Eclipse Collimator에 의한 Z-축 방향 Over Scan Range 감소가 선량과 영상의 질에 미치는 영향

The Study on Effect of Radiation Dose and Image Quality by Application of Eclipse Collimator

Purpose The purpose of this study was to research deacrease effect of radiation dose and quality of image by application of Eclipse collimator that reduce z-axis over scan range by interpolation. Materials and methods Using 256 MlXT applied Edipse col limator, We researched difference of radiation dose that patient was delivered with and without Eclipse collimator by Rando phantom, and measured equivalent dose that is different in decrease of z-axis over scan range by Eclipse collimator using thermo-luminescence dosimeter(TLD) and evaluated change of quality of image by radiation dose decrease using AAPM phantom. Results According to the application of Eclipse collimator in an experiment that use Rando phantom. CTDIvol reduced radiation dose of approximately 0.06% by 0.2 mGy from 32.9 mGy to 33.1 mGy. DLP reduced radiation dose of approximately 11% by 75mGyㆍcm from 626.86 mGyㆍcm to 701.86 mGyㆍcm. 10.23 mSv’s equivalent dose decreased by application of Eclipse collimator appeared in an experiment that use TLD, This result displayed decrease of equivalent dose of approximately 8.9%. Region of over scan range reduced equivalent dose of approximately 9.47 mSv. also this result displayed radiation decreased effect of approximately 22.86%. Image estimation of CT number(p=0.344) and noise(p=0.375) by decreased radiation dose was exposed that big difference does not exist. Conclusion By Eclipse collimator that reduce z-axial over scan range reduced radiation dose without decline of image quality exposure that was exceeded to patient could be line approximately 9~11%. If apply Eclipse collimator in various region for example young child examination, examination of organ that radiation sensitivity is high, and examination who wanted follow up case etc, we will get a high radiation dose efficiency.