• Progress in Medical Physics
• /
• v.17 no.4
• /
• pp.212-223
• /
• 2006

Positional accuracy of the on-board imager (OBI) isocenter with gantry rotation was presented in this paper. Three different type of automatic evaluation methods of discrepancies between therapeutic and OBI isocenter using digital image processing techniques as well as a procedure stated in the customer acceptance procedure (CAP) were applied to check OBI isocenter migration trends. Two kinds of kV x-ray image set obtained at OBI source angle of $0^{\circ},\;90^{\circ},\;180^{\circ},\;270^{\circ}$ and every $10^{\circ}$ and raw projection data for cone-beam CT reconstruction were used for each evaluation method. Efficiencies of the methods were also estimated. If a user needs to obtain an isocenter variation map with full gantry rotation, a method taking OBI image for every $10^{\circ}$ and fitting with 5th order polynomial was appropriate. However for a mere quality assurance (QA) purpose of OBI isocenter accuracy, it was adequate to use only four OBI Images taken at the OBI source angle of $0^{\circ},\;90^{\circ},\;180^{\circ}\;and\;270^{\circ}$. Maximal discrepancy was 0.44 mm which was observed between the OBI source angle of $90^{\circ}\;and\;180^{\circ}$ OBI isocenter accuracy was maintained below 0.5 mm for a year. Proposed QA program may be helpful to Implement a reasonable routine QA of the OBI isocenter accuracy without great efforts.

• Journal of Environmental Science International
• /
• v.13 no.6
• /
• pp.519-525
• /
• 2004

Air pollution from the Daegu industrial complex (Die) in Korea has been a common nuisance and cause of complaints for nearby residents. The current study measured the indoor and outdoor levels of six VOC (benzene, toluene, ethylbenzene, and three isomeric xylenes) at two residential areas with a different proximity to the ODIC, plus the ambient levels at two industrial areas within the boundary of the DDIC. The QA/QC program included the range of correlation coefficient (0.94-0.99) for calibration curves, within the permissible range. Toluene was the most abundant VOC in the ambient air both in residential and industrial areas. Both indoor and outdoor air concentrations of all target VOC except benzene were higher in residential area near the DIC compared to that further away from the DIC. Moreover, the ambient air concentrations of all target VOC except benzene for two industrial sites (A and B) were significantly higher than the outdoor or indoor air concentrations in the two residential areas. The findings further suggested that VOC ambient levels measured in a residential area near the DIC be used as a potential indicator of odor-causing unidentified air pollutants transported from the DIC. Moreover, it was found that the elevated ambient toluene levels outweighed the indoor sources with respect to the environmental exposure of residents nearby the DIC. However, in the residential area further away from the DIC, the toluene indoor sources outweighed the outdoor sources.

• Quality Improvement in Health Care
• /
• v.4 no.2
• /
• pp.174-183
• /
• 1997

Background : Medical records thought to be reflecting the quality of medicine. By this ground, examination of medical records can be served to evaluate, and to improve the quality of medical care. To examine the medical records, we need some standards or checklists which can be used to sort out the problems. Methods: We developed checklists for medical records evaluation. We studied 1,677 medical records about its completeness using this checklists in one educational hospital. Survey was completed by 5 well trained staffs of medical record department. Results are analyzed. SPSS/PC+ program was used for statistics. Results : 13.8% of discharge summary was incomplete. Recording of the demographic information was also poor in incomplete medical records compared to complete ones. Progress note was recorded average 4.16 times during 11.9 hospital days. After 4th hospital day, recording rate of progress note dropped sharply. Rate of professor's signature on operation records was poor(27%). He or she who described the discharge summary well also wrote progress note well. Conclusions: Fill-up of demographic date should be stressed during medical record education program. Strategy to create the environment emphasizing the responsibility of professor on quality medical record should be made. We suggest new index (number of records/hospital stay) for the evaluation of completeness of progress note.

• Hwankyungkyoyuk
• /
• v.10 no.2
• /
• pp.311-324
• /
• 1997

General citizens can be a valuable resource for various types of environmental monitoring when they are well-trained and managed. Successful use of volunteer monitors depends on understanding that citizens are partners sharing expanded roles as the guardians of their local environment. Citizen volunteer monitoring programs are developed for three reasons: 1) to supplement environmental data collected by professional staffs in governmental agencies and scientific institutions; 2) to educate the public about local environmental problems; 3) to build a constituency of citizen to practice sound environmental management at a local level and build public support for environmental protection. All three goals can be achieved with a well-organized program which provides useful and credible data. Initial step in planning a successful volunteer monitoring project is to clearly identify the use to be made of the data. Technical advice from the identified potential user groups should be convened early in the planning stage to refine the program objectives and determine if volunteers can provide the level of expertise required. Data users must have confidence in the representativeness, consistency, and accuracy of data collected by volunteers. Effective quality assurance and quality control(QA/QC) procedures are essential to ensure the utility of environmental monitoring data. Volunteers must be trained in advance to carry out specific environmental monitoring tasks. Another components of successful volunteer monitoring programs is to give the volunteers praise and feedback as well as to encourage experienced volunteers to impose increased responsibilities. The increase of volunteer monitoring programs in Korea will play a major role in developing a participatory system in which the people are "empowered" to make decisions and make a difference.

• Progress in Medical Physics
• /
• v.22 no.3
• /
• pp.131-139
• /
• 2011

A method to get a size of the radiation isocenter of linear accelerators using star-shot images was presented and a computer program was developed to automate the method. Accuracy of the method was verified. The developed program was used to measure sizes of the radiation isocenters for a Clinac 21EX (Varian, USA) using data of quality assurance (QA) performed from June 2008 to December 2010. To calculated the size of radiation isocenter, positions of two points on each central ray of the star-shot image were found and the equation of the central ray was determined using the positions of two points. Using the equations of central rays the radius of the minimum circle intersecting all the central rays, which is one half of the size of radiation isocenter, was calculated. The program measured x-intercepts and y-intercepts of the central rays within errors of 0.084 mm and sizes of radiation isocenters within 0.053 mm. All the errors were less than the spatial resolution of star-shot images 0.085 mm. The radiation isocenter sizes of Clinac 21EX were $0.33{\pm}0.27mm$, $0.71{\pm}0.36mm$, $0.50{\pm}0.16mm$ for collimator, gantry and couch respectively. During the measurement period all the measured sizes were less than 2.0 mm and within tolerance. The developed program could calculate the size of radiation isocenters and it would be helpful to routine QA.

• Progress in Medical Physics
• /
• v.29 no.2
• /
• pp.59-65
• /
• 2018

This paper describes the clinical use of the dose verification of multileaf collimator (MLC)-based CyberKnife plans by combining the Octavius 1000SRS detector and water-equivalent RW3 slab phantom. The slab phantom consists of 14 plates, each with a thickness of 10 mm. One plate was modified to support tracking by inserting 14 custom-made fiducials on surface holes positioned at the outer region of $10{\times}10cm^2$. The fiducial-inserted plate was placed on the 1000SRS detector and three plates were additionally stacked up to build the reference depth. Below the detector, 10 plates were placed to avoid longer delivery times caused by proximity detection program alerts. The cross-calibration factor prior to phantom delivery was obtained by performing with 200 monitor units (MU) on the field size of $95{\times}92.5mm^2$. After irradiation, the measured dose distribution of the coronal plane was compared with the dose distribution calculated by the MultiPlan treatment planning system. The results were assessed by comparing the absolute dose at the center point of 1000SRS and the 3-D Gamma (${\gamma}$) index using 220 patient-specific quality assurance (QA). The discrepancy between measured and calculated doses at the center point of 1000SRS detector ranged from -3.9% to 8.2%. In the dosimetric comparison using 3-D ${\gamma}$-function (3%/3 mm criteria), the mean passing rates with ${\gamma}$-parameter ${\leq}1$ were $97.4%{\pm}2.4%$. The combination of the 1000SRS detector and RW3 slab phantom can be utilized for dosimetry validation of patient-specific QA in the CyberKnife MLC system, which made it possible to measure absolute dose distributions regardless of tracking mode.

• Quality Improvement in Health Care
• /
• v.5 no.2
• /
• pp.238-256
• /
• 1998

Background : There have been many studies and efforts about quality management in health services, but these were not focused on the thinking ability of the personnel. In this study, We planned to define the relationship between Quality Management(QM) and thinking skill, and analyzed critical thinking skill and problem solving ability of the nurses for QM in healthcare. Methods : We surveyed 260 nurses in 3 hospitals by using questionnaires about thinking skills and QM from November 18 to 28, 1998. The response rate was 76.9%. We described and analyzed the data by descriptive statistics, t-test, ANOVA, Pearson correlation, and non-parametric Friedman test using SPSS Win 7.5. Results : This study revealed that 1) understanding level of QM concepts was very low and insufficient, 2) willingness to practice QM in healthcare was relatively high and affirmative, but the positive attitude taking part in the program of QM is very low(4.5%), 3) even though the necessity of QM was recognized, actual application of critical thinking skills and problem solving abilities is lacking, 4) the production of idea for QM was the most insufficient, and so the next of the problem solving process(QA cycle) was the same. Conclusion : Based on the above results, we can conclude that understanding the concepts of QM is very important to solve problems about QM in healthcare. For development of thinking skill to promote critical problem solving ability for QM in healthcare, it is necessary to improve curriculum of nursing education and teaching-learning methods of QM strategy and technique.

• Quality Improvement in Health Care
• /
• v.9 no.1
• /
• pp.74-89
• /
• 2002

Background : The purpose of this study was to investigate the incidence of unplanned endotracheal extubation and to identify the influencing factor of unplanned extubation in ICUs for providing baseline data in developing prevention strategies and administrative standards. the medical records and hospital information system. In order to analyze factors related to unplanned extubation, the subjects of this study were divided by unplanned extubation group and planned extubation group and were matched by its sex, age, and disease groups in a ratio of one to two. The data were analyzed by descriptive statistics, ${\chi}^2$- test, t-test, Fisher's exact test, and logistic regression analysis with SPSSWIN 10.0 program. Result : 1) Forty-seven(4.99%) of 942 intubated patients experienced unplanned extubation 65 times during the twelve-month period. Thirtyfour( 72.34%) of 47 unplanned extubated patients required reintubation, whereas thirteen patients(27.66%) did not. 2) About half of unplanned extubation(46.8%) occurred during the night shift. 3) As for the nursing activity, respiratory nursing activity score(P=.0.06) and total nursing activity score(P=.011) showed statistically significant differences between unplanned extubation group and planned extubation group. 4) As for the patient status, unplanned extubation group showed more lower consciousness level(P=.000), more irritable or agitated behavior(P=.000), and had more applied physical restraints(P=.000) than planned extubation group. 5) As for the intubation related variables, unplanned extubation group revealed more intubated with respiratory failure(P=.000), more dependent on mechanical ventilation(P=.015) than planned extubation group. 6) Factors affecting unplanned extubations in intensive care unit patients were irritable or agitated behavior(odds ratio=13.757), night shift(odds ratio=7.166), and mechanical ventilation(odds ratio=6.257) from conditional logistic regression analysis. Conclusion : The most affecting factor of unplanned extubation was agitated or irritable behavior. Therefore the results of this study could be helpful to ICU nurses for meticulous care, decision making, timely intervention, and development of intervention strategies for preventing unplanned extubation.

• Journal of Radiation Protection and Research
• /
• v.44 no.1
• /
• pp.43-52
• /
• 2019

Background: The mid-term performance of clinical linear accelerator (LINAC) during volumetric modulated arc therapy (VMAT) treatment period is not performed in clinical practice and usually replaced with one-time plan quality assurance (QA). In this research we aim to monitor daily reproducibility of VMAT delivery from tracking individual leaf movement error and dosimetric error to evaluate the mid-term quality of the machine used. Materials and Methods: First, multileaf collimator (MLC) information was imported into MATLAB program to determine which of the MLC leaves in the leaf bank had the maximum RMS position error (maxRMS). We estimated where the maximum positional errors (maxPE) of the chosen leaf occur along its path length and tracked its daily variations over the entire treatment period. Secondly, picture information of dosimetric error from portal dosimetry was imported into MATLAB where representative high gamma index region (HGR) was determined as HGR with length of > 1 cm and their centers were daily tracked. Results and Discussion: The maxPEs in the brain and tongue cases were distributed broader than in other cases, but all data were found located within ${\pm}0.5mm$. From first day to last day all of five cases show the similar visual pattern of HGRs and Centers of the longest HGRs remained within ${\pm}1mm$ of that in first day. These findings prove excellent mid-term performance of the LINAC used in VMAT treatments over a full course of treatment. Conclusion: Tracking the daily location changes of leaf movement and dosimetric error can be a good indicator of predicting the daily quality like stability and reproducibility of beam delivering in VMAT treatment.

• The Journal of Korean Society for Radiation Therapy
• /
• v.24 no.2
• /
• pp.197-203
• /
• 2012

Purpose: In this study, we considerate our radiation therapy process for the breast cancer patient implanted a pacemaker applying the machine movement surgery, shielding, beam selection. Materials and Methods: We perform radiation therapy to a 54 years old, breast cancer patient implanted a pacemaker. The patient underwent a surgery to move the position of a pacemaker to right side breast after consultation with cardiology department. Prescribed dose was 5,040 cGy and daily dose 180 cGy for 28 fractions. The 10 MV photon energy, field size 0/$9.5{\times}20$ cm, half beam and opposing portal irradiation are used. To find out appropriate thickness of shielding board, we carried out an experiment using a solid water phantom ($30{\times}30{\times}7$ cm), a Farmer-type chamber (TN30013, PTW, Germany) and a shielding board (Pb $28{\times}27{\times}0.1$ cm). We calculated expected absorbed dose to te pacemaker with absorb ratio and shielding ratio. In the PTP system (Eclipse, Varian, USA), we figured out how much radiation would be absorbed to the machine with and without shielding. First day of the radiation therapy, we measured head scatter to the pacemaker with MOSFET Dose Verification System (TN-RD-70-W, Medical Canada Ltd., Canada). Results: In the phantom measurement, we found out appropriate thickness was 2 mm of shielding board. In the RTP, when using 2 mm shielding the pacemaker will be absorbed 11.5~38.2 cGy and DVH is 77.3 cGy. In the first day of the therapy, 4.3 cGy was measured so 120.4 cGy was calculated during total therapy. The patient was free from any side effects, and the machine also normally functioned. Conclusion: As the report of association which have public confidence became superannuated, there is lack of data about new machine. We believe that radiation therapy to thiese kind of patients could be done successfully with co-operation, patient-suitable planning, accurate QA, frequent in-vivo dosimetry and monitoring.