• Title/Summary/Keyword: Irradiation Effect

Search Result 2,395, Processing Time 0.027 seconds

An Experimental Study on the Effectiveness of Microwave Hyperthermia Combined with Radiation on the Small and Large Intestine in rats (흰쥐의 장조직에 X-선 조사와 마이크로파 온열요법의 효과에 관한 실험적 연구)

  • Ahn, Kyung-Sook;Lee, Kyung-Ja;Rhee, Chung-Sik
    • Radiation Oncology Journal
    • /
    • v.5 no.2
    • /
    • pp.83-95
    • /
    • 1987
  • The synergistic effect of combining radiation therapy and hyperthermia kills significantly more cells than using either modality alone. The reason for enhanced cell killing from the combined treatment is that the two modalities are complementary. For histopathological exmination, 102 rats were divided into 4 groups as hyperthermia, radiation, hyperthermia combined with radiation and normal control groups. The effect of prior irradiation (6-15 Gy of X-ray) on the response of small and large bowel of rats to $40^{\circ}C-44^{\circ}C$ (for 30 minutes) microwave (2450 MHz) hyperthermia was investigated. The musculature of the small and large intestine remained intact and the circumference of the histological sections were not significantly altered by the heated at $43^{\circ}C$ for 30 minutes. Thermal enhancement ratios of normal tissue is 1.0 Thermal enhancement ratio was not increased in combination therapy by evaluation of histopathologic changes in small and large intestine.

  • PDF

The Effect of Therapy Oriented CT in Radiation Therapy Planning (치료 계획용 전산화 단층촬영이 방사선 치료계획에 미치는 효과)

  • Kim, Sung-Kyu;Shin, Sei-One;Kim, Myung-Se
    • Radiation Oncology Journal
    • /
    • v.5 no.2
    • /
    • pp.149-155
    • /
    • 1987
  • The success of radioation therapy depends on exact treatment of the tumor with significant high dose for maximizing local control and excluding the normal tissues for minimizing unwanted complications. To achieve these goals, correct estimation of target volume in three dimension, exact dose distribution in tumor and normal critical structures and correction of tissue inhomogeneity are required. The effect of therapy oriented CT (plannng CT) were compared with conventional simulation method in necessity of planning change, set dose, and proper distribution of tumor dose. Of 365 new patients examined, planning CT was performed in 104 patients $(28\%)$. Treatment planning was changed in $47\%$ of head and neck tumor, $79\%$ of intrathoracic tumor and $63\%$ of abdmonial tumor. in breast cancer and musculoskeletal tumors, planning CT was recommended for selection of adequate energy and calculation of exact dose to critical structures such as kidney or spinal cord. The average difference of tumor doses between CT planning and conventional simulation was $10\%$ in intrathoracic and intra-abdominal tumors but $20\%$ in head and neck tumors which suggested that tumor dose may be overestimated in conventional simulation Although some limitations and disadvantages including the cost and irradiation during CT are still criticizing, our study showed that CT Planning is very helpful in radiotherapy Planning.

  • PDF

Verification of Dose Distribution for Stereotactic Radiosurgery with a Linear Accelerator (선형가속기를 이용한 방사선 수술의 선량분포의 실험적 확인)

  • Park Kyung Ran;Kim Kye Jun;Chu Sung Sil;Lee Jong Young;Joh Chul Woo;Lee Chang Geol;Suh Chang Ok;Kim Gwi Eon
    • Radiation Oncology Journal
    • /
    • v.11 no.2
    • /
    • pp.421-430
    • /
    • 1993
  • The calculation of dose distribution in multiple arc stereotactic radiotherapy is a three-dimensional problem and, therefore, the three-dimensional dose calculation algorithm is important and the algorithm's accuracy and reliability should be confirmed experimentally. The aim of this study is to verify the dose distribution of stereotactic radiosurgery experimentally and to investigate the effect of the beam quality, the number of arcs of radiation, and the tertiary collimation on the resulting dose distribution. Film dosimetry with phantom measurements was done to get the three-dimensional orthogonal isodose distribution. All experiments were carried out with a 6 MV X-ray, except for the study of the effects of beam energy on dose distribution, which was done for X-ray energies of 6 and 15 MV. The irradiation technique was from 4 to 11 arcs at intervals of from 15 to 45 degrees between each arc with various field sizes with additional circular collimator. The dose distributions of square field with linear accelerator collimator compared with the dose distributions obtained using circular field with tertiary collimator. The parameters used for comparing the results were the shape of the isodose curve, dose fall-offs fom $90\%$ to $50\%$ and from $90\%\;to\;20\%$ isodose line for the steepest and shallowest profile, and $A=\frac{90\%\;isodose\;area}{50\%\;isodose\;area-90\%\;isodose\;area}$(modified from Chierego). This ratio may be considered as being proportional to the sparing of normal tissue around the target volume. The effect of beam energy in 6 and 15 MV X-ray indicated that the shapes of isodose curves were the same. The value of ratio A and the steepest and shallowest dose fall-offs for 6 MV X-ray was minimally better than that for 15 MV X-ray. These data illustrated that an increase in the dimensions of the field from 10 to 28 mm in diameter did not significantly change the isodose distribution. There was no significant difference in dose gradient and the shape of isodose curve regardless of the number of arcs for field sizes of 10, 21, and 32 mm in diameter. The shape of isodose curves was more circular in circular field and square in square field. And the dose gradient for the circular field was slightly better than that for the square field.

  • PDF

Definitive Radiotherapy of Non-Small Cell Lung Cancer (비소세포 폐암의 근치적 방사선치료)

  • Lee, Jong-Young;Park, Kyung-Ran
    • Radiation Oncology Journal
    • /
    • v.13 no.4
    • /
    • pp.303-309
    • /
    • 1995
  • Purpose : The effect of dose escalation of up to 6500 cGy on local control and survial was investigated in locally advanced non-small cell lung cancer. Materials and Methods: Ninety eight patients with biopsy-proven unresec-table non-small cell lung cancer without distant metastases or medically inoperable patients with lower-stage were treated with definitive radio-therapy alone. Group A was treated by thoracic irradiation, 6000 cGy or less in total tumor dose with daily fractions of 180 to 200 cGy; and group B was treated with 6500 cGy of same daily fractions. Results : The actuarial overall survival rate for the entire group was 54% at 1 year, 26.6% at 2 years and 16.4% at 3 years with a median survival time of 13 months. Statistically significant prognostic factors that affect survival rate were stage and N-stage. However, no improvement in local control and survival has been seen with higher dose radiotherapy(group B). Conclusion : Dose escalation of up to 6500 cGy was no effect on local control and survival rate. To increase the survival rate of non-small cell lung cancer hyperfractionated radiotherapy or concurrent chemoradiotherapy should be considered.

  • PDF

Study on Determination of Boron using the PGAA Facility at HANARO Research Reactor (하나로의 즉발감마선 방사화분석 장치를 이용한 붕소의 정량에 대한 연구)

  • Chung, Young-Sam;Cho, Hyun-Jae;Moon, Jong-Hwa;Kim, Sun-Ha;Kim, Young-Jin
    • Analytical Science and Technology
    • /
    • v.16 no.5
    • /
    • pp.391-398
    • /
    • 2003
  • Basic research for the determination of boron content in biological sample has been carried out using the PGAA facility of the 24MW research reactor(HANARO). For investigation of characteristics for the measurement condition, neutron flux and its homogeneity were measured at irradiating geometry. The size of thermal neutron beam collimated from beam guide is $2{\times}2cm^2$ at the sample position. The neutron flux measured was the range of $1.0{\sim}6.5{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$, and flux distribution from center within the radius of 4.5 mm and 9.0 mm was $5.77{\pm}0.71{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$ and $4.68{\pm}1.64{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$, respectively. Accordingly, sample size is adjusted within 10 mm for a homogeneous irradiation of high quality. Measurement system is designed to reduce the background source by Compton scattering and to improve the analytical sensitivity. To investigate the energy calibration and Compton suppression effect of gamma-ray counting system, the background conditions on both of Compton and single-mode were measured using NaCl standard. On the other hand, degree of spectral interference for sodium 472 keV peak as a matrix effect in the sample is established for an accurate boron analysis, and then boron content in three certified reference materials (NIST SRM 1570a, 1547, 1573a) was measured by using two modes and the results were compared with each other.

The Alleviative Effect of White Tea Water Extract on Inflammation and Skin Barrier Damage (백차 열수추출물의 자외선 조사에 의한 피부염증 및 피부장벽손상 완화 효과)

  • Lee, Kyung-Ok;Kim, Young-Chul;Chang, Byung-Soo
    • Applied Microscopy
    • /
    • v.41 no.3
    • /
    • pp.197-204
    • /
    • 2011
  • To investigate the alleviative effect of white tea water extract on the inflammation and skin barrier damage, skin aging animal model was produced by the irradiation of UVB to the backs of hairless mice for 12 weeks. And then experimental materials were applied topically for 4 weeks. At the 28th day of experiment, positive control (PC, 0.01% retinoic acid treatment) and experimental groups (E1, 1% white tea water extract treatment; E2, 2% white tea water extract treatment) had significantly (p<0.001) lower values of both skin erythema index and transepidermal water loss (TEWL) than the control (C, saline treatment) group. The appearance of mast cell and the degree of its degranulation in dermal and subcutaneous layers were remarkably reduced in E1 and E2 groups compared to the C group. It is found that white tea water extract is effective in skin barrier damage and inflammation in hairless mouse.

Inhibitory Effects of Nude Pack Containing Black Tea Water Extract on Skin Wrinkle Formation in Hairless Mice (홍차추출물 함유 누드팩의 Hairless 마우스 피부주름 형성 억제효과)

  • Kim, Young-Chul;Park, Eun-Ye;Kim, Sang-Nam;Yoo, Yong-Gi;Park, Mi-Soon;Lee, Gui-Yeong;Lee, Suk-Jun;Chang, Byung-Soo
    • Applied Microscopy
    • /
    • v.41 no.2
    • /
    • pp.129-137
    • /
    • 2011
  • The aim of this study was to evaluate the inhibitory effect of nude pack containing black tea water extract (NPBT) on skin wrinkle formation in hairless mice. Skin wrinkles were induced by UVB irradiation to the backs of hairless mice for 5 weeks. And at the same time, NPBT was applied topically. Wrinkle formation, histological changes, expression of matrix metalloproteinase-3 (MMP-3) and protein activities of MMP-2 and MMP-9 were observed or analyzed. Wrinkles for the control group were formed as a pattern of deep furrows and thick crests. Whereas wrinkles for the NPBT treated group were formed as a pattern of shallow furrows and thin crests, and their wrinkle areas were significantly (p<0.001) lower than the control group. Collagen fibers were arranged irregularly and sparse in density and some elastic fibers were degenerated in the control group, while they were almost intact in the NPBT treated group. MMP-3 mRNA expression in the control group was significantly (p<0.001) higher than the normal group, and that of NPBT treated group was significantly (p<0.001) lower than the control group. The NPBT treated group showed remarkably lower protein activities of MMP-2 and MMP-9 than the control group. NPBT could have a considerable inhibitory effect on skin wrinkle formation in hairless mice.

Beneficial Effect of a Collagen Peptide Supplement on the Epidermal Skin Barrier (콜라겐 펩타이드의 피부 장벽 보호 효과)

  • Kim, Jeong-Kee;Lee, Ji-Hae;Bae, Il-Hong;Seo, Dae-Bang;Lee, Sang-Jun
    • Korean Journal of Food Science and Technology
    • /
    • v.43 no.4
    • /
    • pp.458-463
    • /
    • 2011
  • Recent studies have revealed that collagen peptide (CP) plays a protective role in skin by improving the activity of antioxidants and acts as an inducer of skin regeneration by positive feedback. In this study, we focused on the beneficial effect of reinforcing the CP skin barrier. To evaluate the skin barrier, hairless mice were exposed to UVB irradiation and acetone-treatment, with or without oral administration of CP. The effects on skin appearance, trans-epidermal water loss, epidermal thickness, and cytokine content were measured using bioengineering and histochemical methods. In the CP treated group, the skin had better appearance and less damage than that of the control. Furthermore, in HaCaT cells, the amount of serinepalmytoyl transferase (SPT) mRNA increased by about 1.6-fold after treatment (CP, 100 mg/L), reflecting that CP can induce SPT expression and reinforce the recovery of skin barrier function. These results suggest that CP is not only an anti-wrinkling agent but also a potent candidate as an epidermal moisturizer.

PHOTOCATALYTIC ANTIEUNGAL ACTIVITY AGAINST CANDIDA ALBICANS BY $TiO_2$ COATED ACRYLIC RESIN DENTURE BASE

  • Yang Ji-Yeon;Kim Hee-Jung;Chung Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.44 no.3
    • /
    • pp.284-294
    • /
    • 2006
  • Statement of problem. Proliferation of Candida albicans is primarily within the plaque on the fitting surface of the denture rather than on the inflamed mucosa. Consequently, the treatment of the denture is equally important as treatment of the tissue. Cleansing and disinfection should be efficiently carried-out as the organisms can penetrate into the voids of the acrylic resin and grow in them, from which they can continue to infect and reinfect bearing tissues. Purpose. The purpose of this study was to evaluate the applicability of photocatalytic reaction to eliminate Candida albicans from acrylic resin denture base, and to investigate the anti-fungal effect with various UVA illumination time. Materials and Methods. The specimens were cured by the conventional method following the manufacturer's instruction using thermal polymerized denture base resin (Vertex RS: Dentimex, Netherlands). $TiO_2$ photocatalyst sol(LT), which is able to be coated at normal temperature, was made from the Ti-alkoxide progenitor. The XRD patterns, TEM images and nitrogen absorption ability of the $TiO_2$ photocatalyst sol(LT) were compared with the commercial $TiO_2$ photocatalyst P-25. The experimental specimens were coated with the mixture of the $TiO_2$ photocatalyst sol(LT) and binder material (silane) using dip-coater, and uncoated resin plates were used as the control group. Crystallinity of $TiO_2$ of the specimen was tested by the XRD. Size, shape and chemical compositions were also analyzed using the FE-SEM/ EDS. The angle and methylene blue degradation efsciency were measured for evaluating the photocatalytic activity of the $TiO_2$ film. Finally, the antifungal activity of the specimen was tested. Candida albicans KCTC 7629(1 ml, initial concentration $10^5$ cells/ ml) were applied to the experiment and control group specimens and subsequently two UVA light source with 10W, 353 nm peak emission were illuminated to the specimens from 15cm above. The extracted $2{\mu}l$ of sample was plated on nutrient agar plate ($Bacto^{TM}$ Brain Heart Infusion; BD, USA) with 10 minute intervals for 120 minute, respectively. It was incubated for 24 hours at $37^{\circ}C$ and the colony forming units (CFUs) were then counted. Results. Compared the characteristics of LT photocatalyst with commercial P-25 photocatalyst, LT were shown higher activity than P-25. The LT coated experimental specimen surface had anatase crystal form, less than 20 nm of particle size and wide specific surface area. To evaluate the photocatalytic activity of specimens, methylene blue degradation reaction were used and about 5% of degradation rate were measured after 2 hours. The average contact angle was less than $20^{\circ}$ indicating that the LT photocatalyst had hydrophilicity. In the antifungal activity test for Candida albicans, 0% survival rate were measured within 30 minute after irradiation of UVA light. Conclusion. From the results reported above, it is concluded that the UVA-LT photocatalytic reaction have an antifungal effect on the denture surface Candida albicans, and so that could be applicable to the clinical use as a cleaning method.

Effects of Tumor Microenvironmental Factors on DNA Methylation and Radiation Sensitivity in A549 Human Lung Adenocarcinoma

  • Oh, Jung-Min;Kim, Young-Eun;Hong, Beom-Ju;Bok, Seoyeon;Jeon, Seong-Uk;Lee, Chan-Ju;Park, Dong-Young;Kim, Il Han;Kim, Hak Jae;Ahn, G-One
    • Journal of Radiation Protection and Research
    • /
    • v.43 no.2
    • /
    • pp.66-74
    • /
    • 2018
  • Background: Tumor response to anticancer therapies can much be influenced by microenvironmental factors. In this study, we determined the effect of these microenvironmental factors on DNA methylation using A549 human lung adenocarcinoma cell line. Materials and Methods: We subjected A549 cells to various conditions mimicking tumor microenvironment including hypoxia, acidosis (sodium lactate), oxidative stress ($H_2O_2$), bystander effect (supernatant from doxorubicin (Dox)-treated or irradiated cells), and immune cell infiltration (supernatant from THP-1 or Jurkat T cells). Genomic DNA was isolated from these cells and analyzed for DNA methylation. Clonogenic cell survival, gene expression, and metabolism were analyzed in cells treated with some of these conditions. Results and Discussion: We found that DNA methylation level was significantly decreased in A549 cells treated with conditioned media from Dox-treated cells or Jurkat T cells, or sodium lactate, indicating an active transcription. To determine whether the decreased DNA methylation affects radiation sensitivity, we exposed cells to these conditions followed by 6 Gy irradiation and found that cell survival was significantly increased by sodium lactate while it was decreased by conditioned media from Dox-treated cells. We further observed that cells treated with conditioned media from Dox-treated cells exhibited significant changes in expression of genes including BAX and FAS (involved in apoptosis), NADPH dehydrogenase (mitochondria), EGFR (cellular survival) and RAD51 (DNA damage repair) while sodium lactate increased cellular metabolism rather than changing the gene expression. Conclusion: Our results suggest that various tumor microenvironmental factors can differentially influence DNA methylation and hence radiosensitivity and gene expression in A549 cancer cells.