• Journal of radiological science and technology
• /
• 제34권1호
• /
• pp.27-33
• /
• 2011

Along with the developments of science technology, up-to-date medical radiation equipments are introduced. Those equipments has brought many progresses in diagnosing patients not only in the quantitative aspects but in the qualitative ones. Especially, in the case of dental radiography, patients can be exposed more than CT, cone beam computed tomography (CBCT). In this study, we used human phantom and TLD-100H to measure the organ dose in each dental radiography and computed the effective dose according to ICRP (International Committee for Radioactivity Prevention) 60, 103. We measured the effective dose to be 5.1 and $29.5{\mu}Sv$ in the panoramic radiography and 11.2 and $14.4{\mu}Sv$ in the cephalometric radiography respectively. We also executed the CBCT and CT test on the maxillaries and the mandibles and found the amounts of effective dose were 53.7, 209.6, 129, and $391.5{\mu}Sv$ respectively in the CBCT and $93.3{\mu}$, 139.5, 282.7 and $489.7{\mu}Sv$ in the CT test. Consequently, it was shown that the effective dose in the CBCT test was lower than one in the CT test, but was higher in both panoramic and cephalometric radiography.

• Progress in Medical Physics
• /
• 제21권3호
• /
• pp.246-252
• /
• 2010

The purpose of this study provides measurements of radiation dose from MDCT of head, chest, abdomen and pelvic examinations. A series of dose quantities that are measured of patient weight to compare the dose received during MDCT examinations. Data collected included: weight together with CT dose descriptors, volume CT dose index (CTDIvol) and dose length product (DLP). The effective dose was also estimated and served as collective dose estimation data. Data from 1,774 adult patients attending for a CT examination of the head (n=520) or chest (n=531) or abdomen (n=724) was obtained from spiral CT units using a same CT protocol. Mean values of CTDIvol was a range of 48.6 mGy for head and 6.9, 10.5 mGy for chest, abdomen examinations, respectively. And mean values of DLP was range of 1,604 $mGy{\cdot}cm$ for head, 250 $mGy{\cdot}cm$ for chest, 575 $mGy{\cdot}cm$ for abdomen examinations, respectively. Mean effective dose values for head, chest, abdominal CT were 3.6, 4.2, and 8.6 mSv, respectively. The degree of CTDIvol and DLP was a positive correlation with weight. And there was a positive correlation for weight versus CTDIvol ($r^2$=0.62), DLP ($r^2$=0.694) in chest. And head was also positive correlation with weight versus CTDIvol ($r^2$=0.691), DLP ($r^2$=0.741). We conclude that CTDIvol and DLP is an important determinant of weight within the CT examinations. The results for this study suggest that CT protocol should be tailored according to patient weight.

• Journal of the Korean Society of Radiology
• /
• 제11권3호
• /
• pp.109-115
• /
• 2017

The purpose of this study was to evaluate the clinical efficacy of 128 MDCT (multi-detector computed tomography) for reducing the CareDose 4D dose and comparing the image quality with the fixed tube current technique. For this purpose, we conducted the phantom and clinical studies to evaluate the exposure dose and image of the subject before and after applying the CareDose 4D system in abdominal examination using 128 MDCT. In the phantom study, ROI (Region of interest) was located at the center, 3, 6, 9, 12 o'clock, into two groups: group A without CareDose 4D and Group B applied were measured. In the clinical study, ROI was located at the liver 8 segments, divided into two groups too. The measured items were CT number, noise, and dose length product (DLP) dose. The result of CTDIvol (CT Dose Index volume) measurements in phantom and clinical studies were lower than those before CareDose 4D application, and dose and effective dose were also measured lower (p<.05). There was no difference in CT number before and after application (p>.05). In conclusion, using CareDose 4D, we can obtain optimal image information without deteriorating image quality while reducing patient dose.

• Journal of radiological science and technology
• /
• 제31권1호
• /
• pp.11-16
• /
• 2008

Purpose : The aim of this study was to predict radiation dose at 1 meter with BMI(body mass index) in thyroid cancer patients treated with radio-iodine and provide the efficient guideline in the management of patients. Methods : 140 patients from thyroidectomy for thyroid cancer were enrolled. All subjects under went 150 mCi radio-iodine therapy and performed whole body scan 1 week later. BMI(weight divided by square of height) was calculated to evaluate the amount of fatty tissue indirectly. The radiation dose at 1 meter was measured initially and on 2nd days. the relation of values with BMI were analyzed statically. As for the method of statistical analysis, using Med calc Version 9,2,2,0 Program. Results : (1) The initial effective dose was inversely correlated with the BMI. Significance level was 0.0004. (2) We obtained the following formula from the data of initial effective dose and BMI: Y = -30.91X + 350.4(${\mu}Sv/h$)(Y: initial radiation dose, x: Group). (3) After 21.55 hours, than radiation dose was less than those recommended by ICRP or NRC in 53% of the population. Conclusion : Using BMI, the initial radiation dose and 2nd days dose can be predicted in thyroid cancer patients before radio-iodine therapy. It may be used for predicting the time of discharge and control the isolation room. We were able to predict the radiation exposure after discharge using this calculated value.

• Proceedings of the Korean Nuclear Society Conference
• /
• 한국원자력학회 1998년도 추계학술발표회요약집
• /
• pp.339-339
• /
• 1998

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
• /
• pp.369-370
• /
• 2019

• Korean Journal of Environmental Agriculture
• /
• 제19권4호
• /
• pp.324-327
• /
• 2000

Soybean (Glycine max L. cv. Hwangkeum) seeds were irradiated with the dose of $0{\sim}20$ Gy to investigate the effect of the low dose ${\gamma}-ray$ radiation on the early growth and resistance to subsequent high dose of radiation. Germination rate was not enhanced in the seeds irradiated with low dos ${\gamma}-ray$ but plant height and fresh weight increased in the low dose irradiation group. The optimal radiation dose for the growth increasing was 8 Gy in soybean plant. Growth inhibition of soybean plants by high dose radiation was noticeably reduced by pre-irradiation of low dose radiation, Resistance to subsequent high dose of radiation was effective in 8 Gy and 20 Gy irradiation group.

• Journal of Radiation Protection and Research
• /
• 제26권3호
• /
• pp.291-298
• /
• 2001

The designed release rate of liquid effluents from radwaste treatment system should be calculated and evaluated during normal operation, including anticipated operational occurrence and be assured that the release concentration and off-site dose at unrestricted area do not exceed the limits of regulation. The expected annual release rate and off-site dose for the currently operating nuclear power plants in Korea had been calculated and evaluated using PWR-GALE and LADTAP-II which was based on USNRC Regulatory Guide 1.109. Recently, the MOST Notice 2001-2 related to release concentration and off-site dose at unrestricted area was revised to reflect the concept of ICRP-60. It is necessary for KORI 3&4 to re-calculate the release concentration and off-site dose and to compare these results with the limits of regulation. As the results of assessment, we confirmed that the release concentrations were less than its limits of MOST Notice 2001-2 and the off-site dose at unrestricted area using K-DOSE60 was 3.61E-03 mSv/yr to the age of five for the effective dose, and 4.10E-2 mSv/yr to thyroid of the age of five for the organ equivalent dose. We also confirmed the off-site dose was within the limits of MOST Notice 2001-2. Therefore, the release concentration and off-site dose re-evaluated at unrestricted area in KORI 3&4 were well below the regulation limits of MOST Notice 2001-2.

• The Journal of the Korea Contents Association
• /
• 제11권4호
• /
• pp.244-252
• /
• 2011

This study was to estimate the radiation dose associated with 64-slice multidetector CT(MDCT) in clinical practice and quantify the potential cancer risk associated with these examinations. Lifetime attributable risks(LAR) were estimated with models developed in the national Academies' Biological Effects of Ionizing Radiation VII report. Mean effective dose were 1.48mSv in Brain axial scan, 7.66mSv in chest routine contrast, 12.17mSv in coronary angiogram, 24.52mSv in Dynamic abdomen scan. LAR estimates for brain routine varied from 1 in 7463 for man to 1 in 4926 for women. In chest routine with contrast, LAR varied from 1 in 1449 for men to 1 in 952. LAR of Abdomen dynamic CT varied from 1 in 453 for men to 1 in 298 for women. So, 64-slice MDCT scan is associated with non-negligible LAR of cancer. Doses can be reduced by careful attention to scanning protocol.

• Journal of Korean Neurosurgical Society
• /
• 제42권3호
• /
• pp.159-167
• /
• 2007

Vestibular schwannoma (VS) is a benign tumor typically originated in the schwann cell of vestibular nerve and usually accompany hearing symptom. Microsurgical removal and radiosurgery have a great role for the treatment of VS. Recently radiosurgery has been considered as an alternative or primary treatment for VS with the tremendous increase of patients who were treated with gamma knife radiosurgery (GKS) though microsurgery still takes the premier. By many published results, it is proved that GKS is a effective and noninvasive technique for VS, especially small sized tumors with satisfactory tumor control rate. The authors assumed that GKS can be expected to achieve satisfactory tumor control rate for small VS under 5cc in volume. A major interest regarding radiosurgery nowadays is to determine the optimal radiation dose for hearing preservation to improve the quality of life of patients. The more high radiation dose are used for effective tumor growth control, the more radiation-related complications like as hearing deficit, the impairment of other cranial nerve function are increased. Since 1990's the mean radiation dose for tumor margin was more than 18 Gy, but there were high complication rate in spite of good tumor growth control. After the year of 2000, under the influence of advanced neuro-imaging techniques and radiosurgical planning system which enable clinicians to do more precise planning, marginal dose for VS has been decreased to 12-13 Gy and the radiation-related complications has been reduced. But because there may be a unexpected radiation induced complications as time goes by after the latency period, optimal radiation dose for VS should be established on the basis of more long term follow-up observation.