• Progress in Medical Physics
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• v.13 no.3
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• pp.149-155
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• 2002

Recent advances in radiation transport algorithms, computer hardware performance, and parallel computing make the clinical use of Monte Carlo based dose calculations possible. To compare the speed and accuracies of dose calculations between different developed codes, a benchmark tests were proposed at the XIIth ICCR (International Conference on the use of Computers in Radiation Therapy, Heidelberg, Germany 2000). A Monte Carlo treatment planning comprised of 28 various Intel Pentium CPUs was implemented for routine clinical use. The purpose of this study was to evaluate the performance of our system using the above benchmark tests. The benchmark procedures are comprised of three parts. a) speed of photon beams dose calculation inside a given phantom of 30.5 cm$\times$39.5 cm $\times$ 30 cm deep and filled with 5 ㎣ voxels within 2% statistical uncertainty. b) speed of electron beams dose calculation inside the same phantom as that of the photon beams. c) accuracy of photon and electron beam calculation inside heterogeneous slab phantom compared with the reference results of EGS4/PRESTA calculation. As results of the speed benchmark tests, it took 5.5 minutes to achieve less than 2% statistical uncertainty for 18 MV photon beams. Though the net calculation for electron beams was an order of faster than the photon beam, the overall calculation time was similar to that of photon beam case due to the overhead time to maintain parallel processing. Since our Monte Carlo code is EGSnrc, which is an improved version of EGS4, the accuracy tests of our system showed, as expected, very good agreement with the reference data. In conclusion, our Monte Carlo treatment planning system shows clinically meaningful results. Though other more efficient codes are developed such like MCDOSE and VMC＋＋, BEAMnrc based on EGSnrc code system may be used for routine clinical Monte Carlo treatment planning in conjunction with clustering technique.

• Progress in Medical Physics
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• v.24 no.4
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• pp.243-252
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• 2013

The aim of this study was to clarify the impacts of acquisition parameters on artifacts in four-dimensional computed tomography (4D CT) images, such as the partial volume effect (PVE), partial projection effect (PPE), and mis-matching of initial motion phases between adjacent beds (MMimph) in cine mode scanning. A thoracic phantom and two cylindrical phantoms (2 cm diameter and heights of 0.5 cm for No.1 and 10 cm for No.2) were scanned using 4D CT. For the thoracic phantom, acquisition was started automatically in the first scan with 5 sec and 8 sec of gantry rotation, thereby allowing a different phase at the initial projection of each bed. In the second scan, the initial projection at each bed was manually synchronized with the inhalation phase to minimize the MMimph. The third scan was intentionally un-synchronized with the inhalation phase. In the cylindrical phantom scan, one bed (2 cm) and three beds (6 cm) were used for 2 and 6 sec motion periods. Measured target volume to true volume ratios (MsTrueV) were computed. The relationships among MMimph, MsTrueV, and velocity were investigated. In the thoracic phantom, shorter gantry rotation provided more precise volume and was highly correlated with velocity when MMimph was minimal. MMimph reduced the correlation. For moving cylinder No. 1, MsTrueV was correlated with velocity, but the larger MMimph for 2 sec of motion removed the correlation. The volume of No. 2 was similar to the static volume due to the small PVE, PPE, and MMimph. Smaller target velocity and faster gantry rotation resulted in a more accurate volume description. The MMimph was the main parameter weakening the correlation between MsTrueV and velocity. Without reducing the MMimph, controlling target velocity and gantry rotation will not guarantee accurate image presentation given current 4D CT technology.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.953-961
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• 1998

Background : In recent years, lung cancer has been one of most common cause of death in Korea. Despite many physician's high degree of pessimism about the gains made in treatment, progressive improvement in the survival of lung cancer by treatment has occurred, particulary in the early stages of the disease. However, a lot of patients refuse treatment or give up in the fight against the disease. This study was done to evaluate factors influencing the compliance to therapy and to lead in the establishment of special programs to enhance compliance in patients with lung cancer. Methods: The medical records of 903 patients, whose ECOG(Eastern Cooperative Oncology Group) performance status was 3 or less and whose medical record was relatively satisfactory, among 1141 patients diagnosed with lung cancer between January 1989 and December 1996 were reviewed retrospectively. Compliance was classified into three groups based on the degree of compliance with physicians practice guideline: (a) compliants; (b) patients who initially complied but gave up of themselves midway during the course of treatment; (c) noncompliants who refused the treatment. Results: The overall compliance rate was 63.9%, which was progressively increased from 57.3-61.3% in 1989 and 1990 to 64.2-67.5% in 1995 and 1996. Age, education level and occupation of patients bore statistically significant relationship with the compliance but sex, marital status and smoking history did not. The compliance was significantly higher in patients without symptoms than with, and was also significantly higher in patients with good performance status. The compliance was significantly high in patients with NSCLC(non-small cell lung cancer) compared to SCLC(small cell lung cancer), but after exclusion of stage I and II, among NSCLC, which had higher compliance to surgery there was no significant difference of compliance by histology. The compliance was significantly lower in advanced stage. Conclusion: To enhance the compliance, special care including education programs about therapy including complication and prognosis are necessary, especially for educationally and economically disadvantaged patients.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.47-51
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• 2008

Objective: This study analyzed errors due to rotation or tilt of the magnetic resonance (MR) imaging indicator during image acquisition for a stereotactic radiosurgery. The error correction procedure of a commercially available stereotactic neurosurgery treatment planning program has been verified. Materials and Methods: Software virtual phantoms were built with stereotactic images generated by a commercial programming language, Interactive Data Language (version 5.5). The thickness of an image slice was 0.5 mm, pixel size was $0.5{\times}0.5mm$, field of view was 256 mm, and image resolution was $512{\times}512$. The images were generated under the DICOM 3.0 standard in order to be used with Leksell GammaPlan$^{(R)}$. For the verification of the rotation error correction function of Leksell GammaPlan$^{(R)}$, 45 measurement points were arranged in five axial planes. On each axial plane, there were nine measurement points along a square of length 100 mm. The center of the square was located on the z-axis and a measurement point was on the z-axis, too. Five axial planes were placed at z=-50.0, -30.0, 0.0, 30.0, 50.0 mm, respectively. The virtual phantom was rotated by $3^{\circ}$ around one of x, y, and z-axis. It was also rotated by $3^{\circ}$ around two axes of x, y, and z-axis, and rotated by $3^{\circ}$ along all three axes. The errors in the position of rotated measurement points were measured with Leksell GammaPlan$^{(R)}$ and the correction function was verified. Results: The image registration errors of the virtual phantom images was $0.1{\pm}0.1mm$ and it was within the requirement of stereotactic images. The maximum theoretical errors in position of measurement points were 2.6 mm for a rotation around one axis, 3.7 mm for a rotation around two axes, and 4.5 mm for a rotation around three axes. The measured errors in position was $0.1{\pm}0.1mm$ for a rotation around single axis, $0.2{\pm}0.2mm$ for double and triple axes. These small errors verified that the rotation error correction function of Leksell GammaPlan$^{(R)}$ is working fine. Conclusion: A virtual phantom was built to verify software functions of stereotactic neurosurgery treatment planning program. The error correction function of a commercial treatment planning program worked within nominal error range. The virtual phantom of this study can be applied in many other fields to verify various functions of treatment planning programs.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.3
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• pp.207-216
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• 2010

Objective: This study was performed to clarify the role of HomeoboxA (HOXA) and its related signaling molecules in the decidualization of primary cultured endometrial cells. Methods: Human endometrial tissues were obtained by curettage of hysterectomy specimens from patients with conditions other than endometrial diseases. Tissues were minced and digested with Trypsin-EDTA for 20 min, $37^{\circ}C$. Cells were cultured with DMEM/F12 medium in $37^{\circ}C$, 5% $CO_2$ incubator for 24 hrs. Cells were treated with HOXA10 siRNA and added transforming growth factor (TGF)-${\beta}1$ (10 ng/mL) for 48 hrs to induces decidualization in vitro. Reverse transcription polymerase chain reaction analysis was accomplished to observe the expression of HOXA10, prolactin, cyclooxygenase (COX)-2, peroxisome proliferatoractivated receptor (PPAR)-$\gamma$, and wingless-type MMTV integration site family (Wnt). Results: HOXA10 expression was increased (1.8 fold vs. non-treated control) in TGF-${\beta}1$ treated cells. Decidualization marker, prolactin, was significantly increased in TGF-${\beta}1$ treated cells compared with HOXA10 siRNA treated cells. Endometrial cell differentiation marker, COX-2 was down-regulated by HOXA10 siRNA even if cells were treated with TGF-${\beta}1$. Wnt4 was down-regulated by treated with HOXA10 siRNA, this expression patters was not changed by TGF-${\beta}1$. Expression of PPAR-$\gamma$ was down regulated by TGF-${\beta}1$ in regardless of HOXA10 siRNA treatment. Conclusion: TGF-${\beta}1$ which is induced by progesterone in endometrial epithelial cells may induces stromal cell decidualization via HOXA10 and Wnt signaling cascade.

• Journal of Life Science
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• v.20 no.5
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• pp.729-735
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• 2010

In our previous study, it was reported that an herbal mixture, SH21B, inhibits fat accumulation and adipogenesis both in vitro and in vivo models of obesity. SH21B is a mixture composed of seven herbs: Scutellaria baicalensis Georgi, Prunus armeniaca Maxim, Ephedra sinica Stapf, Acorus gramineus Soland, Typha orientalis Presl, Polygala tenuifolia Willd, and Nelumbo nucifera Gaertner (Ratio 3:3:3:3:3:2:2). The aim of this study was to investigate the detailed molecular mechanisms of the effects of SH21B on various regulators of the adipogenesis pathway. During the adipogenesis of 3T3-L1 cells, SH21B significantly decreased the expression levels of central transcription factors of adipogenesis, such as peroxisome proliferator-activated receptor (PPAR)$\gamma$ and CCAAT/enhancer binding protein (C/EBP)$\alpha$. To elucidate the detailed molecular mechanism of the anti-adipogenic effects of SH21B, we examined the expression levels of the various pro-adipogenic or anti-adipogenic regulators of adipogenesis upstream of $PPAR{\gamma}$ and C/$EBP{\alpha}$. The mRNA levels of Krox20 and Kruppel-like factor (KLF) 15, which are pro-adipogenic regulators, were significantly down-regulated by SH21B treatment, whereas the mRNA levels of C/$EBP{\gamma}$ and KLF5 were not changed. KLF2 and C/EBP homologous protein (CHOP), which are anti-adipogenic regulators, were significantly up-regulated by SH21B treatment. These results suggest that the molecular mechanism of the anti-adipogenic effect of SH21B involves both the down-regulations of pro-adipogenic regulators, such as Krox20 and KLF15, and the up-regulations of anti-adipogenic regulators, such as KLF2 and CHOP, which results in the suppression of central transcription factors of adipogenesis including $PPAR{\gamma}$ and C/$EBP{\alpha}$.

• Journal of Life Science
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• v.20 no.7
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• pp.1054-1065
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• 2010

SH21B is a natural composition composed of seven herbs: Scutellaria baicalensis Georgi, Prunus armeniaca Maxim, Ephedra sinica Stapf, Acorus gramineus Soland, Typha orientalis Presl, Polygala tenuifolia Willd and Nelumbo nucifera Gaertner (Ratio 3:3:3:3:3:2:2). In our previous study, we reported that SH21B inhibited adipogenesis and fat accumulation in 3T3-L1 cells through modulation of various regulators in the adipogenesis pathway. The aim of this study was to analyze the transcriptome profiles for the anti-adipogenic effects of SH21B in 3T3-L1 cells. Total RNAs from SH21B-treated 3T3-L1 cells were reverse-transcribed into cDNAs and hybridized to Affymetrix Mouse Gene 1.0 ST array. From microarray analyses, we identified 2,568 genes of which expressions were changed more than two-fold by SH21B, and the clustering analyses of these genes resulted in 9 clusters. Three clusters among the 9 showed down-regulation by SH21B (cluster 4, cluster 6 and cluster 9), and two clusters showed up-regulation by SH21B (cluster 7 and cluster 8) during the adipogenesis of 3T3-L1 cells. It was found that many genes related to cell proliferation and adipogenesis were included in these clusters. Clusters 4, 6 and 9 included genes which were related with adipogenesis induction and cell cycle arrest. Clusters 7 and 8 included genes related to cell proliferation as well as adipogenesis inhibition. These results suggest that the mechanisms of the anti-adipogenic effects of SH21B may be the modulation of genes involved in cell proliferation and adipogenesis.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.261-268
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• 2010

This study is compared that the dose distribution by experimentation and radiation therapy planning (RTP) when the air cavity region was treated high energy photon. The dose measurements were performed with a 6 MV photon beam of linear accelerator. The polystyrene and self made acyl phantom were similar to tissue density of the human body. A parallel plate chamber was connected to an electrometer. The measurement setup was SCD (Source Chamber Distance) 100 cm and the distance of surface from air cavity was 3 cm. Absorbed dose of interface were measured by area and height. The percent depth dose were measured presence and absence of air cavity, depth according to a ratio of field size and air cavity size. The dose distribution on planning was expressed to do the inhomogeneity correction. As the area of air cavity was increased, the absorbed dose were gradually reduced. It was slightly increased, when the height of air cavity was changed from 0 cm to 0.5 cm. After the point, dose was decreased. In case of presence of air cavity, dose after distal air cavity interface was more great than absence of air cavity. The rebuild up by field size and area of air cavity occurred for field size, $4{\times}4\;cm^2$, $5{\times}5\;cm^2$ and $6{\times}6\;cm^2$, with fixed on area of air cavity, $5{\times}5\;cm^2$. But it didn't occur at $10{\times}10\;cm^2$ field size. On the contrary, the field size was fixed on $5{\times}5\;cm^2$, rebuild up occurred in area of air cavity, $4{\times}4\;cm^2$, $5{\times}5\;cm^2$. but, it did not occur for air cavity, $2{\times}2\;cm^2$, $3{\times}3\;cm^2$. All of the radiation therapy planning were not occurred rebuild up. It was required to pay attention to treat tumor in air cavity because the dose distribution of planning was different from the dose distribution of patient.

• Tuberculosis and Respiratory Diseases
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• v.56 no.1
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• pp.40-50
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• 2004

Background : Radiation pneumonitis(RP) is the major serious complication of thoracic irradiation treatment. In this study, we attempted to retrospectively evaluate the long-term prognosis of patients who experienced acute RP and to identify factor that might allow prediction of RP. Methods : Of the 114 lung cancer patients who underwent thoracic radiotherapy between December 2000 and December 2002, We performed analysis using a database of 90 patients who were capable of being evaluated. Results : Of the 44 patients(48.9%) who experienced clinical RP in this study, the RP was mild in 33(36.6%) and severe in 11(12.3%). All of severe RP were treated with corticosteroids. The median starting corticosteroids dose was 34 mg(30~40) and median treatment duration was 68 days(8~97). The median survival time of the 11 patients who experienced severe RP was significantly poorer than the mild RP group. (p=0.046) The higher total radiation dose(${\geq}60Gy$) was significantly associated with developing in RP.(p=0.001) The incidence of RP did not correlate with any of the ECOG performance, pulmonary function test, age, cell type, history of smoking, radiotherapy combined with chemotherapy, once-daily radiotherapy dose fraction. Also, serum albumin level, uric acid level at onset of RP did not influence the risk of severe RP in our study. Conclusion : Only the higher total radiation dose(${\geq}60Gy$) was a significant risk factor predictive of RP. Also severe RP was an adverse prognostic factor.

• Journal of Gastric Cancer
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• v.7 no.3
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• pp.167-173
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• 2007

Purpose: Mistletoe (Viscum album L.) extract is one of the most widely used agents in alternative cancer therapeutic regimens in Europe. This study was conducted to determine the effect of mistletoe extract on immune function in gastric cancer patients. Materials and Methods: Ten patients that had undergone a curative gastrectomy were enrolled in the prospective study. ABNOBAviscum $Q^{(R)}$ was injected subcutaneously three times a week from postoperative-day 7 to week 16 with an increasing dose. All of the patients simultaneously received chemotheraphy with mitomycin, oral 5-FU and a cisplatin regimen. The WBC count, differential count, lymphocyte/WBC ratio and the level of cytokines (IL-$1{\beta}$, IL-2, IL-6, IFN-$\gamma$, TNF-$\alpha$) were checked in the peripheral blood preoperatively, at postoperative week 8 and at postoperative week 16. Results: The WBC and neutrophil counts significantly decreased after treatment on week 8 and week 16 (P=0.001), but the total eosinophil count was slightly increased (P=0.15). The total lymphocyte count also decreased during treatment but the lymphocyte/WBC ratio was slightly increased without statistical significance (P=0.91). The cytokine levels did not significantly change during treatment. Conclusion: It is somewhat difficult to determine the direct effect of mistletoe therapy on immune function as the effect may be compromised by the concurrent chemotherapy. It can be assumed that the slightly increased lymphocyte/WBC ratio and eosinophil count may be a result of the immunomodulatory effect of the mistletoe extract.