• 한국방사선학회논문지
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• 제14권5호
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• pp.613-618
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• 2020

간동맥화학색전술 중 사용되고 있는 Fast Low Dose C-arm CT의 평균선량을 DSA의 평균선량과 비교해 보고, 전체 누적선량에서 검사기법별 평균선량 분석을 통해 피폭선량을 분석해 보았다. 본원에서 환자 50명을 임의로 선정하여 Fast Low Dose C-arm CT와 DSA의 DAP 및 Air Kerma를 조사하여 비교하였으며, 4가지 검사기법(DSA, Fast Low Dose C-arm CT, Roadmap, Fluoroscopy)의 누적선량(DAP, Air Kerma)이 차지하는 비율을 분석하였다. 통계적인 비교 분석을 위해 통계프로그램 SPSS 20.0을 이용하여 대응표본 T검정, ANOVA 검증(post hoc test : Tukey)하였다. Fast Low Dose C-arm CT가 DSA에 비해 평균선량(DAP, Air Kerma)이 통계적으로 유의하게 낮았다.(p<.001) 간동맥화학색전술에서 항암제 주입 전후로 Fast Low Dose C-arm CT를 적극 활용하여 DSA의 검사 횟수를 줄인다면 환자의 의료방사선 피폭을 감소시킬 수 있다.

• Clinical and Experimental Reproductive Medicine
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• 제28권1호
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• pp.47-53
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• 2001

Objective: This study is to investigate the clinical efficacy of low-dose FSH regimen, comparing with clomiphene citrate and human menopausal gonadotropin (CC/hMG) regimen. Methods: Retrospective study of the ovulatory factor infertility 39 patients who had been treated by intrauterine insemination (IUI). The 31 cycles of 21 patients were stimulated by CC/hMG regimen, the 22 cycles of 18 patients were stimulated by low-dose FSH regimen. We compared the rate of clinical pregnancy, multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) of both group. Results: The rate of clinical pregnancy of the CC/hMG group was 25.7% per cycle, and that of the low-dose FSH group was 54.5% per cycle. The low-dose FSH group showed a higher rate of clinical pregnancy per cycle than CC/hMG group (p=0.028). However, no differences was found statistically in the rate of multiple pregnancy and OHSS between CC/hMG group (22.2%, 5.7%) and low-dose FSH group (33.3%, 13.6%). Conclusion: This study showed that the low-dose FSH regimen is superior to CC/hMG regimen in getting clinical pregnancy, but dose not reduce the ovulation induction complications.

• 대한의생명과학회지
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• 제12권3호
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• pp.289-301
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• 2006

Cardiopulmonary bypass (CPB) for cardiac surgery triggers the production and release of numerous chemotactic substances and cytokines, ensuing systemic inflammatory response that leads to postoperative major organ dysfunction. Traditionally, corticosteroids (steroid) have been administered to patients undergoing cardiac surgery to ward off these detrimental physiologic alterations. However, the majority of the studies have been performed on adult patients with high-dose steroid. We carried out a randomized, prospective, double-blind study to compare the efficacy of low-dose steroid with that of high-dose steroid and to determine the adequate dose of pretreated-steroid for prophylactic effects in pediatric cardiac surgery. Thirty pediatric patients scheduled for elective cardiac surgery were randomly assigned to two groups; fifteen patients received low-dose methylprednisolone (10mg/kg intravenously, n=15, low-dose group) and the others received high-dose methylprednisolone (30mg/kg intravenously, n=15, high-dose group) 1 hour prior to CPB. Arterial blood samples were taken before CPB (Pre-CPB), 10 minutes after start of CPB (CPB-10), and immediately after CPB-end (CPB-OFF) for measuring total leukocyte counts (T-WBC) and diff-counts, platelet counts, interleukin-6 (IL-6), myeloperoxidase (MPO), total antioxidant (TAO), neuron-specific enolase (NSE), troponin I (TNI), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and blood urea nitrogen (BUN) levels. Other parameters such as volumes of urine output, pulmonary index $(PI,\;PaO_2/FiO_2)$, mechanical ventilating period, intensive care unit (ICU)-staying period, postoperative complications (fever, wound problem), postoperative 24 hrs and total volumes in blood loss, and hospitalized days were also assessed. All parameters were compared between two groups. There were no significant differences in T-WBC counts, monocyte fraction, platelet counts, TA levels, NSE levels, creatinine levels, BUN levels, the volumes of total urine output, PI, the incidences of fever and wound problem, postoperative 24hrs- and total-blood loss volumes and ICU-staying period between two groups (P>0.05). At CPB-OFF, neutrophil fraction, MPO level, TNI level, and AST level were higher in the high-dose group than in the low-dose group (P<0.05). IL-6 level at CPB-10 was higher in the high dose-group than in the low-dose group (P<0.05). Furthermore, mechanical ventilating periods and hospitalized days of the high-dose group were significantly longer than those of low-dose group (P<0.05). The high-dose group had significantly low lymphocyte fi-action at CPB-OFF compared with the low-dose group (P<0.001). These findings suggest that pretreatment of high-dose steroid is not superior to that of low-dose steroid regrading its potential benefits in pediatric cardiac surgery. Therefore, the conventional strategy of steroid treatment, high-dose pretreatment, should be modified in the cardiac surgery with CPB. However, further studies must be performed on the larger number of patients in as much as small number of patients in this study.

• Imaging Science in Dentistry
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• 제40권1호
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• pp.15-23
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• 2010

Purpose : This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. Materials and Methods : 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Results : Effective doses in ${\mu}Sv$ ($E_{2007}$) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. Conclusion : From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

• 한국환경보건학회지
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• 제49권1호
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• pp.1-10
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• 2023

Low-dose radiation exposure has received considerable attention because it reflects the general public's type and level of exposure. Still, controversy remains due to the relatively unclear results and uncertainty in risk estimation compared to high-dose radiation. However, recent epidemiological studies report direct evidence of health effects for various types of low-dose radiation exposure. In particular, international nuclear workers' studies, CT exposure studies, and children's cancer studies on natural radiation showed significantly increased cancer risk among the study populations despite their low-dose radiation exposure. These studies showed similar results even when the cumulative radiation dose was limited to an exposure group of less than 100 mGy, demonstrating that the observed excess risk was not affected by high exposure. A linear dose-response relationship between radiation exposure and cancer incidence has been observed, even at the low-dose interval. These recent epidemiological studies include relatively large populations, and findings are broadly consistent with previous studies on Japanese atomic bomb survivors. However, the health effects of low-dose radiation are assumed to be small compared to the risks that may arise from other lifestyle factors; therefore, the benefits of radiation use should be considered at the individual level through a balanced interpretation. Further low-dose radiation studies are essential to accurately determining the benefits and risks of radiation.

• Journal of Korean Biological Nursing Science
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• 제14권1호
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• pp.49-56
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• 2012

Purpose: The purpose of this study was to compare the effects of anorexia induced by consecutive low-dose and high-dose of cisplatin (CDDP) on the hindlimb muscles of rats. Methods: Male Sprague-Dawley rats were assigned to three groups: Control group (C) received a saline (the same dose and duration as the low CDDP group), the high-dose cisplatin (High CDDP) group received a single 5 mg/kg dose of cisplatin, the consecutive low-dose cisplatin (Low CDDP) group had 1 mg/kg of cisplatin administered for five consecutive days. On the 8th day the soleus and gastrocnemius muscles were dissected. Body weight, food intake, activity, muscle weight, Type I, II fiber cross-sectional area (CSA) of the dissected muscles were measured. Results: Body weight, food intake, muscle weight and Type I, II fiber CSA of the High CDDP and Low CDDP groups were significantly less than the C group. The High CDDP group showed significant decreases, compared to the Low CDDP group, in body weight, food intake, activity score, muscle weight and Type I, II fiber CSA. Conclusion: Hindlimb muscle atrophy occurs due to anorexia induced by both consecutive low-dose and high-dose cisplatin. The muscle atrophy induced by consecutive low-dose cisplatin is less apparent than high-dose cisplatin.

• Journal of Korean Neurosurgical Society
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• 제47권4호
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• pp.252-257
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• 2010

Objective : Barbiturate coma therapy (BCT) is a useful method to control increased intracranial pressure (IICP) patients. However, the complications such as hypotension and hypokalemia have caused conditions that stopped BCT early. The complications of low dose BCT with $Bispectral^{TM}$ index (BIS) monitoring and those of high dose BCT without BIS monitoring have been compared to evaluate the efficacy of low dose BCT with BIS monitoring. Methods : We analyzed 39 patients with high dose BCT group (21 patients) and low dose BCT group (18 patients). Because BIS value of 40-60 is general anesthesia score, we have adjusted the target dose of thiopental to maintain the BIS score of 40-60. Therefore, dose of thiopental was kept 1.3 to 2.6 mg/kg/hour during low dose BCT. However, high dose BCT consisted of 5 mg/kg/hour without BIS monitoing. Results : The protocol of BCT was successful in 72.2% and 38.1% of low dose and high dose BCT groups, respectively. The complications such as QT prolongation, hypotension and cardiac arrest have caused conditions that stopped BCT early. Hypokalemia showed the highest incidence rate in complications of both BCT. The descent in potassium level were $0.63{\pm}0.26$ in low dose group, and $1.31{\pm}0.48$ in high dose group. The treatment durations were $4.89{\pm}1.68$ days and $3.38{\pm}1.24$ days in low dose BCT and high dose BCT, respectively. Conclusion : It was proved that low dose BCT showed less severe complications than high dose BCT. Low dose BCT with BIS monitoring provided enough duration of BCT possible to control ICP.

• 대한방사선치료학회지
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• 제1권1호
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• pp.70-78
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• 1985

The intrauterine irradiation is essential to achieve adequate tumor dose to centeral tumor mass in radio therapy for uterine malignancy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The comparison study of currently using 2 systems was undertaken. The simulation films and medical records of 135 patients who was treated with intrauterine irradiation at one of general hospitals in Busan and Seoul between Jan. 1983 and June 1983, were critically analized and physical parameters of low dose rate system and remote controlled high dose rate system were measured. The physical parameters include distances between lateral walls of vaginal fornices, longitudinal and lateral angles of tandem to the body axis, the distance from the external os of uterine cervix to the central axis of ovoids, the radiation dose ratio to rectum and bladder to reference point A. Followings were summary of study results: 1. In distances between lateral walls of vaginal fornices the low dose rate system showed wide distribution and relatively larger distances. In low dose rate system 5.0-5.9 cm was $55.89\%$ 6.0-6.9 cm: $23.53\%$, 4.0-4.9cm: $10.29\%$, 3.0-3.9cm: $10.29\%$, and in high dose rate system 5.0-5.9cm was $80.59\%$, 4.0-4.9cm: $17.91\%$, $6.0\~6.9\;cm:\;1.5\%$. 2. In lateral angulation of tandem to body axis, the low does system revealed mid position (the position along body axis) $64.7\%$, Lt. deviation $19.13\%$ and Rt. deviation $16.17\%$. However the high dose rate system revealed mid position $49.26\%$ Lt. deviation $40.29\%$ and Rt. deviation $10.45\%$. 3. In longitudinal angulation of tandem to body axis the mid position was $11.77\%$ and anterior angulation $88.23\%$ in low dose rate system but in high dose rate system the mid position was $1.56\%$ and anterior angulation $98.44\%$. 4. Down ward displacement of ovoids below external os was only $2.94\%$ in low dose rate system and $67.69\%$ in high dose rate system. 5. The radiation dose ration to rectum to reference point A was $102.70\%$ in high dose rate system and $70.09\%$ in low dose rate system. The dose ratio to bladder to reference point A was $78.14\%$ in high dose rate system and $75.32\%$ in low dose rate system.

• Radiation Oncology Journal
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• 제2권2호
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• pp.261-270
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• 1984

The intrauterine irradiation is essential to achieve adequate tumor dose to central tumor mass of uterine malignancy in radiotherapy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The simulation radiation and medical records of 203 patients who were treated with intrauterine irradiation from Feb. 1983 to Oct. 1983, were critically analized. The physical parameters to include distances between lateral walls of vaginal fornices, longitudinal and lateral angles of tandem applicator to the body axis, the distance from the external os of uterine cervix to the central axis of ovoids were measured for low dose rate irradiation system and high dose rate remote control afterloading system. The radiation doses and dose distributions within cervical area including interesting points and bladder, rectum, according to sources arrangement and location of applicator, were estimated with personal computer. Followings were summary of study results ; 1. In distances between lateral walls of vaginal fornices, the low dose rate system showed as $4\~7cm$ width and high dose rate system showed as $5\~6cm$. 2. In horizontal angulation of tandem to body axis, the low dose rate system revealed mid position$64.6\%$, left deviation $19.2\%$and right deviation $16.2\%$. 3. In longitudinal angulation of tandem to body axis, the mid position was $11.8\%$ and anterior angulation $88.2\%$ in low dose rate system but in high dose rate system, anterior angulation was $98.5\%$. 4. Down ward displacement of ovoids below external os was only $3\%$ in low dose rate system and $66.7\%$ in high dose rate system. 5. In radiation source arrangement, the most activities of tandem and ovoid were 35 by 30 in low dose rate system but 50 by 40 in high dose rate system. 6. In low and high dose rate system, the total doses an4 TDF were 50, 70 Gy and 141, 123, including 40 Gy external irradiation. 7. The doses and TDF in interesting points Co, B, were 93, 47 Gy and 230, 73 in high dose rate system but in low doss rate system, 123, 52 Gy and 262, 75 respectively. 8. Doses and TDF in bladder and rectum were 70, 68 Gy and 124, 120 in low dose rate system, but in high dose rate system, 58, 64 Gy 98, 110 respectively, and then grades of injuries in bladder and rectum were 25, $30\%$ and 18, $23\%$ respectively.

• 방사선산업학회지
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• 제11권3호
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• pp.131-137
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• 2017

To compare the radiation dose and image noise of low dose computed tomography (CT) and high resolution CT using the fixed tube current technique and automatic tube current modulation (CARE Dose 4D). Chest CT and human anthropomorphic phantom were used the RPL (radiophotoluminescence) dosimeters. For image evaluation, standard deviation of mean CT attenuation coefficient and CT attenuation coefficient was measured using ROI analysis function. The effective dose was calculated using CTDIvol and DLP. CARE Dose 4D was reduced by 74.7% and HRCT by 64.4% compared to the fixed tube current technique in low dose CT of chest phantom. In CTDIvol and DLP, the dose of CARE Dose 4D was reduced by fixed tube current technique. For effective dose, CARE Dose 4D was reduced by 47% and HRCT by 46.9% compared to the fixed tube current method, and the dose of CARE Dose 4D was significantly different (p<.05). Noise in the image was higher than that in the fixed tube current technique. Noise difference in the image of CARE Dose 4D in low dose CT was significant (p<.05). The low radiation dose and the noise difference of the CARE Dose 4D were compared with the fixed tube current technique in low dose CT and HRCT using chest phantom. The radiation doses using CARE Dose 4D were in accordance with the national and international dose standards. CARE Dose 4D should be applied to low dose CT and HRCT for clinical examination.