• Title/Summary/Keyword: equivalent dose

Search Result 534, Processing Time 0.028 seconds

The Usefulness of LEUR Collimator for 1-Day Basal/Acetazolamide Brain Perfusion SPECT (1-Day Protocol을 사용하는 Brain Perfusion SPECT에서 LEUR 콜리메이터의 유용성)

  • Choi, Jin-Wook;Kim, Soo-Mee;Lee, Hyung-Jin;Kim, Jin-Eui;Kim, Hyun-Joo;Lee, Jae-Sung;Lee, Dong-Soo
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.15 no.1
    • /
    • pp.94-100
    • /
    • 2011
  • Purpose: Basal/Acetazolamide-challenged brain perfusion SPECT is very useful to assess cerebral perfusion and vascular reserve. However, as there is a trade off between sensitivity and spatial resolution in the selection of collimator, the selection of optimal collimator is crucial. In this study, we examined three collimators to select optimal one for 1-day brain perfusion SPECT. Materials and Methods: Three collimators, low energy high resolution-parallel beam (LEHR-par), ultra resolution-fan beam (LEUR-fan) and super fine-fan beam (LESFR-fan), were tested for 1-day imaging using Triad XLT 9 (TRIONIX). The SPECT images of Hoffman 3D brain phantom filled with 99mTc of 170 MBq and a normal volunteer were acquired with a protocol of 50 kcts/frame and detector rotation of 3 degree. Filterd backprojection (FBP) reconstruction with Butterworth filter (cut off frequencies, 0.3 to 0.5) was performed. The quantitative and qualitative assessments for three collimators were performed. Results: The blind tests showed that LESFR-fan provided the best image quality for Hoffman brain phantom and the volunteer. However, images for all the collimator were evaluated as 'acceptable'. On the other hand, in order to meet the equivalent signal-to-noise ratio (SNR), total acquisition time or radioactivity dose for LESFR-fan must have been increased up to almost twice of that for LEUR-fan and LEHR-par. The volunteer test indicated that total acquisition time could be reduced approximately by 10 to 14 min in clinical practice using LEUR-fan and LEHR-par without significant loss on image quality, in comparison with LESFR-fan. Conclusion: Although LESFR-fan provides the best image quality, it requires significantly more acquisition time than LEUR-fan and LEHR-par to provide reasonable SNR. Since there is no significant clinical difference between three collimators, LEUR-fan and LEHR-par can be recommended as optimal collimators for 1-day brain perfusion imaging with respect to image quality and SNR.

  • PDF

Angiotensin Converting Enzyme Inhibition and Antihypertensive Effects of Phyllostachys pubescens Culm Extracts in Spontaneously Hypertensive Rats (맹종죽 줄기 추출물을 투여한 본태성 고혈압 쥐(SHR)의 ACE 저해 활성 및 혈압 강하 효과)

  • Kim, Jung-Suk;Kim, Mi-Jeong;Park, Min-Hee;Ryu, Bog-Mi;Moon, Gap-Soon
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.37 no.1
    • /
    • pp.27-34
    • /
    • 2008
  • This study investigated the anti-hypertensive effect of Phyllostachys pubescens culm extract (PCE) by examining its effects on renal angiotensin-converting enzyme (ACE) inhibition and blood pressure using the spontaneously hypertensive rat (SHR) system. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly for 8 weeks. Also, total antioxidant capacity and protein oxidation of tissues were examined by plasma Trolox Equivalent Antioxidant Capacity assay (TEAC) and hepatic protein carbonyl values, respectively. Twenty male SHR were randomly divided into four groups: PCE50, PCE100, and PCE500 (50, 100, and 500 mg of PCE per kilogram bodyweight daily, respectively), and control group. At week 2, the SBP in all PCE groups appeared to be significantly lower than the control (p<0.05), whereas the DBP were not different until week 4 (p<0.05). At week 8, SBP in the PCE500 was lower by 20% than the control. PCE groups considerably suppressed ACE dose-dependently compared with the control. Plasma TEAC and hepatic protein carbonyl values indicated increased antioxidative activity due to the PCE feed. No adverse effect was observed on the liver of SHR as there was no difference for the GOT and GPT values among the groups. Results of this study suggest that ACE inhibition may be one possible mechanism for the blood pressure lowering effect of PCE; thus, long term consumption of PCE may be beneficial in preventing high blood pressure along with the increased antioxidative status.

In Vivo Preperation of Standard Reference Materials of Lead in Blood (생체내 혈중 납 표준물질의 제조)

  • Chung, Kyou-Chull;Choi, Ho-Chun
    • Journal of Preventive Medicine and Public Health
    • /
    • v.28 no.4 s.51
    • /
    • pp.863-873
    • /
    • 1995
  • This report describes a preperation and characterization of canine blood lead(Pb) standard reference material(SRM). Three adult beagle dogs(A, B, and C)were orally dosed with gelatin capsules containing $Pb(NO_3)_2$, equivalent to $10\sim80mg$ Pb/kg body weight. Blood was drawn 24 hours after the dose from the cephalic vein into lead free 500ml Pyrex beaker in which EDTA.K was contained as an anticoagulant. The amount of lead given to individual dog was varied arbitrarily. Three month later, 3 canine animals were orally dosed with lead secondarily to make mixed SRM(D1) which was mixed different concentrations of lead in bloods with A1, B1, and C1 in vitro. The SRMs for A, B, C, A1, B1, C1, and D1 were distributed 2ml each into more than 300 lead free bottles, and were stored in refregerator at $4^{\circ}C$. The amount of lead in canine whole blood samples were determined using a Varian 30A atomic absorption spectrophotometer(AAS) with a model GTA-96 graphite tube atomizer with D2 background correction and a Hitachi Z-8100 AAS with Zeeman background correction. The sensitivity and detection limits for lead determination of Varian 30A were $0.46{\mu}g/L,\;0.34{\mu}g/L,\;and\;0.56{\mu}g/L,\;0.14{\mu}g/L$ of Hitachi Z-8100, respectively. Day to day variations in determination of blood lead concentration in a certain sample were $31.11{\pm}1.36{\mu}g/100ml$ by Varian 30A, and $33.08{\pm}0.82{\mu}g/100ml$ by Hitachi Z-8100, showing the difference of 3% between the two results. At the blood lead concentrations of $56.31{\pm}1.98{\mu}g/100ml(A),\;40.89{\pm}0.80{\mu}g/100ml(B),\;59.01{\pm}1.38{\mu}g/100ml(C)$, the precisions of replicated measurements by AAS were 3.52%, 1.96%, and 2.34%, respectively. Coefficient variation(CV) of SRMs(A, B, and C) within a standard sample were ranged from 0.92% to 7.50%, and those between 5 standard samples were 1.21%, 2.64%, and 1.11%, respectively, showing inter-vial variation of $1{\mu}g/100ml$. Lead levels in SRMs during one month storage were unchanged. The overall recoveries were $89.6\sim100.4%,\;91.6\sim101.9%,\;90.3\sim100.0%$ for A, B, and C SRMs, means were $56.46{\pm}2.69{\mu}g/100ml,\;39.35{\pm}1.89{\mu}g/100ml,\;57.40{\pm}2.31{\mu}g/100ml$, and measurement ranges were$52.88{\pm}59.26{\mu}g/100ml,\;37.47{\pm}41.68{\mu}g/100ml,\;54.80{\pm}60.69{\mu}g/100ml$, respectively. Those results were laid within confidence limits values. The lead concentrations in the mixed sample(D1) stored over one month period were ranged from $32.76{\mu}g/100ml\;to\;33.54{\mu}g/100ml$, with CV ranging from 1.2% to 2.7%. The results were similiar to each of single samples(A1, B1, and C1) in respect of homogeneity and stability. Results of the mixed blood sample analysed after 1 month storage at $4^{\circ}C$ by four other laboratories(L1, L2, L3, L4) were similar with those of our laboratory($L5;31.18{\pm}0.24{\mu}g/100ml$, acceptable range by $CDC;25.18\sim37.18{\mu}g/100ml$), showing the concentrations of $25.91{\pm}1.19{\mu}g/100ml(L1),\;34.16{\pm}0.22{\mu}g/100ml(L2),\;35.68{\pm}0.85{\mu}g/100ml(L3),\;30.95{\pm}0.46{\mu}g/100ml(L4)$ in a each samples.

  • PDF

Evaluation of the Usefulness of the Transmittance of Metal Filaments Fabricated by 3D Printers in Radiation Therapy (방사선 치료에서 3D 프린터로 제작된 금속 필라멘트의 투과율에 관한 유용성 평가)

  • Kwon, Kyung-Tae;Jang, Hui-Min;Yoon, Myeong-Seong
    • Journal of the Korean Society of Radiology
    • /
    • v.15 no.7
    • /
    • pp.965-973
    • /
    • 2021
  • Since radiation therapy is irradiated with high-energy X-rays in a variety of at least 20 Gy to 80 Gy, a high dose is administered to the local area where the tumor is located, and various side effects of some normal tissues are expected. Currently, in clinical practice, lead, a representative material, is used as an effort to shield normal tissues, but lead is classified as a heavy metal harmful to the human body, and a large amount of skin contact can cause poisoning. Therefore, this study intends to manufacture a measurement sheet that can compensate for the limitations of lead using the materials Tungsten, Brass, and Copper of the 3D printer of the FDM (Fused Deposition Modeling) method and to investigate the penetration performance. Tungsten mixed filament transmission measurement sheet size was 70 × 70 mm and thickness 1, 2, 4 mm using a 3D printer, and a linear accelerator (TrueBeam STx, S/N: 1187) was measured by irradiating 100 MU at SSD 100 cm and 5 cm in water using a water phantom, an ion chamber (FC-65G), and an elcetrometer (PTW UNIDOSE), and the permeability was evaluated. As a result of increasing the measurement sheet of each material by 1 mm, in the case of Tungsten sheet at 3.8 to 3.9 cm in 6 MV, the thickness of the lead shielding body was thinner than 6.5 cm, and in case of Tungsten sheet at 4.5 to 4.6 cm in 15 MV. The sheet was thinner than the existing lead shielding body thickness of 7 cm, and equivalent performance was confirmed. Through this study, the transmittance measurement sheet produced using Tungsten alloy filaments confirmed the possibility of transmission shielding in the high energy region. It has been confirmed that the usability as a substitute is also excellent. It is thought that it can be provided as basic data for the production of shielding agents with 3D printing technology in the future.