Jae-Sung Kim

Seoul National University Hospital, Sŏul, Seoul, South Korea

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Publications (87)208.77 Total impact

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    ABSTRACT: Because miR-146a expression in articular chondrocytes is associated with osteoarthritis (OA), we assessed whether miR-146a is linked to cartilage degeneration in the spine. Monolayer cultures of nucleus pulposus (NP) cells from the intervertebral discs (IVD) of bovine tails were transfected with a miR-146a mimic. To provoke inflammatory responses and catabolic extracellular matrix (ECM) degradation, cells were co-treated with interleukin-1 (IL-1). Transfection of miR-146a decreases IL-1 induced mRNA levels of inflammatory genes and catabolic proteases in NP cells based on quantitative real-time reverse transcriptase PCR (qRT-PCR) analysis. Similarly, miR146a suppresses IL-1 induced protein levels of matrix metalloproteinases and aggrecanases as revealed by immunoblotting. Disc segments from wild type (WT) and miR-146a knockout (KO) mice were cultured ex vivo in the presence or absence of IL-1 for 3days. Histological and immuno-histochemical (IHC) analyses of disc organ cultures revealed that IL-1 mediates changes in proteoglycan (PG) content and in-situ levels of catabolic proteins (MMP-13 and ADAMTS-5) in the nucleus pulposus of the disc. However, these IL-1 effects are more pronounced in miR-146a KO discs compared to WT discs. For example, absence of miR-146a increases the percentage of MMP-13 and ADAMTS-5 positive cells after treatment with IL-1. Thus, miR-146a appears to protect against IL-1 induced IVD degeneration and inflammation. Stimulation of endogenous miR-146a expression or exogenous delivery of miRNA-146a are viable therapeutic strategies that may decelerate disc degeneration and regain a normal homeostatic balance in extracellular matrix production and turn-over.
    Gene 10/2014; · 2.20 Impact Factor
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    ABSTRACT: The aim of this study was to examine the clinical implications of a pathologically complete response after neoadjuvant chemoradiotherapy (CRT) followed by local excision for patients with cT2 rectal cancer who refused radical surgery.
    Cancer research and treatment : official journal of Korean Cancer Association. 07/2014; 46(3):243-249.
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    ABSTRACT: To find the applicability of adjuvant radiotherapy for extrahepatic bile duct cancer (EBDC), we analyzed the pattern of failure and evaluate prognostic factors of locoregional failure after curative resection without adjuvant treatment.
    Radiation oncology journal. 06/2014; 32(2):63-9.
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    ABSTRACT: The aim of this study was to compare the dosimetric performance and to evaluate the pretreatment quality assurance (QA) of a portal dosimetry and a commercial two-dimensional (2-D) array system. In the characteristics comparison study, the measured values for the dose linearity, dose rate response, reproducibility, and field size dependence for 6-MV photon beams were analyzed for both detector systems. To perform the qualitative evaluations of the 10 IMRT and the 10 VMAT plans, we used the Gamma index for quantifying the agreement between calculations and measurements. The performance estimates for both systems show that overall, minimal differences in the dosimetric characteristics exist between the Electron portal imaging device (EPID) and 2-D array system. In the qualitative analysis for pretreatment quality assurance, the EPID and 2-D array system yield similar passing rate results for the majority of clinical Intensity-modulated radiation therapy (IMRT) and Volumetric-modulated arc therapy (VMAT) cases. These results were satisfactory for IMRT and VMAT fields and were within the acceptable criteria of γ%≤1, γavg<0.5. The EPDI and the 2-D array systems showed comparable dosimetric results. In this study, the results revealed both systems to be suitable for patient-specific QA measurements for IMRT and VMAT. We conclude that, depending on the status of clinic, both systems can be used interchangeably for routine pretreatment QA.
    Journal- Korean Physical Society 04/2014; 64(8):1207-1212. · 0.51 Impact Factor
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    ABSTRACT: Pre-operative chemoradiotherapy (CRT) is the standard treatment in clinical stage T3/4 or node positive rectal cancer. However, there are no established biomarkers that can predict the pathological response and clinical outcome to CRT. Immunohistochemical staining was performed in tissue arrays constructed from core tissue specimens taken before treatment and from operative specimens from 112 patients who received 5-FU based pre-operative CRT and surgery. Expression of Ki67, TS, BAX, EpCAM, p53, p21, EGFR, CD44, CD133, CD166, HIF1alpha and ALDH1 were assessed and correlated with tumor regression grades and disease free survival. Of the 112 patients (M/F 74/38, median age: 62), 20 (17.9%) patients achieved pathologic complete remission (pCR). In analyzing the associations between marker expressions and tumor regression grades, high p21 expression at the pretreatment biopsy was significantly associated with non-pCR (p = 0.022) and poor disease free survival (median DFS - low vs high p21: 75.8 vs 58.1 months, p = 0.002). In the multivariate analysis, high p21 expression level at the pre-treatment biopsy was significantly associated with poor DFS (p = 0.001, HR 6.14; 95% CI 2.03, 18.55). High CD166 expression level at the pretreatment biopsy was also associated with poor DFS (p = 0.003; HR 5.61; 95% CI 1.81, 17.35). These show high p21 and CD166 expression at the pretreatment biopsy were associated with tumor regression and poor prognosis in patients treated with 5-FU based CRT. Larger, prospective and functional studies are warranted to determine the role of p21 and CD166 as predictive biomarker of response to CRT.
    BMC Cancer 04/2014; 14(1):241. · 3.33 Impact Factor
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    ABSTRACT: Although lateral pelvic node dissection (LPND) is recommended for rectal cancer with clinically metastatic lateral pelvic lymph nodes (LPNs), LPNs may respond to neoadjuvant chemoradiotherapy (nCRT). Our aim was to determine the optimal indication for LPND after nCRT for mid/low rectal cancer. Of 2,263 patients with clinical stage II/III mid/low rectal cancer who were managed at three tertiary referral hospitals, 66 patients underwent curative surgery including LPND after nCRT were included in this study. Risk factors for LPN metastasis were retrospectively analyzed and oncologic outcomes determined according to LPN response to nCRT. Persistent LPNs greater than 5 mm on post-nCRT magnetic resonance imaging were significantly associated with residual tumor metastasis, unlike responsive LPN after nCRT (short-axis diameter ≤5 mm) (pathologically, 61.1 % [22 of 36] vs. 0 % [0 of 30], P < 0.001). Multivariable analysis revealed post-nCRT LPN size as a significant and independent risk factor for LPN metastasis (odds ratio 2.390; 95 % confidence interval 1.104-4.069). Over a median follow-up of 39.3 months, the recurrence rate was lower in patients with responsive nodes than in patients with persistent nodes (20 % [6 of 30] vs. 47.2 % [17 of 36], P = 0.012). The 5-year overall survival and 5-year disease-free survival rates were lower in patients with persistent LPN than in patients with responsive LPN (44.6 % vs. 77.1 %, P = 0.034; 33.7 % vs. 72.5 %, P = 0.011, respectively). In mid/low rectal cancer with clinically metastatic LPNs, the decision to perform LPND should be based on the LPN response to nCRT.
    Annals of Surgical Oncology 03/2014; · 4.12 Impact Factor
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    ABSTRACT: The aim of the present study was to investigate and compare the effects of diferuloylmethane (curcumin) and diphenyldifluoroketone (EF-24) on cell growth and apoptosis induction in human osteogenic sarcoma cells. This was examined by MTT assay, nuclear DAPI staining, caspase-activation assay, flow cytometry analysis and immunoblotting in Saos2 human osteogenic sarcoma cells. Curcumin and EF-24 inhibited the growth of Saos2 cells in a dose-dependent manner. The apparent potency of EF-24 was more than 3-fold higher that of curcumin. Treatment with curcumin or EF-24 resulted in nuclear condensation and fragmentation in the cells. The caspase-3/-7 activities were detected in living cells treated with curcumin or EF-24. Flow cytometry showed that the rate of apoptosis was increased by curcumin and EF-24 compared to the control. Curcumin and EF-24 promoted the proteolytic cleavages of procaspase-3/-7/-8/-9 with increases in the amount of cleaved caspase-3/-7/-8/-9. The curcumin- or EF-24-induced apoptosis in the Saos2 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3 and poly(ADP-ribose) polymerase. Immunoblotting revealed the Bid and Bcl-2 proteins to be downregulated, and truncated-Bid, Bax and p53 proteins to be upregulated by curcumin and EF-24. Curcumin and EF-24 increased the Bax/Bcl-2 ratio significantly. These results suggest that the curcumin and EF-24 inhibit cell proliferation and induce apoptotic cell death in Saos2 human osteogenic sarcoma cells via both the mitochondria-mediated intrinsic pathway and the death receptor-mediated extrinsic pathway, and may have potential properties for anti-osteosarcoma drug discovery.
    Oncology Reports 03/2014; · 2.30 Impact Factor
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    ABSTRACT: Compared to most normal cells that express L-type amino acid transporter 2, L-type amino acid transporter 1 is highly expressed in cancer cells and presumed to support their elevated growth and proliferation. This study examined JPH203, a potent and selective L-type amino acid transporter 1 inhibitor, and its ability to suppress YD-38 human oral cancer cell growth. The YD-38 cells express L-type amino acid transporter 1 with its associating protein 4F2 heavy chain, but not L-type amino acid transporter 2. JPH203 and BCH, a non-selective L-type amino acid transporter inhibitor, completely inhibited l-leucine uptake in YD-38 cells. As expected, the intrinsic affinity of JPH203 to inhibit l-leucine uptake was far more efficient than BCH. Likewise, JPH203 and BCH inhibited YD-38 cell growth, with JPH203 being superior to BCH. JPH203 up-regulated the population of apoptotic YD-38 cells through the activation of apoptotic factors, including caspases and PARP. These results suggest that the inhibition of L-type amino acid transporter 1 activity via JPH203, which may act as a potential novel anti-oral-cancer agent, leads to apoptosis by inducing the intracellular depletion of the neutral amino acids essential for cancer cell growth in YD-38 human oral cancer cells.
    Journal of Pharmacological Sciences 02/2014; · 2.15 Impact Factor
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    ABSTRACT: MicroRNAs (miRNAs) play an essential role in regulating cell differentiation either by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontoblastic cell differentaion is largely unknown. In the present study, we demonstrate that the expression of miR-27 was significantly increased during MDPC-23 odontoblastic cell differentiation. Furthermore, the up-regulation of miR-27 promotes the differentiation of MDPC-23 odontoblastic cells and accelerates mineralization without cell proliferation. In addition, our results of target gene prediction revealed that the mRNA of adenomatous polyposis coli (APC) associated with Wnt/β-catenin signaling pathway has miR-27 binding site in the its 3'UTR and is suppressed by miR-27. Subsequentially, the down-regulated APC by miR-27 triggered the activation of Wnt/β-catenin signaling through accumulation of β-catenin in the nucleus. Our data suggests that miR-27 promotes MDPC-23 odontoblastic cell differentiation by targeting APC and activating Wnt/β-catenin signaling. Therefore, miR-27 might be considered a critical candidate as an odontoblastic differentiation molecular target for the development of miRNA based therapeutic agents in the dental medicine.
    Gene 01/2014; · 2.20 Impact Factor
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    ABSTRACT: MicroRNAs (miRNAs) regulate cell differentiation by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontogenic differentiation is largely unknown. In this present study, we observed that the expression of miR-663 increased significantly during differentiation of MDPC-23 cells to odontoblasts. Furthermore, up-regulation of miR-663 expression promoted odontogenic differentiation and accelerated mineralization without proliferation in MDPC-23 cells. In addition, target gene prediction for miR-663 revealed that the mRNA of the adenomatous polyposis coli (APC) gene, which is associated with the Wnt/β-catenin signaling pathway, has a miR-663 binding site in its 3'-untranslated region (3'-UTR). Furthermore, APC expressional was suppressed significantly by miR-663, and this down-regulation of APC expression triggered activation of Wnt/β-catenin signaling through accumulation of β-catenin in the nucleus. Taken together, these findings suggest that miR-663 promotes differentiation of MDPC-23 cells to odontoblasts by targeting APC-mediated activation of Wnt/β-catenin signaling. Therefore, miR-663 can be considered a critical regulator of odontoblast differentiation and can be utilized for developing miRNA-based therapeutic agents.
    Biochemical and Biophysical Research Communications 01/2014; · 2.28 Impact Factor
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    ABSTRACT: A significant proportion of patients undergoing salvage radiotherapy (RT) for biochemical recurrence (BCR) following radical prostatectomy (RP) may again experience BCR after salvage RT. Thus, we evaluated the clinical significances of different parameters on the biochemical outcome of RT in salvage setting.
    PLoS ONE 01/2014; 9(7):e103574. · 3.53 Impact Factor
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    ABSTRACT: Licochalcone A (Lico-A) is a natural phenol licorice compound with multiple bioactivities, including anti-inflammatory, anti-microbial, anti-fungal and osteogenesis-inducing properties. In the present study, we investigated the Lico-A-induced apoptotic effects and examined the associated apoptosis pathway in KB human oral cancer cells. Lico-A decreased the number of viable KB oral cancer cells. However, Lico-A did not have an effect on primary normal human oral keratinocytes. In addition, the IC50 value of Lico-A was determined to be ~50 µM following dose-dependent stimulation. KB oral cancer cells stimulated with Lico-A for 24 h showed chromatin condensation by DAPI staining, genomic DNA fragmentation by agarose gel electrophoresis and a gradually increased apoptotic cell population by FACS analysis. These data suggest that Lico-A induces apoptosis in KB oral cancer cells. Additionally, Lico‑A‑induced apoptosis in KB oral cancer cells was mediated by the expression of factor associated suicide ligand (FasL) and activated caspase-8 and -3 and poly(ADP-ribose) polymerase (PARP). Furthermore, in the KB oral cancer cells co-stimulation with a caspase inhibitor (Z-VAD-fmk) and Lico-A significantly abolished the apoptotic phenomena. Our findings demonstrated that Lico‑A-induced apoptosis in KB oral cancer cells involves the extrinsic apoptotic signaling pathway, which involves a caspase-dependent FasL-mediated death receptor pathway. Our data suggest that Lico-A be developed as a chemotherapeutic agent for the management of oral cancer.
    Oncology Reports 12/2013; · 2.30 Impact Factor
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    ABSTRACT: A novel fibrinolytic enzyme was purified from Lyophyllum shimeji, a popular edible mushroom in Asia. The enzyme was purified using combination of anion exchange chromatography on a Mono Q 5/5 column and size exclusion gel filtration chromatography on Superdex 200 100/300 column. This purification protocol resulted 80.9-fold purification of the enzyme and a final yield of 5.7%. The molecular weight of the purified enzyme was estimated to be 21 kDa by SDS-PAGE and size exclusion gel filtration. The N-terminal amino acid sequence was found to be ITFQSASP, which is dissimilar from that of known fibrinolytic enzymes. The purified enzyme was a neutral protease with an optimal reaction pH and temperature of 8.0 and 37°C, respectively. Enzymatic activity was inhibited by Cu(2+) and Co(2+). It was also significantly inhibited by PMSF and TPCK. Furthermore, it was found to exhibit a higher specificity for S-7388, a well-known chymotrypsin chromogenic substrate, indicating chymotrypsin like serine metalloprotease. The relative fibrinolytic activity of 5 μg purified enzyme have two fold more activity than 1 unit/ml of plasmin on fibrin plate. Furthermore, purified enzyme preferentially hydrolyzed the Aα-chain followed by the Bβ- and γ-chain of fibrinogen, which is precursor of fibrin. Therefore, these data suggests that the fibrinolytic enzyme derived from edible mushroom, L. shimeji, might be useful for thrombolytic therapy and preventing thrombotic disease.
    Journal of Bioscience and Bioengineering 12/2013; · 1.74 Impact Factor
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    ABSTRACT: We used an endorectal balloon (ERB) for prostate immobilization during intensity-modulated radiotherapy (IMRT) for prostate cancer treatment. To investigate the dosimetric effects of ERB-filling materials, we changed the ERB Hounsfield unit (HU) from 0 to 1000 HU in 200-HU intervals to simulate the various ERB fillings; 0 HU simulated a water-filled ERB, and 1000 HU simulated the densest material-filled ERB. Dosimetric data (coverage, homogeneity, conformity, maximal dose, and typical volume dose) for the tumor and the organs at risk (OARs) were evaluated in prostate IMRT treatment plans with 6-MV and 15-MV beams. The tumor coverage appeared to differ by approximately 1%, except for the clinical target volume (CTV) V100% and the planning target volume (PTV) V100%. The largest difference for the various ERB fillings was observed in the PTV V100%. In spite of increasing HU, the prostate IMRT plans at both energies had relatively low dosimetric effects on the PTV and the CTV. However, the maximal and the typical volume doses (D25%, D30%, and D50%) to the rectal wall and the bladder increased with increasing HU. For an air-filled ERB, the maximal doses to the rectal wall and the monitor units were lower than the corresponding values for the water-filled and the densest material-filled ERBs. An air-filled ERB spared the rectal wall because of its dosimetric effect. Thus, we conclude that the use of an air-filled ERB provides a dosimetric benefit to the rectal wall without a loss of target coverage and is an effective option for prostate IMRT treatment.
    Journal- Korean Physical Society 11/2013; 63:1637-1643. · 0.51 Impact Factor
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    ABSTRACT: MicroRNA (miRNA) is a small noncoding RNA molecule, 19-25 nucleotides in length, which regulates several pathways including cell development, cell proliferation, carcinogenesis, apoptosis, etc. In this study, the over-expression of microRNA-205 (miR-205) increased the number of apoptotic cells by at least 4 times compared to the control. In addition, over-expressed miRNA in KB oral cancer cells triggered apoptosis via the caspase cascade, including the cleavage of caspase-9, caspase-7, caspase-3, and PARP. Flow cytometry showed that apoptotic cell death was increased significantly by 35.33 % in KB oral cancer cells with over-expressed miR-205 compared to the control. The microarray data showed that axis inhibitor protein 2 (Axin2) was down-regulated in KB oral cancer cells transfected with miR-205. In addition, Axin2 was down-regulated by approximately 50 % by over-expressed miR-205 at both the mRNA and protein levels. Interestingly, Axin2 was up-regulated in KB oral cancer compared to human normal oral keratinocytes. Furthermore, the cell cytotoxicity and apoptotic population of KB oral cancer cells were increased significantly after Axin2 siRNA transfection. These results suggest that Axin2 is might be as potential oncogene in KB oral cancer cells. The luciferase assay showed that over-expressed miR-205 in KB oral cancer cells suppressed AXIN2 expression through an interaction with its own binding site at AXIN2 3'UTR (64-92). These results suggest that miR-205 is a novel anti-oncogenic miRNA in KB oral cancer cells, and may have potential applications in oral cancer therapy.
    Molecular and Cellular Biochemistry 10/2013; · 2.33 Impact Factor
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    ABSTRACT: To evaluate the role of salvage radiotherapy (RT) for the treatment of regional lymph node recurrence (RLNR) after radical surgery in advanced gastric cancer. We retrospectively analyzed medical records of 26 patients who underwent salvage treatment after diagnosis of RLNR between 2006 and 2011. Patients with peritoneal seeding or distant metastasis were excluded. Eighteen patients received RT with or without chemotherapy and the other 8 did chemotherapy only without RT. A three-dimensional conformal RT was performed with median dose of 56 Gy (range, 44 to 60 Gy). Sixteen patients had fluoropyrimidine-based chemotherapy, 5 did taxane-based chemotherapy, and irinotecan was applied in 4. With a median follow-up of 20 months (range, 5 to 57 months), median overall survival (OS) and progression-free survival (PFS) after diagnosis of RLNR were 29 months and 12 months in the entire patients, respectively. Radiotherapy (p = 0.007) and disease-free interval (p = 0.033) were statistically significant factors for OS in multivariate analysis. Median OS was 36 months in patients who received RT and 16 months in those who did not. Furthermore, delivery of RT (p < 0.001), complete remission after salvage treatment (p = 0.040) and performance status (p = 0.023) were associated with a significantly better PFS. Gastrointestinal toxicities from RT were mild in most patients. Salvage RT combined with systemic chemotherapy may be an effective treatment managing RLNR from advanced gastric cancer.
    Radiation oncology journal. 09/2013; 31(3):147-54.
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    ABSTRACT: Patients with insufficient residual alveolar bone height are often treated using short implants. Historically, short implants are associated with higher failure rates. However, recent research has shown short implants with modified surfaces to have success rates similar to those of longer implants. This retrospective report aimed to evaluate clinical outcomes of 8-mm widediameter, moderately rough threaded implants in the posterior maxilla. From June 2008 through May 2010, 16 patients were identified who had been treated with short implants. The mean age of the patients was 50.4 years, the mean primary stability of the implants was 66 ISQ, the mean secondary stability was 75.6, and the mean loading time was 16.2 months. There were no failed implants. The mean marginal bone loss at final follow-up was 0.04 mm. This study exhibited excellent short-term clinical outcomes.
    The International journal of periodontics & restorative dentistry. 07/2013; 33(4):e95-e100.
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    ABSTRACT: OBJECTIVE: Examine whether altered expression of microRNAs in central nervous system components is pathologically linked to chronic knee joint pain in osteoarthritis. METHODS: A surgical animal model for knee joint OA was generated by medial meniscus transection in rats followed by behavioral pain tests. Relationships between pathological changes in knee joint and development of chronic joint pain were examined by histology and imaging analyses. Alterations in microRNAs associated with OA-evoked pain sensation were determined in bilateral lumbar dorsal root ganglia (DRG) and the spinal dorsal horn by microRNA array followed by individual microRNA analyses. Gain- and loss-of-function studies of selected microRNAs (miR-146a and miR-183 cluster) were conducted to identify target pain mediators regulated by these selective microRNAs in glial cells. RESULTS: The ipsilateral hind leg displayed significantly increased hyperalgesia after 4 weeks of surgery and sensitivity was sustained for the remainder of the 8 week experimental period (F = 341, P < 0.001). The development of OA-induced chronic pain was correlated with pathological changes in the knee joints as assessed by histological and imaging analyses. MicroRNA analyses showed that miR-146a and the miR-183 cluster were markedly reduced in the sensory neurons in DRG (L4/L5) and spinal cord from animals experiencing knee joint OA pain. The downregulation of miR-146a and/or the miR-183 cluster in the central compartments (DRG and spinal cord) are closely associated with the upregulation of inflammatory pain mediators. The corroboration between decreases in these signature microRNAs and their specific target pain mediators were further confirmed by gain- and loss-of-function analyses in glia, the major cellular component of the central nervous system (CNS). CONCLUSION: MicroRNA therapy using miR-146a and the miR-183 cluster could be powerful therapeutic intervention for OA in alleviating joint pain and concomitantly regenerating peripheral knee joint cartilage.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 06/2013; · 6.04 Impact Factor
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    ABSTRACT: This study is intended to investigate the effects of surface dose from air gaps under the bolus in clinically used oblique photon beams by using a Markus parallel-plate chamber and a metal-oxide semiconductor field-effect transistor (MOSFET) dosimeter. To evaluate the performances of the two detectors, the percentage surface doses of the MOSFET dosimeters in without an air gap under the bolus material were measured and compared with those of the Markus parallel-plate chamber. MOSFET dosimeters at the surface provided results mostly in good agreement with the parallel-plate chamber. The MOSFET dosimeters seemed suitable for surface dose measurements having excellent accuracy for clinical used photon beams. The relative surface doses were measured with air gaps (2, 5, 10 mm) and without an air gap under 3 different bolus setups: (1) unbolused (no bolus), (2) 5-mm bolus, and (3) 10-mm bolus. The reductions in the surface dose substantially increased with small field size, thick bolus, and large air gap. The absolute difference in the reductions of the surface dose between the MOSFET dosimeter and the Markus parallel-plate chamber was less than 1.1%. Results at oblique angles of incidence showed larger reductions in surface dose with increasing angle of incidence. The largest reduction in surface dose was recorded for a 6 × 6 cm 2 field at a 60 • angle of incidence with an 10-mm air gap under a 10-mm bolus. When a 10-mm bolus was used, a reduction in the surface dose with an air gap of up to 10.5% could be achieved by varying the field size and the incident angle. Therefore, air gaps under the bolus should be avoided in radiotherapy treatment, especially for photon beam with highly oblique angles of incidence.
    Journal- Korean Physical Society 03/2013; 61:1143-1147. · 0.51 Impact Factor
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    ABSTRACT: In this study, the effect of the beam energy on the intensity modulated radiation therapy (IMRT) plan for prostate cancer was studied for competing IMRT plans optimized for delivery with either 6-or 15-MV photons. This retrospective planning study included 10 patients treated for localized prostate cancer at the Seoul National University Bundang Hospital. A dose of 66 Gy was prescribed in 33 daily fractions of 2 Gy. For inverse IMRT treatment planning, we used a 7-coplanar non-opposed beam arrangement at 0, 50, 100, 150, 210, 260, and 310 degree angles. To ensure that differences among the plans were due only to energy selection, the beam arrangement, number of beam, and dose constraints were kept constant for all plans. The dose volume histograms (DVHs) for the 6-and 15-MV plans were compared for the planning target volume (PTV) and for organs at risk (OAR), such as the rectum, bladder and both femoral heads. The conformal index was defined as the ratio of the 95% isodose volume divided by the PTV volume enclosed by the 95% isodose line, because we selected the 95% isodose line as our reference. Doses received by the 95% and 5% volume of the PTV were less than or equal to 1% for 6-MV compared to the 15-MV IMRT plan for 10 patients. Percentage of doses received by the 10% volume of the bladder and rectum were less than or equal to 1%. Percentage of doses received by the 30 and 50% volume of bladder and rectum were 1 ∼ 2% higher for 6-MV photons. Also, percentage of dose received by the 10% and 50% volume of the right and the left femur heads were 4 ∼ 5% higher for 6-MV photons. The mean homogeneity index for the 6-MV and 15-MV photon plans was 1.06. The mean conformity index of 95% was 1.04 ± 0.01 and 1.12 ± 0.02 for 6-MV and 15-MV, respectively, but this difference was not statistically significant. The mean monitor unit was 812 ± 40 and 716 ± 33 for the 6-MV and the 15-MV photon plans, respectively. The 6-MV photon plan delivers 13.4% more MU than the 15-MV plan. The-15 MV dose distributions and DVHs of the PTV generated by the clinical treatment planning calculations were as good as, or slightly better than, those generated for 6-MV photons. The organs at risk, such as the rectum, bladder, and femoral head were also similar, with the DVH curve for the 6-MV plan being slightly higher near the low-dose region, but lower near the high-dose region. Therefore, we recommend the use of 15-MV photons for IMRT of prostate cancer to achieve better in target coverage, in addition, the integrated dose can be reduce by using IMRT with 15 MV photons.
    Journal- Korean Physical Society 03/2013; 59(59). · 0.51 Impact Factor

Publication Stats

745 Citations
208.77 Total Impact Points

Institutions

  • 2010–2014
    • Seoul National University Hospital
      • • Department of Radiation Oncology
      • • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2008–2014
    • Seoul National University Bundang Hospital
      • • Department of Radiation Oncology
      • • Department of Surgery
      Sŏul, Seoul, South Korea
  • 2007–2014
    • Chosun University
      • • Oral Biology Research Institute
      • • Department of Biotechnology
      Gwangju, Gwangju, South Korea
  • 2013
    • Konkuk University Medical Center
      • Department of Radiation Oncology
      Changnyeong, South Gyeongsang, South Korea
  • 2009–2013
    • Rush University Medical Center
      • • Section of Rheumatology
      • • Department of Biochemistry
      Chicago, IL, United States
    • Chungnam National University
      • Department of Radiaton Oncology
      Daiden, Daejeon, South Korea
  • 2012
    • Catholic University of Korea
      • College of Medicine
      Seoul, Seoul, South Korea
  • 1999–2009
    • Korea Hydro and Nuclear Power - Central Research Institute
      Sŏul, Seoul, South Korea
  • 2006
    • Seoul National University
      • Department of Radiation Oncology
      Sŏul, Seoul, South Korea
  • 2005
    • Dongshin University
      Eidō, North Chungcheong, South Korea
  • 2001
    • Kepco
      Sŏul, Seoul, South Korea