• 제목/요약/키워드: Dose Evaluation

검색결과 1,853건 처리시간 0.027초

디지털 진단방사선촬영에서 부가여과판 사용에 따른 피폭선량 감소와 화질 개선 (Reduction of Patient Dose Exposure and Improvement of Image Quality by Use of Additional Filtration in Digital Radiology)

  • 문수정;김영근;이성길
    • 대한디지털의료영상학회논문지
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    • 제12권1호
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    • pp.19-25
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    • 2010
  • This study is mainly for the reduction of exposure dose by using a heavy elements filter(Gd) in the digital radiology. They contained heavy elements filter of Gd and X-ray beam hardening filters such as Al and Cu. According to the results of experimental evaluation, X-ray property was not changed with variety of kVp in the case of the Gd filter. The surface dose and absorption dose were increased in order of Cu and Al. The contrast of image showed the higher value in order of Cu, Al and Gd. While the use of Gd has increased the numerical value of the CR image, and grayscale has decreased noise value of the DR image.

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Evaluation of the Single-Dose Toxicity of TA Pharmacopuncture in Rats

  • Hwang, Ji Hye;Jung, Hyo Won;Jung, Chul
    • 대한약침학회지
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    • 제22권3호
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    • pp.171-175
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    • 2019
  • Objectives: TA is a polyherbal extract comprising seven herbs, typically used for the pharmacopuncture treatment of patients with traffic accident- related injuries and musculoskeletal diseases. This animal study was conducted to evaluate the safety of the TA extract, using a single-dose toxicity test. Methods: The dose range and sampling time were first established. Six- week-old Sprague-Dawley rats were administered 1.0 mL of TA or normal saline (control), intramuscularly, for the single-dose toxicity test. The general condition, mortality, and histology of all rats were observed for 2 weeks. Results: No abnormal symptoms or deaths were observed in any group. The body weights of the rats in the TA and control groups were similar. No significant differences in histopathology were observed between the groups. Conclusion : Our study indicates that 1.0 mL of TA extract may be safely administered for pharmacopuncture for treatment of patients in traditional medicine clinics.

Evaluation of the Antidiabetic, Islet Protective and Beta-Cell Regenerative Effects of Tinospora crispa (L.)

  • Yusof, Norafiqah;Goh, May P. Y.;Ahmad, Norhayati
    • Natural Product Sciences
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    • 제28권3호
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    • pp.105-114
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    • 2022
  • Tinospora crispa (L.) is a medicinal plant traditionally used to treat various ailments including diabetes. The stem has been widely studied for its antidiabetic properties, however the antidiabetic potential of its leaves has not been explored. This study investigates the antidiabetic properties of methanolic T. crispa stem and leaves extracts on alloxan-induced diabetic rats. The stems and leaves were extracted using Soxhlet extraction with methanol as solvent. Crude extracts were administered at 500 mg/kg body weight (BW) (high dose) and 250 mg/kg BW (low dose) via oral route to alloxan induced diabetic rats. T. crispa stem and leaves extracts was found to significantly reduce blood glucose following a twelve-week treatment period. The highest mean difference in blood glucose level was exhibited by animals in the high dose treated stem and low dose leaf extracts. Both extracts showed approximately 75% percentage recovery from hyperglycaemia. The highest regenerative capacity was observed in animals treated with the low dose leaf extract.

음질을 기초한 교통소음의 척도화에 관한 연구 (A Study of the Evaluation Scale of Traffic Noise base on Sound Quality Index)

  • 허덕재;조경숙
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.1280-1284
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    • 2006
  • This paper describes the methodology for environmental assessments of traffic noise sources. An attempt is made to establish evaluation scale relationships between noise quality Parameters and subjective degrees annoyance. Subjective experimental was conducted to determine the subjective degrees annoyance that scaling score compare with reference and varieties noise source about modified traffic noises with $40{\sim}85dB$. Also a correlation analysis between noise rating index and satisfactory percentage of the noise dose response curves varied with response was conducted. As a result of study, subjective annoyance degree has not correlation of proportional linearity to the A weight noise level, but has correlation of proportional linearity to the index composed to loudness and tonality. It is suggested to be resonable level 4.9 (equivalence about 53dB) index on the out door noise limits for traffic noise and to be 6 step scale base on the linearity for evaluation traffic noise.

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RADIATION SHIELDING EVALUATION OF IP-2 PACKAGES FOR LOW- AND INTERMEDIATE-LEVEL RADIOACTIVE WASTE

  • Kim, Min-Chul;Choi, Jong-Rak;Chung, Sung-Hwan;Ko, Jae-Hoon
    • Nuclear Engineering and Technology
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    • 제40권6호
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    • pp.511-516
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    • 2008
  • Korea Hydro & Nuclear Power Co., Ltd. (KHNP) developed new IP-2 packages to transport low- and intermediate-level radioactive waste (LILW) steel drums from nuclear power plants to a disposal facility in accordance with IAEA and Korean transport regulations of radioactive material. Radiation shielding evaluation of the packages was carried out to demonstrate compliance with the regulatory requirements for IP-2 packages of radioactive material. Dose rate limits of LILW drums contained in the packages were determined.

Evaluation of absorbed dose in monkey and mouse using 18F-FDG PET and CT density information

  • Kim, Wook;Lee, Yong Jin;Park, Yong Sung;Cho, Doo-Wan;Lee, Hong-Soo;Han, Su-Cheol;Kang, Joo Hyun;Woo, Sang-Keun
    • 대한방사성의약품학회지
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    • 제3권1호
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    • pp.18-24
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    • 2017
  • Patient-specific image-based internal dosimetry involves using the patient's individual anatomy and spatial distribution of radioactivity over time to obtain an absorbed dose calculation. Individual absorbed dose was calculated by accumulated activity multiply S-value of each organs. The aim of this study was to calculate the S-values using Monte Carlo simulation in monkey and mouse and evaluation of absorbed dose in each organ. Self-irradiation S-value of monkey heart self-irradiation was 3.15E-03 mGy-g/MBq-s, lung self-irradiation was 8.94E-04 mGy-g/MBq-s and liver self-irradiation S-value was 2.23E-03 mGy-g/MBq-s. Mouse heart self-irradiation S-value was 1.95E-01 mGy-g/MBq-s, lung was 9.59E-02 mGy-g/MBq-s, and liver was 1.40E-03 mGy-g/MBq-s. The results of this study show that the calculation protocol of image based individual absorbed dose of each organ using Monte Carlo simulation. Therefore, this study may be applied to calculate human specific absorbed dose.

Evaluation of Relative Fluoride Toxicity and Its Impact on Growth, Economic Characters and Fecundity of the Silkworm, Bombyx mori L.

  • Ramakrishna, S.;Nath, B.Surendra;Jayaprakash
    • International Journal of Industrial Entomology and Biomaterials
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    • 제8권2호
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    • pp.151-159
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    • 2004
  • A detailed evaluation of relative toxicity of fluoride to die 5th instar larvae of PM and NB$_4$D$_2$ races of silkworm and the effects of lethal, sublethal and prevailing levels of fluoride in groundwater on the growth, economic characters and fecundity of the silkworm, Bombyx mori (Lepidoptera: Bombycidae) were studied. The feeding of mulberry, Morus alba leaves treated with lethal and sublethal doses of fluoride to PM and NB$_4$D$_2$ races of silkworms from the beginning of the 5th instar to the end of the feeding period resulted in significant reduction in growth, single cocoon weight, single shell weight, silk index, average filament length, and fecundity when compared to controls. These manges were more pronounced on exposure to lethal dose than sublethal dose and in general, the changes induced by fluoride were more striking in NB$_4$D$_2$ than PM, indicating the greater resistance of PM to higher fluoride levels. Groundwater quality in sericulturally important villages of Karnataka and Andhra Pradesh States has been studied with special reference to the presence of fluoride. On exposure to dose of prevailing levels in the waters of sericulturally important areas, die changes observed on growth, economic characters and fecundity were slightly lower when compared to controls and the decrease was found to be insignificant (P$\geq$0.05). It was concluded that, though minute dose (4.0 ppm) of fluoride did not have any toxic impact, it is toxic at higher concentrations to silkworms.

뇌전산화단층검사에서 방사선량 저감을 위한 최적화 프로토콜 연구 (Optimization of Brain Computed Tomography Protocols to Radiation Dose Reduction)

  • 이재승;권대철
    • 대한의용생체공학회:의공학회지
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    • 제39권3호
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    • pp.116-123
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    • 2018
  • This study is a model experimental study using a phantom to propose an optimized brain CT scan protocol that can reduce the radiation dose of a patient and remain quality of image. We investigate the CT scan parameters of brain CT in clinical medical institutions and to measure the important parameters that determine the quality of CT images. We used 52 multislice spiral CT (SOMATOM Definition AS+, Siemens Healthcare, Germany). The scan parameters were tube voltage (kVp), tube current (mAs), scan time, slice thickness, pitch, and scan field of view (SFOV) directly related to the patient's exposure dose. The CT dose indicators were CTDIvol and DLP. The CT images were obtained while increasing the imaging conditions constantly from the phantom limit value (Q1) to the maximum value (Q4) for AAPM CT performance evaluation. And statistics analyzed with Pearson's correlation coefficients. The result of tube voltage that the increase in tube voltage proportionally increases the variation range of the CT number. And similar results were obtained in the qualitative evaluation of the CT image compared to the tube voltage of 120 kVp, which was applied clinically at 100 kVp. Also, the scan conditions were appropriate in the tube current range of 250 mAs to 350 mAs when the tube voltage was 100 kVp. Therefore, by applying the proposed brain CT scanning parameters can be reduced the radiation dose of the patient while maintaining quality of image.

두부 CT에서 차폐기법과 새로운 관전류변조기법에 따른 눈의 선량과 화질평가 (The Evaluation of Eye Dose and Image Quality According to The New Tube Current Modulation and Shielding Techniques in Brain CT)

  • 권순무;김정수
    • 한국방사선학회논문지
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    • 제9권5호
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    • pp.279-285
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    • 2015
  • 두부 CT 검사에서 눈의 수정체는 높은 방사선 감수성으로 보호되어야 할 장기 중에 하나이다. 두부 CT 검사에서 눈의 피폭선량감소 목적으로 사용되는 비스무스 차폐체는 현저한 선량 감소 효과가 있지만 화질저하의 문제점이 있다. 본 연구는 인체팬텀을 이용한 두부 CT 검사에서 피폭 선량을 줄이기 위해 사용되는 관전류변조기법인 new organ based-tube current modulation, longitudinal-TCM, angular-TCM과 차폐기법인 비스무스, 납 안경을 사용하여 눈의 선량과 화질의 변화 정도를 평가하였다. 연구결과, new OB-TCM에서 눈의 선량은 25.88% 감소되었으며 비스무스를 사용한 검사와 비교하여 CT number, 노이즈, SNR의 변화가 작은 것을 확인하였다. 따라서 new OB-TCM을 임상의 두부 CT 검사에 적용할 경우, 눈의 피폭선량을 감소시키면서 영상의 화질 저하를 방지할 수 있을 것으로 기대된다.

Low-dose CT Image Denoising Using Classification Densely Connected Residual Network

  • Ming, Jun;Yi, Benshun;Zhang, Yungang;Li, Huixin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권6호
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    • pp.2480-2496
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    • 2020
  • Considering that high-dose X-ray radiation during CT scans may bring potential risks to patients, in the medical imaging industry there has been increasing emphasis on low-dose CT. Due to complex statistical characteristics of noise found in low-dose CT images, many traditional methods are difficult to preserve structural details effectively while suppressing noise and artifacts. Inspired by the deep learning techniques, we propose a densely connected residual network (DCRN) for low-dose CT image noise cancelation, which combines the ideas of dense connection with residual learning. On one hand, dense connection maximizes information flow between layers in the network, which is beneficial to maintain structural details when denoising images. On the other hand, residual learning paired with batch normalization would allow for decreased training speed and better noise reduction performance in images. The experiments are performed on the 100 CT images selected from a public medical dataset-TCIA(The Cancer Imaging Archive). Compared with the other three competitive denoising algorithms, both subjective visual effect and objective evaluation indexes which include PSNR, RMSE, MAE and SSIM show that the proposed network can improve LDCT images quality more effectively while maintaining a low computational cost. In the objective evaluation indexes, the highest PSNR 33.67, RMSE 5.659, MAE 1.965 and SSIM 0.9434 are achieved by the proposed method. Especially for RMSE, compare with the best performing algorithm in the comparison algorithms, the proposed network increases it by 7 percentage points.