If large-scale testing programs are being used, OSCE stations may be duplicated into two or more sites. There are a few studies on the reliability of OSCE with duplicated stations in Korea. The purpose of this study was to investigate the effect of duplication on the reliability of OSCE. At Hanyang university college of medicine, an OSCE is given to all senior medical students(91 per class) upon completion of all clinical clerkship rotations. The examination consisted of twenty one stations and eighteen cases that represented commonly encountered problems in primary care. Each station required seven minutes for its administration, with 6 to 6.5 minutes for the student-SP or model encounter, during which the students performs a complete focused history and/or physical examination and/or procedure and/or management, and another 0.5 to 1 minutes for the evaluator to feedback case-related comments. We analysed the reliability of duplication by comparing total OSCE scores and case scores between two exam sites. We also evaluated the reliability of duplicated stations from student's and professor's subjective response to the OSCE. All 91 fourth-year students attended the OSCE. Standardized Cronbach coefficient of the OSCE was 0.67. The station scores and OSCE total scores were different between two duplication sites. The total OSCE score of one site was slight higher than that of the other site(p=0.03). Of total 19 stations in which students were evaluated by staff evaluator, six stations are more advantageous to one part compared with counterpart stations, other six stations are vice CONCLUSIONS: OSCE reliability can be affected by duplication of examination sites and inter-rater reliability is the most important determining factor. The results demonstrate a need for caution in the interpretation of scores obtained from OSCE with duplicated stations.
Clinical Clerkship ; Humans ; Korea ; Physical Examination ; Primary Health Care

OBJECTIVES: With the increased use of computed tomography (CT) in clinics, dose reduction is the most important feature people seek when considering new CT techniques or applications. We developed an intensity-weighted region-of-interest (IWROI) imaging method in an exact half-fan geometry to reduce the imaging radiation dose to patients in cone-beam CT (CBCT) for image-guided radiation therapy (IGRT). While dose reduction is highly desirable, preserving the high-quality images of the ROI is also important for target localization in IGRT. METHODS: An intensity-weighting (IW) filter made of copper was mounted in place of a bowtie filter on the X-ray tube unit of an on-board imager (OBI) system such that the filter can substantially reduce radiation exposure to the outer ROI. In addition to mounting the IW filter, the lead-blade collimation of the OBI was adjusted to produce an exact half-fan scanning geometry for a further reduction of the radiation dose. The chord-based rebinned backprojection-filtration (BPF) algorithm in circular CBCT was implemented for image reconstruction, and a humanoid pelvis phantom was used for the IWROI imaging experiment. RESULTS: The IWROI image of the phantom was successfully reconstructed after beam-quality correction, and it was registered to the reference image within an acceptable level of tolerance. Dosimetric measurements revealed that the dose is reduced by approximately 61% in the inner ROI and by 73% in the outer ROI compared to the conventional bowtie filter-based half-fan scan. CONCLUSIONS: The IWROI method substantially reduces the imaging radiation dose and provides reconstructed images with an acceptable level of quality for patient setup and target localization. The proposed half-fan-based IWROI imaging technique can add a valuable option to CBCT in IGRT applications.
Cone-Beam Computed Tomography* ; Copper ; Humans ; Image Processing, Computer-Assisted ; Methods ; Pelvis ; Radiation Exposure ; Radiotherapy, Image-Guided*