• Radiation Oncology Journal
• /
• v.12 no.2
• /
• pp.233-241
• /
• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.

• BMB Reports
• /
• v.34 no.2
• /
• pp.123-129
• /
• 2001

Cellular response to ionizing radiation is affected by cell types, radiation doses, and post-irradiation time. Based on the trypan blue dye exclusion assay in normal oral mucosal cells (OM cells), a 48 h post-irradiation was sufffcient and an adequate time point for the evaluation of radiation sensitivity Its $LD_{50}$ was approximately 1.83 Gy To investigate possible biomarkers useful for the biological radiodosimetry of normal epithelial cells (p53, c-fos, cyclin D1, cdc-2, pRb) EGF receptor phosphorylation and Erk activation were evaluated at different radiation doses and different post-irradiation times. From 0.5 Gy, p53 was accumulated in the nucleus of basal cells of the OM raft culture at 4 h post-irradiation and sustained up to 24 h post-irradiation, which suggests that radiation-induced apoptosis or damage repair was not yet completed. The number of p53 positive cells and biosynthesis of p53 were correlated with radiation doses. Both cyclin D1 and c-fos were only transiently induced within 1 h post-irradiation. Cyclin D1 was induced at all radiation doses. However, cfos induction was highest at 0.1 Gy, approximately 7.3 fold more induction than the control, whose induction was reduced in a reverse correlation with radiation dose. The phosphorylation pattern of cdc-2 and pRb were unaffected by radiation. In contrast to A431 tails overexpressing the EGF receptor approximately 8.5 fold higher than normal epithelial, the OM cells reduced the basal level of the EGF receptor phosphorylation in a radiation dose dependent fashion. In conclusion, among radiation-induced biomolecules, the p53 nuclear accumulation may be considered for the future development of a useful marker far biological radiodosimetry in normal epithelial tissue since it was sustained for a longer period and showed a dose response relationship. Specific c-fos induction at a low dose may also be an important finding in this study It needs to be studied further for the elucidation of its possible connection with the low dose radio-adaptive response.

• Applied Biological Chemistry
• /
• v.51 no.2
• /
• pp.148-152
• /
• 2008

This study was to elucidate the effect of low dose gamma (${\gamma}$)-ray irradiation on the germination, seedling growth and antioxidant activity in sunflower seeds. The seed germination was stimulated in the range of 2.7${\sim}$8.0% by low dose ${\gamma}$-ray irradiation compared with that of the control; however, the germination of seeds stored for 4 months after irradiated was decreased at all low dose ${\gamma}$-ray irradiation groups. Especially, the germination rate of 32 Gy-irradiated seed group was much lower than that of the other groups and 8 Gy was the optimal radiation dose for germination at room temperature. Though there was variation with storage time and temperature, seedling growth stored at 10$^{\circ}C$ for 4 months after irradiated was promoted at the 1 Gy ${\gamma}$-ray irradiation group compared to seed stored at 25$^{\circ}C$. For the antioxidant activity of ${\gamma}$-ray irradiated seeds extract, 4 Gy and 32 Gy groups were significantly increased by 68.83% and 95.44%, respectively, compared to control at the concentration of 100 ${\mu}g$/ml.

• Imaging Science in Dentistry
• /
• v.34 no.2
• /
• pp.99-106
• /
• 2004

Purpose: To investigate the effects of irradiation on the phenotypic expression of the MC3T3-El osteoblastic cell line, especially on the osteonectin and bone sialoprotein. Materials and Methods: Cells were irradiated with a single dose of 0.5, 1, 4 and 8 Gy at a dose rate of 5.38 Gy/min using Cs-I37 irradiator. After specimens were harvested, total RNA was extracted on the 3rd, 7th, 14th, 21st day after irradiation. The total RNA was reverse-transcribed and the resulting cDNAs were subjected to amplification by PCR with a pair of primers. Results: The irradiated cells showed a dose-dependent increase in osteonectin mRNA expression when compared with the unirradiated control group. The irradiated cells showed no difference in bone sialoprotein mRNA expression when compared with the unirradiated control group. In accordance with the duration of culture period after irradiation, the level of osteonectin mRNA expression showed no difference, but it increased a little at the 21st day in the 4 and 8 Gy exposure groups. In the case of bone sialoprotein, however, the level of mRNA expression increased significantly at the 3rd and 7th day after irradiation, but it showed no difference at the 14th and 21st day when compared with the control group. Conclusion: These results showed that each single dose of 0.5, 1, 4 and 8 Gy influenced the mRNA expression of osteonectin and bone sialoprotein at the calcification stage of osteoblastic cells, suggesting that single dose of irradiation affected the osteoblastic bone formation at the cell level.

• Korean Journal of Environmental Biology
• /
• v.19 no.4
• /
• pp.270-277
• /
• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers induced in vitro of two potato (Solanum tuberosum L. cv. Dejima and cv. Superior) cultivars with different storage duration were irradiated with ${\gamma}$ radiation at the dose of $0.5{\sim}30$ Gy. Sprouting rate, growth and tuber yield of ‘Dejima’ microtuber were increased by ${\gamma}$ radiation in the range of $2{\sim}16$ Gy. In the microtuber of ‘Superior’, the sprouting rate was promoted by 2 Gy and 4 Gy irradiation, and the growth and tuber yield by 0.5 Gy and 4 Gy irradiation. There were not that much difference in chlorophyll content of potato plantlet by the low dose ${\gamma}$ irradiation. These results suggested that low dose ${\gamma}$ radiation stimulated the dormancy breaking and potato growth.

• Korean Journal of Veterinary Research
• /
• v.38 no.4
• /
• pp.679-685
• /
• 1998

We have studied, by a nonisotopic in situ DNA end-labeling (ISEL) technique, frequency of apoptosis in the external granular layer (EGL) of the cerebellum after whole-body irradiation of newborn mice and intestinal crypt cell of adult mice by gamma-rays from $^{60}Co$. The extent of changes following 2 Gy(10.9 Gy/min) was studied at 2, 4, 6, 8, 12, or 24h after exposure. The maximal frequency was found 4-8h after exposure. The mice that received 0.18, 0.36, 0.54, 1.08, 1.98, or 3.96 Gy were examined 6h after irradiation. Measurements performed after irradiation showed a dose-related increase in apoptotic cells in each of the mice studied. The dose-response curves were analyzed by a linear-quadratic model; frequency(%) of apoptotic cell in the newborn mice cerebellum was ($13.49{\pm}1.175$)D+$(-1.52{\pm}0.334)D^2$+0.048($r^2=0.981$, D = dose in Gy) and frequency(number per crypt) of apoptotic cell in the intestinal crypt of adult mice was ($3.857{\pm}0.420$)D+$(-0.535{\pm}0.120)D^2$+0.155($r^2=0.952$, D = dose in Gy). It provides the basis required for a better understanding of results which will be obtained in any further studies for biological responses of radiation using newborn and adult mice.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.7
• /
• pp.94-106
• /
• 2003

A pilot study was performed to examine the feasibility of UV disinfection system and the reactivation of indicator microorganisms (TC, FC, E. coli) after UV irradiation for agricultural reuse of reclaimed water. Photoreactivation and dark repair enable UV-inactivated microorganisms to recover and may reduce the efficacy of UV inactivation, which might be drawbacks of the UV disinfection method. The effluent of biofilter for 16-unit apartment house was used as input to the UV disinfection system, and average SS and BOD concentration were 3.8 and 5.7 mg/L, respectively, and the mean level of total coliform was in the range of $1.0\times10^4$ MPN/100mL. UV disinfection was found to be effective and it reduced mean concentration of indicator microorganisms (total coliform, fecal coliform, and E. coli) to less than 100 MPN/100mL within 60s exposure using 17, 25, and 40W lamps. Two UV doses of 6 and 16 mW$\cdot$s/$\textrm{km}^2$ were applied and microorganisms reactivation was monitored under the dark, photoreactivating light, and solar irradiation. Microorganisms reactivation was observed in the UV dose of 6 mW$\cdot$s/$\textrm{km}^2$, and numbers increased up to 5% at the photoreactivating light and 1% at the dark. However, microorganisms were inactivated rather than reactivated at the solar radiation and numbers decreased to non-detectible level about below 2 MPN/100mL in 4 hours. In the case of 16 mW$\cdot$s/$\textrm{km}^2$, microorganism reactivation was not observed indicating that UV dose might affect the reactivation process such as photoreactivation and dark repair. Therefore, concerns associated with microorganism reactivation could be controlled by sufficient UV dose application. Agricultural reuse of reclaimed water might be even less concerned due to exposure to the solar irradiation that could further inactivate microorganisms. The pilot study result is encouraging, however, sanitary concern in water reuse is so critical that more comprehensive investigation is recommended.

• Journal of Yeungnam Medical Science
• /
• v.6 no.2
• /
• pp.103-111
• /
• 1989

The object of this study was to determine the radiation effect on the urinary bladder and to establish the basic data for optimal fraction schedule on the whole abdominal irradiation of the mice. Although radiation damage of the urinary bladder is one of the dose-limiting factor for treatment of lower abdominal cancer, such as uterine cervical or rectal cancer, systematic histopathological study of total dose and recovery duration is very rare, especially in conventional fractionation regimen of clinical use. Authors used 198 mice and analyzed histopathological findings according to total dose(40 & 50GY) and recovery duration(1-15 weeks after completion of irradiation). The results were summarized as follows : 1. No definite difference of radiosensitivity was noted between male and female group. 2. Most of mucosal injuries were recovered within 14 weeks in 40 GY irradiated group. 3. Vascular injury and change of connective tissue were prominent and persisted even mild degree until 15 weeks after completion of irradiation in 50 GY irradiated group. 4. Although follow up duration of this study(105 days) was not enough to compare life span of mice, this study emphasized that precious schedule for treatment planning was necessary for preventing or reducing of later complication.

• Korean Journal of Food Science and Technology
• /
• v.17 no.3
• /
• pp.186-191
• /
• 1985

The effect of gamma irradiation on the physicochemical properties of chicken meat and its sensory quality were investigated during 41 days of storage at 3 to $4^{\circ}C$ following irradiation of 5 to 10 kGy. Immediately after irradiation, the water holding capacity of chicken meat decreased slightly with the increase of irradiation dose, whereas during storage, the water holding capacity of irradiated groups was superior to that of the nonirradiated ones. With increasing the irradiation dose and storage time, the TBA values of irradiated groups were higher than those of nonirradiated ones. The volatile basic nitrogen content of nonirradiated group markedly increased over 20mg% by microbial spoilage from the 10th day of storage, however, the irradiated groups of over 8 kGy showed only the 16 to 18mg% until 41 days of storage. The irradiated groups had a slight irradiation-odour that dissipated during up to 3 days of storage, and also they showed a slight pink discoloration in the carcasses and this tendency was much more pronounced with increasing irradiation dose. The nonirradiated group gave off an off-odour due to the spoilage around 5 to 7 days of storage and showed a change in meat appearance, while the irradiated groups of over 5 kGy maintained a fresh state during the 25 to 30 days of storage.

• Preventive Nutrition and Food Science
• /
• v.14 no.4
• /
• pp.362-366
• /
• 2009

To determine the effect of electron-beam irradiation on the contents of polymethoxylated flavones (PMFs) extracts from citrus pomaces (CP), CP was irradiated at 0, 1, 2, or 5 kGy. Methanol extract of the irradiated CP were prepared and the PMF (nobiletin, sinensetin, and tangeretin) content of the extract was determined. Nobiletin and sinensetin of CP extract significantly increased with irradiation dose-dependent. However, electron-beam irradiation decreased the amount of tangeretin in the CP extract. These data suggest that irradiation can liberate phenolic compounds such as nobiletin or sinensetin, but tangeretin might have different pathway of conversion by irradiation. Therefore, irradiation can be a tool to change the composition of PMFs in CP.