• The Journal of Korean Society for Radiation Therapy
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• v.1 no.1
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• pp.47-51
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• 1985

Authors describe some useful data when constructing tissue-equivalent compensators which would compensate tissue deficit in the treatment field of high energy electromagnetic radiation Tissue equivalent compensator is made of lucite. The ratio of compensator thickness to the thickness of tissue deficit depends on radiation energy, field size and the distance from the compensator to patient skin. When the compensator is separated from skin surface, the thickness ratio is always smaller than 1.0. This means that the larger the separation, the contribution to the total dose by means of scattered radiation from a tissue equivalent compensator is smaller. Authors propose that the thickness of lucite as tissue equivalent compensator is 0.57 times tissue deficit and the separation between compensator and skin is at least 15m for Co-60 gamma ray and 25cm for 10MV X-ray.

• The Journal of Korean Society for Radiation Therapy
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• v.8 no.1
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• pp.55-61
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• 1996

A radiation beam incident on irregular or sloping surface produces an inhomogeneity of absorbed dose. The use of a tissue compensator can partially correct this dose inhomogeneity. The tissue compensator should be made based on experimentally measured thickness ratio. The thickness ratio depends on beam energy, distance from the tissue compensator to the surface of patient, field size, treatment depth, tissue deficit and other factors. In this study, the thickness ratio was measured for various field size of $5cm{\times}5cm,\;10cm{\times}10cm,\;15cm{\times}15cm,\;20cm{\times}20cm$ for 4MV X-ray beams. The distance to the compensator from the X-ray target was fixed, 49cm, and measurement depth was 3, 5, 7, 9 cm. For each measurement depth, the tissue deficit was changed from 0 to(measurement depth-1)cm by 1cm increment. As a result, thickness ratio was decreased according to field size and tissue deficit was increased. Use of a representative thickness ratio for tissue compensator, there was $10\%$ difference of absorbed dose but use of a experimentally measured thickness ratio for tissue compensator, there was $2\%$ difference of absorbed dose. Therefore, it can be concluded that the tissue compensator made by experimentally measured thickness ratio can produce good distribution with acceptable inhomogeneity and such tissue compensator can be effectively applied to clinical radiotherapy.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.133-140
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• 1989

Three-dimension paraffin compensator was designed to construct the tissue equivalent compensator for irregular body contours and obiliques beam incidence. The ratio of compensator thickness to tissue deficit was depended on field size, depth and air gap because the scattered dose loss. The ratio of compensator-tissue was optimized 0.79, 0.73, 0.61 and 0.56 in 6MV x-rays as function of field size $4{\times}4$, $10{\times}10$, $20{\times}20$ and $30{\times}30cm^2$ respectively. in our study. Using this tissue equivalent compensator, it can be got 2% difference of dose at same mid-plane in phantom study.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.186-192
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• 2002

Purpose : Measurement of transmission dose is useful for in vivo dosimetry. In this study, previous algorithm for estimation of transmission dose was modified for use in cases with tissue deficit. Materials and Methods : The beam data was measured with flat solid phantom in various conditions of tissue deficit. New algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. The algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients using multiple sheets of solid phantoms. Results : The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ${\pm}1.0\%$ in most situations and within ${\pm}3.0\%$ in experimental settings with irregular contours mimicking breast cancer treatment set-up. Conclusion : Developed algorithm could accurately reflect the effect of tissue deficit and irregularly shaped body contour on transmission dosimetry.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1165-1172
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• 2002

The effects of salicylic acid(SA) and water deficit on growth and proline accumulation were investigated in cucumber(Cucurmis sativus L.) seedlings. Exogenous application of SA(100 $\mu$M-1 mM) led to a noticeable decrease in root and shoot growth, and dry weight of seedlings. Anatomical observation on leaf of cucumber revealed that the thickness of all leaf tissue components decreased in SA-treated plants. The effect was most pronounced on the width of the adaxial epidermis. In the separate effects of SA(0, 100, 500 and 1000 $\mu$M) and water deficit induced by PEG(0, 4.4, 7.0 and 9.6 %) on growth, the water deficit treatments had greater effects on growth traits than SA. Combinations of SA and PEG(SA+PEG) decreased shoot and root dry matter, and root length. Proline increased slightly in SA-treated seedlings, but exhibited a marked increase in water deficit application. Combinations of SA+PEG induced higher proline in both shoots and roots than SA stress alone. Shoots had higher proline than roots. Our data support a role of SA potentiating the osmotic stress response of germinating cucumber seedling.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.123-132
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• 1989

A radiation beam incident on an irregular or sloping surface produces the non-uniformity of absorded dose. The use of a tissue compensator can partially correct this dose inhomogeneity. The tissue compensator is designed based on the patient's three dimensional contour. After required compensator thickness was determined according to tissue deficit at $25cm\pm25cm$ field size, 10cm depth for 6MV x-rays, tissue deficit was mapped by isoheight technique using laser beam system. Compensator was constructed along the designed model using 0.8mm lead sheet or 5mm acryl plate. Dosimetric verification were peformed by film dosimetry using humanoid phantom. Dosimetric measurements were normalized to central axis full phantom readings for both compensated and non-compensated field. Without compensation, the percent differences in absorbed dose ranged as high as $12.1\%$ along transverse axis, $10.8\%$ along vertical axis. With the tissue compensators in place, the difference was reduced to $0\~43\%$ Therefore, it can be concluded that the compensator system constructed by isoheihnt technique can produce good dose distribution with acceptible inhomogeneity, and such compensator system can be effectively applied to clinical radiotherapy.

• Journal of Oriental Neuropsychiatry
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• v.21 no.1
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• pp.71-88
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• 2010

Objectives: This research investigates the effect of the DHJHT extract on Alzheimer's disease. Specifically, the effects of the DHJHT extract on (1) the behavior (2) the infarction area of the hippocampus, and brain tissue injury in AD mice induced with ${\beta}A$ were investigated. Methods: The effects of the DHJHT extract on the proinflammation cytokines mRNA expression and production of BACE, APP and ${\beta}A$ in in BV2 microglial cell line treated by lipopolysacchaide(LPS) plus ${\beta}A$ were investigated. The effects of the DHJHT extract on the behavior of the memory deficit mice induced by scopolamine were investigated. Results: 1. The DHJHT extract suppressed the expression of IL-$1{\beta}$, IL-6, TNF-$\alpha$, COX-2, and NOS-II, BACE and APP mRNA in BV2 microglial cell line treated by LPS plus ${\beta}A$. 2. The DHJHT extract suppressed the expression of ${\beta}A$ production in BV2 microglial cell line treated with LPS plus ${\beta}A$. 3. The DHJHT extract showed significantly inhibitory effect on the scopolamine-induced impairment of memory in the experiment of Morris water maze. 4. The DHJHT group suppressed the expression of IL-$1{\beta}$, TNF-$\alpha$, MDA, and CD68+/CD11b+ in the brain tissue of the mice with AD induced by ${\beta}A$. 5. The DHJHT group reduced the infarction area of hippocampus, and controlled the injury of the brain tissue in the mice with AD induced by ${\beta}A$. 6. The DHJHT group reduced tau protein, and GFAP in the brain tissue of the mice with AD induced by ${\beta}A$. Conclusions: These results suggest that the DHJHT group may be effective for the treatment of AD. Thus, DHJHT could be considered among the future therapeutic drugs indicated for the treatment of AD.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.46-48
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• 2013

Chondrosarcoma is a very uncommon malignant primary bone tumor, especially, it occurs extremely rare in the spine. A 52-year-old man was admitted to the emergency room with sudden paraplegia. Twelve hours prior to a paraplegic event, he visited an outpatient clinic with discomfort and tenderness around the medial border of the right scapular, and his neurologic status was absolutely intact. Magnetic resonance imaging showed a lobulated soft tissue mass from T3 to T5, which extended to the epidural space. Computed tomography scans showed soft tissue mass on the spinal posterior arch and osteolytic change of the adjacent bony structures. Emergent surgery was performed and the lesion was removed. Dark reddish blood and gel-like material were encountered around the dura and posterior arch during the operation. Multiple pulmonary nodules were found on a chest CT scan and a biopsy of one of them had been proven to be a metastasis of chondrosarcoma. The histologic examination showed dedifferentiated chondrosarcoma. The patient's neurologic deficit was improved slowly from ASIA A to ASIA D. Chondrosarcoma in the spine is extremely rare, even more with acute hemorrhage and sudden expansion into the epidural space. We named it chondrosarcoma apoplexy. We should consider the possibility of a hemorrhagic event when the patient's neurologic deficit worsens suddenly with spinal bone tumor.

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.89-96
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• 1998

The diurnal changes of the stomatal conductance, transpiration and leaf water potential were measured in order to assess the water relations characteristics of Pueraria thunbergiana in August of 1995 and 1996. The results showed two different responses depending on the duration of rainless days. The microclimatic conditions were highly stressful on 2 August. Daily maximum temperature reached to $39.0{\circ}C$ and vapor pressure deficit was 3.55 KPa. During this time the leaf water potential decreased to -1.02 MPa and a marked reduction of stomatal conductance was shown. However, on 15 August the stomatal conductance increased with increment of photon flux density, and transpiration was highly maintained during the day time. Minimum leaf water potential was only -0.47 MPa in spite of high transpiration rate. Furthermore, on 15 August reduced leaf water potential during the day time was recovered rapidly with decrease of photon flux density, whereas recovery of leaf water potential on 2 August was delayed. However, reduced leaf water potential on 2 August was recovered untile the next dawn. Osmotic potential at turgor loss point of Pueraria thunbergiana on 2, 3 and 15 August was -1.79, -1.70 and -1.60 MPa, respectively. The vapor pressure deficit is more contributive to the regulation of stomatal conductance than leaf water potential.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2002.05b
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• pp.465-467
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• 2002

The effects of salicylic acid (SA) on growth and proline were investigated in cucumber seedlings. Exogenous application of SA(100 uM - 1mM) led to a noticeable decrease in root and shoot growth, and dry weights of seedlings. Anatomical observation on leaf anatomy of cucumber revealed that the thickness of all leaf tissue components decreased in SA-treated plants. The effect was most promounced on the width of the adaxial epidermis. In the separate and simultaneous effects of SA and water deficit induced by PEG on growth and proline accumulation, the water deficit treatments had greater effects on growth traits and proline content than SA. Combinations of SA and PEG decreased dry matter and root length, and resulted in higher proline in both shoots and roots than SA stress alone. Shoots had higher proline than roots.