• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제25권4호
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• pp.295-303
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• 1999

Presented in this paper are the experimental results that measure rapid prototyping (RP) errors in 3D medical models. We identified various factors that can cause dimensional errors when producing RP models, specifically in maxillofacial areas. For the experiment, we used a human dry skull. A number of linear measurements based on landmarks were first obtained on the skull. This was followed by CT scanning, 3D model reconstruction, and RP model fabrication. The landmarks were measured again on both the reconstructed models and the physical RP models, and these were compared with those on dry skull. We focused on major sources of errors, such as CT scanning, conversion from CT data to STL models, and RP model fabrication. The results show that the overall error from skull to RP is $0.64{\times}0.36mm(0.71{\times}0.66%)$ in absolute value. This indicates that the RP technology can be acceptable in the real clinical applications. A clinical case that has applied RP models successfully for treatment planning and surgical rehearsal is presented. Although the use of RP models is rare in the medical area yet, we believe RP is promising in that it has a great potential in developing new tools which can aid diagnosis, treatment planning, surgical rehearsal, education, and so on.

• 보험의학회지
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• 제18권
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• pp.107-110
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• 1999

The disorders of congenital metabolic errors causing mental retardation can be prevented by early diagnosis and treatment. We analysed 144,000 neonatal blood samples for phenyketonuria(PKU), maple syrup urine disease(MSUD), homocystinuria(HCU) and histidinuria(HE) by bacterial inhibition method, and galactosemia(GAL) by Paigen method. In our survey, the positive were 4 samples in PKU(4mg/dl;2, 6mg/dl;1, 8mg/dl;1), 8 samples in MSUD(4mg/dl;2, 6mg/dl;2, 8mg/dl;3, 10mg/dl;1), 4 samples in HCU(4mg/dl;2, 6mg/dl;2), 4 samples in Galactosemia(4mg/dl;2, 6mg/dl;1, 8mg/dl;1), respectively. while, no one was positive in HE. The frequncy rate were 1/36,000 for PKU, HCU and GAL, 1/18,000 for MSUD, respectively. But those for HE couldn't be detected in our survey. In this study, the hightest frequency rate was 1/18,000 of MSUD, following were 1/36,000 for PKU, HCU and GAL, respectively. As results our data, it is our opinion that neonatal screening should be performed in terms of national policies for ealy diagnosis and theraphy.

• 대한방사선치료학회지
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• 제24권1호
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• pp.23-30
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• 2012

목 적: Analytical Anisotropic Algorithm (AAA)을 사용하여 계산된 폐 부위 방사선치료계획은 Pencil Beam Convolution (PBC) Algorithm 기반의 MU 검증 프로그램을 이용하였을 때 MU의 오차가 발생하여 MU 검증 프로그램 사용에 어려움이 있다. 본원에서는 AAA를 사용하여 계산된 치료계획을 검증할 방법에 대하여 연구하였다. 대상 및 방법: Eclipse treatment planning system (Version 8.9, Varian, USA)을 사용하여 폐 부위 정위적체부방사선치료(Stereotactic Body Radiation Therapy, SBRT) 7건에서의 총 57개 조사야(Field) 각각에 대하여 선량계산 알고리즘으로 PBC와 AAA를 사용하여 계산하였다. 수립된 치료계획의 MU를 자체 개발하여 사용 중인 MU 검증 프로그램의 MU와 비교 분석하였다. PBC 알고리즘과 AAA에서 발생한 오차에 영향을 미칠 수 있는 조사야크기(Field size), 방사선이 폐 조직을 통과한 거리, 방사선이 종양 조직을 통과한 거리, 유효깊이(Effective depth) 등 4가지 변수에 대하여 오차와의 상관관계를 상용 프로그램을 이용하여 분석하였다. 결 과: PBC 알고리즘의 오차는 $0.2{\pm}1.0%$로 나타났으며 AAA의 오차는 $3.5{\pm}2.8%$로 나타났다. 또한, 오차에 영향을 미칠 수 있는 4가지 변수에 대해 분석한 결과, 방사선이 폐 조직을 통과한 거리와 MU의 오차와의 관계에서 상관계수 0.648 (P=0.000)로 유의하게 증가하였고, ${\Delta}_{AAA}$=L.P 0.00903+0.02048이라는 MU 보정인자를 산출해 낼 수 있었으며 MU 보정인자를 MU 검증 프로그램에 적용한 결과, 적용 전 $3.5{\pm}2.8%$의 오차는 $0.4{\pm}2.0%$ 이내로 줄어들었다. 결 론: 본 연구에서는 방사선이 폐 조직을 통과한 거리가 커질수록 MU 검증 프로그램과의 오차가 커짐을 알아냈으며, MU보정인자라는 간단한 방법을 통해 AAA 알고리즘의 MU를 검증할 수 있게 되었다.

• 한국의학물리학회지:의학물리
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• 제26권4호
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• pp.286-293
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• 2015

본 연구의 목적은 폐암의 정위체부방사선 치료 환자에 대하여 정위체부고정기구 사용 유무에 따른 셋업 정확성을 비교 평가하고자 한다. 본원에서 정위체부방사선치료를 받은 총 40명의 환자를 대상으로, 정위체부고정기구를 기반으로 한셋업 방식의 환자군 20명과 고정기구 없이 Wing board를 사용한 환자군 20명으로 구분하여 각 셋업오차를 비교, 분석 하였다. 폐암의 정위체부방사선치료는 총 4~5회에 걸쳐 48~60 Gy 조사되었다. 매 치료 전, 먼저 레이저를 이용하여 환자를 치료중심점에 위치시킨 후 On-board kV 영상장치를 이용하여 2차원 직각영상을 얻어 척추를 기준으로 환자의 위치를 조정한 다음, 3차원 체적 영상을 획득 하여 종양의 위치를 치료중심점에 일치시키고, 마지막으로 호흡에 의한 종양의 위치 확인 및 조정을 위해 2차원 직각 투시영상을 이용하였다. 각 과정에서 얻은 테이블 이동 및 회전 값을 조사하여, 셋업 군별로 계통오차 및 랜덤오차를 구하였다. 고정기구 사용유무에 따른 통계적 유의성을 검증하기 위하여 계통오차에 대한 t-test 시행을 하였고, 셋업의 재현성의 차이를 보기위해 랜덤오차에 대한 F-test를 시행하였다. 나아가 이러한 셋업 방식의 차이가 셋업 여유분의 크기 결정에 영향이 있는지 여부를 평가하기위해 치료계획체적의 여유분을 계산하여 두 방식의 차이를 비교하였다. 정위체부 고정기구를 사용했을 때의 셋업 오차는 수직방향, 길이방향, 수평방향으로 각각 $0.05{\pm}0.25cm$, $0.20{\pm}0.38cm$, $0.02{\pm}0.30cm$이었다. 반면에, Frameless immobilizer을 사용한 단순 고정방법을 사용했을 때의 셋업 오차는 수직방향에서만 통계적으로 유의하게 $-0.24{\pm}0.25cm$으로 증가함을 보였으나, 길이방향, 수평방향에 대해서는 각각 $0.06{\pm}0.34cm$, $-0.02{\pm}0.25cm$의 작거나 비슷한 결과값을 보였다. 정위체부 고정기구를 사용했을 경우, 수직방향, 수직방향 및 길이방향으로의 여유분은 각각, 0.67 cm, 0.99 cm, 0.83 cm였고, Frameless immobilizer시 수직방향으로 0.75 cm, 길이방향으로 0.96 cm, 수평방향으로 0.72 cm로써 수평방향에서 최대 0.11 cm 차이가 남을 알 수 있었다. 결론적으로 정위체부고정기구를 사용하는 것이 환자 자세 재현성을 향상시켜 셋업 오차를 환자의 전후, 위아래 방향으로의 약 0.1~0.2 cm씩 줄일 수 있을 것으로 평가하였다. 다만 정위체부 고정기구 사용에 따른 시간 소요 및 치료절차의 복잡성에 비해 그 효과는 그리 크지 않았다.

• 방사선산업학회지
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• 제12권4호
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• pp.317-324
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• 2018

The results of bone mineral density analysis using DXA were compared between automatic and manual methods. The purpose of this paper is to verify the range of errors of each analysis method in the same patient and select a proper method to minimize errors. Comparisons between automatic and manual analysis methods were made using BMD, BMC and AREA. Basal and follow up examinations were performed with the patients of normal, osteopenia and osteoporosis. In the basal examinations, the precision errors between automatic and manual method showed 1.9% in normal, 3.1% in osteopenia and 3.8% in osteoporosis. In case of follow up studies, the precision errors between automatic and manual method showed 2.3% in normal, 3.2% in osteopenia and 3.5% in osteoporosis. BMC and AREA also showed a tendency to increase precision errors on osteopenia and osteoporosis. Therefore, a manual method would be a better option to minimize errors in patients with osteopenia and osteoporosis.

• 간호행정학회지
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• 제21권3호
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• pp.254-262
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• 2015

Purpose: This study was done to apply failure mode & effect analysis (FMEA) to chemotherapy in order to reduce prescribing, dispensing and administering errors related to treatment and provide patients with a safe medical environment. Methods: A one group pre-post test design was used to verify the effects using the tool for FMEA in chemotherapy. Results: There was a statistically significant decrease in prescribing errors from 11.47% to 3.18%; administering errors decreased but they were not statistically significant. In a addition, there was no change in dispensing errors. Conclusion: The results show that FMEA removed risk factors that might occur during the process of chemotherapy and that it was an effective tool for prevention of negligent accident occurring in actual patients.

• Safety and Health at Work
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• 제7권1호
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• pp.6-11
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• 2016

Background: A permit to work (PTW) is a formal written system to control certain types of work which are identified as potentially hazardous. However, human error in PTW processes can lead to an accident. Methods: This cross-sectional, descriptive study was conducted to estimate the probability of human errors in PTWprocesses in a chemical plant in Iran. In the first stage, through interviewing the personnel and studying the procedure in the plant, the PTW process was analyzed using the hierarchical task analysis technique. In doing so, PTWwas considered as a goal and detailed tasks to achieve the goal were analyzed. In the next step, the standardized plant analysis risk-human (SPAR-H) reliability analysis method was applied for estimation of human error probability. Results: The mean probability of human error in the PTW system was estimated to be 0.11. The highest probability of human error in the PTW process was related to flammable gas testing (50.7%). Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

• The Korean Journal of Legal Medicine
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• 제42권4호
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• pp.141-145
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• 2018

There have been many radiographic studies on age estimation that evaluate reduction in size of dental pulp cavity with secondary dentin formation. The Paewinsky method reported high accuracy in estimating ages by measuring the width of the pulp cavity in panoramic radiographs. The aim of this study was to evaluate the application of the Paewinsky method to digital periapical radiographs. This study was conducted on 103 cases that reported to the Section of Human Identification of the National Forensic Service. The age was calculated by applying the Paewinsky method that measures the root and pulp canal width at three points in a tooth. The estimation results were compared with those calculated by the Johanson method. When the Paewinsky models were applied to digital periapical radiographs, the errors were significantly greater as compared to the original study. The errors of the maxillary second premolar and mandibular lateral incisor were greater than those of the maxillary central incisor, lateral incisor, mandibular canine, and first premolar. Furthermore, errors of the age estimation models in level C were greater than those in levels A and B. This study could be a reference for the application of the Paewinsky method to digital periapical radiographs.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2005년도 제30회 춘계학술대회
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• pp.68-70
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• 2005

To precisely localize target in prostate cancer, image-guided radiotherapy was performed using the $ExacTrac^{\circledR}$ x-ray system (Brainlab, Germany) with implanted markers. For three prostate cancer patients, three gold markers were implanted into prostate. Orthogonal portal images were acquired every treatment and CT scans were repeated 3～5 times during the course of treatment. After correcting setup errors calculated by the system, the position of the implanted markers and the distance between them were detected in daily portal images and in CT images, and analyzed retrospectively. Deviation of the relative position of the implanted markers and the distance between them were less than 1 mm in lateral, longitudinal, and vertical direction for three patients, both in portal images and CT images. This study reveals that image-guided radiotherapy using the $ExacTrac^{\circledR}$ system is useful to verify positioning errors and localize prostate target with implanted markers, reducing the planning target volume (PTV) margin as well as irradiation to rectum and bladder.

• 기본간호학회지
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• 제21권4호
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• pp.403-412
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• 2014

Purpose: Shift work disrupts the synchronization between the human biological clock and the environment. Sleep disturbances are common for shift work nurses, and may threaten patient safety. This study was done to investigate the sleep characteristics and medication errors (ME) of intensive care unit (ICU) nurses who work shifts, and ascertain if there is an association between these factors. Methods: Data were collected using a self-report questionnaire from 126 ICU nurses on three shifts. Collected data included their sleep characteristics including sleep patterns and sleep disturbances, and ME for the past 2 weeks. Results: There were significant differences in sleep duration and sleep latency according to shift. Day shift nurses had the shortest sleep duration, and their sleep latency was the longest (about 49 minutes) compared to nurses on evening and night shifts; 54% reported sleep disturbances, 16% experienced ME, and among these nurses 50% were on the night shift. Logistic regression analysis revealed significant associations between nurses' sleep duration and ME (adjusted OR 0.52 [95% CI 0.32-0.85]). Conclusions: The results confirmed that shift work nurses in the ICUs experience sleep disturbance, and that less sleep is associated with ME.