Mutation Test v2 was the first liquid biopsy test approved as a companion diagnostic test for patients with NSCLC treated with tyrosine kinase inhibitors. We tested for the EGFR mutation in 116 plasma samples archived in the biobank, and the results were compared with those obtained in the tissue or cytology EGFR mutation test. The EGFR mutation-positive rate from archived plasma was lower than that determined from tissue or cytology at 19.0% and 53.4%, respectively, and the concordance rate between the two tests was 58.6%. Of interest, five (4.3%) samples showed the T790M mutation in the plasma test, whereas this mutation was only detected in two (1.7%) tissue/cytology samples. Five (4.3%) samples were additionally positive in the plasma test. Overall, these results indicate that archived plasma samples can serve as an alternative source for the plasma EGFR mutation test when tissue samples are not available, and can improve precision medicine and long-term follow-up in a noninvasive manner.
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http://dx.doi.org/10.1089/bio.2018.0126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703236PMC
August 2019

Feasibility and accuracy of UF/NCI phantoms and Monte Carlo retrospective dosimetry in children treated on National Wilms Tumor Study protocols.

Pediatr Blood Cancer 2018 12 12;65(12):e27395. Epub 2018 Aug 12.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland.

Purpose: This pilot study was done to determine the feasibility and accuracy of University of Florida/National Cancer Institute (UF/NCI) phantoms and Monte Carlo (MC) retrospective dosimetry and had two aims: (1) to determine the anatomic accuracy of UF/NCI phantoms by comparing 3D organ doses in National Wilms Tumor Study (NWTS) patient-matched UF/NCI phantoms to organ doses in corresponding patient-matched CT scans and (2) to compare infield and out-of-field organ dosimetry using two dosimetry methods-standard radiation therapy (RT) treatment planning systems (TPS) and MC dosimetry in these two anatomic models.

Methods: Twenty NWTS patient-matched Digital Imaging and Communications in Medicine (DICOM) files of UF/NCI phantoms and CT scans were imported into the Pinnacle RT TPS. The NWTS RT fields (whole abdomen, flank, whole lung, or a combination) and RT doses (10-45 Gy) were reconstructed in both models. Both TPS and MC dose calculations were performed. For aim 1, the mean doses to the heart, kidney, thyroid gland, testes, and ovaries using TPS and MC in both models were statistically compared. For aim 2, the TPS and MC dosimetry for these organs in both models were statistically compared.

Results: For aim 1, there was no significant difference between phantom and CT scan dosimetry for any of the organs using either TPS or MC dosimetry. For aim 2, there was a significant difference between TPS and MC dosimetry for both CT scan and phantoms for all organs. Although the doses for infield organs were similar for both TPS and MC, the doses for near-field and out-of-field organs were consistently higher for 90% to 100% of MC doses; however, the absolute dose difference was small (<1 Gy).

Conclusions: This pilot study has demonstrated that the patient-matched UF/NCI phantoms together with MC dosimetry is an accurate model for performing retrospective 3D dosimetry in large-scale epidemiology studies such as the NWTS.
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http://dx.doi.org/10.1002/pbc.27395DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6561477PMC
December 2018

Outcomes are equivalent for two-column acetabular fractures either with or without posterior-wall fractures.

Arch Orthop Trauma Surg 2018 Sep 17;138(9):1223-1234. Epub 2018 May 17.

Department of Orthopaedic Surgery, School of Medicine, Keimyung University, 56 Dalseong-Ro, Joong-Gu, Daegu, 41931, South Korea.

Introduction: It is likely that posterior-wall involvement in association with two-column fractures plays a pivotal role in outcomes because of the potential for hip instability if it is not anatomically reduced and fixed. Uncertainty remains about how this fracture is best treated, especially regarding how posterior-wall involvement may affect functional results.

Materials And Methods: To better understand the role that posterior-wall involvement may play in determining functional results, we compared data for outcomes for patients with posterior-wall involvement and for those without in a consecutive series of two-column fractures. Between 2000 and 2013, 42 patients who underwent surgical treatment for two-column acetabular fractures were evaluated after a minimum follow-up period of 1 year. Data were prospectively collected and retrospectively evaluated. Of the 42 patients, 25 had only a two-column fracture (group 1) and 17 had a two-column fracture with posterior-wall involvement (group 2).

Results: There were no differences between groups in terms of reduction accuracy, radiographic results, clinical results, or complication rates. All hips in patients with internal fixation for the associated posterior-wall fracture had anatomical reduction. At the latest follow-up evaluation, three patients from group 1 (without posterior-wall involvement) and three patients from group 2 (with posterior-wall involvement) had undergone total hip arthroplasty.

Conclusion: These results suggest that a posterior-wall fracture in a two-column fracture does not compromise functional outcomes when the treatment algorithm discussed here is followed.
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http://dx.doi.org/10.1007/s00402-018-2953-6DOI Listing
September 2018

Comparison of normal tissue dose calculation methods for epidemiological studies of radiotherapy patients.

J Radiol Prot 2018 Jun 11;38(2):775-792. Epub 2018 Apr 11.

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States of America.

Radiation dosimetry is an essential input for epidemiological studies of radiotherapy patients aimed at quantifying the dose-response relationship of late-term morbidity and mortality. Individualised organ dose must be estimated for all tissues of interest located in-field, near-field, or out-of-field. Whereas conventional measurement approaches are limited to points in water or anthropomorphic phantoms, computational approaches using patient images or human phantoms offer greater flexibility and can provide more detailed three-dimensional dose information. In the current study, we systematically compared four different dose calculation algorithms so that dosimetrists and epidemiologists can better understand the advantages and limitations of the various approaches at their disposal. The four dose calculations algorithms considered were as follows: the (1) Analytical Anisotropic Algorithm (AAA) and (2) Acuros XB algorithm (Acuros XB), as implemented in the Eclipse treatment planning system (TPS); (3) a Monte Carlo radiation transport code, EGSnrc; and (4) an accelerated Monte Carlo code, the x-ray Voxel Monte Carlo (XVMC). The four algorithms were compared in terms of their accuracy and appropriateness in the context of dose reconstruction for epidemiological investigations. Accuracy in peripheral dose was evaluated first by benchmarking the calculated dose profiles against measurements in a homogeneous water phantom. Additional simulations in a heterogeneous cylinder phantom evaluated the performance of the algorithms in the presence of tissue heterogeneity. In general, we found that the algorithms contained within the commercial TPS (AAA and Acuros XB) were fast and accurate in-field or near-field, but not acceptable out-of-field. Therefore, the TPS is best suited for epidemiological studies involving large cohorts and where the organs of interest are located in-field or partially in-field. The EGSnrc and XVMC codes showed excellent agreement with measurements both in-field and out-of-field. The EGSnrc code was the most accurate dosimetry approach, but was too slow to be used for large-scale epidemiological cohorts. The XVMC code showed similar accuracy to EGSnrc, but was significantly faster, and thus epidemiological applications seem feasible, especially when the organs of interest reside far away from the field edge.
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http://dx.doi.org/10.1088/1361-6498/aabd4fDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007019PMC
June 2018

A Novel Method to Extend a Partial-Body CT for the Reconstruction of Dose to Organs beyond the Scan Range.

Radiat Res 2018 06 4;189(6):618-626. Epub 2018 Apr 4.

a   Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland 20850.

Epidemiological investigation is an important approach to assessing the risk of late effects after radiotherapy, and organ dosimetry is a crucial part of such analysis. Computed tomography (CT) images, if available, can be a valuable resource for individualizing the dosimetry, because they describe the specific anatomy of the patient. However, CT images acquired for radiation treatment planning purposes cover only a portion of the body near the target volume, whereas for epidemiology, the interest lies in the more distant normal tissues, which may be located outside the scan range. To address this challenge, we developed a novel method, called the Anatomically Predictive Extension (APE), to extend a partial-body CT image stack using images of a computational human phantom matched to the patient based on their height and weight. To test our method, we created five APE phantoms from chest and abdominal images extracted from the chest-abdomen-pelvis (CAP) CT scans of five patients. Organ doses were calculated for simple chest and prostate irradiations that were planned on the reference computational phantom (assumed patient geometry if no CT images are available), APE phantoms (patient-phantom hybrid given a partial-body patient CT) and full patient CAP CT scans (ground truth). The APE phantoms and patient CAP CT scans resulted in nearly identical dosimetry for those organs that were fully included in the partial-body CT used to construct the APE. The calculated doses to these same organs in the reference phantoms differed by up to 20% and 52% for the chest and prostate cases, respectively. For organs outside the scan coverage, the reference phantom showed, on average, dose differences of 31% (chest case) and 41% (prostate case). For the APE phantoms, these values were 26% (chest) and 17% (prostate). The APE method combines patient and phantom images to improve organ dosimetry both inside and outside the scan range. We intend to use the APE method for estimating dose for organs peripheral to the treatment fields; however, this method is quite generalizable with many potential applications.
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http://dx.doi.org/10.1667/RR14999.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384816PMC
June 2018

Suppression of the ERK-SRF axis facilitates somatic cell reprogramming.

Exp Mol Med 2018 02 23;50(2):e448. Epub 2018 Feb 23.

Laboratory for Cancer & Stem Cell Biology, Plant Engineering Institute, Department of Molecular Biology, Sejong University, Seoul, Korea.

The molecular mechanism underlying the initiation of somatic cell reprogramming into induced pluripotent stem cells (iPSCs) has not been well described. Thus, we generated single-cell-derived clones by using a combination of drug-inducible vectors encoding transcription factors (Oct4, Sox2, Klf4 and Myc) and a single-cell expansion strategy. This system achieved a high reprogramming efficiency after metabolic and epigenetic remodeling. Functional analyses of the cloned cells revealed that extracellular signal-regulated kinase (ERK) signaling was downregulated at an early stage of reprogramming and that its inhibition was a driving force for iPSC formation. Among the reprogramming factors, Myc predominantly induced ERK suppression. ERK inhibition upregulated the conversion of somatic cells into iPSCs through concomitant suppression of serum response factor (SRF). Conversely, SRF activation suppressed the reprogramming induced by ERK inhibition and negatively regulated embryonic pluripotency by inducing differentiation via upregulation of immediate early genes, such as c-Jun, c-Fos and EGR1. These data reveal that suppression of the ERK-SRF axis is an initial molecular event that facilitates iPSC formation and may be a useful surrogate marker for cellular reprogramming.
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http://dx.doi.org/10.1038/emm.2017.279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5903827PMC
February 2018

The Effectiveness of Personalized Bowel Preparation Using a Smartphone Camera Application: A Randomized Pilot Study.

Gastroenterol Res Pract 2017 8;2017:4898914. Epub 2017 Aug 8.

Department of Computer Engineering, Inje University, Gimhae, Republic of Korea.

Background: We aimed to investigate the effectiveness of a smartphone application that analyzes and judges the optimal dosage of polyethylene glycol (PEG) for bowel preparation.

Methods: Patients were assigned to use the smartphone camera application (app group) or written instructions (non-app group). The smartphone camera application was programmed to analyze the bowel preparation quality and automatically determine the dosage of PEG from an analysis of stool images. In contrast, the non-app group consumed PEG solution according to the manual.

Results: The primary outcome was the quality of the bowel preparation based on blinded ratings using the Ottawa bowel preparation scale (OBPS). There was no statistically significant difference in the mean OBPS scores between the two groups ( = 0.950). However, the app group consumed a lower dose of PEG than the non-app group (mean dosage (mL): 3713.2 ± 405.8 versus 3979.2 ± 102.06, = 0.001). The app group (5-point Likert scale; mean score 4.37 ± 0.895) had high acceptance of the application.

Conclusions: Although the app group consumed a lower PEG dose, the bowel preparation quality was similar in the two groups. Moreover, use of the smartphone camera application enhanced compliance with the bowel preparation.
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http://dx.doi.org/10.1155/2017/4898914DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5591918PMC
August 2017

Correlation of hypoxia inducible transcription factor in breast cancer and SUVmax of F-18 FDG PET/CT.

Nucl Med Rev Cent East Eur 2017 ;20(1):32-38

Department of Nuclear Medicine, Catholic University of Daegu School of Medicine.

Background: Tumor hypoxia induces the expression of several genes via the hypoxia-inducible transcription factor-1 alpha (HIF-1a). It is associated with the prognosis of several cancers. We studied the immunohistochemical expression of HIF-1a in patients with invasive ductal cancer (IDC) of the breast and the possible correlation with the maximum standardized uptake value of the primary tumor (pSUVmax) as well as other biological parameters. Prognostic significance of pSUVmax and expression of HIF-1a for the prediction of progression-free survival (PFS) was also assessed.

Material And Methods: Two-hundred seven female patients with IDC who underwent pretreatment fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) were enrolled. The pSUVmax was compared with clinicopathological parameters including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), axillary lymph node (LN) metastasis, stage and HIF-1a expression. The prognostic value of pSUVmax for PFS was assessed using the Kaplan-Meier method.

Results: pSUVmax was significantly higher in patients with HIF-1a expression ≥ 2 compared to patients with HIF-1a expression < 2 (5.2 ± 4.5 vs. 3.7 ± 3.1, p = 0.008). pSUVmax was also significantly higher in higher stage (p < 0.000001), ER-negative tumors (p < 0.0001), PR-negative tumors (p = 0.0011) and positive LN metastasis (p = 0.0013). pSUVmax was significantly higher in patients with progression compared to patients who were disease-free (6.8 ± 4.4 vs. 4.1 ± 3.7, p = 0.0005). A receiver-operating characteristic curve demonstrated a pSUVmax of 6.51 to be the optimal cutoff for predicting PFS (sensitivity: 53.6%, specificity: 86.0%). Patients with high pSUVmax (> 6.5) had significantly shorter PFS compared to patients with low pSUVmax (p < 0.0001).

Conclusions: pSUVmax on pretreatment F-18 FDG PET/ CT reflect expression of HIF-1a and can be used as a good surrogate marker for the prediction of progression in patients with IDC. The amount of FDG uptake is determined by the presence of glucose metabolism and hypoxia in breast cancer cell.
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http://dx.doi.org/10.5603/NMR.a2016.0043DOI Listing
February 2017

Giant Brunner's Gland Hamartoma of the Duodenal Bulb Presenting with Upper Gastrointestinal Bleeding and Obstruction.

Clin Endosc 2016 Nov 13;49(6):570-574. Epub 2016 Oct 13.

Division of Gastroenterology, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.

Brunner's gland hamartomas are small benign lesions that are most commonly found in the bulb of the duodenum. They are very uncommon, and most are found incidentally during upper gastrointestinal series or esophagogastroduodenoscopy. The lesions tend to be asymptomatic, but patients may present with symptoms of duodenal obstruction or hemorrhage secondary to ulceration. Histologically, a Brunner's gland hamartoma consists of the components of Brunner's gland cells, as well as glandular, adipose and muscle cells. In this study, we report the case of a 30-year-old man who presented with upper gastrointestinal bleeding and obstructive symptoms due to a giant Brunner's gland hamartoma in the duodenal bulb. The hamartoma was successfully removed by endoscopic resection. No significant complications were observed. Microscopically, the lesion was found to be entirely composed of variable Brunner's glands and adipocytes.
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http://dx.doi.org/10.5946/ce.2016.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5152786PMC
November 2016

A novel conformal superficial high-dose-rate brachytherapy device for the treatment of nonmelanoma skin cancer and keloids.

Brachytherapy 2017 Jan - Feb;16(1):215-222. Epub 2016 Oct 4.

Department of Physics, East Carolina University, Greenville, NC.

Purpose: To develop a novel conformal superficial brachytherapy (CSBT) device as a treatment option for the patient-specific radiation therapy of conditions including superficial lesions, postsurgical positive margins, Dupuytren's contractures, keloid scars, and complex anatomic sites (eyelids, nose, ears, etc.).

Methods And Materials: A preliminary CSBT device prototype was designed, built, and tested using readily available radioactive seeds. Iodine-125 (I) seeds were independently guided to the treatment surface to conform to the target. Treatment planning was performed via BrachyVision Planning System (BPS) and dose distributions measured with Gafchromic EBT3 film. Percent depth dose curves and profiles for Praseodymium-142 (Pr), and Strontium-90/Yttrium-90 (Sr-Y) were also investigated as potential sources. Results achieved with Sr-Y and electron external beam radiation therapy were compared and Monte Carlo N-Particle eXtended 2.6 simulations of Pr seeds were validated.

Results: BPS was able to predict clinical dose distributions for a multiple seeds matrix. Calculated and measured doses for the I seed matrix were 500 cGy and 473.5 cGy at 5 mm depth, and 171.0 cGy and 201.0 cGy at 10 mm depth, respectively. Results of Sr-Y tests demonstrate a more conformal dose than electron EBRT (1.6 mm compared to 4.3 mm penumbra). Measured Pr doses were 500 cGy at surface and 17.4 cGy at 5 mm depth.

Conclusions: The CSBT device provides a highly conformal dose to small surface areas. Commercially available BPS can be used for treatment planning, and Monte Carlo simulation can be used for plans using beta-emitting sources and complex anatomies. Various radionuclides may be used in this device to suit prescription depths and treatment areas.
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http://dx.doi.org/10.1016/j.brachy.2016.09.002DOI Listing
July 2017

Four-dimensional dose reconstruction through in vivo phase matching of cine images of electronic portal imaging device.

Med Phys 2016 Jul;43(7):4420

Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354.

Purpose: A method is proposed to reconstruct a four-dimensional (4D) dose distribution using phase matching of measured cine images to precalculated images of electronic portal imaging device (EPID).

Methods: (1) A phantom, designed to simulate a tumor in lung (a polystyrene block with a 3 cm diameter embedded in cork), was placed on a sinusoidally moving platform with an amplitude of 1 cm and a period of 4 s. Ten-phase 4D computed tomography (CT) images of the phantom were acquired. A planning target volume (PTV) was created by adding a margin of 1 cm around the internal target volume of the tumor. (2) Three beams were designed, which included a static beam, a theoretical dynamic beam, and a planning-optimized dynamic beam (PODB). While the theoretical beam was made by manually programming a simplistic sliding leaf motion, the planning-optimized beam was obtained from treatment planning. From the three beams, three-dimensional (3D) doses on the phantom were calculated; 4D dose was calculated by means of the ten phase images (integrated over phases afterward); serving as "reference" images, phase-specific EPID dose images under the lung phantom were also calculated for each of the ten phases. (3) Cine EPID images were acquired while the beams were irradiated to the moving phantom. (4) Each cine image was phase-matched to a phase-specific CT image at which common irradiation occurred by intercomparing the cine image with the reference images. (5) Each cine image was used to reconstruct dose in the phase-matched CT image, and the reconstructed doses were summed over all phases. (6) The summation was compared with forwardly calculated 4D and 3D dose distributions. Accounting for realistic situations, intratreatment breathing irregularity was simulated by assuming an amplitude of 0.5 cm for the phantom during a portion of breathing trace in which the phase matching could not be performed. Intertreatment breathing irregularity between the time of treatment and the time of planning CT was considered by utilizing the same reduced amplitude when the phantom was irradiated. To examine the phase matching in a humanoid environment, the matching was also performed in a digital phantom (4D XCAT phantom).

Results: For the static, the theoretical, and the planning-optimized dynamic beams, the 4D reconstructed doses showed agreement with the forwardly calculated 4D doses within the gamma pass rates of 92.7%, 100%, and 98.1%, respectively, at the isocenter plane given by 3%/3 mm criteria. Excellent agreement in dose volume histogram of PTV and lung-PTV was also found between the two 4D doses, while substantial differences were found between the 3D and the 4D doses. The significant breathing irregularities modeled in this study were found not to be noticeably affecting the reconstructed dose. The phase matching was performed equally well in a digital phantom.

Conclusions: The method of retrospective phase determination of a moving object under irradiation provided successful 4D dose reconstruction. This method will provide accurate quality assurance and facilitate adaptive therapy when distinguishable objects such as well-defined tumors, diaphragm, and organs with markers (pancreas and liver) are covered by treatment beam apertures.
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http://dx.doi.org/10.1118/1.4954317DOI Listing
July 2016

Analysis of Migration Patterns of Disk Fragments and Contributing Factors in Extruded Lumbar Disk Herniation.

PM R 2017 01 16;9(1):15-20. Epub 2016 Jun 16.

Department of Rehabilitation Medicine, Dongsan Medical Center, School of Medicine, Keimyung University, Daegu, Korea; Pain Research Center, School of Medicine, Keimyung University, Daegu, Korea(¶).

Background: The exact location of migrated extruded lumbar disk fragments is an important consideration in selecting a treatment plan. However, few descriptive reports of the migration pattern of extruded lumbar disk fragments are available.

Objective: To examine the distribution of disk fragments and possible contributing factors that affect their migration.

Design: Retrospective descriptive study.

Setting: Tertiary university outpatient and inpatient clinic.

Patients: A total of 164 patients diagnosed with a symptomatic extruded lumbar disk from January 2011 to December 2012.

Methods: Lumbar spine magnetic resonance imaging scans of patients were retrospectively reviewed. The term "migration" was defined as the horizontal and vertical displacement of extruded material away from the opening in the annulus through which the material has extruded. Migration of the disk material was recorded in both the horizontal and vertical plane. In the horizontal plane, migration was recorded as central, paracentral, subarticular, or foraminal. In the vertical plane, migration was recorded as rostral or caudal.

Main Outcome Measurements: The pattern of migration and the associated factors (age and the level of herniation) were analyzed.

Results: Rostral and caudal migration was observed in 27% (95% confidence interval [CI], 21%-35%) and 73% (95% CI, 66%-79%) of the patients. Central, paracentral, subarticular, and foraminal migration was observed in 6% (95% CI, 3%-11%), 67% (95% CI, 60%-74%), 18% (95% CI, 13%-25%), and 9% (95% CI, 5%-14%) of the patients, respectively. A significant increase was observed in the incidence of rostral migration with increasing age (P = .048). A significant association was also noted between migration in the horizontal plane and increasing age (P = .01). A significant increase occurred in the incidence of foraminal extrusion with increasing age (P = .01). A significant association was found between migration in the vertical plane and horizontal plane; in patients with foraminal herniations, migration was always rostral (P < .001).

Conclusion: The migration of extruded lumbar disk materials follows some general patterns. The results of this study may help spine interventionists and surgeons choose appropriate treatments for patients who have radiculopathy associated with lumbar disk extrusions.

Level Of Evidence: IV.
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http://dx.doi.org/10.1016/j.pmrj.2016.06.007DOI Listing
January 2017

Erratum: Tracheal Involvement in Crohn Disease: the First Case in Korea.

Clin Endosc 2016 May;49(3):310

Division of Gastroenterology, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.

[This corrects the article on p. 202 in vol. 49, PMID: 26879553.].
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http://dx.doi.org/10.5946/ce.2015.059.e1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895941PMC
May 2016

A Monte Carlo calculation model of electronic portal imaging device for transit dosimetry through heterogeneous media.

Med Phys 2016 May;43(5):2242

Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354.

Purpose: To develop and evaluate a fast Monte Carlo (MC) dose calculation model of electronic portal imaging device (EPID) based on its effective atomic number modeling in the XVMC code.

Methods: A previously developed EPID model, based on the XVMC code by density scaling of EPID structures, was modified by additionally considering effective atomic number (Zeff) of each structure and adopting a phase space file from the EGSnrc code. The model was tested under various homogeneous and heterogeneous phantoms and field sizes by comparing the calculations in the model with measurements in EPID. In order to better evaluate the model, the performance of the XVMC code was separately tested by comparing calculated dose to water with ion chamber (IC) array measurement in the plane of EPID.

Results: In the EPID plane, calculated dose to water by the code showed agreement with IC measurements within 1.8%. The difference was averaged across the in-field regions of the acquired profiles for all field sizes and phantoms. The maximum point difference was 2.8%, affected by proximity of the maximum points to penumbra and MC noise. The EPID model showed agreement with measured EPID images within 1.3%. The maximum point difference was 1.9%. The difference dropped from the higher value of the code by employing the calibration that is dependent on field sizes and thicknesses for the conversion of calculated images to measured images. Thanks to the Zeff correction, the EPID model showed a linear trend of the calibration factors unlike those of the density-only-scaled model. The phase space file from the EGSnrc code sharpened penumbra profiles significantly, improving agreement of calculated profiles with measured profiles.

Conclusions: Demonstrating high accuracy, the EPID model with the associated calibration system may be used for in vivo dosimetry of radiation therapy. Through this study, a MC model of EPID has been developed, and their performance has been rigorously investigated for transit dosimetry.
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http://dx.doi.org/10.1118/1.4945276DOI Listing
May 2016

Radiological Stability after Revision of Infected Total Knee Arthroplasty Using Modular Metal Augments.

Knee Surg Relat Res 2016 Mar 29;28(1):55-61. Epub 2016 Feb 29.

Department of Orthopedic Surgery, Keimyung University School of Medicine, Daegu, Korea.

Purpose: To evaluate the radiological stability according to the number of modular augments after revision of infected total knee arthroplasty (TKA).

Materials And Methods: Between February 2006 and September 2013, 37 patients (39 knees) followed ≥2 years after revision of infected TKA using modular metal augments for bone defects were reviewed retrospectively. We divided the patients into 3 groups according to the number of augments into group A (≤2 augments, 14 knees), group B (3-4 augments, 18 knees), and group C (5≥ augments, 7 knees) and evaluated the width of radiolucent zones around the implant at the last follow-up.

Results: There were 3 Anderson Orthopedic Research Institute type I, 33 type II, and 3 type III bone defects. The mean number of radiolucent zones of group A was 3 and the sum of width averaged 4.4 mm. In group B, the values were 4.8 and 6.2 mm, respectively. In group C, the values were 8.1 and 12.9 mm, respectively. The differences between the three groups were statistically significant.

Conclusions: In revision TKA with modular metal augmentation caused by infected TKA, increased modularity can result in radiological instability.
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http://dx.doi.org/10.5792/ksrr.2016.28.1.55DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4779806PMC
March 2016

Tracheal Involvement in Crohn Disease: the First Case in Korea.

Clin Endosc 2016 Mar 16;49(2):202-6. Epub 2016 Feb 16.

Division of Gastroenterology, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.

Respiratory involvement in Crohn disease (CD) is rare condition with only about a dozen reported cases. We report the first case of CD with tracheal involvement in Korea. An 18-year-old woman with CD was hospitalized because of coughing, dyspnea, and fever sustained for 3 weeks. Because she had stridor in her neck, we performed computed tomography of the neck, which showed circumferential wall thickening of the larynx and hypopharynx. Bronchoscopy revealed mucosal irregularity, ulceration, and exudates debris in the proximal trachea, and bronchial biopsy revealed chronic inflammation with granulation tissue. Based on these findings, we suspected CD with tracheal involvement and began administering intravenous methylprednisolone at 1 mg/kg per day, after which her symptoms and bronchoscopic findings improved.
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http://dx.doi.org/10.5946/ce.2015.059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4821520PMC
March 2016

Gender Affects Early Postoperative Outcomes of Rotator Cuff Repair.

Clin Orthop Surg 2015 Jun 18;7(2):234-40. Epub 2015 May 18.

Department of Orthopedic Surgery, Hanmi Hospital, Daegu, Korea.

Background: The literature does not provide consistent information on the impact of patients' gender on recovery after rotator cuff repair. The purpose of this study was to determine whether gender affects pain and functional recovery in the early postoperative period after rotator cuff repair.

Methods: Eighty patients (40 men and 40 women) were prospectively enrolled. Pain intensity and functional recovery were evaluated, using visual analog scale (VAS) pain score and range of motion on each of the first 5 postoperative days, at 2 and 6 weeks and at 3, 6, and 12 months after surgery. Perioperative medication-related adverse effects and postoperative complications were also assessed.

Results: The mean VAS pain score was significantly higher for women than men at 2 weeks after surgery (p = 0.035). For all other periods, there was no significant difference between men and women in VAS pain scores, although women had higher scores than men. Mean forward flexion in women was significantly lower than men at 6 weeks after surgery (p = 0.033) and the mean degree of external rotation in women was significantly lower than men at 6 weeks (p = 0.007) and at 3 months (p = 0.017) after surgery. There was no significant difference in medication-related adverse effects or postoperative complications.

Conclusions: Women had more pain and slower recovery of shoulder motion than men during the first 3 months after rotator cuff repair. These findings can serve as guidelines for pain management and rehabilitation after surgery and can help explain postoperative recovery patterns to patients with scheduled rotator cuff repair.
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http://dx.doi.org/10.4055/cios.2015.7.2.234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515465PMC
June 2015

Reconstruction of organ dose for external radiotherapy patients in retrospective epidemiologic studies.

Phys Med Biol 2015 Mar 26;60(6):2309-24. Epub 2015 Feb 26.

Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA.

Organ dose estimation for retrospective epidemiological studies of late effects in radiotherapy patients involves two challenges: radiological images to represent patient anatomy are not usually available for patient cohorts who were treated years ago, and efficient dose reconstruction methods for large-scale patient cohorts are not well established. In the current study, we developed methods to reconstruct organ doses for radiotherapy patients by using a series of computational human phantoms coupled with a commercial treatment planning system (TPS) and a radiotherapy-dedicated Monte Carlo transport code, and performed illustrative dose calculations. First, we developed methods to convert the anatomy and organ contours of the pediatric and adult hybrid computational phantom series to Digital Imaging and Communications in Medicine (DICOM)-image and DICOM-structure files, respectively. The resulting DICOM files were imported to a commercial TPS for simulating radiotherapy and dose calculation for in-field organs. The conversion process was validated by comparing electron densities relative to water and organ volumes between the hybrid phantoms and the DICOM files imported in TPS, which showed agreements within 0.1 and 2%, respectively. Second, we developed a procedure to transfer DICOM-RT files generated from the TPS directly to a Monte Carlo transport code, x-ray Voxel Monte Carlo (XVMC) for more accurate dose calculations. Third, to illustrate the performance of the established methods, we simulated a whole brain treatment for the 10 year-old male phantom and a prostate treatment for the adult male phantom. Radiation doses to selected organs were calculated using the TPS and XVMC, and compared to each other. Organ average doses from the two methods matched within 7%, whereas maximum and minimum point doses differed up to 45%. The dosimetry methods and procedures established in this study will be useful for the reconstruction of organ dose to support retrospective epidemiological studies of late effects in radiotherapy patients.
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http://dx.doi.org/10.1088/0031-9155/60/6/2309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422070PMC
March 2015

An engagement factor for caregiver radiation dose assessment with radioiodine treatment.

Radiat Prot Dosimetry 2015 Mar 15;163(4):499-508. Epub 2014 Jul 15.

Department of Radiological Science, Kangwon National University, Samcheok, Korea.

This study aims to suggest ways to better manage thyroid cancer patients treated with high- and low-activity radioiodine ((131)I) by assessing external radiation doses to family members and caregivers and the level of radiation in the surrounding environment. The radiation doses to caregivers of 33 inpatients (who were quarantined in the hospital for 2-3 d after treatment) and 31 outpatients who received radioiodine treatment after thyroidectomy were measured using passive thermoluminescence dosemeters. In this study, 33 inpatients were administered high-activity (100-200 mCi) (131)I, and 31 outpatients were administered low-activity (30 mCi) (131)I. The average doses to caregivers were measured at 0.61 mSv for outpatients and 0.16 mSv for inpatients. The total integrated dose of the recovery (recuperation) rooms where the patients stayed after release from hospital was measured to be 0.83 mSv for outpatients and 0.23 mSv for inpatients. To reflect the degree of engagement between the caregiver and the patient, considering the duration and distance between two during exposure, the authors used the engagement factor introduced by Jeong et al. (Estimation of external radiation dose to caregivers of patients treated with radioiodine after thyroidectomy. Health Phys 2014; 106: :466-474.). This study presents a new engagement factor (K-value) of 0.82 obtained from the radiation doses to caregivers of both in- and out-patients treated with high- and low-activity radioiodine, and based on this new value, this study presented a new predicted dose for caregivers. A patient treated with high-activity radioiodine can be released after 24 h of isolation, whereas outpatients treated with low-activity radioiodine should be isolated for at least 12 h.
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http://dx.doi.org/10.1093/rpd/ncu231DOI Listing
March 2015

Estimation of external radiation dose to caregivers of patients treated with radioiodine after thyroidectomy.

Health Phys 2014 Apr;106(4):466-74

*Korea Institute of Nuclear Safety; †Hanyang University; ‡East Carolina University; §Kyungpook National University School of Medicine; **Eulji University Hospital; ††Korea Advanced Institute of Science and Technology.

Due to the remarkable increase in thyroid cancer cases, the number of patients treated with radioiodine (I) shows a sharply increasing trend in recent years. Accordingly, radiation exposure of other people, particularly caregivers or comforters, after release of patients from hospitals is getting more attention than ever. In the present study, empirical equations are proposed for estimation of doses to caregivers. Only patients administered with therapeutic amounts of ¹³¹I after thyroidectomy were considered. External radiation doses to 70 caregivers or family members were measured using thermoluminescence dosimeters (TLDs). The mean, external, effective dose to caregivers, during a nursing period of 5-9 d after patient quarantine for 3-4 d in the hospital, was 0.12 ± 0.10 mSv. This is only 2.5% of the dose limit recommended by the International Commission on Radiological Protection for caregivers. By analyzing those individual doses to the caregivers, values of a factor affecting caregiver doses, K, are obtained for use in estimation of caregivers' doses. The factor reflects the degree of engagement of the caregiver to the patient, and hence it is named the "engagement factor." The mean value of the engagement factor in this study was 1.3 ± 0.88. With the help of the engagement factor, the total external dose to a caregiver can be estimated as 1.1 × Q₀ × e⁻⁰·⁰⁵(Tr) mSv, where Q₀ is the administered activity of ¹³¹I (GBq) and T(r) is the patient's release time (h) after admistration of radioiodine. Based on the dose estimation model developed in this study, by comparing the cost of extended quarantine against that incurred by release of the patient, including the burden of radiation exposure of caregivers or family members, the reasonableness of current quarantine periods was revisited. It was found that the dichotomous policy (i.e., hospitalizing patients administered ¹³¹I over 1.1 GBq for a period of 3-4 d compared with treating other patients administered below 1.1 GBq as outpatients) is unjustifiable; this is particularly true for those treated with a few GBq. Based upon the dose estimation model presented herein, tables suggesting an appropriate quarantine period depending upon the activity of the administered ¹³¹I are provided for use as reference in deciding when to release patients treated with therapy levels of ¹³¹I after thyroidectomy.
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http://dx.doi.org/10.1097/HP.0b013e3182a415ebDOI Listing
April 2014
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