• Title/Summary/Keyword: Absorbed dose rate

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The Effects of Local Anesthetic Agent and Epinephrine on Blood Flow of Femoral Artery in Rabbit (가토에서 국소 마취제와 Epinephrine이 대퇴동맥이 혈류에 미치는 영향)

  • Oh, Soo-Won;Koo, Gil-Hoi;Lee, Choon-Hi
    • The Korean Journal of Pain
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    • v.9 no.1
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    • pp.46-56
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    • 1996
  • Many surgeons and anesthesiologists prefer using vasoconstrictor mixed with local anesthetic agent to reduce the incidence of side effects and prolong the duration of analgesia because most local anesthetic agents, except cocaine, were believed to possess vasodilating effect. However, some investigators recently reported vasoconstricting effect of local anesthetic agents. There is still controversy on the vasoactive effect of local anesthetic agents. So this study is aimed to clarify the vasoactive effect of local anesthetics in the animal model resembling clinical settings. Rabbits were anesthesized with ketamine and haloghane, and respirations were controlled with Harvard animal ventilator. Lidocaine (0.5%, 1.0%, 1.5%) and bupivacaine (0.125%, 0.25% and 0.5%) with or without 1:100,000 epinephrine were subdermaly injected on the femoral bupivacaine of the femoral artery were measured with Doppler flow meter in vivo. The mean arterial pressure, pulse rate, arterial blood gases, pH and level of serum electrolytes were measured at every 2 minute interval for 30 minutes. Results were as follows: 1) There was no significant vasoconstriction with 0.5% lidocaine and 0.125% bupivacaine. 2) Statistically significant (p<0.05) vasodilations were observed with lidocaine (1.0~2.0%) and bupivacaine (0.25~0.5%). 3) There were no changes on the duration of vasodilation induced by local anesthetic agents of various concentrations. 4) Onset of vasodilation induced by local anesthetic agents of high concentration were faster than that of lower concentrations. 5) In the mixed injection group of epinephrine and local anesthetic agent, the vasoconstriction induced by epinephrine was completely reversed by local anesthetics, approximately 5 minutes later. In conclusion, local anesthetic agents at dose exceeding 1.0% lidocaine and 0.25% bupivacaine increase local blood flow significantly in animal study in vivo which is applicable in human clinical settings. The increase blood flow may be due to dilatation of blood vessel. Further study on the analysis of association between amount of absorbed local anesthetics in blood vessels and dilatation of blood vessels is needed.

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The Roles of Gold Plate (140${\mu}{\textrm}{m}$) Loaded on TLD-100 Chips in the High Energy Radiation Beams (고에너지 광자선속에서 TLD-100 chip 위에 있는 금박막(140 ${\mu}{\textrm}{m}$) 역할)

  • Vahc, Young-Woo;Park, Kyung Ran.
    • Progress in Medical Physics
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    • v.6 no.2
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    • pp.51-60
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    • 1995
  • Lithium Fluoride (LiF; TLD-100) crystal chips are normally used as thermolu minescence dosimeters (abbreviated as NC-100) for estimating the absorbed dose to the skin of a patient or in a solid water phantom undergoing radiotherapy with megavoltage photon (6 and 15MV) beams. In general, investigation has revealed a reduction in the sensitivity of NC-100 chips after many runs through heating cycles. A TLD-100 chip laminated with gold plate (140${\mu}{\textrm}{m}$) on the upper surface layer of its face toward the photon beam (abbreviated as GC-100) has properties different from that of a NC-100 chip activated by incident photons and contaminant electrons with various lower energies coming from the gantry head and air. Activation of the valence band electrons of GC-100 chips by incident photons, positrons and electrons-which come from the gold plate by mainly pair production process and partly from Compton scattering-results in more enhanced signal intensity, higher response per monitor unit, as well as a good linearity with monitor units and independence of dose rate. Since the electron beams (6 and 15 MeV) do not have the probability of pair production process with gold plate, there is only a small difference (about a 3.3% increase for 15 MeV) in the signal gaps in the TL readout for electron beams between GC- and NC-100 chips. The 3.3% increase is entirely due to the buildup caused by the 140 m gold plate. The sensitivity of GC-100 chips is much more susceptible to high energy photon beams than electron one because of pair production. The interaction of high energy photon with a material of high atomic number, such as the good plate in this case, results in a considerably significant probability of pair production. The gold plate on the NC-100 chips acts as not only an intensifier of their signals but also acts as a filter of contaminant electrons in therapeutic high energy X-ray beams.

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Phase I Clinical Trial of Prostate-Specific Membrane Antigen-Targeting 68Ga-NGUL PET/CT in Healthy Volunteers and Patients with Prostate Cancer

  • Minseok Suh;Hyun Gee Ryoo;Keon Wook Kang;Jae Min Jeong;Chang Wook Jeong;Cheol Kwak;Gi Jeong Cheon
    • Korean Journal of Radiology
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    • v.23 no.9
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    • pp.911-920
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    • 2022
  • Objective: 68Ga-NGUL is a novel prostate-specific membrane antigen (PSMA)-targeting tracer based on Glu-Urea-Lys derivatives conjugated to a 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA) chelator via a thiourea-type short linker. This phase I clinical trial of 68Ga-NGUL was conducted to evaluate the safety and radiation dosimetry of 68Ga-NGUL in healthy volunteers and the lesion detection rate of 68Ga-NGUL in patients with prostate cancer. Materials and Methods: We designed a prospective, open-label, single-arm clinical trial with two cohorts comprising six healthy adult men and six patients with metastatic prostate cancer. Safety and blood test-based toxicities were monitored throughout the study. PET/CT scans were acquired at multiple time points after administering 68Ga-NGUL (2 MBq/kg; 96-165 MBq). In healthy adults, absorbed organ doses and effective doses were calculated using the OLINDA/EXM software. In patients with prostate cancer, the rates of detecting suspicious lesions by 68Ga-NGUL PET/CT and conventional imaging (CT and bone scintigraphy) during the screening period, within one month after recruitment, were compared. Results: All 12 participants (six healthy adults aged 31-32 years and six prostate cancer patients aged 57-81 years) completed the clinical trial. No drug-related adverse events were observed. In the healthy adult group, 68Ga-NGUL was rapidly distributed, with the highest uptake in the kidneys. The median effective dose coefficient was calculated as 0.025 mSv/MBq, and cumulative activity in the bladder had the highest contribution. In patients with metastatic prostate cancer, 229 suspicious lesions were detected using either 68Ga-NGUL PET/CT or conventional imaging. Among them, 68Ga-NGUL PET/CT detected 199 (86.9%) lesions and CT or bone scintigraphy detected 114 (49.8%) lesions. Conclusion: 68Ga-NGUL can be safely applied clinically and has shown a higher detection rate for the localization of metastatic lesions in prostate cancer than conventional imaging. Therefore, 68Ga-NGUL is a valuable option for prostate cancer imaging.

The Direct Decomposition of Ion-Exchange Resins by Fenton's Reagent (펜톤시약에 의한 이온교환수지의 직접산화분해)

  • Kim, Kil-Jeong;Shon, Jong-Sik;Ryu, Woo-Seog
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.3
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    • pp.221-227
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    • 2007
  • Fenton's reagent is applied to directly decompose the ion-exchange resins, IRN-78 and the mixed resin with IRN-77. The newly applied procedures is to dry the resin first and the catalyst solution is completely absorbed into the resin, then a limited dose of $H_2O_2$ is introduced for an effective reaction between the reagents within the resin. As a characteristic on the decomposition of IRN-78, the resin mixture should be heated to $40^{\circ}C$ to induce the initial reaction and lag time is also needed for about 20 minutes until the main reaction occurs. The effectiveness of the decomposition is investigated using $CuSO_4,\;Cu(NO_3)_2\;and\;FeSO_4$ as a catalyst and the decomposition rate is compared depending on the concentration of each catalyst and the amount of $H_2O_2$. The most effective catalyst was found to be $FeSO_4$ for IRN-78 alone and the mixed resin with IRN-77, and $FeSO_4$ showed a special effect that the reaction was initiated without heating and a lag time. Furthermore, the optimum concentration of the catalyst for each resin and the mixed one is suggested in the view point of the amount of $H_2O_2$ needed and the stability of the decomposition reaction.

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Oral Bioavailability for Sub-micron Particle Curcumin (TheracurminCR-033P) and Absorption Rate by Product Composition in Healthy Human Volunteers (서브마이크론 입자 형태 커큐민의 생체 흡수율 및 제품 조성에 따른 흡수율 동등성 연구)

  • Park, Hee Jung;Takahashi, Tsukasa;Ozawa, Hitomi
    • Food Engineering Progress
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    • v.21 no.3
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    • pp.273-279
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    • 2017
  • Curcumin have various health-beneficial properties in numerous studies. However, its bioavailability is low due to its limited intestinal uptake and rapid metabolism. This study aimed to evaluate the pharmacokinetics of newly developed sub-micron particle curcumin with increased water dispersibility (Theracurmin(R) CR-033P). Plasma curcumin levels were measured at 0, 1, 2, 4, 8 h after Theracurmin(R) CR-033P intake using high-performance liquid chromatography. For analyzing pharmacokinetics of Theracurmin(R) CR-033P, eighteen healthy subjects were recruited and received Theracurmin(R) CR-033P at a single oral dose containing curcumin 30 mg. $C_{max}$ was 28.14 ng/ml, and the area under the curve for 8 h was estimated to be 104.36 ng/ml. Based on the area under the plasma concentration (AUC), the bioavailability of sub-micron particle curcumin was higher 22-, 35-, 28-fold than native curcumin in men, women, and all subjects, respectively. For comparing by formulation, seven healthy subjects were recruited and received two type of treatment: (1) existing dosage form 300 mg (contained curcumin 30 mg) ${\times}$ 3 capsule, (2) high dosage form 300 mg (contained curcumin 90 mg) ${\times}$ 1 capsule + placebo 300 mg ${\times}$ 2 capsule. In the cross-over study, there was no significant differences in $C_{max}$ and AUC of plasma curcumin. In conclusion, submicron particle curcumin with increased water dispersibility significantly improved its oral bioavailability and women absorbed curcumin more effectively than men. Different formulation of Theracurmin(R) CR-033P has shown equivalent to the reference in terms of pharmacokinetics.